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GOVERNMENT OF INDIA

MISCELLANEOUS PUBLICATION NO. 30, PART-XXII

GEOLOGY AND MINERAL RESOURCES OF INDIA

2009

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GEOLOGICAL SURVEY OF INDIA Miscellaneous Publication No. 30 Part – XXII

CONTENTS

Page No

GEOLOGY OF INDIA 1 COVER PAGE 1 INTRODUCTION 2 PENINSULAR INDIA 5 INTRODUCTION 5 DHARWAR CRATON 5 TRANSITION ZONE 9 SOUTHERN GRANULITE TERRAIN 10 EASTERN GHATS MOBILE BELT 14 EASTERN INDIAN CRATON 15 CENTRAL PRECAMBRIAN SHIELD 19 BASTER CRATON 21 BUNDELKHAND CRATON 26 WESTERN PRECAMBRIAN SHIELD 27 BGC 28 ARAVALLI-DELHI MOBILE BELTS 29 PURANA BASINS 32 GONDWANA BASINS 37 DECCAN TRAP VOLCANISM 42 INDO-GANGETIC-BRAHMAPUTRA PLAIN 43 EXTRA-PENINSULAR INDIA 43 ARUNACHAL HIMALAYA 46 CENOZOIC FORMATIONS 47 QUATERNARY FORMATIONS 48 Andaman Nicobar Islands 49 Lakshwadeep Islands 50 MINERAL RESOURCES OF INDIA 51 Introduction 51 DIAMOND 54 GOLD 78 BASE METALS 89 BARYTE 130 PGE and CHROMITE 131 IRON ORE 135 MANGANESE 137 MOLYBDENUM 138 TIN, TUNGSTEN 139 URANIUM 140 BAUXITE 140 NON-METALLIC and INDUSTRIAL MINERALS 141

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Magnesite 141 Limestone 142 Apatite & Rock Phosphate/Phosphatic Nodules 143 Asbestos 144 Borax 144 Stibnite 144 Fossil Fuel 145 Graphite 147 Ilmenite,Rutile, Monazite and Garnet sands 147 Gypsum 148 Apatite 148 Precious and Semi-precious Stones 149

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GEOLOGY OF INDIA

INTRODUCTION India extends for about 3200 km from north to south and 2900 km from west to east and is located

between latitudes 6o 45′ North at Indira Point, southernmost tip of the Great Nicobar Island and also

the southernmost point of land in the territory of India, to little above 370 North and longitudes 68o

East to 97o East. India has a diverse geology with different rock types representing the complete

spectrum ranging in age from some of the oldest Archaean metamorphites/granitoids to the

youngest Quaternary alluvium. Indian sub-continent is tectonically and physiographically divided

into three broad domains i.e. the Peninsular India, the Extra-Peninsular India and the Indo-Gangetic

Brahmaputra Plains. Indo-Gangetic plain is sandwiched between the Precambrian rocks of the

Peninsular India and the highly deformed suites of the Himalaya of Extra-Peninsular India.

Physiographically, Peninsular India is constituted of vast plateaus and mountains. The most

important mountain ranges of the Peninsula are The Western Ghats (Sahyadri), the Satpura Range,

the Aravalli Range, the Vindhyan Range and the Eastern Ghats. The major plateaus of Peninsular

India are the Deccan, Malwa, Bundelkhand and Chhotanagpur of which Deccan is the largest. The

major rivers that originate in Peninsular India are Chambal and Son in the north, Damodar in the

east, Tapti and Narmada in the west and Godavari, Krishna and Cauvery in the south. Except for

Tapti and Narmada which flow westerly into Arabian Sea, all rivers drain into the Bay of Bengal.

The Plateau of Peninsular India is surrounded by coastal plains of Arabian Sea on the west and Bay

of Bengal to the east. The east and west coasts meet at the southern tip of Peninsula bordered by the

Indian Ocean. The Indian Republic includes two groups of islands – The Lakshwadeep Islands in

Arabian Sea and Andaman Nicobar Islands in the Bay of Bengal.

The Himalayan Mountain Ranges-extend for about 2500 km (with an average width of about

240 km) all along the northern borders of the Indian sub-continent from Jammu and Kashmir in the

west to Arunachal Pradesh in east-form the Extra-Peninsular Region. Himalaya is broadly divided

into (i) Siwaliks (ii) Lesser Himalaya (iii) Higher Himalaya and (iv) Tethyan or Trans-Himalaya

across its length. The major rivers originating from the great Himalayan mountain ranges are the

Indus, Ganges and Brahmaputra.

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The average elevation of the Indo-Gangetic-Brahmaputra plain lying between Peninsular and

Extra-Peninsular India 150 m with a low gradient of almost zero level at the Sunderbans Delta of

Bengal to about 300 m in the Upper Ganga plain of Punjab.

PENINSULAR INDIA Peninsular India, the main repository of economic minerals, exposes rock units of almost entire

spectrum of geological era. Remnants of Archaean sialic crust, preserved only in isolated small

patches along with the oldest supracrustals are recorded from south, east, central and western parts

of the country. These Achaean nuclei are later accreted with the fold belt sequence, which

transgresses well within the Proterozoic, and display some tectono- magmatic episodes. The middle

to upper part of the Proterozoic era (Meso- to Neo- Proterozoic) is mainly characterized by the

development of major intracratonic basins (namely Cuddapah, Godavari, Indravati, Chhattisgarh,

Vindhyan etc.).Gondwana rocks spanning between late Paleozoic and Mesozoic period. These litho

packages are developed in faulted graben. The evidences of marine transgression during Mezozoic

era are well documented both in the East and West Coasts. However, the most spectacular event of

this era is the Deccan volcanism which covers vast tracts of western, central and southern India.

Temporally comparable volcanic events Rajmahal and Sylhet traps along with oldest volcanic event

(Panjal traps) are recorded from the eastern and northren part respectively. Compared to the earlier

geological periods, Tertiary era is not well represented. It is preserved only in small isolated basins

in Southern, Eastern and North eastern parts of the region. However, both temporal and spatial

development of Quaternary sequences are well documented throughout the country including its

coastal tracts.

INDO – GANGETIC BRAHMAPUTRA PLAIN

The tectonic trough sandwiched between peninsular shield in the south and Himalayan Mountains in

north formed due to the upliftment of the Himalaya, has been filled up by the sediments derived

from both sides, especially from Himalaya by rivers like Ganges, Brahmaputra and Indus and has

been termed as Indo-Gangetic-Brahmaputra alluvial plain and stretches across northern India from

Assam and Bengal in the east through Bihar and U.P. to Punjab on the west.

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EXTRA-PENINSULAR REGION

The Himalayan mountain chain occurring all along northern part of India can be divided into four

contrasting longitudinal litho-cum-morphotectonic belts from south to north, viz. i) Foot hill belt ii)

Main Himalayan belt iii) Indus-Shyok belt and iv) Karakoram belt.

The foothill Himalaya is a 10- to 50- km- wide belt of Miocene to Recent Molasse belt of

Siwalik and other foothills comprising the Subathu, Murree with the Siwaliks resting on the

Proterozoic component of the Indian Shield.

This is followed to the north by Main Himalayan belt, comprising Lesser and Higher

Himalaya, represented by sizeable portion of the geological sequences of Proterozoic age with

Phanerozoic cover of varying thickness in different parts.The foothill Himalaya is overlain by

alluvium and separated from the Lesser Himalaya by the north dipping fault commonly known as the

Main Boundary Fault (MBF) or the Main Boundary Thrust (MBT) in Garhwal, Kumaon, Nepal,

Darjeeling, Bhutan and Arunachal Pradesh Himalaya and known as the Krol Thrust in eastern

Himachal Pradesh and Murree Thrust in Jammu area. This belt is involved in western syntaxial bend

of the Himalaya. The Main Frontal Thrust (MFT) limits the margins of the Siwalik Zone against the

Ganga Plains.

The Lesser Himalaya is 60 to 80 km wide and is a discontinuous belt stretching between the

MBT in the south and the Main Central Thrust (MCT) in the north. It consists of autochthonous late

Proterozoic sediments, thrust over by three vast nappes that are built up successively of Palaeozoic

sediments, Precambrian epi-metamorphics and mesograde metasediments. The epi-metamorphic and

meso-metamorphic nappes throughout their extent are characterized by early Proterozoic (≈ 1900

Ma) and Early Palaeozoic granitic bodies of large dimension.

The MCT separates the Lesser Himalaya from the Higher Himalaya to its north.The Higher

Himalaya marks the region of highest peaks of Himalaya (Nunkun, Leopargial, Kedarnath,

Badrinath, Nanda Devi, Api, Dhaulagiri, Everest, Kanchanjunga), made up of 10-15- km- thick

Precambrian crystallines exhumed up and intruded by granites, some of which are Tertiary in age.

The Indus Shyok belt/the Tethys Himalaya extends to the south of the Trans-Himalayan

Karakoram belt and comprises ophiolite mélange (Indus ophiolite and associated formation) and

plutonic rocks (Ladakh granitoid complex) of the Indus Shyok belt. These predominantly

fossiliferous sediments range in age from late Proterozoic to Eocene. Sporadic occurrence of

chromite have been reported from the ultrabasic rocks associated with Dras volcancs from

Ophioleite-Melange zone.

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Karakoram belt, the northernmost zone comprises Palaeozoic and Mesozoic sedimentary

sequences on a metamorphic basement of unknown age. This Trans-Himalayan belt lies to the north

of the Indus Suture Zone in Ladakh region and extends eastward into Tibet. No important mineral

occurrence is known from this belt.

The different tectonic domains as depicted above are enumerated in detail in the following

pages with emphasis mainly on the potential mineral occurrences in India. Keeping mineralization

aspect in view, geology of Tertiary and Quaternary Period are not described in detail.

PENINSULAR INDIA

The geology of Peninsular India constituting different Archaean cratons- Dharwar, Bastar,

Singhbhum, Aravalli and Bundelkhand several mobile belts like Southen Granulite Teranin, Eastern

Ghats, Satpura, Delhi etc. Proterozoic sedimentary basins, Gondwana troughs, Deccan Trap and the

younger sedimentary basins is discussed below with a brief note on the stratigraphic locales, treated

regionwise with major tectonics. Prognastic mineralised sectors are described in detail for future

investigation and associated mining.

DHARWAR CRATON

The Dharwar Craton is essentially covered by the States of Karnataka and Andhra Pradesh. The

Dharwar craton is a typical Archaean granite-greenstone terrane with a gneissic basement of

tonalite-trondhjemite-granodiorite (TTG) composition known as Peninsular Gneiss. The granite-

greenstone terrain exposes rocks older than 2500 Ma. It is bounded by Southern Granulite Terrain

(SGT) to the south and Eastern Ghats Mobile Belt (EGMB) to the east, Arabian sea to the west,

northwest-southeast trending Godavari Graben to the northeast and to the north with Deccan trap

cover. The Dharwar Craton is divided into two sub-provinces – Eastern Dharwar Craton (EDC) and

Western Dharwar Craton (WDC) with Chitradurga Boundary Fault located along the eastern margin

of the Chitradurga schist belt as the boundary between them (Swami Nath et al., 1976; Drury et al.,

1984; Chadwick et al., 2000). Some workers believe that the Closepet Granite, which is located ~50

km east of the Chitradurga Boundary Fault represents the boundary between the EDC and WDC

(Naqvi and Rogers, 1987; Gupta et al., 2003; Moyen et al., 2003). Although the actual boundary

between the two cratonic blocks remains debatable there are notable differences in lithology and

metamorphism of the two blocks. The WDC is dominantly occupied by TTG gneisses (3.0 – 3.4 Ga)

with minor schist belts of Sargur age (3.0 – 3.3 Ga), major schist belts of Dharwar age (2.9 – 2.6 Ga)

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containing predominant platformal sediments, and a few late Archaean granitoid plutons dated in the

range of 2.60 to 2.65 Ga (Jayananda et al., 2006 and references therein). On the other hand, the EDC

is characterised by voluminous late Archaean granitoids (2. 51 – 2.75 Ga) (the “Dharwar batholith”

of Chadwick et al., 1996, 2000) with minor TTG gneisses and thin volcanics-dominated schist belts

of Dharwar age.

The Western Block of the craton comprises large schist belts (Dharwar type) accumulated in

distinct sedimentary basins and the Eastern Block is characterized by voluminous juvenile granites

and remobilised gneiss with remnants of schist belts (Kolar type). The schist belts in the craton are

metamorphosed under greenschist to amphibolite facies conditions. The profusion of granitoids is

responsible for low-pressure high Temperature metamorphism (andalusite-sillimanite type) in the

EDC in contrast to the intermediate- pressure regional metamorphism (kyanite-sillimanite type) in

the WDC.

The southern part of the craton exhibits a transition zone from low- to high-grade rocks. The

abundance of younger granites in the north and granulites in the south distinguishes the Eastern

block as a reactivated zone of mobilized gneisses and granites around the centrally located Archaean

nucleus (Western Block). The Chitradurga schist belt of Western Karnataka is one of the longest

greenstone belts showing several phases of deformation (Radhakrishna and Vaidyanathan, 1997).

The major part of Dharwar craton is covered by an extensive group of grey gneisses

designated as “Peninsular Gneiss” which was further divided into older (Peninsular Gneiss-I) and

younger (Peninsular Gneiss-II) based on isotopic age data (Beckinsale et al.,1980; Meen et al.,1992;

Nutman et al.,1992). These gneisses contain enclaves of deformed and metamorphosed

amphibolitic-and granulitic-grade rocks indicating the existence of an older group of sediments and

associated igneous intrusives and are referred to as Sargur Group or ancient supracrustals. The

lithological types include fuchsite quartzite with layers of chromite and barite, biotite schists with

garnet, kyanite, sillimanite, cordierite, corundum, staurolite, marbles and calc-silicate rocks,

serpentinised komatiites, banded iron formation and chromite-bearing ultramafic complexes.

Peninsular Gneiss-I consists mainly of amphibolite-facies gneisses of tonalitic-trondhjemitic

– granodioritic composition (TTG) with four major components, namely, (i) a layered and banded

complex consisting of quartzofeldspathic biotite gneiss alternating with amphibolites and ultramafic

material, (ii) banded hornblende-biotite migmatitic gneiss, (iii) banded migmatitic garnet-bearing

paragneiss and (iv) homogeneous trondhjemitic-granitic plutons. These gneisses act as the basement

for a widespread belt of schists.

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Peninsular Gneiss-II is comprised mainly of gneissic rocks with granodioritic and granitic

composition, representing remobilised parts of an older crust with abundant younger granites and is

found in the eastern parts of the Karnataka State.

The prominent schist belts of craton in Karnataka are grouped and describe under the

Dharwar Supergroup which is divided into two groups-the older Bababudan Group (2.8GA)

compising orthoquartite, metabasalt and magnetite rich Banded Iron Formation. Overlying this is a

more extensive Chitradurga Group(2.6GA) composed of schistose rocks, largely sedimentary in

character, comprising conglomerates, quartzite, limestone, Ingladal volcanics, greywacke and

associated manganiferous and ferruginous chert. The youngest series of sediments, mostly

greywackes in composition and intercalated with cherty iron formation is represented by

“Ranibennur Formation”, which occupies the topmost formation within the Chitradurga Group

(Radhakrishna and Vaidyanathan, 1997).

The end of the Dharwar Cycle is marked by“Closepet Granite” represented by granitic

intrusion in a narrow belt 50 km wide. This belt of younger potassic granites mark a major geo-

suture or joining between two distinct crustal blocks, western block with a number of well-

developed low-grade granite-greenstone belts with iron and manganese ores and eastern block

marked mainly by younger gneiss of granitic and granodioritic composition enclosing a number of

narrow linear bands of auriferous schist belts. Collision of the two blocks has resulted in the

emplacement of granites along the line of junction of the two blocks (Radhakrishna and

Vaidyanathan, op.cit). Besides, there are other isolated masses of younger granites outcropping away

from these linearly disposed granites like those of Chitradurga, Arsikere and Banawar in the west

and Patna, Torangal, Bellary and Raichur in the east.

More than 60% of the State of Andhra Pradesh makes up the eastern part of the Dharwar

craton and 10% of this cratonic part is covered by rocks of the Proterozoic platformal basins viz., the

Cuddapah, Pakhal and Bhima. The major part of Andhra Pradesh is covered by“Peninsular Gneiss”.

The different units of the Peninsular Gneissic Complex includes three discrete units based on

composition, structure and mutual relations viz. (i) gneissic rocks, (ii) hornblende-bearing granitoids

and (iii) younger granites. In the northern part, different units of the Peninsular Gneiss and the

younger K-rich granites are described as the ‘Granitoid-Migmatite Complex’ (Naqvi and Rogers,

1987).

The supracrustal rocks from Andhra Pradesh occur in the cratonic part and in the marginal

zone with marked similarities to the Kolar-type schist belts of the Karnataka State and are composed

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of matabasalt, mata-acid volcanics, volcanicconglomerate and minor BIF. The Nellore Schist Belt is

with Subordinate representation of meta sedminents. Three prominent greenstone belts occur in the

southern part of the State with discontinuous trace of the belts into the adjoining parts of Karnataka

State viz. (i) the Veligallu – Gadwal belt, (ii) the South Kolar or Bisanattam – Kadiri belt and (iii)

the Ramagiri –Penakacherla belt.

The Dharwar granite-greenstone terrane shows effects of three phases of deformation (Naha

et al., 1986). While the earlier two deformations gave rise to the NNW-SSE to NW-SE- trending

penetrative fabric marked by the general schistosity, and major faults and shears parallel to it, the

third produced broad warps along E-W to ENE-WSW-trending axes. The terrane is affected by

NNW-SSE to NW-SE-trending transcrustal faults/shears which are intersected by major ENE-WSW

to E-W and NE-SW-trending faults/lineaments. According to a structural model of the Dharwar

craton, the WDC represents a major synclinorium, while the EDC represents a major anticlinorium,

the limb portion of which is occupied by the Closepet Granite. After granate emplacemena the

Craton attained rigidity and later magmatic events like mafic dyke activity and Kimberlite activity is

along the deep crustal faults/fractures.

The generalized stratigraphic sequence pertaining to the granite-greenstone terrane of

Dharwar craton is shown in Table 1.

Table 1. Major Rock Types Group Age Era

Kimberlite Puranabasans Maficdyke Potassic granites

Cuddapah, Kaladgi, Bhima Younger granites

1800MA 2000MA 2600 Ma

PROTEROJIC LATE ARCHAEAN

Greywackes Manganese marker horizon, Limestone Mafic volcanics Oligomict conglomerate

Felsic Complex (Cu) Iron Formation (Au,Fe,Mn) Younger Greenstones (Cu, Zn, As, Sb) (Au, U)

ARCHAEAN

Peninsular Gneiss (beryl, columbite, tantalite, Li mica)

3000 Ma ARCHAEAN

Mafic – ultramafic rocks Ancient supracrustal rocks

Older Greenstones Kolar Group (Au, Ag, Cu, W) Sargur group

3300 – 3000 Ma

ARCHAEAN

Mafic? Felsic rocks Older gneisses 3300 Ma ARCHAEAN BASE NOT IDENTIFIED

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The linear belts of oldest supracrustal rocks (Sargur, Nuggihalli, Sathyamangalam and

Wynad) in this region are mainly represented by intercalated sequences of sediments and

volcanogenic assemblages, which are the locales of deposition of minerals. Important deposits

within these belts are Gold deposit of Kolar, Ramagiri-Penakacherla, Hutti, Maski, Gadag, Raichur

and Wynad schist belt of Kerala; Magnetite quartzite of the Sargur belt of Karnataka. Within the

Peninsular Gneiss and platformal sediments of Proterozoic age, the diamondiferous

kimberlite/lamproite bodies intrude. Kimberlites and lamproites, host rocks for diamonds are

distributed in the States of Andhra Pradesh and Karnataka, in the eastern tectonic block of Dharwar

Craton (EDC) which was stabilised by ~ 2500 Ma. EDC hosts these bodies along or at the

intersection of the post-Cuddapah reactivated ENE-WSW and NW-SE fracture / fault systems and /

or at the closure of domal structures. The geological milieu (granite-gneiss of PGC) and tectonic

setup favoured emplacement of more than 65 kimberlites and 46 lamproites. Kimberlites discovered

in southern India till now are restricted to the EDC and are distributed in four kimberlite fields, viz.

Wajrakarur Kimberlite Field (WKF), Narayanpet Kimberlite Field (NKF), Tungabhadra Kimberlite

Field (TKF) and Raichur Kimberlite Field (RKF) while lamproites occur in two fields, viz.

Ramadugu and Krishna. Gold, iron, manganese and titaniferous-vanadiferous magnetite deposits

are reported from the schist belts of Gadwal, Chitradurga, Holenarsipur, Khammam and Nellore.

TRANSITION ZONE

The Marginal Transitional Zone (MTZ) occurs between the Dharwar craton to the west and the

Eastern Ghat Mobile Belt in the east and is made up of granite gneiss and supracrustal rocks,

reworked and overprinted by younger deformational events. The schistose rocks of the Nellore –

Khammam belt, trending parallel to the East Coast occupies the transition zone along the eastern

margin of the craton. Recent studies brought to light the existence of Kandra Ophiolite Complex in

southern part of Nellore schist belt. Close to the vicinity of eastern margin of Cuddapah basin a

number of granite bodies occur within the schistose rocks of Nellore schist belt.

This zone is underlain by Archaean schistose and granitic rocks and was intensely reactivated

during the Middle to Late Proterozoic periods. As a result, the MTZ, the eastern margin of the

Cuddapah basin and the EGMB know as Prakasam Alkaline Province (Leenandam 1980) the locie of

igneous activity with the emplacement of anorthosites all along the mobile belt, alkaline and sub-

alkaline plutons close to the western margin of the mobile belt, syenite and granite close to the

eastern margin of the Cuddapah basin. The well-known Kunavaram alkaline complex occurs within

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the MTZ. Alkali syenite and related granites also occur outside the province. The world famous mica

(muscovite) mines at Gudur are located in the Nellore Schist belt.

SOUTHERN GRANULITE TERRAIN

The Southern Granulite Terrane (SGT) is to the south of the Dharwar craton having a gradational

boundary difined by the Fermor Line. The SGT is amalgamated to the Proterozoic pandian granulite belt

along Palghat-Cauvery shear zone.

The SGT is mainly exposed in the States of Tamil Nadu, Kerala and southern part of

Karnataka comprising the Coorg Biligirirangan hills granulite belt of Karnataka in the north and the

Nilgiri Madras granulite belt of Tamil Nadu in the south divided by the Moyar shear zone. This

Proterozoic terrain comprises the northern Periyar-Madurai granulite belt (Chetty, 1996; Yoshida et

al., 1996), also referred to as the Madurai Block (Harris and Santosh,1993) with intercalated

charnockite (charnockitic massifs of Nilgiri hills, Kollimalai and Pachchamalai hills along Cauvery

shear zone) and metasedimentary (pelitic) sequence and the southern Kerala Khondalite belt. Other

major rock units along the Cauvery shear zone,considered as ancient suture (Gopalakrishnan et al.,

1990; Viswanathan et al., 1990), includes sheared charnockitic and migmatitic gneisses intruded by

layered anothositic rocks around Bhavani and Sittampundi. It also consists mainly of high-grade

remnants of greenstone belts (Sathyamangalam Group) along with supracrustal enclaves of the

mobile belt, namely, quartzites, pelites.

The Palghat shear zone is represented by a distinct geomorphic expression, a physiographic

low, bounded by Nilgiri hills in the north and Anaimalai and Palni ranges in the south. The dominant

rock types along the shear zone include migmatitic gneisses and banded charnockites. Achankovil

shear zone is another major shear zone exposed in the southern tip of SGT. The regional fabric and

fold patterns around Kodaikanal and Madurai blocks are abruptly truncated at this zone

(Narayanaswamy and Purnalakshmi, 1967). Sporadic lenses of ultrabasic rocks occur within the

garnetiferous granitic gneisses.

In the southern flank of the Palghat gap, up to the north of the Achankovil shear zone, the

rocks are predominantly charnockites, charnockitic gneisses and other gneisses with occasional

assemblages of metasediments in the Idukki-Munnar region representing the western continuation of

the Madurai block in Tamil Nadu. Within the southern part of the Palghat gap, charnockitic patches

and hornblende-biotite gneisses predominate. Towards the central and the northern parts of the gap,

migmatitic gneisses (hornblende-biotite gneisses) and patches of amphibolites, calc-granulites and

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granites are exposed. Northern flank of the gap consists of a metasedimentary sequence of

khondalite and calc-granulite with crystalline limestone bands. Granulites, schists and gneisses,

intruded by acid and alkaline plutons, constitute the northernmost parts of the State. Sporadic late

Archaean – early Proterozoic granites and associated pegmatites as also Mesozoic-Cenozoic dykes

intrude these rocks.

The Kerala region is an important segment of the SGT, where major units of the Archaean

continental crust, such as granulites, granites, gneisses and greenstones are preserved. Southern part

of the State, south of Achankovil shear zone, exposes an assemblage of migmatised meta-

sedimentary and meta-igneous rocks (khondalite-charnockite assemblages).

The southern tip of the Peninsula is represented by the Nagercoil Charnockitic massif (or the

Nagercoil block), a distinctly charnockitic unit with metasedimentary intercalations.

Several intrusive igneous bodies of distinctive petrological and petrochemical attributes of

Proterozoic age occur amidst the granulites, Sittampundi, Torappadi, Thenmudianur, and Mamandur

in Tamil Nadu and Ezhimala gabbro-granophyre Complex, Perinthatta anorthosite and Adakkathodu

gabbro in Kerala; Alkaline magmatism is recorded in the form of several syenite-carbonatite bodies.

The alkaline-related plutonism was widespread in the north in parts of Vellore, Dharmapuri and

Salem Districts, where a number of ultramafic-syenite-carbonatite bodies of Elagiri, Koratti,

Samalpatti and Pakkanadu occur in a NNE-SSW-trending zone extending from Gudiyattam in the

north to Bhavani in the south over about 200km. Besides these silica-saturated alkali plutons, there

are two bodies of silica-undersaturated syenite complexes, namely the Pikkili and the Sivamalai

syenites. In contrast to the saturated syenites, these bodies are devoid of carbonatite association and

are characterized by pyroxene syenite, ijolite, nepheline syenite and corundum syenite. Minor

carbonatites with magnetite have been recorded along the slopes of the Western Ghats near the

Kerala border around Kambamettu and Kothagudi in Theni District. Minor veins of siderite-

ankerite-bearing carbonatite with rare sovite types are recorded in the carbonated zone in Attur

valley in Salem District. The Salem ultramafic body, famous for its magnesite deposit is considered

to be related to this syenite-carbonatite activity. The time of emplacement of these alkaline plutons

has been well constrained by different isotopic systematics.

The SGT was earlier considered to be the southern extension of the granite-greenstone terrain

of Dharwar Craton exposed at a deeper tectonic level. This concept was based on the observation

that the grade of metamorphism gradually increases from north to south. Geochronological and

isotopic studies have brought to light that the southern part of the SGT lying south of Palghat –

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Cauvery Lineament (PCL) has a geological history distinctly different from the Dharwar Craton.

These studies have shown that the terrain lying north of PCL shows crustal growth during the period

from 3400 to 2500 Ma. In contrast, crustal growth in the terrain south of PCL is considered to have

taken place predominantly during post-Archaean times, as constrained by Nd model ages (Harris et

al., 1994). This terrain might have witnessed several cycles of metamorphism, the most pervasive

being the 550-Ma Pan-African granulite facies event as constrained by isotopic systematics

(Unnikrishnan Warrier et al., 1995b; Jayananda et al., 1995, Bartlett et al., 1995, Ghosh et al., 1998).

In view of the contrasting geological history recorded by the terrains north and south of PCL, the

SGT has been divided into the northern Archaean Craton (Dharwar Craton) and the southern

Proterozoic (Pandian) Mobile Belt (GSI, 1994) with the PCL marking the boundary between them.

The generalised stratigraphic sequence of SGT is shown in Table 2.

Table 2: SGT Stratigraphy

Major Rock Types

Group (with mineral occurrences)

Age

Era

Alkali granite, granite, grano -phyre & acid intrusive Massive & incipient charnockite, cordie- rite charnockite

Younger Granite (W) Charnockite (Younger)

550-390 Ma 550 Ma

PALAEOZOIC to NEO- PROTEROZOIC

Gabbro Anorthosite

Ultrabasic / basic (Younger) (Mo)

700 -600Ma

Carbonatite,ultrabasic complex Alkaline complex Alkaline rock Epidote-hornblende gneiss

Alkali Complex (Younger) (U, Th, Y, Nb, Ta, Be, & REE)

700 – 900 Ma

NEO- PROTEROZOIC

Basic dyke Basic intrusive 1600 – 2100 Ma MESO- PROTEROZOIC

Carbonatite and alkaline dyke Syenite complex Ultrabasic complex

Alkali Complex (Older)

1900 – 2300 Ma PALAEO- PROTEROZOIC

15

Older grantie / granitoid Pink migmatite Pink augen gneiss Hornblende gneiss Hornblende-biotite gneiss Garnetiferous quartzo-feldspathic gneiss Garnet-biotite gneiss

Migmatite Complex (Peninsular Gneissic Complex II) (Fe)

2200–2550 Ma LATE ARCHAEAN TO PROTEROZOIC

Basic and ultramafic rock Magnetite quartzite Pyroxene granulite Charnockite

Charnockite Group

2600 Ma LATE ARCHAEAN

Calc-granulite Limestone Quartzite Garnet-sillimanite-graphite gneiss

Khondalite Group

Quartzo-feldspathic rock Amphibolite Banded ferruginous quartzite

Kolar Group (Au)

2900 Ma

Pink migmatite Granitoid gneiss Fissile hornblende gneiss

(Peninsular Gneissic Complex I) (Bhavani Group)

3000 Ma

Ultramafic / mafic, ultrabasic rock

Layered ultramafic / mafic, ultrabasic complex (PGE, Cr)

3000 – 3100Ma

Amphibolite, calc-silicate rock, basic and ultrabasic rock, sillimanite-kyanite-corundum-mica schist, fuchsite-kyanite ferruginous quartzite, talc-tremolite schist etc.

Sathyamangalam Group of Tamil Nadu;Wynad Schist Complex of Kerala (Pb,Zn,Cu,Ag,Cd)

3200 Ma

ARCHAEAN

BASE NOT KNOWN

The SGT is associated with the metallogeny of the metallic minerals, broadly grouped under

the categories – Gold mineralization in Archaean greenstone belts of Veppanapalli and Bargur

sectors in Krishnagiri district, Banded Iron Formation (BIF) in parts of Dharmapuri, North

Arcot,Villupuram and Salem districts; PGE and chromite mineralization in Archaean ultramafic-

mafic-anorthosite complexes of Sittampundi and Mettuppalaiyam. Also recorded Base metal

mineralization in the Mamandur area of Cuddalore district of Tamil Nadu, shear controlled

Molybdenum mineralization related to Neoproterozoic magmatism in shear zones; Rare metals (U-

16

Th-Nb-Ta-Y, Be) and REE mineralization associated with Neoproterozoic alkaline-carbonatite

complexes of northern Tamil Nadu and granites and pegmatites in central Tamil Nadu, and

Tungsten mineralization (Skarn type) in calc-granulites associated with Neoproterozoic granites in

the Karungalagudi area, Madurai district, Tamil Nadu.

EASTERN GHATS MOBILE BELT

The Dharwar craton is bounded in the northeast by the Eastern Ghats Mobile Belt EGMB),

extending for over 1000 km covering a distance of more than 600 km of Andhra Pradesh from

Ongole in the southern part of the State into Orissa in a northeasterly direction along the eastern

coast of the Indian Peninsula, is widest in Orissa (~ 300 km) and covers the major part of southern

Orissa. This is a granulite terrain mainly made up of charnockite, khondalite, quartzite, calc-

granulite, pyroxene granulite and leptynites. The EGMB includes two broad litho-stratigraphic

groups, the Charnockite and the Khondalite Groups, together forming the Eastern Ghats Supergroup,

intruded by layered anorthosite and associated mafic and chromiferous ultramafics and alkaline

complexes.

Both its northern and western contacts respectively with NOC and Bastar cratons are

tectonised. This is a typical Proterozoic mobile belt skirting Archaean cratonic blocks and

characterized by strong linearity, ductile deformation, high grade of metamorphism and a high

gravity gradient along its contact zone with cratons. Age data available from the isotopic studies

have provided new insight in to the chronostratigraphy of the events of this Precambrian terrane

which range from late Archaean to Pan-African (Sarkar and Paul, 1998, Krause et al.. 2001, Aftalion

et al., 2000 and Crowe et al., 2001).

The EGMB in Orissa is separated from the Western Orissa Sector by an abrupt geomorphic

and geophysical (Bouger gravity) discontinuity, also confirmed by deep seismic sounding (Kaila and

Bhatia, 1981), and extends from the southern tip of Orissa to Sambalpur.The eastern boundary of the

EGMB is probably marked by another major lineament along which they abruptly meet the coastal

alluvia. The Chilka lake anorthosites occur along this lineament.

The EGMB has a broad arcuate trend with a westward convexity, in conformity with the

shapes of the Nellore schist belt and the eastern margin of the Cuddapah basin, on the west. Broadly

EGMB has a NNE-SSW trend in the southern part but changes to NE-SW trend at west of Eluru.

After a gap of about 40 km occupied by the Gondwana sediments of the Godavari graben, NW of

Eluru, the western margin of the EGMB skirts the eastern fringes of the Bastar craton of Madhya

17

Pradesh. The eastern margin of the EGMB, along the East Coast is covered with Gondwana, Tertiary

and Quaternary formations.

The contact between the cratonic gneisses and the EGMB is a major tectonic feature marked

by gabbro-anorthosite and alkaline plutons of Middle Proterozoic age (1600-1000 Ma). The Nellore

Schist Belt in the southeast and Khammam Schist Belt in the northeast probably represent the

remnants of an originally single N-S-trending schist belt that got dismembered during the

development of the EGMB and its subsequent deformation.

These mobile belt granulites (EGMB) have contrasting geochemical attributes than the

cratonic granulites of SGT (Subba Rao, 1980). EGMB granulites are rich in REE with K-rich

alkalies compared to Na, Rb, Ba and Th-rich alkalies of SGT.

This belt is famous for its large resources of bauxite (formed mainly by supergene

enrichment of Al from metapelitic protoliths (khondalites), variety of dimension stones (commercial

granites) using charnockite, leptynites, granitoids, anorthosite and alkaline rocks, occurrences of a

variety of gemstones including emerald, chrysoberyl, aquamarine, ruby, sapphire, topaz and garnet,

resources of high-grade graphite and manganese ore and are being exploited locally.

EASTERN INDIAN CRATON

The Singhbhum-Orissa or Eastern Indian Craton (EIC) comprises Archaean nucleus of South

Singhbhum, Proterozoic Dalma volcanic belt and the Chotanagpur Gneissic Complex (CGC) in the

north. The Singhbhum nucleus (Naqvi and Rogers, 1987), a triangular region flanking Bastar Craton

in the west, is bounded by Copper Thrust Belt (CTB; also called Singhbhum Shear Zone) in the

north, Sukinda thrust in the south, high-grade metamorphic Satpura belt in the northwest and Eastern

Ghat granulite belt in the southwest. This is the richest mineralised cratonic block in India and

geographically the EIC comprise western part of the State of West Bengal, southern part of

Jharkhand and northern part of Orissa.

The geology of EIC is detailed in Table 3.

Table 3. Stratigraphy of EIC (as given in Balasubrahmanyan, 2006)

_________________________________________________________________________

Newer dolerite dykes and sills 1600-950 Ma

Mayurbhanj Granite 2100 Ma

Gabbro-anorthosite-ultramafics

Kolhan Group 2100-2200 Ma

-------------------------------------Unconformity---------------------------------------------

18

Jagannathpur/Malangtoli and Dhanjori-Simlipal lavas, 2300 Ma Quartzite-conglomerate (Dhanjori Group) Pelitic and arenaceous metasediments with mafic sills 2400-2300 Ma (Singhbhum Group) --------------------------------------Unconformity--------------------------------------------- Singhbhum Granite III 3100 Ma Epidiorites (intrusives) Iron Ore Group (IOG volcano-sediments) ---------------------------------------Unconformity-------------------------------------------- Singhbhum Granite I and II, Nilgiri Granite, Bonai Granite 3300 Ma Older metamorphic Group (OMG) and Older Metamorphic Tonalitic Gneiss (OMTG) folding and metamorphism 3500-3400 Ma OMTG 3775 Ma OMG ? 4000 Ma ______________________________________________________________________

A major section of this craton is occupied by the Singhbhum granite batholith complex

covering an area of about 10,000 sq km. A number of shallow basins (the supracrustals) within and

around the periphery of this granite batholith are also present viz. iron ore basins in the western

sector containing large economic deposits of iron ores, banded haematite quartz, Simlipal-Dhanjori

basin comprising volcanics and volcanoclastic sediments, etc.

Enclaves of older rocks like the Older Metamorphic Group (OMG) of igneous and

sedimentary rocks now metamorphosed to amphibolite facies (ortho- and para-amphibolite

respectively) and the Older Metamorphic Tonalite Gneisses (OMTG) occur as remnants within the

batholithic complex. The OMTG intrudes synkinematically into the OMG amphibolites indicating

that the latter is the oldest unit (Sharma et al., 1994). Presence of large number of enclaves of OMG-

OMTG association occurring throughout the batholithic complex attests to the extensive nature of

these rocks before the intrusion of the Singhbhum Granite.

The Iron Ore Group (IOG) of rocks (the major supracrustal unit in EIC) deposited subsequent

to OMG-OMTG. IOG constitutes low-grade metasediments including phyllites, tuffaceous shales,

banded hematite quartz/jasper (BHQ/BHJ), iron-ore,ferruginous banded quartzite, local dolomite,

19

acid intermediate and mafic volcanics as well as mafic sill-like intrusives. Deposition of IOG is

followed by intrusion of Singhbhum granite batholith representing dominant crustal growth in this

craton. From field evidence, trace, REE and isotope geochemistry (Saha, 1994), it has been

considered that this vast granite batholith can be grouped into three different phases according to

their time of emplacement which are as follows: Phase I: Dalima and Rajnagar-Kuyali units, Phase

II: Besoi, Hatgamaria and Keonjhargarh-Bhaunra units and Phase III: Haludpukur-Chapra,

Kalikapur-Matku, Saraikela-Jorapokhar-Tiring, Gorumahisani, Gamaria-Khorband-Karanjia units.

A pause in crustal growth followed the intrusion of Singhbhum Granite and was interrupted

by a sedimentary cycle (the Singhbhum Group) and a volcano-sedimentary cycle (the Dhanjori

Group) respectively. The Singhbhum Group metasedimentaries, mainly confined to the areas close

to CTB, extend across the thrust zone to SW of Baharagora over an extensive area up to the base of

Simlipal hill range. Singhbhum Group starts with the Chaibasa Formation containing garnet,

staurolite, kyanite-bearing mica schists with numerous bands of quartzites and ortho- and para-

hornblende schist. This is followed by Dhalbhum Formation at the top containing phyllites with a

few quartzite bands, chlorite, magnetite and chlorite phyllites and epidiorite sills. Towards the top,

the Singhbhum Group is terminated with the eruption of Dalma volcanics.

The Dhanjori basin, resting unconformably over the IOG in the NE part of the craton,

predominantly consists of volcanics and volcanoclastic sediments. Vast copper deposit within the

low-grade metavolcanic member has been extensively mined. The Dhanjori volcano-sedimentary

assemblage is considered to represent a greenstone cycle (Gupta et al., 1985) within the south

Singhbhum Proterozoics. The sequence comprises a lower unit of metapelites, psammites with

ultramafics and mafics (gabbro/dolerite) and an upper predominantly volcanic unit comprising mafic

ultramafic tuffs, intrusives, metabasalts and tuffaceous sediments.The lower ultramafics have

distinct komatiitic affinity with definitive spinifex textures (found only within this unit of EIC;

Majumder, 1996).The upper Dhanjori basaltic suite comprises alkali olivine basalts passing upwards

into K-poor oceanic tholeiites. An extensive granite granophyre complex occurring along the

western margin of the main Dhanjori basin has obliterated the contact between the Dhanjoris and

Archaean Singhbhum granite complex. Another large Proterozoic basin, called Simlipal basin

(Iyenger and Banerjee, 1964) forming Simlipal hill range, is a large oval-shaped basin of mafic

volcanics. The basin comprises spilitic lavas and tuffs along with basal arkose-orthoquartzites and

overlies the Archaean basement and two thick inter-trappean orthoquartzite bands.Two other large

volcanic suites were formed during this period namely, the Jagannathpur lava and Malangtoli

20

lava.These two lava formations are considered as post-Singhbhum granite and pre-Kolhan age (Saha,

1994). Compositionally these lavas display three distinct types viz. low-grade metabasalts, meta-

andesite and meta-oligoclase andesite.

The Proterozoic Dalma belt, lying north of CTB and sandwiched between the Singhbhum

nucleus in south and high-grade CGC in the north, is a 200-km-long and 3-7-km-wide arcuate belt

and mainly comprises greenschist facies rocks of Singhbhum Group and meta-volcanics.The belt has

been intensely folded into a synclinorium along E-W to NE-SW axes which is refolded at the eastern

and western extremities (Saha, 1994). Stratigraphically, the rocks of this belt are classsified into a

lower and upper member. The lower member comprises of phyllites (often carbonaceous),

quartzites, shale, high-magnesian komatiitic serpentinised peridotites, lavas and vitric tuffs with

quench textures, volcanoclastics, etc. Concordant basic-ultrabasic plutonic bodies (gabbro,

pyroxenites) of considerable dimensions are also found interlayered with the tuffaceous horizons in

the eastern sector. The upper Dalma member is represented by high iron - low potash tholeiitic

basalts along with some rhyolites. Dalma volcanics bear considerable similarity with Dhanjori

volcanics, though the former contains less basaltic komatiites. Stratigraphically, however, Dhanjori

have always been considered as either equivalent to Dalma or slightly older.

The Proterozoic volcano-sedimentary cycle is followed by intrusions of large isolated

granitoid bodies like Kuilapal and Chakradharpur granites (CKPG) in the NE and southern margin of

Dalma belt respectively. The Kuilapal granite is an ellipsoidal granite gneiss body occurring within

moderately high-grade metamorphosed pelitic schist and interbanded hornblende schist, talc schist

and conglomerate. Its composition varies from trondhjemite to tonalite. The CKPG is an east-west-

trending elongated body with numerous enclaves of amphibolites, chlorite schist, talc-schist, rootless

intercalations of arkose-conglomerate and quartzite (Bhaumik and Basu, 1984). Other acid plutons,

intruded along the southern margin of CTB, are the soda granite and the Arkasani granophyre.

After the relatively minor Proterozoic crust building episode within the Dalma belt, there was

a pause followed by the final crust forming events in this area beginning with the emplacement of

gabbro-anorthosite complex along the eastern margin of Singhbhum granite batholith extending

from Butgora in the north to Nausahi in the south. This is followed by emplacement of Mayurbhanj

Granite (MBG) covering approximatly 1000 sq km (Saha, 1994). The MBG was overlain by the

Kolhan Group of sediments. The sediments are sandstone, shale, argillaceous limestone and

orthoquartzite. The final stabilisation of this craton is marked by the intrusion of spectacular set of

reticulating basic dyke swarm, known as Newer dolerite dyke swarm (NDD), mainly confined in the

21

southern part of CTB. NDD is considered to be the youngest magmatic activity and stratigraphic unit

(op.cit) in EIC.

The Chhotanagpur Granite Gneiss Complex (CGC) occupies a considerable area in the

northern part of EIC and is intrusive into the schists in the south (Dunn and Dey, 1942). The

Chhotanagpur Gneiss Complex (CGC), extending from Chhattisgarh in the west through Orissa and

Jharkhand up to parts of the districts of Purulia, Bankura, Birbhum and Medinipur of West Bengal in

the east, forms an integral segment of the Precambrian Continental Shield of Eastern India. The

major parts of CGC occurring in south Bihar and northern part of Jharkhand and in West Bengal is a

vast gneissic terrain exposing complex assemblages of diversified rocks, which have witnessed

several periods of magmatism, tectonism, sedimentation, metamorphism, partial melting and

mineralisation that have altered the pre-existing volcanic, plutonic and sedimentary rocks to a

gneiss-granulite-granite association.

In northeast India, the Meghalaya is a huge geomorphic up-arch of Precambrian

metamorphic rocks with a narrow southern fringe. The northern limits of the Meghalaya uplands are

marked by the Brahmaputra Plain.The various rock groups occupying the region includes Bomdila

Group, Sung Valley alkaline carbonatite complex, basement gneisses of Meghalaya Plateau and

granitoids of EIC like Kyrdem, Nongpoh and Mylliem.

This part of the Peninsular Indian Shield is associated with the mineralization of copper in

Mosabani-Bedi –Rakha mines in Jharkhand; Jaduguda uranium mineralization; iron, manganese,

chromium, vanadium, titanium,gold, copper, molybdenum in the mafic magmatic provinces in

Jharkhand and north Orissa; tin, niobium, lithium, beryllium occurrences in late Proterozoic granite-

syenite-gabbroic province in western Orissa, occurrences of lead-copper, phosphorite, mica and

manganese in the carbonate-rich mobile belt of Gangpur-Chotanagpur and granite plutons with

associated pegmatites and quartz veins carrying beryllium, tin, tungsten, uranium and tantalum.

CENTRAL INDIAN PRECAMBRIAN SHIELD

The Central Indian Shield is a mosaic of two crustal provinces, the Southern Crustal Province

(SCP) and Northern Crustal Province (NCP) separated by a prominent East -West trending Central

Indian Shear (CIS)/ Central Indian Tectonic Zone (CITZ). The Western part of thei sector is

blanketed by thick pile of Deccan Traps (i.e major part of Maharashtra and Western part of

Madhyapradesh) The SCP is with Archien nuclei known as Bastor Craton. The Baster Craton is

bounded to the North East by Mahanadi graben, of the South West by Godawari graben; to the North

22

Weas by Satpura Mobile Belt and to the South East by Easternghats Mobile Belts. Bhopalpatanam

Granalite Belt is seen to shoulder along the Godawari Graben. The domain to north of the Son-

Narmada-Tapti (SONATA) lineament is named as the Bundelkhand Protocontinent (BP) or the NCP

consisting of the Bundelkhand craton, surrounded by the Vindhyans and the fold belts of Aravalli-

Delhi in Rajasthan. To the south, Deccan Protocontinent (DP) or the SCP occurs with the

Singhbhum-Bastar-Dharwar Cratons (Yedeker, 1986; Yedeker et al., 1990; Acharyya and Roy,

2000). The Bundelkhand Craton (BDC) in the north and the Bastar Craton (BC) in the south have

Archaean nuclei. The supracrustal belts in northern and western parts include the Mahakohal, Sakoli,

Sausar Groups apart from the Dongargarh Supergroup, whereas to the south and east the Sukma,

Bengpal and Bailadila Groups form the main lithotectonic associations.The Abujhmar Group is a

volcano-sedimentary ensemble in contrast to Chhattisgarh, Indravati, Pakhal and Sullavai Groups

constituting important Purana cover sedimentary sequences.

The simplified stratigraphy of Central Indian Precambrian Shield (CIPS) is given in Table 4.

Table 4: Stratigraphy of CIPS (simplified after Sarkar et al., 1990)

Major Rock Types Group Age Era

Supracrustal rocks, granite and gneiss

Khairagarh Belt, Granite in Satpura Belt; as Tirodi Gneiss (Sausar Group)

800 Ma

NEOPROTEROZOIC

Kimberlites Majhgaon, Hinota diatremes

1200-1000 Ma

NEOPROTEROZOIC to MESO-

Mafic dykes, granite,gneiss

Mafic dykes and granite in Bastar craton, Abhujmar Group, Keskal granite, Amgaon Gneiss, Tirodi Gneiss

1500 Ma

MESOPROTEROZOIC

Sonakhan, Bailadila, Khairagarh, Gwalior, Sausar, (?) Sakoli, Chilpi Groups

1600 Ma 1600 Ma

MESOPROTEROZOIC

Granite Sukma, Pujariguda, Burgudem, Paliam-Darba, Cholanguda granite (Sn – W mineralization)

2200 Ma

PALAEOPROTEROZOIC

Granite, gneiss, volcanics Bundelkhand Granite, Khairagarh, Chilpi Ghat, Abujhmar Volcanics, Chilpi Group, Sausar Group, Dongargarh Granite, Malanjkhand tonalite-granodiorite Gneiss, Nandgaon Group,

2400-2300 Ma

PROTEROZOIC To

23

Mahakoshal Group LATE ARCHAEAN Gneiss Abujhmar, Nandgaon,

and (?) Sakoli Groups 2600-2500 Ma

LATE ARCHAEAN

Metasediments Bengpal, Amgaon, Sukma Groups

ARCHAEAN

Gneissic Complex Bundelkhand, Baya and Sukma Gneiss

? 3600 Ma

ARCHAEAN

BASTAR CRATON

The Bastar Craton (BC) is bounded to the northeast by Mahanadi graben, to the southwest by the

Pranhita-Godavari graben, to the northwest by Satpura mobile belt, and to the southeast by Eastern

Ghats Mobile Belt. The cratonic components of Bastar includes Basement Gneiss (≈ 3.5Ga)

followed by the (i) Sukma metamorphic suite (≈ 2.6 Ga), Bengpal Group (≈2.3 Ga), Bailadila Group

(2.1 Ga), undifferentiated granites and basic dykes (Ramakrishnan, 1990).Dutta et al. (1981) indicate

a Narainpur Group above the Bailadila Group with sandstone, conglomerate and mafic volcanics.

Sukma Group comprises slivers of quartzite, pelites, calc-silicates, BIF and amphibolites. The

Bengpal Group of rocks consists of low-to medium-grade volcanosedimentary sequence of

amygdular metabasalt, quartzite, conglomerate and andalusite and chloritoid schist. Bailadila Group,

consisting of quartzite, phyllite and BIF, hosts iron-rich deposits; (ii) Sonakhan belt is endowed with

greenstone-granitoid association; (iii) Kotri-Dongargarh belt of volcanosedimentary-granite

association of Dongargarh Supergroup is represented by older Nandgaon Group of basic and acid

lava and pyroclastics, the Dongargarh granite and younger Khairagarh Group of volcano-

sedimentary sequence; (iv) Sakoli belt comprises distinct low-grade supracrustrals of bimodal

volcanics, pelitics and quartzite laid on Amgaon Gneisses of 2.5 Ga, and (v) the cover sequence of

the Chhattisgarh, Indravati, Albaka and Sullavai Supergroup / Group.

The NCP includes (i) The Central Indian Tectonic Zone with gneiss- supracrustal-granite

litho-associations of Mahakoshal, Sausar and Betul-Chhindwara belts and the granulites in Sausar

terrain. (ii) Bundelkand gneiss-granitoid terrain with enclaves of minor supracrustal belts, and (iii)

Cover sequences of Vindhyan and Bijawar Supergroup /Group.

Archaean gneisses and high-grade granulitic/charnockitic rocks are exposed mainly in the

southern part of the region. This includes gneissic rocks of Pranhita- Godavari valley, charnockitic

suite of rocks along the Wainganga valley in Bhandara and Chandrapur districts, the gneisses and

associated supracrustals of Bastar area, the Tirodi gneisses of Nagpur-Seoni area

24

(Narayanswamy,1962), gneisses and supra crustals occurring to the east of Sakoli basin in Gondia-

Bhandara- Rajnandgaon sector grouped as Amgaon Group (Sarkar, 1958).

The Bastar/Amgaon/Tirodi gneisses and associated supracrustals include upper amphibolite

facies, high-grade gneiss-migmatite with supracrustals including metasediments (quartzite – BIF –

carbonate - pelite) and meta-igneous (amphibolite, ultramafic) litho-types. The supracrustals are

interleaved with gneissic rocks that contain relicts of TTG suite, the whole setup being dismembered

by younger granitic intrusives in different areas of the region.

The gneisses exposed south of Sakoli fold belt in Gadchiroli, Chandrapur, Nagpur and

Bhandara districts are generally referred as Bengpal Gneisses. This belt is about 200km X 60km2

and further southward merges with the gneissic country of Bastar area where these have been named

as Bengpal (Sukma) Gneiss-supracrustals. Gneiss migmatites include banded gneiss, stromatic

gneiss and leucocratic gneiss containing meta-sedimentary, meta-igneous and TTG restites. Banded

magnetite quartzite, hornblende schists, pyroxene-bearing gneisses, quartzite and pelitic schists

occurring as thin bands are scattered over a wide area. Towards eastern part it is designated as Baya

Gneiss. The closing of the Sukma Orogeny is indicated by the Sukma granite gneiss at ≈ 2.6 Ga.

The maximum age for Bengpal Group of rocks is set by the intrusive Paliam and Darba granites

with whole-rock isochron age at 2308± 48 Ma (Sri = 0.735) with mineral ages of 2050 Ma and 1620

Ma.

Quartzite bands of Bailadila Group extend along strike for several kilometres in the

southern parts of Gadchiroli District and are interbanded with other meta-sedimentary rocks. They

show gradational contact with BIF and calc-silicates rocks. Quartzites include orthoquartzites, at

times micaceous, calcareous and ferruginous, and commonly contain minor amounts of graphite.

Magnetite – specularite form BMQ (BIF) with impersistent folded quartz-magnetite banding on

milimetre to centimetre scale extending for several kilometres and contains 67 to 68 % Fe. Two such

important patches are seen in parts of Chhattisgarh.

The Sonakhan Group of rocks occurs in the eastern part of Chhattisgarh State. This

comprises continental bimodal, basalt-rhyolite association of volcanics with greywackes and

conglomerates. The quartz veins in the bimodal volcanics are gold-bearing.

The Nandgaon Group comprises Bijli volcanics and Pitepani basic volcanics. Bijli consists

mainly of rhyolite and sandstone. Pitepani volcanics mainly includes massive to porphyritic basalt

with rare pillow structure. The rocks are well exposed in the eastern part of Bhandara district in

25

Salekasa area and extend southwards in Korchi area of Gadchiroli district and in parts of

Rajnandgaon district of Chhattisgarh.

The Sakoli Group covering an area of about 3500 sq km in parts of Nagpur, Bhandara and

Gadchiroli districts of the Maharashtra comprises a metamorphosed volcano- sedimentary sequence.

The volcanic to sedimentary rocks ratio is about 1:4. Both mafic and felsic volcanic rocks are

present in nearly equal proportions. Sakoli Group includes metasediments dominated by phyllite

(carbonaceous at places), mica schist (with varying proportions of magnetite, andalusite, chloritoid,

garnet and staurolite), metabasalts, metarhyolites and banded iron formation (BIF). Quartz-

tourmaline rock (tourmalinite) and banded garnet-amphibole-biotite-quartz rock (BGA, possibly a

variant of banded manganiferous iron formation) are the other significant rocks of this group. Quartz

veins, alkali-feldspar granite, pegmatite and amphibolite/gabbro are the intrusives in the Sakoli

Group. The meta-basalt are iron-rich tholeiite while meta-rhyolite are represented by pyroclastics,

tuffs and flows with composition ranging from rhyolite to rhyodacite.

The gneiss and older supracrustals (Sukma-Amgaon) encircling the Sakoli Group represent

basement to the Sakoli sequence and also occur as inliers within the Sakoli Fold Belt.

The 75-km-wide and 300-km-long Sausar Fold Belt in Madhya Pradesh is trending E-W,

curvilinear (southerly convex) belt extending from Balaghat in the east to Chindwara in the west,

exposing a central domain of dominantly supracrustal rocks (metamorphosed quartzite, pelites and

carbonates) and characterized by lack of volcanic rocks. It is intimately associated with a variety of

granitic rocks of anatectic origin. The Sausar Mobile Belt (SMB) displays the Sausar Group together

with some granulites, Tirodi Gneiss and the Augen Gneiss. It is confined between the northern

Bundelkhand Protocontinent and the south Deccan / Bhandara Protocontinent. This Proterozoic major

crustal belt is said to have three lithotectonic units – (i) Mafic granulite-felsic migmatite gneiss – the

Tirodi biotite Gneiss, (ii) Augen Gneiss, foliated granite, and (iii) Sausar Group comprising calc-

silicate gneiss, calcite marble, dolomite marble and quartzite (Bhowmik et al., 1999). The southern

periphery of the supracrustal sequence reveals linear suite of two-pyroxene granulite-charnockite-

metapelite granulite lenses and pods. The granulites reveal the pre-Sausar structure (Narayanaswami et

al.,1963). The main Sausar Orogeny is ≈ 1000-Ma Grenvillian age implying granulite metamorphism

as pre-Grenvillian. The Tirodi Gneiss indicates an age of 1525 ± 70 Ma with a mineral isochron at 860

Ma (Sarkar et al., 1986). The Tirodi biotite Gneiss considered earlier to be a migmatised Sausar

supracrustal unit, is now related to a granulite-facies metamorphism in Ramakona – Katangi granulite

belt preceding the deposition of the supracrustals.

26

The Makrohar granulites occurring as a belt to the south of the Son-Narmada South Fault

(SNSF), south of Mahakoshal Belt and intruded by gabbro-anorthosite and granite are thought to

represent granulite metamorphism at ≈ 1.7 Ga (Pichai Muthu, 1990; Roy and Prasad, 2003).

The Mahakoshal Group is a supracrustal sequence with dominant metasediments and

subordinate tholeiite metavolcanics with intrusive dunite-peridotite and occasional sills of soda-

granite. The group has a faulted contact with the Archaean gneisses and migmatites between

Jabalpur and Sidhi comprising the Agori and Parsoi Formations in which intrusives occur. The

contact of this group with the Jungel Group is also faulted. The contact with the Vindhyan

Supergroup lying above is also faulted. The lower Agori Formation consists of pillow-pahoehoe

toes, bomb agglomerate, volcanic breccia, tuff and chert. This group of rocks occurs as a horst in the

Satpura axis.

The Betul supracrustal belt is a granitoid gneiss tract between Mahakoshal Belt to the

north and the Sausar supracrustal belt in the south. This has quartzite, pelite, calc-silicate, BIF,

garnet-anthophyllite schist intruded by mafic, ultramafic and granitic rocks with bimodal volcanics –

a low K-tholeiitic basalt and calc-alkaline to alkaline rhyolite.Three phases of folding with

amphibolite-facies grade of metamorphism and intrusion of granite are noted. In the northern part of

this belt peridotite, pyroxenite, gabbro, norite and diorite have BIF granulite enclaves.

Volcano-sedimentary sequences of the Khairagarh and Abujhmar groups and sediments of

Chilpi Group belonging to Palaeo-Mesoproterozoic unconformably overlie the older sequences and

the granite in the Mailkala range and Abujhmar plateau region. Pakhal Supergroup belonging to

Mesoproterozoic occupies the Godavari valley region. Platformal cover sequence of the

Chhattisgarh Supergroup of Meso-Neoproterozoic occupies the Chhattisgarh plains.

The Dongargarh Supergroup occurs to the west of Chhattisgarh basin and to the east of

Sakoli synclinorium. This group overlies Amgaon and Sakoli Groups, comprising the lower igneous

suite of Nandgaon Group and upper sedimentary igneous alternation of Khairagarh Group separated

by a pronounced unconformity subsequent to the emplacement of the Dongargarh Granite.

The Khairagarh Group is exposed in the central part of the Dongargarh Belt south of Deori

and around Darekasa of Maharashtra and in Rajnandgaon district of Chhattisgarh state. The Bortalao

Formation forms the lowermost litho-sequence of the Khairagarh Group, which unconformably

overlies the volcanic rocks of Nandgaon Group and the Dongargarh Granite. It forms an E-W-

trending belt of varying width on the flanks of normal and inverted canoe-shaped folds and saddle

folds in the area south and west of Deori and NNE-SSW-trending limb of syncline in east of

27

Salekasa. Impersistent beds of conglomerate often occur at the base of this formation consisting of

well-rounded pebbles, cobbles and boulders of variously coloured Bijli rhyolites, Dongargarh

granite, arkose, vein quartz, quartzite, chert, trachyte, basalt and andesite in a fine-grained matrix.

The Sitagota volcanics overlie this and comprise dull green basalt with minor tuffs and

agglomerates. Karutola Formation disconformably overlies the Sitagota volcanics and consists of

fine-to coarse-grained, well-bedded pure and ferruginous quartzites. It is followed by the

Mangikhuta volcanics consisting of non-porphyritic, amygdaloidal pyroxene tholeiite with minor

intertrappean, laminated shale and siltstone. Ghogra Sandstone is mainly quartz-arenite in

composition, and this lithounit is considered by Yedekar and Jain (1996) as intraformational between

Mangikhuta and Kotima Formations.

Several major faults have been recorded mostly affecting the lithounits of the Khairagarh

Group, which include N-S-trending Darekasa Fault (Sarkar, 1957-58). Dhara-Kamarwara and Tappa

faults also extend in N-S direction for tens of kilometres at the eastern margin of the Khairagarh

Group.

The Kotri Belt is the southern extension of the Dongargarh belt with comparable

stratigraphy. Mahla Formation and Rhyolite Formation represent the Nandgaon Group of

Dongargarh supergroup in the Kotri Belt. The Abujhmar Group in the Kotri Belt is correlatable with

Khairagarh Group. The belt occurs in northwestern part of the Gadchiroli district of Maharashtra and

partly in adjoining parts of Chhattisgarh and includes a litho-assemblage of locally significant

conglomerate, chlorite schist, muscovite schist and sericite quartzite associated with meta-ultramafic

and gabbro bodies. The intrusives within the belt are coarse pink granites, which are correlatable

with the Dongargarh Granite. The meta-ultramafics show alteration of original pyroxene to an

assemblage of serpentinite-tremolite and tremolite-serpentinite-actinolite. The BIF includes

carbonate-and sulphide-bearing bands, often being pyritiferous. Quartzite includes conglomeratic

bands of local importance.

The Amgaon Gneiss, located in the southern and northern part of the triangular belt with

Sakoli, Sausar and Dongargarh supracrustals and granulite belts, is intruded by the Dongargarh

quartz monzonite and Malanjkhand granodiorite, known as Dongargarh Granite. This granite,

exposed in several batholiths and stocks parts of Bhandara and Gadchiroli districts of Maharashtra

and Rajnandgaon district of Chhattisgarh States, is one of the oldest rapakivi epizonal coarse-grained

granite with porphyritic, equigranular and microgranite textures and devoid of pegmatites, dated at ≈

2.4 Ga. The isotopic age data points to a temporal association among Malanjkhand granodiorite,

28

Bijli rhyolite and Dongargarh granite. It is emplaced between older Nandgaon Group and younger

Khairagarh Group.

BUNDELKHAND CRATON

This highly deformed granite-greenstone terrain consists of the Bundelkhand Granite massif

with an aerial extent of 26,000 km2 bounded by the Great Boundary Fault to its west, the Son-

Narmada North Fault of Central Indian Tectonic Zone to its south, Ganga Foreland to its north and

wrapped around by the extensive Vindhyan Basin. This cratonic area comprises ultramafics,

amphibolite, fuchsite quartzite, banded iron formation, schists, marble, calc-silicate rocks and

tonalite-trondhjemite-granodiorite (TTG) intruded by undeformed hornblende-, biotite- and leuco

granitoids. Dykes of porphyry, acid volcanics, rhyolite breccia and pegmatite veins pervade the

massif. The NE quartz reefs and NW swarm of mafic dykes terminate the activity in this massif. The

Bundelkhand Granite consists of an early porphyritic phase followed by several intrusive phases of

monzonite, leucogranite, diorite-syenite-granite and other porphyries with three generations of

dolerites. Bundelkhand Granite has been isotopically dated at ≈ 3.3 Ga.

Large-scale granitoid magmatism of batholithic dimension around 2.5-2.2 Ga (Bundelkhand

Granite, Dongargarh Granite, Malanjkhand Granite) in the Central Indian Shield probably reflects

the late archaean - early Proterozoic cratonisation in this part of the shield area (Ramachandra, 1994;

Ramachandra and Roy, 1998).

Kimberlites occur as intrusives into Bastar craton. Other mineralisation in this part of the

shield area includes the Malanjkhand copper in granodiorite; alkali granite and granodiorite in the

Mahakoshal Group hosting copper mineralisation at Karaudiya in tholeiitic metabasalts; stratiform

zinc sulphide mineralization at Kholari-Bhaonri in the lower part of Bhiwapur Formation and vein

type copper-galena-gold-tungsten mineralization with platinum incidence at Kholari-Bhaonri-

Ranbori and Ranmangli areas in the upper part of the Bhiwapur Formation of Sakoli Group; minor

gold-silver-tin-molybdenum occurrences in BIF of Sakoli Group; workable Khobna tungsten

prospect of Umrer Tehsil of Nagpur district, Maharashtra State hosted by the quartz-chlorite mica

schist of the Sakoli Group; skarn type of tungsten (scheelite) occurrences along with minor

sulphides of base metals in amphibolite within tourmaline granite at Umrer and in

marble/calcareous quartzite at Kosamtondi-Bagarban-Kheripur areas; occurrences of manganese

ores associated with ‘Gondites’ of Sausar Group; uranium mineralization in a 100-km-long shear

zone in crystalline rocks from River Mahan in the west of Surguja district of Madhya Pradesh

29

extending to the east in Palamau district of Jharkhand State and uranium deposits in metarhyolite

and metabasics in periphery or close to the Dongargarh Granite at Bodal and Bhandaritola; fluorite

occurrences within sheared Dongargarh Granite at Chandidongri. Laterite with pockets of bauxite

forms capping at a number of places over these rocks in Keshkal-Amabera area.

WESTERN INDIAN PRECAMBRIAN SHIELD

The Precambrian of the Western Indian Shield from east to west comprises the Banded

Gneissic Complex (BGC) or craton and the Aravalli – Delhi mobile belts with the Trans-

Aravalli basins encompassing the area west of the Aravalli mountains. The stratigraphy of the area

is summarized in Table 5.

Table 5: Stratigraphy of Western Indian Precambrian Shield (after Gupta et al., 1980)

Major Rock Types / Group

Supergroup Age Era

Erinpura Granite Malani Volcanics Godhra Granite and Gneisses

1600 – 700 Ma

NEOPROTEROZOIC

Punagarh and Sindreth Groups Sendra-Ambaji Granites Kishengarh Syenite Phulad Ophiolite Suite Kumbhalgarh and Ajabgarh Groups Gogunda and Alwar Groups

Delhi Supergroup

2000-1600 Ma

MESOPROTEROZOIC

Champaner Group Lunavada Group (Udaipur, Salumbar, Udai-sagar and Darwal Granites) Rakhabdev Ultramafic Suite Jharol Group and Dovda Group Nathdwara Group Bari Lake and Kankroli Groups Udaipur Group Debari group

Aravalli Supergroup

2500-2000 Ma

PALAEO- PROTEROZOIC

Undifferentiated Granite Ranthambor Group Berach and Jahazpur Granites Rajpura-Dariba, Pur-Banera Jahazpur Groups and Sawar Group Hindoli Group, Mangalwar Complex and Sandmata Complex Mafic and ultramafics; Untala and Gingla Granites

Bhilwara Supergroup

≥ 2500 Ma

ARCHAEAN

30

BGC

The oldest cratonic nucleus of the Western Indian Shield, the BGC, occupies a large tract in the

Mewar plains of south and east Rajasthan. It is bounded on the west and southwest by Proterozoic

fold belts of the Aravalli and Delhi Supergroups, while an arcuate belt of low-grade volcano-

metasedimentaries (Gwalior Series in Heron, 1953; Eastern Aravalli belt in Gupta, 1934, and

Hindoli Group in Gupta et al., 1981) and Vindhyan platformal sediments demarcate the eastern

boundary of this craton. The Deccan Traps delimit the southern boundary of its outcrop area (Gupta

and Malhotra, 2000). The older component of the Aravalli craton occurs in the BGC in the eastern

and southeastern parts of the Aravalli Range. The BGC is a time transgressive crystalline complex,

comprising gneisses of amphibolite to granulite facies derived from plutonic, volcanic and

sedimentary protoliths. The crystallines are intruded by granitic plutons of several generations

ranging in age from Archaean to Middle Proterozoic. The sedimentary component is dominantly

pelitic and is well exposed on the eastern margin of the Delhi Supergroup. The volcanic component

is represented by basic lavas now occurring as hornblende schist or amphibolite (Heron, 1953;

Roy,1988, 1991; Sinha Roy, 1985 and Sinha Roy et al., 1992). Metamorphic and structural studies

have clearly demonstrated that the BGC was the crystalline basement over which Proterozoic rocks

of Aravalli and Delhi Supergroups were deposited.

The BGC was later on reclassified as the Bhilwara Supergroup comprising (1) the

Sandmata Complex which is subdivided into three formations viz., the Baranch, Badnor and

Shambhugarh Formations, and intruded by Gyangarh-Asind Charnockite-enderbite, Amet Granite,

Anjana Granite, etc; (2) the Mangalwar Complex which is subdivided into the Lasaria, Kekri, Sarara,

Mando Ki Pal, Suwana, Potla and Rajmahal Formations; and (3) the Hindoli Group which is

subdivided into the Bhadesar, Sujanpura and Nangauli Formations. The metamorphic-cum-

migmatitic contact between the Sandmata Complex and the Mangalwar Complex practically

coincides with the Delwara lineament.

The Sandmata Complex comprises migmatite, composite gneiss/bimodal gneiss, calc- gneiss,

garnet-sillimanite gneiss, garnet-staurolite-sillimanite schist, chlorite-biotite schist, mica schist,

cordierite-garnet pelitic gneiss, enderbite charnockite, pyroxene granulite, norite, hornblende schist,

amphibolite, epidiorite and quartzite. The complex is further characterized by preponderance of

acid, and mafic igneous suite of rocks. The term Sandmata Complex is restricted to the ductile shear

zone bounded by granulite-facies rocks, with the absence of charnockite and eclogite but the

presence of high-alumina granite, basic granulite, leptynite and norite dykes.

31

The Mangalwar Complex is considered presently as representing Archaean primary granite–

greenstone belt. In the northern part, migmatitic gneiss-amphibolite association of the greenstone

sequence is represented by banded bimodal gneiss, amphibolite, pelitic schist, fuchsite quartzite,

quartzite, chert, BIF, calc-silicate rock and marble. In the sourthern part of BGC terrain, mafic

enclaves, represented by amphibolite, migmatised gabbroic rock and chlorite schist , are by far the

most prolific of the suite. High-magnesia mafic and ultramafic enclaves include tremolite-actinolite

schist, grunerite-garnet schist, magnetite and garnet- bearing chlorite-actinolite schist, chlorite schist,

talc-chlorite schist and talcose serpentinites with asbestos veins. Besides, long linear bodies of felsic

volcanics in the form of qurtzo-feldspathic rocks are also present.

The Hindoli Group comprises a low-grade (greenschist facies) sequence predominated by

turbidite and volcanics. The arcuate belt of the nearly continuous Hindoli Group, interrupted by

Berach Granite, occurs along the eastern and southeastern flank of the BGC/Mangalwar Complex. In

the southern end of the Hindoli belt, the Hindoli Group is overlain unconformably by the Vindhyan

Supergroup of rocks and further south by the Deccan Trap basalts.

Overlying the Hindoli Group of rocks and Mangalwar Complex with an unconformity occur

the next younger groups of rocks classified as the Rajpura-Dariba (subdivided into the Bhinder,

Malikhera, Dariba, Sindesar and Satdudhia Formations), Pur-Banera (classified into the Pur, Pansal,

Rewara, Tiranga and Samodi Formations), Jahazpur and Sawar Groups (subdivided into the Morhi

and the Ghatiali Formations) which are exposed in a series of isolated linear belts. All these

synformal metasedimentary basins/structures of Lower Proterozoic age occur in disjointed belts as

outliers and they are mostly composed of dolomite, marble, calc-gneiss, calcareous biotite schist,

graphite-kyanite-staurolite schist, garnetiferous mica schist, chert, banded ferruginous chert and

quartizite.

The BGC are devoid of mineralization except for the Rampura-Agucha zinc-lead deposits.

ARAVALLI-DELHI MOBILE BELTS

The Aravalli and Delhi mobile belts, also known as fold belts or shear belts, are the major

components of the western Indian Precambrian shield. These belts are metallogenically important

with copper, zinc and lead mineralization with gold, tin and tungsten at places.

The Aravalli-Delhi Province is composed of Proterozoic supracrustals sequences classified

as the Aravalli Supergroup (Early Proterozoic) and Delhi Supergroup (Early to Middle

Proterozoic). Metamorphic and structural parameters backed up by geochronological data have

32

clearly demonstrated that the BGC was a crystalline basement upon which the rocks of the

Proterozoic Aravalli and Delhi Supergroups were deposited. Besides, evidences of an unconformity

between the BGC and the overlying supracrustal suites have been widely proposed. The Delhi

Supergroup occurs in the form of two distinct fold belts, i.e., the North Delhi Fold Belt (NDFB) in

Alwar, Dausa, Jaipur, Bharatpur, Sikar and Jhunjhunu districts and the South Delhi Fold Belt

(SDFB) in Ajmer, Pali, Rajsamand, Udaipur and Sirohi distrcits. Recent mapping by GSI in the

Khetri area have identified and separated the Khetri fold belt (Khetri basin) from the NDFB by a

basement-cover sequence separable from the main NDFB of the Alwar-Bayana-Lalsot basin.

The rocks of the Aravalli Supergroup show an inverted V-shaped map pattern with an

arcuate disposition with the apex of the V located near Nathdwara. The width of the belt in the north

is about 40 km gradually fanning out to 150 km in the south in Gujarat state. The Aravalli

Supergroup shows two distinct ‘facies sequence’ indicating deep-sea and near-shore shelf

environments interpreted by many as eugeosynclinal-miogeosynclinal couple or as foreland-

hinterland duplex. The eastern part of the Supergroup is occupied by carbonate, conglomerate,

quartzite, phyllite and proximal greywacke representing shelf facies, whereas the western part of the

Supergroup has a totally carbonate free distal facies, with thin bands of arenite, representing deep-

water facies. Metabasic volcanics occur near the base of Aravalli Supergroup. The ultramafic rocks,

represented mainly by serpentinite and its metasomatic alteration products, occur in the Aravalli

Supergroup in the Rakhabdev-Dungarpur area and in the area between Jharol and Gogunda.

Intrusives within the Aravalli - Fold Belt include Jaisamand Granite, Ahar River Granite, Udaisagar

and Dakan Granite, Salumbar Granite, Lakapa Granite and Dudar Gneiss. The Aravalli Supergroup

has been subdivided into a tripartite lower Delwara Group, middle Debari Group and the upper

Jharol Group. The Delwara Group forms the basal part of the Aravalli Supergroup initiating with

basal conglomerate followed upwards by basic volcanics and associated pyroclastics, shallow marine

carbonate and carbonaceous sediments with local development of phosphatic and non-phosphatic

algal biostromes. The Debari Group is mainly composed of a thick sequence of conglomerate-

quartzite followed by dolomitic limestone and mica schist sequence. The Jharol Group is a thick

flysch-like accumulation in a distal trough represented by dominantly phyllite and intercalated

quartzite with minor carbonate rocks. The Debari and the Jharol Groups exposed in Rajasthan are

represented by the Lunavada (subdivided into Kalinjara, Wagidora and Kadana Formation) and the

Champaner Groups (subdivided into Lambia, Khandia, Narukot, Jaban, Shivrajpur, Rajgarh

Formation) in Gujarat state.

33

The Delhi Supergroup metasediments and related extrusive igneous rocks rest

unconformably or with a structural discordance over the Bhilwara Supergroup in the northeastern

and the central parts and over the Aravalli metasediments(?BGC) in the southwestern part of

Rajasthan and contiguous parts of Gujarat. The Delhi Supergroup forming the Delhi fold belt of

Rajasthan and Gujarat occurs in two sectors, viz., (1) in Alwar-Bayana-Khetri region, and (2) along

a narrow linear belt (Main Delhi Synclinorium of Heron, 1953) forming the rib of the Aravalli

mountain range in central and southwestern Rajasthan and northern Gujarat. The two sectors differ

in terms of lithofacies, structure, magmatism and metallogeny. The Khetri fold belt (Khetri basin)

has been identified and separated from the NDFB in the Khetri area by a basement-cover sequence

separable from the main NDFB of the Alwar-Bayana-Lalsot basin. The major stratigraphic units of

the Delhi Supergroup in the NDFB are the lower Raialo Group (mainly calcareous), the middle

Alwar Group (mainly areanaceous and sub-divided into Rajgarh, Kankwarhi and Pratapgarh

Formations in the Alwar-Jaipur basin and Jogipura, Badalgarh, Bayana and Damdama Formations in

the Bayana-Lalsot basin) and the upper Ajabgarh Group (mainly argillaceous constituting a lower

Kushalgarh Formation and an upper Weir Formation).

Five lithotectionic units, namely, Basantgarh, Barotiya, Sendra, Rajgarh and Bhim, have

been delineated from west to east, all of them together forming the SDFB in Rajasthan and Gujarat.

Tectonic discordance in the form of early ductile shear zones and superposed brittle-ductile shear

zones demarcate the boundary surfaces of each unit. Another group of rocks, namely, the Devgarh

Group, occurring east of the Bhim Group, is tentatively included in the eastern basin. The rock types

of the SDFB continue towards south into Gujarat.

The magmatic activity during the Meso- to Neoproterozoic times are represented by the

Sendra-Ambaji granite gneiss, Godhra granite gneiss, Erinpura Granite and Idar Granite. Several

important alkaline and other igneous complexes of Gujarat include the Barda Igneous Complex,

Alech Hill Complex, Osham Hill Complex, Mount Girnar Complex, Kanessara Igneous Complex,

Rajula Suite of rocks, Chamardi-Choghat Complex, Pavagarh Volcanic Complex, Phenai Mata

Complex, and Amba Dongar Complex.

The Rajpura-Dariba-Bethumni belt of polymetallic sulphide mineralization in Aravalli

Supergroup is rich in ores of zinc, lead, copper, silver, cadmium with minor gold and

molybdenum. The Lower Aravalli rocks of Udaisagar-Umra Belts, Udaipur district host uranium

and copper and phosporite deposits around Udaipur and Sallopat in Banswara district. The major

Pb-Zn reserves are hosted in Bhilwara-Aravalli Supergroup rocks in Agucha, Kayar-Ghughra,

34

Zawar, Rajpura-Dariba, Pur-Banera belts of Rajasthan with association of silver with Pb-Zn ores of

Zawar, Rajpura-Dariba, Bharak areas of Udaipur, Rajsamand and Bhilwara districts. The major

reserves of gold are from the Jagpura-Bhukia belt in Banswara district of Rajasthan. (Five parallel

lode bearing) zones extending over a total strike length of 2 km are delineated. Minor occurrences

are noted in Hinglaz Mata area (Dungarpur district) Ladera area (Jaipur district), and from associated

copper ores of the Khetri copper belt. Besides, gold is also noted to occur in Pindwara-Watera belt,

which is about 20 km long.

PURANA BASINS

Peninsular India witnessed the development of a number of large intracratonic/ pericratonic

platformal sedimentary basins, referred to as Purana (meaning ‘old’) basins by Holland (!907),

during late Palaeoproterozoic to Neoproterozoic period. The basins to the south of the Son-Narmada-

Tapti (SONATA) lineament occur as isolated basins, wheras the sediments to the north form a

continuous Vindhyan Basin. Most of these basins except Kaladgi-Bhima, have contact with the

mobile belts. This includes Cuddapah, Kaladgi-Bhima, Pakhal, Indravati, Abujhmar, Chhattisgarh

and Vindhyan.

Cuddapah Basin

The Cuddapah Basin, the southernmost intracratonic basin, is crescent shaped with its convex side

towards west and with a 450- km- long concave eastern thrusted contact. It lies above the Peninsular

Gneiss and the linear greenstone belts of Kadiri, Gadwal and Velligallu with a marked

nonconformity. The sedimentary fill is largely arenaceous and argillaceous with subordinate

calcareous and dolomitic components, intruded by sills and basaltic flows. Calcareous precipitates

dominate the Kurnool Group,deposited in a basin temponally and spatially overlapping the

Cuddapah Supergroup.

The Cuddapah Supergroup of rocks is subdivided into three groups, namely i) Papaghni

Group ii) Chitravati Group iii) Nallamalai Group and one formation, namely iv) Srisailam Quartzite

while Kurnool is retained as a separate single Group (Nagaraja Rao et al., 1987). The gencralised

stratigraphy is shown in Table 6.

35

Table 6: Stratigraphy of Cuddapah Supergroup and Kurnool Group

________________________________________________________________________

Major Rock Types Supergroup/Group

Nandyal Shale

Koilkuntla Limestone

Paniam Quartzite Kurnool Group

Owk Shale

Narji Limestone

Banganapalli Quartzite (diamoma bering conglomerate)

---------------------------------------------Unconformity--------------------------------------------

Srisailam Quartzite

---------------------------------------------Unconformity--------------------------------------------

Cumbum(Pullampet) Formation Nallamalai Group

Bairenkonda Nagari Quartzite

-------Angular unconformity-----

Gandikota Quartzite Cuddapah

Tadpatri Formation Chitravati Group Supergroup

Pulivendla Quartzite

--------Disconformity--------------

Vempalle Formation Papaghni Group

Gulcheru Quartzite

------------------------------------------Unconformity-----------------------------------------------

Archaean

This basin is historically famous for the world renowned diamonds like the Koh-i-noor, the

Great Moghul, the Hope and the Orloff identified in the kimberlite diatremes of EDC at Wajrakarur

in Anantapur district of Andhra Pradesh and Narayanpet in Mahbhubnagar district of Andhra

Pradesh and lamproite dykes at Chelima-Zangamrajupalle and Krishna lamproite fields. Basemetal

mineral deposits are known in the Cumbum Formation, Vempalle and Tadpatri Formations spread

in Agnigundala, Zangamrajupalle-Varikunta, Rayavaram-Chinavani-Palle, and Gani-Kalva and

Pulivendla belts. The largest barite deposit in the world with a reserve of 74 million tonne is

located in Mangampeta in Cuddapah district in the Pullampet Shale of the Cuddapah Supergroup.

36

Besides, this basin has huge reserves of cement-grade limestone in the Narji limestone in Kurnool

and Palnad subbasins; chrysotile variety of asbestos mined in the Pulivendla serpentinised belt and

phosphorite occurrences in Tadpatri, Cumbum Formations and Srisailam Quartzites of Cuddapah

Supergroup.

Kaladgi and Badami basin

The Kaladgi and Badami sediments, exposed in northwestern Karnataka extending to South-Western

Maharashtra, represent intracratonic basins occurring above the Archaean Dharwar greenstones with

a nonconformity and partly covered by the uppermost cretaceous Tertiary Deccan Traps to its north

and west.The sediments consist of orthoquartzite-argillite-carbonate association without volcanics

and are least metamorphosed and deformed..

Cement-grade limestone of Bagalkot, haematite iron ore occurrences in Kerkalmati and

usage of Kerur arenites as dimensional stone are the mineral resources found in these platformal

sediments.

Bhima Basin

This is the smallest and youngest of the Purana basins located in Karnataka and Andhra Pradesh

overlying Archaean basement rocks and covered by Deccan Traps and consists of clastic sediments

and limestone.

Mineral potential in the sediments of this basin includes cement-grade limestone, use of

limestone as dimensional stone, nodules or layers of barytes, and phosphorite within shale.

Pakhal Basin

The Proterozoic Pakhal Basin extends in NW- SE direction for 350 km along the Pranhita –

Godavari Valley from Andhra Pradesh in the SE to Maharashtra in the NW. The sediments of the

basin occur as two mutually parallel belts, with about 40- km- wide stretch of Gondwana sediments

separating them. The southwestern belt extends from Khammam in the southeast to Adilabad in the

northwest and extends further into Maharashtra State. The northeastern belt extends from a little

north of Bhadrachalam in the southeast, to a little beyond Chanda (Maharashtra) in the northwest.

The Pakhal Basin includes unmetamorphosed (except locally) and unfossiliferous sediments of the

Pakhal Supergroup, unconformably overlain by the rocks of Penganga Group and Sullavai

Sandstone.The Pakhal Supergroup correlatable to the Cuddapah Supergroup rest on the Archaean

Gneiss Complex. The Penganga Group of rocks is correlated with the rocks of Kurnool Group.

37

Conglomerate, arkose, shale, dolomite and quartzite characterize the Pakhals, arkose and limestone

the Penganga, and sandstone the Sullavai.

Mineral resources includes streaks and disseminations of copper ores (chalcopyrite) in

dolomite, shale or quartzite (with old workings) near Venkatapuram, Sarkar Ragaboyanagudem and

Manikaran villages; barytes at Sripuram, Cheruvapuram and Pochavaram, clay at Marigundem,

cement- and flux- grade limestone from Putunur, Cherla, and Madharam shales and west of Gunjeda;

haematite iron ore from the ferruginous grits and quartzites extending from Bayyaram to Nilavanch;

quartzite of this basin are used for refractory purposes in ferrosilicon industry; dimensional stones in

Sullavai sandstone and Jakkaram arkose have been quarried from Chavai, Ramagundam and

Amarapad areas.

Indravati Basin

The Proterozoic Indravati Basin in the Bastar Craton extends for 9000 km2 revealing flat- lying

sandstone, shale, limestone and stromatolitic dolomite above the Archaean basement. Kimberlite -

clan rocks were discovered in this basin in Tokapal Kimberlite Field. The rocks of this basin are

classified into three formations, of which the middle Kanger Formation represents a deep

intracratonic basinal system with deposition of lime-mud used in cement and flux.

Ampani Outlier An outlier, 220 km2 in extent, located west of Ampani reveals a 280- m- thick sequence of polymict

conglomerate, subarkosic sandstone, siltstone and shale with calcareous sediments.This incomplete

sequence has been correlated with the basal stage of the Indravati-Chhattisgarh Basin and Upper

Kurnool equivalent of Cuddapah Basin (Balakrishnan and Babu, 1987).

Abujhmar Basin

The Abujhmar Plateau of Bastar district, Chhattisgarh State, exposes the sediments in a 3000 km2

rectilinear basin trending NNW-SSE overlying Bengpal, Bailadila and Nandgaon Groups. This basin

is bounded on the west by the NNE-SSW- trending Kotri Lineament, on the south by the WNW-

ESE trending lineament and the Indravati river, and the BIF of Bailadila Group underlie in the north.

The sediments are metamorphosed locally, and carry a pile of lavas and intruded by dykes and sills.

They are correlated with the Cuddapah Basin and Dhanjori Group of south Singhbhum and

considered younger to Nandgaon Volcanics.

38

Chhatisgarh Basin

The Chhattisgarh Basin covers an area of 33,000 km2 in the Chhattisgarh State. It has a lower

arenaceous and an upper argillaceous-calcareous sedimentary sequence and overlies the Archaean

granite gneiss and supracrustals of Chilpi and Sonakhan Groups. The isolated basins of Indravati,

Ampani and others are considered to have been part of a Greater Chhattisgarh Basin. They have tuffs

and pyroclastics and had a rift history. The Chhattisgarh Basin is correlated with Lower Vindhyan,

Indravati, Kurnool and Bhima basins of Peninsular India.

Recent exploration for diamond in Pairi-Khariar basin has resulted in the discovery of five

kimberlite pipes, two of which are diamondiferous. In this Mainpur Kimberlite Field, more than

forty mineral indicator zones were detected by stream sediment sampling.

Vindhyan Supergroup

The Vindhyan Supergroup is 1 to 4 km thick and extends for about 60,000 km2 in a curvilinear basin

surrounding the Bundelkhand Granite massif and bounded by the Son-Narmada-Tapti (SONATA)

Lineament in the south, the Great Boundary Fault (GBF) of Rajasthan in the west and Ganga

alluvium to its north. A small outlier, the Bhaunathpur Basin of Vindhyan Formation is situated

south of Son River in Jharkhand. It is correlated with the Marwar Supergroup of Trans-Aravalli

region of Rajasthan. Though the basin to the north of the SONATA and east of GBF is generally

depicted as Vindhyan, it is represented in Himalaya by the Hazara Slate, Attock Slates, Simla Slate,

Haimanta Group and the Salt Range beds. Vindhyan sedimentation commenced later than the

Cuddapah Basin at around 1400 Ma and continued to the end of the Proterozoic to terminate before

Cambrian (≈ 570 Ma). Several works have been carried out in this basin in the last 150 years in

search of diamonds, limestone and dimensional stones.

The Vindhyan Supergroup has been classified into four groups Semri, Kaimur, Rewa, and

Bhander – and twenty-three formations.

The Vindhyan basin is a major storehouse for limestone, diamonds, glass sands and building

stones. Occurrence of copper, lead, zinc mineralization and native sulphur are noted at Semri in

Bundelkhand; reported occurrence of galena from Narsinghpur; pyrites from Amjhor, Banjari and

Rohtas Fort; dolomitic limestone, laterite, bauxite, ochre, clay and potash are known and explored to

a varying degree.

39

Trans-Aravalli Basins

The Proterozoic-Mesozoic basins in the terrain west of the Aravalli-Delhi mobile belt are known as

the Trans-Aravalli, bounded in the south by the Satpura trend and Son-Narmada rift and separated

from the Himalayan belt in the north by the Lahore-Delhi shallow ridge. Extensive mafic and

ultramafic rocks separate this Indus Basin from the Baluchistan Basin. The shelf of Rajasthan is

connected to that of Gujarat with a ridge known as the Jaisalmer Mari Arch with the NW-SE Kanoi

Fault truncating the Arch in Thar Desert. The Kutch Basin has Nagar Parkar Massif, Rann of Kutch

depression and Mainland High. The Kathiawar uplift to the south and Radhanpur Barmer Arch to the

east form boundaries.

The Marwar Supergroup and the Mesozoic basins occurring in Rajasthan are correlated with the

Vindhyan Supergroup. The Upper Proterozoic - Early Cambrian evaporite basin of 50,000km2 area,

with the Hanseran Evaporite Group and Nagaur Group constituting the Marwar Supergroup, occurs

in Trans-Aravalli Vindhyans, below 300m of Quaternary sediments in the semi-desert areas of

Punjab, Haryana and Rajasthan extending beyond to the Salt Range occurrences. The evaporite

sequence is 100-160m thick with halite, potassic salts, dolomite/dolomitic limestone,

anhydrite/gypsum and clay.

GONDWANA BASINS

The Gondwana sedimentation which was commenced in Late Carboniferous after the Hercynian

orogeny (mid-Carboniferous), during which almost whole of land surface is represented by

nondeposition except the Tethyan margins. Fall in sea level has been attributed to the glacio-eustatic

drawdown during the accumulation of ice on uplifted high grounds.

During late Carboniferous, the Gondwana supercontinent rotated clockwise almost 180o

bringing the eastern and northern margin of Gondwanaland from equatorial position to high southern

palaeolatitude resulting in widespread glacio-marine and rift-related sedimentation in many of the

Gondwana basins during early Permian (Fig.5, Acharyya, 1998).

Most part of Talchir sequence is unfossiliferous and the only fossil-bearing horizon within

Talchir is at the top part associated with grey shale and limestone band that indicate a Sakmarian

age. There is more than 500m thick Talchir sequence present in many basins. Recent borehole data

by ONGC from west coast show the presence of recycled Upper Carboniferous palynomorphs,

which is supposed to have been leaked from the Gondwana sediments underlying the Deccan Trap.

Considering the stratigraphic position of Sakmarian fossil prompt us visualising the remote

40

possibility of presence of some Upper Carboniferous sediments within the basal part of Talchir

Formation in the deeper part of some basins.

Palynoevents in Indian Gondwanas correlatable to the multiple marine transgressions caused by

deglaciation covered part of Palaeo-Tethyan and Panthalassan margins and extended deep into the

plate interior in almost all the continents except Antarctica during Sakmarian. Marine Eurydesma

and Deltopecten fauna is found in India (both in peninsular and extrapeninsular basins)

(Sinor,1922;Ghosh,1954; Dutt1965; Reed, 1932; Sahni & Srivastava,1956; Mishra et al.,1961;

Dickins & Shah,1977). Two distinct groups of marine fossils associated with this transgression were

initially reported from Upper part of Talchir Formation in Daltonganj, Manendragarh, Umaria, and

Badhaura. Based on their recent finding of Eurydesma fauna in western part of Satpura basin Ghosh

(2003) proposed a single marine front from east and considered the somewhat different fossil

assemblage of Umaria as due to some local bathymetric reasons. He has excluded the fossils of

Badhaura from the Gondwana gamut.

During Karharbari Formation which is represented by coarse clastic dominated proximal sequence

where fluvial processes dominate. e.g. presence of conglomerate at the contact of Barakar and

Karharbari formation is quite common in many coalfields (e.g. Talchir, Ib Vally, Raniganj,

Bisrampur, North Karanpura. A coarsening up sequence, starting with the shale facies at the top of

Talchir Formation and ending at the top of Karharbari Formation is quite distinct. It may indicate

the lowering of base level related to regressive phase of the sea. Scarcity of plant fossils might

indicate that a periglacial environment persisted during the deposition of Karharbari Formation.

However, the environment was conducive enough to promote sufficient growth of vegetation

resulting in deposition of coal particularly where fluvial system was established.

Deposition of coal bearing Permian Barakar & Raniganj formations under post glacial warmer

condition in a fault-controlled subbasinal structure is quite distinct with enlargement of basinal area,

which is more conspicuous in Damodar valley basin belt.

The extinction of invertebrate at Palaeozoic & Mesozoic boundary is considered globally,

though among the taxa Arthopods do not record any sharp break while ostracodes, Cochostracan &

conodonts straddle this boundary. Where as land plants started to diversify their ecological niches

much later than the marine invertebrates. The plants were more dependent on the climatic zonality and

related regional lithogenetic variability while invertebrates were more acclimatic, global but

determined by specifics of habit. During the transition of Permo-Triassic boundary paleoenvironment

might brought drastic lithological changes in other Gondwana continents , but exclusively in the

41

Indian continent, it can be stated that" a rotation/ movement of the Indian Gondwana during Permian

period was halted at the P-T Boundary and thereby some of the Lithologenetic Belt transgressed in

Triassic. Hence, favouring the Plant’s life to also transgress.

The fossil spores & pollens are considered to reflect the past plant life accurately because of

Taphonomic factors & hence episodic changes in lineages of presence of a short interval of the

temporal scale in the Stratigraphy are well documented by the study of Sporae Dispersae. It is also

well known in the Lower Permian, the climate was too favourable for triggering the rampant rise of the

glossopteris flora , giving rise thereby to form huge coal deposits in Gondwana Basins. Therefore, it

is opined that Palynology is the best suited tool for Gondwana Sequence because of their dominantly

Non-marine depositional environment. More over, Palaeo-climate and the nature of precursor

vegetal matter are the prime determinants for formation of different type of heterolithic coal in Indian

Gondwana Basins. Since the introduction of the term"Gondwana" by Sir Medlicott (1872) no serious

attempt was made to define the “Gondwana” into litho. Bio or chrono stratigraphic divisions and

thereby to correlate them.

Krishnan and Jacob (1956) had made an earliest recorded attempt to build up the International

Stratigraphic Laxicon of Gondwana. Subsequently, in 1971 need of Stratigraphic standardization was

actually conceived by adoption of a standard code by the Committee on Stratigraphic Nomenclature

of India( Geo.Surv.Ind.Misc.Pub. no-20,1971) and which was ratified by the International Sub-

Committee on Stratigraphic Classification (ISSC) in 1972. There after no serious attempt was made to

re-classify/ re-build the Gondwana Stratigraphy.

The different Lithostratigraphic marker horizons of some selective Coalfields have

already been prepared by the CW, GSI while carrying out 50 K Map compilation work, with the

different Palyno-event-marker zones.

General geological sequence of the respective coalfields is enclosed in Annexure-I

It has been found that marine flooding surfaces within the Permian can be used to define

sequence boundaries as well as time slots for dealing with the stratigraphy of the Gondwana Period.

On this basis, the Gondwana lithosequences of different basins within India, could be grouped

under specific time slots which may serve as powerful tools to arrive at a reasonable correlation

framework, These time planes can be recognized as distinctive Gondwanide events.

Plant fossils, so far reported from different Gondwana Basins are very wide ranging thus

helping in no way to ascertain any specific age. Palynological data has its own constraints and till date

is at best can be considered as corroborative. Vertebrate fossils are few in India, excepting few instances

42

and in most cases are not very helpful in assigning pinpoint age. Moreover, any radiometric age

data, for any of the formation in Gondwana basins of India is not available. Based on available

tectonic, sedimentological, palaeontological and palaeomagnetic data total span of deposition of the

Gondwana Sequence in India was considered to be initiated in Late Carboniferous after the Hercynian

orogeny (mid-Carboniferous), by glaciations during which almost whole of land surface was

represented by non-deposition except the Tethyan margins. Fall in sea level has been attributed to the

glacio-eustatic drawdown during the accumulation of ice on uplifted high grounds (Veevers and

Powell, 1987), which was subsequently affected by the severe erosion ,causing little sedimentation

in the low lying peripheral parts in the north and south of Gondwanaland (Ilummedin and other

basins of Africa in the North and the foreland basins, Parana-Karoo-Falkland-Elsworth-Bowen. in the

south where Early Carboniferous/ Devonian rocks are preserved)and at places the sedimentary

packages were totally eroded down even to Precambrian level.

Abundance of coal and carbonaceous materials in the immediately succeeding Permian sediments also

suggest an ameliorated humid climate and which was subsequently fluctuated gradually with time

along with some what rifting of different basins.

The end of deposition is considered as the product of major rifting activities as a result of Pangean

break-up. Termination of Gondwana sedimentary deposition in India is considered to be terminated by

the deposition of Bagra, Chikiala formations during early Cretaceous with the outpouring of Rajmahal

Group of volcanics around 110-118 Ma, where as the Deccan Traps erupted around 65 Ma.

Distensional tectonics, related to the movement of the Gondwana continents during Cretaceous, was

accompanied by voluminous eruption of tholeiitic flood basalt and emplacement of sills and dykes.

Igneous activity within the Gondwana basins of peninsular India is represented by dykes/sills of

dolerite/basalt and lamprophyre and basic flows as found in many coalfields. Although there were

differences in opinion regarding the actual age of these intrusive/effusive, it is more or less accepted

that there are two major events of volcanic activity which can be correlated with the Rajmahal Trap

and the Deccan Trap. Moreover in most of the cases these intrusives are found to follow the

preexisting faults and never displaced by them.

Trachyandesite porphyry is found to occur along the southern main boundary fault of

Raigarh Coalfield, Mahanadi Valley Basin (Chakraborty, 1999).The rock is intrusive within the

basement granite and also directly in contact with the Talchir Formation.

43

Almost all the coalfields/basins of the Gondwana contain dykes/sills of dolerite/basalt of

varying dimensions except the Talcher and Ib coalfields of Mahanadi Basin and Godavari Valley

Basin. The origin of these intrusives have been linked with Deccan/Rajmahal Trap.

Rajmahal Trap exposed along the western margin of Bengal Basin covering the Gondwana

beds of Damodar-Rajmahal Gondwana basins. Volcanic flows in Meghalaya, better known as Sylhet

Trap, are considered to be the equivalents of Rajmahal Trap.

Lamprophyre dykes and sills occurring in Indian Gondwana form a consanguinous suite

ranging from ultrabasic mica peridotite to micro-syenite assemblages. They are mainly reported

from the Damodar Valley Basin close to Rajmahal and the preponderance diminishes towards west

beyond Bokaro coalfield. They have a preference for coal seams and invade them at coal-sandstone

interface.

Rajahmundry Trap occupies about 35 sq km in Rajahmundry area at the north western fringe

of Krishna Godavari Basin. Deep drilling by ONGC revealed presence of older trap equivalent to

Rajmahal Trap below the Rajahmundry Trap (Biswas,1996).The upper flow (Rajahmundry Trap)

overlies the Maastrichtian –Campanian sediments while the lower flow (Rajmahal equivalent)

occurs below the Albian sediments

Tripartite Classification of Gondwana exclusively on the basis of floral remains (e.g.-Lower-

Glossopteris, Middle -Dicrodium & Upper-Pterophyllum) is more acceptable and seems valid. The

Middle Gondwana is also characterized by the record ofTriassic Reptiles. Amphibians and Estheriids.

However, it is necessary to follow a uniform standard/code in conformity with the

International practice while doing interbasinal correlation of different Gondwana basins of Peninsular

India. As in widely separated Gondwana basins closely related Unit/Member/Formation so far

defined are encountered with gross lithofacies variation along with diversified' fossil record, this

Lacuna/Paradox still persists.

The lithological/ sedimentation breaks, as depicted were not synchronous throughout and

varied from one basin to basin, e.g. in the type area of Kamthi, there is a significant phase of pre-

Kamthi erosion, but in other part it is gradual. Thus the entire lower Gondwana sedimentation (as

mentioned in the Annexur-I ) reflect both gradual/ conformable ( e.g Mahanadi Basin) and

abrupt/sharp relation by the presence of paleosol zones( e.g. South Rewa Basin). To sort out these

paradoxes, the attempt has been made to define the entire gamout of Gondwana sedimentation by

Palyno-Events/ sequences. Indian Permian coal deposits of Gondwana Sequence are well known for

their energy resources and to varying degrees for metallurgical purposes. Besides, recently it assumed

44

significance repository of coal bed methane. Refractory clays are also present within Permian

sediments. It was envisaged that an integral part of the project would be to locate new virgin

potential area, particularly for coal and also for other commodities like refractor clay and uranium.

.

Age Damodar-Koel

Rajmahal Son Sat pura Mahanadi Godavari

Early Cret

Bansa/Chandia JabalpurBagra

Chikiala

GangapurLate Jura-Early Cret

Dubrajpur

Mid JurassicKota

Early Jurassic

Late Triassic

Supra-Panchet Kamthi

(undifferentiated)

Dharmaram

Maleri

late Mid. Triassic

Mid. Pachmarhi/ Denwa

Bhimaram

early Mid Triassic

Lr. Pachmarhi

Yerrapalli

Up. Kamthi

Early Triassic

late Late Perm.

Panchet

Raniganj

Pali

Raniganj Bijori Raniganj

Mid. Kamthi

Lr. Kamthi

early Late Perm. Barren Measures

Barren Measures

Motur Barren Measures

Barren Measures

late Early Perm. Barakar Barakar Barakar Barakar Barakar Barakar

early Early Perm. Talchir Talchir Talchir Talchir Talchir Talchir

Parsora

STRATIGRAPHIC CORRELATION OF GONDWANA SEQUENCE OF P ENINSULAR INDSTRATIGRAPHIC CORRELATION OF GONDWANA SEQUENCE OF P ENINSULAR IND IAIA

(Tiki)

Up. Pachmarhi

Panchet

DECCAN TRAP (CONTINENTAL BASALT) VOLCANISM

Deccan Traps, the second most extensive geological formation in Peninsular India occupies major

part (≈75%) of the Maharashtra State. It extends from Kutch in Gujarat in the west to as far as

Belgaum in Karnataka in the south to Rajamundry in Andhra Pradesh in the southeast to Sirguja in

Madhya Pradesh in the east to a few remnants in the bauxite laterites in Ranchi-Palamau in

Jharkhand. They comprise tholeiitic flood basalts with some picrites. The traps rest on Upper

Cretaceous strata. The isotopic ages indicate a 69 to 64 Ma period for the eruption with peak around

a narrow span of 1 Ma around 65 Ma. The intertrappean fossils are Upper Cretaceous to Lower

Eocene in age. The Bagh beds in lower Narmada Valley and the Lametas of Jabalpur constitute

important infratrappean datums. Native copper has been reported from the Deccan basalts near

45

Handigund (16°25': 75°05'), Belgaum district, Karnataka. Magnetite, haematite and maghemite are

other associated minerals.

INDO-GANGETIC – BRAHMAPUTRA PLAIN

Indo-Gangetic Plain extends from Aravalli - Delhi ridge in the west to the Rajmahal hills in the east.

Indo-Gangetic (Ganga) Plain occupies the major part of the States of Haryana and Punjab with the

upper and part of the middle part of the Ganga Plain in Uttar Pradesh. The rest of the middle part of

the Ganga Plain falls in Bihar and the terminal part comes in West Bengal where the Bhagirathi river

Plains to Indo-Bangladesh border in the east. The Brahmaputra Plains cover the whole of Assam

Plains. The Ganga Plain is a part of the 'Indo - Gangetic Foreland Basin'. This foreland basin is

developed during upper Tertiary and is closely related to the birth and rise of Himalaya.

This Plain exposes fluvial sediments of Quaternary period. Subsurface exploration,

particularly for petroleum, has revealed that a thick pile of alluvium rests over the Siwalik sequence

of Neogene - Early Pleistocene period. This alluvium constitutes sedimentary fill of the Ganga

Foredeep – the youngest foreland basin. The foredeep sediments extend much to the south of the

depositional boundary of the Siwalik Foredeep and rest over the Cratonic rocks of Precambrian

period. The thickness of the alluvium increases towards north and is maximum adjacent to the Foot

Hill Fault (FHF) that marks the northern limit of the Ganga Foredeep Basin.

EXTRA-PENINSULAR REGION

The Himalayan mountain chain constituting the Extra- Peninsular Region resulted due to

continent - continent collision process during Tertiary period. The evolution of the Himalaya – the

largest of the mountain ranges – can be described in a simple way (Balasubrahmanyan, 2006). A sea

named variously as the Tethys or Purana evolved to the north of the Indian Shield providing the base

for Lesser Himalaya characteristics at 2000 Ma ago. The withdrawal of this sea marks the beginning

and the breakway of Tibetan microcontinent and development of Tethys Himalaya. During the

tectonically unstable period between Permian and Cretaceous, submarine topography changed with

formation of volcanic chain of islands. The movement of Indian plate over 7000 km to the north

subsequent to the breaking from Africa-Madagascar resulted in notable changes in the geography of

Asia, with Deccan Trap volcanism and formation of the Indo-Tsangpo suture welding India with the

rest of Asia. The contemporary deformation and metamorphism resulted in initiation of major crustal

46

fractures of the Main Central Thrust and Main Boundary Thrust and evolution of the Siwalik basin

and leucogranite intrusions of Himalaya.

The Sub-Himalaya, Lesser Himalaya, Higher Himalaya and the Trans-Himalaya are the

morphotectonic and lithostratigraphic zones from south to north.

(i) The Sub-Himalaya lies in the extreme south and separated from the northern Lesser Himalaya by

Main Boundary Thrust. This is a 10- to 50- km- wide zone immediately north of the Ganga-

Brahmaputra alluvium of Miocene to Tertiary age. The Molasse belt in Siwalik and other foothills

with the Main Frontal Thrust (MFT) limit the orogenic margins of the Himalaya against the Ganga

Brahmaputra Plains.This is constituted of Early Tertiary (Subathu-Dagshai-Kasauli-Chunabati-

Yinkiong) and Late Tertiary (Siwalik) rocks.

There are two belts of Sub-Himalayan Tertiary coalfields trending WNW-ESE in Jammu-

Kashmir.

(ii) The Lesser Himalaya is a 60- to 80- km- wide zone stretching between the Main Boundary

Thrust(MBT) in the south and the Main Central Thrust (MCT) in the north and is made up of

autochthonous sedimentaries of Precambrian (Shali-Deoban-Tejam belt) and Palaeozoic-Mesozoic

age (Krol-Tal-Subathu) thrust overlain by epizonal metamorphic(Chail-Ramgarh) and mesozonal

metamorphic(Jutogh-Munsiari) thrust sheets. At places, the crystalline thrust sheets have been

removed by deep erosion in river valleys exposing the autochthonous sedimentaries of Shali-

Degboon-Tejam belt as tectonic windows such as Kishtwar window, Kulu-Rampur window, Shali

window, Chareota window, etc. It has Riphean to Palaeozoic platform sediments with some

characters of the Peninsular Shield and is overlain by thrust sheets and crystalline nappes.

(iii) The Higher Himalaya is a 10- to 15- km- wide zone of Precambrian crystallines exhumed along

the greatest uplifted terrain with highest peaks of Himalaya (NunKun, Leopargial, Kedarnath,

Badrinath, Nanda Devi, Api, Dhaulagiri, Everest, Kanchanjunga, etc.), made up of katazonal

metamorphics (kyanite-sillimanite gneisses, migmatites and calc-silicates) and intruded by granites

some of which are of Tertiary age. Metamorphic crystalline sequences of the Higher Himalaya are

overlain unconformably by predominantly marine sediments of Paleozoic and Mesozoic age in parts

of Kashmir, Spiti-Zanskar (H.P.) and Kumaon Garhwal (U.P.) in the Higher Himalayan Tethyan

basins. Sporadic occurrences of bedded barite and polymetallic sulphide mineralisation have been

reported from Garbyang and Ralam Formations of Uttar Pradesh.

(iv)The Tethys Himalaya extends to the south of the Trans - Himalayan ranges and comprises

predominantly fossiliferous sediments ranging in age from Late Proterozoic to Eocene. This belt

47

bears an unconformable or faulted contact with the Higher Himalaya, the basement to the Tethyan

sedimentary sequence.

Tethyan sequence containing fossiliferous Palaeozoic rocks is well exposed in Garhwal and

Kumaon region, Kinnaur basin, Lahul and Spiti in Himachal Himalaya, as Lachi, So Lamo

Formation in Sikkim Himalaya. The Martoli Group, about 4500 m thick, consisting of phyllites,

mica schist, quartzite, with lenticles of marble in the upper part overlies the Central Crystallines with

a tectonic contact. This Group is also intruded by granite, pegmatite and quartz veins. Earlier

workers considered it to be of Precambrian age, forming the basement for the fossiliferous

Palaeozoic sequence.

(v) Trans - Himalaya, lies to the north of the Indus Suture Zone in Ladakh region and extends

eastward into Tibet. It is characterized by a huge discontinuous, nearly 2600-km-long batholith

comprising rocks ranging from gabbro to granite. The Trans-Himalayan lithotectonic units north of

the Indus Suture Zone includes the Ladakh batholith/magmatic arc (Ladakh Granitoid Complex),

Shyok Suture Zone, Karakoram batholith/magmatic arc (KGC) and the Karakoram Supergroup and

the Tso Morari Crystalline Complex This zone represents the lithounits brought together during the

Eocene collision of North Indian plate elements with the trailing edge of Eurasian plate, i.e. the

Lhasa block. The Indus-Tsangpo suture zone (ITSZ) extends as a linear belt all along the Indus-

Tsangpo valleys between the Higher Himalaya to the south and Karakorum – Gangdse ranges to the

north. It is best exposed for about 500 km in the Ladakh region and is referred as the Indus suture

zone. This narrow linear belt comprises two units, tectonically juxtaposed, one including basal

ophiolite followed by basic volcanics and flyschoid sediments and another by ophiolitic melange.

This zone is separated from the Tethys Himalaya by Dras Thrust in the south and from the

Karakorum Tethys and Granitoid Complex by the Shyok Thrust in the north.

Two belts of granitoid complexes lie in the Trans-Himalayan region of Ladakh. The northern

belt called the Karakorum Granitoid Complex, lies to the north of the Indus Suture Zone and

intrudes the Late Palaeozoic metamorphites. The southern belt called the Ladakh Granitoid Complex

intrudes the Upper Cretaceous-Eocene rocks of the Indus Suture Zone. Karakorum Granitoid

Complex (KGC) is a linear batholithic body, about 20 km wide and 150 km long stretching NW-SE

and occupies higher peaks of the Eastern Karakorum and the Pangong mountains.This granitoid belt

extends into the Western Karakorum across Baura range, Hispar, Biafo to the west of Baltaro.

The ITSZ branches into two thrusts―Main Mantle and Main Karakorum―with rocks in

between comprising the rocks of the Kohistan Zone. Along the Karakorum Highway, in a north to

48

south section, the K2 consists of Yasin flyschoid sediments, Chitra volcanics, the Kohistan-Ladakh

batholith, the Chilas Layered Complex and the Jijal Complex.

Arunachal Himalaya

The correlation of Arunachal geology with the other parts of Himalaya is a complex job

fraught with uncertaintes. Hence the geology has been dicussed separately following broad

Himalayan classification. Bomdila Group comprise a sequence of low-to medium-grade

metasediments with associated gneisses and younger granitoids occupying expansive areas

throughout the lesser Himalaya of Arunachal Pradesh from Siang valley in the east to Kameng

valley and Bhutan in the west. Similar sequence of rocks is known as Ithun Formation and Rikor

Group in Dibang valley and Lohit valley areas. Tilung Formation and Namdhapa Crystalline

Complex are also included in this group. The granitic and gneissic rocks of Bomdila Group are

garnet bearing and highly deformed and mylonitised under ductile domains. The ultramafic bodies

intruding the para-metamorphites of Ithun Formation in Myodia area have minor amounts of

Platinum Group of elements.The lesser Himalayan zones of Arunachal Pradesh are classified into

two parts: (i) The Kameng, Subansisri and Siang Himalaya and (ii) Lohit Himalayan). In Kameng-

Subansisri-Siag Himalaya, the Tertiaries, Gondwana, Bichom Group and the metamorphic rocks are

regionally disposed in ENE-WSW to NE-SW trend. In the lower Himalayan region NNE-SSW to N-

S trends are superimposed on the above regional trends. In the Lohit Himalayas the rocks exposed

belong to Bomdila Group, Tenga and Miri Formations and Upper Siwaliks. A diorite-granodiorite

Complex considered to be of Late Paleozoic age is also exposed in Lohit Himalayas .

From west to east the Bomdila Group is overlain by the Dirang Formation till east of

Subansiri River. In Siyom and Siang River sections, Sela Group of Higher Himalaya comprising

high-grade schists, migmatites and gneisses overlie the Dirang schists in the higher Himalaya of

Kameng district of Arunachal. Rocks of khondalite affinity of Southern Granulite Belt are noticed in

the form of graphite-bearing quartz-biotite-sillimanite schists in the Simi Member of Khetabari

Formation of Precambrian age in Upper Subansiri district.The NNW-SSE Trans-Himalayan Belt of

Arunachal Pradesh exposed in the Upper Siang, Upper Dibang and Lohit valley areas is juxtaposed

against the rocks of the Himalayan belt along the Tidding Suture. The Trans-Himalayan belt

comprises two distinct lithopackages viz, i) the suture package comprising Yang Sang Chu

Formation and Tidding Formation with serpentinites, and metavolcanics and ii) the Lohit Granitoid

Complex and the Etalin Formation, the latter occurring as restites. The total assemblage of the suture

package resembles an ophiolitic melange.

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The Upper Tertiary (Mio-Pliocene) molassic sediments constituting the Siwalik Group

occurs as a linear belt along the foothills of Arunachal Pradesh extending from Bhutan to just east of

Pasighat where it is overlapped by the alluvium. However, it re-appears on the left bank of Dibang

River where it is tectonically overlain by the rocks of the Bomdila Group along the Roing Fault,

which is considered as the continuation of the Mishimi Thrust. The Siwalik Group is bounded to the

north by the Main Boundary Fault along which the Pre-Tertiary sequence has been brought over and

its southern limit with the alluvium of the Brahmaputra River. The Tertiary sequence of Arunachal

Pradesh is classified into Dafla, Subansiri and Kimin Formations broadly corresponding to the

Lower, Middle and Upper sub-divisions of the Siwalik Group of northwestern Himalaya and are

considered as the northward extension of the Tertiary sequence of Assam.

Massive and vesicular basaltic and andesitic rocks of Abor volcanics of Phanerozoic age are

associated with Miri Quartzites. The rocks overlying the Miri Quartzite are cherts, shales, black

shales and carbonates, developed in the western flank of Subansiri valley, Igo valley, Basar-Along

areas and in Siang valley areas in Arunachal Pradesh.

CENOZOIC FORMATIONS OF THE SHIELD

In the southern peninsular India, the Tertiary sequence is well developed. In Tamil Nadu, the

Ariyalur Group of Upper Cretaceous is overlain conformably by a sequence of limestone, calcareous

shale/mud, clay and sandstone of Paleocene age. This sequence is named as Niniyur Formation in

the Tiruchirapalli sub-basin with its equivalent in Pondicherry sub-basin as Karasur Formation.

Rocks of Mio-Pliocene age (early Neogene) termed as Cuddalore Formation occupy a large area

along the coast overlapping the Mesozoic sediments and at places over the crystalline basement.

Cuddalore Formation contains large quantities of fossil wood around Tiruvakkarai in Villupuram

District which have been declared and maintained as a National Fossil Wood Park by GSI. Thick

lignite beds at Neyveli in Cuddalore District were originally thought to belong to Cuddalore

Formation.

In the coastal tract of Tuticorin and Tirunelveli districts, the Mio-Pliocene group is

represented by fine-grained limestone and gritty sandstone intercalated with pebble beds, found to

overlie the Archaean unconformably and below the Recent formations. These are referred to as

Panamparai Sandstone. Along the west coast of Kanyakumari district, a sequence of sandstone and

clay with thin lignite seams is recorded. These are correlated to Warkhali beds of Mio-Pliocene age

of south Kerala and are similar to Cuddalore Formation. Beds of shelly limestone, clay and grit,

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intercalated with lignite layers are recognised in the southern coastal tracts of South Kanara district;

these quasi-indurated sequences of sediments are considered to be the extension of Warkhali Beds

occupying further south of Kerala. These Miocene beds, about 20 m thick and unconformably

overlying the weathered gneisses and charnockites are capped by laterites.

In the East Coast, the Tertiary rocks are represented by algal limestone in subcrops at

Debagram, Jaguli, Jalangi and parts of Medinipur, Bankura, Bardhaman and Birbhum

Districts of West Bengal. Recently, Distichoplax biserialis, an index fossil of the Palaeocene age

was recognized in the subcrop samples from boreholes of ONGC .

During early Eocene period, upheaval confined along a narrow NE-SW-trending track

resulted in intrusion of ultramafic cumulates and volcanic members resulting in the formation of the

Ophiolite suite of rocks comprising tectonised peridotite, cumulate ultramafics including dunite,

peridotites and pyroxenites that are exposed in the eastern fringe of North-Eastern Region for about

200 km from Moreh in Manipur in south to north-east of Chiphur in Nagaland in north. Mid-Eocene

sediment is represented by polymictic conglomerate, tuffaceous greywacke and lithic feldspathic

arenite. Chromite is the main economic mineral of the ophiolite suite of rocks with Cr2O3 >45% and

low TiO2. Parts of the ophiolite belt have been explored for chromite and other metals like Ni, Co,

Cu, etc.

The Tertiary rocks of northeast India rest over the weathered platforms of Precambrian

rocks, and these comprise of both shelf and geosynclinal-facies sediments of Eocene age represented

by the Jaintia and Disang Groups respectively. The overlying Barail (Oligocene), Surma (Lower

Miocene), Tipam (Upper Miocene), Dupi tila (Mio-Pliocene) and Dihing (Pliocene) Groups also

represent both shelf and geosynclinal facies. The Tertiary sedimentary history of Assam is an

integral part of the tectono-sedimentary setting of the Tertiary sediments of the north-east India and

is influenced by the prominent ‘Brahmaputra Arch’ running parallel to Brahmaputra River. The

shelf-facies sediments (Jaintia Group) of Eocene age are calcareous and abundantly fossiliferous. In

Meghalaya, Tertiary coal occurrences are recorded in Jaintia Group.

QUATERNARY FORMATIONS

The Quaternary sediments in the peninsular India occur along the coastal tracts and inland river

valleys by narrow continuous palaeo-beach ridges, interrupted by the prograding deltas of major

rivers. They are represented by thick blankets of alluvium, gravel and colluvial deposits, beach sand,

51

kankar, soils of various types and laterite. The Quaternary sediments were laid down in four major

depositional environments, namely fluvial, fluvio- marine, marine and aeolian.

The Quaternaries in Rajasthan and Gujarat are assorted deposits of aeolian, fluvial and

lacustrine origin. They occur mostly in a large tract in western Rajasthan known as the Thar Desert.

One of the important Quaternary episode in Gujarat is the formation of the Rann Surface,—a vast,

marshy, saline tract extending for about 300 km in east-west direction in Kachchha region of

Gujarat.

A major part of the area flanking the Brahmaputra River in Lower and Upper Assam is

covered by thick Quaternary fluvial sequence. Quaternary sequence located in Imphal valley of

Manipur are of both laccustrine and fluvial types. Recent deposits in northeast India are represented

by sand-silt-clay sequence in Brahmaputra and Surma River valleys in Assam and in the foot hills of

Garo and Khasi hills of Meghalaya. Minor recent sediments also occur in Manipur, Mizoram and

Nagaland.

The Quaternary sand deposits along the coastal tracts of Kerala and Tamil Nadu are

economically exploitable for ilmenite, rutile, zircon and monazite.

Andaman & Nicobar Islands

The Andaman-Nicobar Islands represent part of an arcuate island-arc chain, running from

Myanmar to Indonesia to Indo-Sumatra subduction zone, flanked on the west by the Bay of Bengal

and on the east by the Andaman Sea, constituting the southern most part of the Indian subcontinent

covering an area of 8249 km2. The Andaman & Nicobar (A & N) Islands represent the subaerial part

of the submarine fore-arc ridge of the Indonesian Island-arc system. An active zone of subduction

along the Andaman-Java trench lies on the west of the Andaman-Nicobar Islands and continues

southward into Indonesia. Underthusting of the Indian oceanic plate below the Eurasian plate since

Cretaceous to present day along this subduction resulted in the formation of a wide accretionary

prism and upbuilding of a high forarc-outerarc ridge known as Andaman-Nicobar ridge.

The ophiolite occurrences in Andaman Islands are interpreted as thrust slices of oceanic crust

scraped off the subducting slab at the toe of the accretionary complex. The outerarc-forearc terrain

constituting the Andaman-Nicobar Islands is characterized by a complex mosaic of different

geological provinces each having its own record of origin and geological evolution vis-a-vis mineral

potentiality. Rocks of the Andaman Islands are technically thrusted into a narrow north-south-

trending and linear belt paralleling the north-south trend of the Andaman-Java subduction. Older

52

continental metamorphic rocks occur as small enclaves within the ophiolite-melange packages.

Ophiolitc rocks in Andaman occur as north-south trending dismembered units of subhorizontal

sheets thrusted over the much younger Andaman Flysch. They are Cretaceous-Palaeocene in age and

are intermittently exposed from the saddle reef of North Andaman to almost the southern tip of the

Great Nicobar Island. Rutland Island in the southern tip of South Andaman Island hosts the largest

exposure of the ophiolites. The Ophiolites, their cover sediments and the Andaman Flysh together

are folded into an open anticline (Ray, 1982). Sets of mesoscopic folds occur in all the sedimentary

units associated with ophiolites.

Recent Volcanism in Andaman & Nicobar Islands In Andaman & Nicobar Islands, Narcondam and Barren are the two small volcanic islands of

Quaternary age, located about 100 km north and northeast of Port Blair on Andaman Sea. The

Narcondam is considered to be a dormant type while the Barren has the history of recurring volcanic

eruption since pre-historic age (Halder et al., 1992). The Barren Island volcano, the only active

volcano in the Indian subcontinent has recently exploded during May 1991 after lying dormant for a

long time.Subsequently it erupted again during 2005, 2006 and in 2009.

The Barren Island volcano is characterized by resurgent volcanism, with three distinct volcanic

episodes recorded so far. An initial submarine volcanism, possibly taking place in late to post-

Pleistocene time formed a giant volcanic cone representing the ancestral / primordial Barren Island.

This ancient volcanic cone was at times blown out and a thick pile of pyroclastics got deposited over

the surface of the relict cauldron. Olivine basalt represents the first phase of eruption, while the

second phase witnessed the eruption of high-alumina olivine basalt. The recent basaltic andesite

eruption contains phenocrysts of plagioclase, diopsite, augite and titanomagnetite set in a hyalopilitic

groundmass.

Lakshadweep Islands

The Union Territory of Lakshadweep forms a NE-SW-trending archipelago in the Laccadive-Chagos

ridge system in the Arabian Sea, 220-440 km off the west coast of India. It is located between 8º and

12º30" North latitude and 71º and 74 º East longitudes and consists of twelve atolls, three reefs and

five submerged banks, with a total of about 36 islands and islets, roughly covering 32 sq km.

Geologically, all the islands are made up of coralline limestone and calcareous coralline sand and its

variants. Mineral occurrences include Coralline Limestone,Calcareous sand with high CaO content

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and Guano deposits (P2O5- 8-11.72%) in Pilli island 30 km NW of Kavaratti. (0.12 million tonnes

estimated by IBM in 1970).

MINERAL RESOURCES OF INDIA

INTRODUCTION

India has a rich tradition of mineral exploration. Innumerable old workings, slag heaps are

the tell tale signs of this glorious tradition. The flourishing diamond industry in the Deccan peninsula

mainly in the Golconda kingdom, has attracted the world’s attention during the historical time.

Copper, iron, and gold were also used locally since the day of Indus valley civilizations. East India

Company started exploration for coal in the eighteenth century with setting up of Geological Survey

of India, the premier Earth science organisation and the second oldest survey of the country, in 1851

for the systematic geological survey and prospecting for coal. India was a notable producer of gold

in the early part of twentieth century and major exporter of mica, sillimanite, kyanite, magnetite and

chromite. Metallurgical industry started with the setting up of steel plants at Burnpur, Jamshedpur

and copper smelter at Ghatsila. Second World War created great demand for various minerals and

metals including those of strategic importance viz tungsten. Industrial policy formulated after

Independence, brought about a radical change in the mining and metallurgical industry. During the

post Independence period, GSI has embarked upon the exploration for minerals particularly in

favourable geological milieu spread over the Dharwar, Bastar, Singhbhum and Aravalli cratons. The

investigations carried out since 1960s provide us first hand information of different mineral

occurrences as well as their potential. Keeping in tune with the modern trends of mineral

exploration, the GSI oriented its programmes through multidisciplinary surveys and from time to

time equipped with state-of-the-art laboratories to back up its various exploration programmes. The

efforts have led to discovery of several mineral deposits in virgin areas in different parts of the

country. A few other central and state government organisations were also involved in mineral

exploration now and then, mostly in collaboration with foreign organisations. The liberalization of

our National Mineral Policy in 1993 paved the way for entry of private entrepreneurs, including

those from overseas for carrying out mineral exploration. The database developed by GSI has been

found very useful for taking investment decisions by the Multi National Companies.

An ore or mineral deposit represents a geochemically anomalous concentration of elements

in a very limited sector of the crust. The crustal elements have to undergo enrichment upto several

54

orders to attain the status of an economic deposit. The concentration of Clarke varies from element

to element depending on the economic utilization. The genesis of economic deposits is therefore

essentially a question of enrichment. The crustal processes associated with crustal growth and

recycling leading to metal concentration and formation of deposits is refeered by the

term’metallogeny’.

In the Indian context major metallogenic episodes have taken place during Archaean,

Archaean-Proterozoic Transition and Proterozoic proper. Thus large deposits of base metal and

basemetal-noble metals, Iron, manganese and chromium etc were formed in distinct episodes mostly

from Archaean to Mesoproterozoic.

Crustal evolution during Archaean: The Archaean forms the formative stages of the earth’s history,

core segregation, major out gassing, meteoric bombardment and formation of primeval crust (Piranjo

1992). Archaean heat flow between 3.8 and 2.5 Ga is estimated to have been 2.5 to 4 times its

present value. As a result lithosphere was presumably thin and somewhat buoyant. Subduction, if

any, was probably little developed and mantle convection gave rise to a series of small jostling

lithospheric plates. Initially these were made-up of mafic and ultramafic rocks. Later perhaps in

response to partial melting of this lithosphere and the products of erosion of the early consolidated

magmas, ore felsic rocks were formed and accreted leading to the formation of first sialic

microplates. The aggregation of these micropltaes could have given rise to Protocontinents, and

eventually together near continental size cratonic areas. These cratons were composed of granitic

rocks and greenstone belts.

The Proterozoic Eon was the most significant one when intraplate tectonics played a major

role in earth’s evolution of magmatism, metamorphism and ore genesis. The Archaean Proterozoic

boundary was a major turning point in crustal evolution and represents a diachronous and

transitional period ranging from 3 Ga to 2.5 Ga. Massive crustal growth, lithospheric thickening,

decrease in heat flow and a possible change in mantle convection pattern occurred, The presence of

an unconformity is typical separating highly deformed Archaean rocks from the little deformed

Proterozoic cratonic sequences. A major intrusive event characterised by large-scale granitic

magmatism is identified between 2.67 and 2.5 Ga .The aggregation of a super continental mass

resulted in the accumulation of heat in the mantle beneath.

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Genesis and localisation of economic deposits:The grouping of commercial types of ore deposits is

based on a single genetic classification ie endogenous, exogenous and metamorphogenic series. The

endogenic series incorporates magmatic, pegmatitic, metasomatic greisen type etc, carbonatite,

skarn, plutonogenic hydrothermal, volcanogenic hydrothermal, massive sulfides and stratiform type

groups. The exogenic include weathering, placer, sedimentary, mineralised waters and brines.

Endogenic cycle and endogenic deposits: Magmatic deposits:

Magmatic cycle (both extrusive and intrusives) is responsible for concentration of many

important metallic deposits. A genetic connection between both is often difficult to establish because

exhalation carrying ore minerals get intermixed with the hydrosphere and atmosphere and are

deposited as chemogenic sediments. To this class belong the sedimentary exhalative deposits closely

related to time and space with volcanic episodes (e.g. BIF, deposits of stratiform Zinc, Volcanic

Hosted Massive type Sulphide type Pb-Zn-Cu deposits).

Ores may be genetically related to specific intrusives as magmatic concentration and

magmatic emanation exuded from magma during its consolidation. Some of them are early

magmatic and late magmatic with reference to the intrusion. The podiform chromite mineralsiation

associated with ultramafic rocks are examples of deposits of early magmatic concentration.

Hydrothermal origin is attributed to many of the metalliferous deposits of copper, gold, lead

etc and fluorite, barite deposits. The mineral rich solutions migrated from magma source gets

precipatetd at different levels in the crust along strcturally favourable traps depending on the ambient

pressure temperature conditions of precipitation at different crustal levels. The following table

summarizes some empirical data on the igneous rock-ore linkage.

Rock Type Associated Ore

Kimberlite and Lamproite Diamond

Dunite-Peridotite, Pyroxenite Chromite, Nickel, Platinum Group

Norite-Gabbro- Anorthosite PGE, Ti and Vanadium bearing Magnetite, native

copper, silver, cobalt, nickel

Dolerite, diorite, monzonite Magnetite, copper, gold

Granodiorite, quartz monzonite Porphyry copper,-gold-Mo-Ag-

Syenite Magnetite, gold

Nephelene syenite Corundum

Granite and granite pegmatite Tin-Tungsten, Uranium, radium, beryl, tourmaline

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Exogenic cycle and exogenic deposits:

The mineral deposits formed at deeper zones of the crust under high temperature and

pressure conditions are unstable in the interface of atmosphere, hydrosphere and biosphere which are

characterised by low temperature, low pressure and abundant water. All these lead to geochemical

fractionation of elements, which incidentally leads to formation of a number of mineral deposits.

Enrichment of iron, Nickel, and aluminium takes place in the weathering cycle under warm tropical

conditions in the form of laterite and bauxite cappings. This type of deposits is abundant in the

Precambrian shield of Indian Peninsula. It represents insitu products of interaction of the stable

crustal blocks with the dynamic atmosphere. Mechanical concentration of resistant minerals results

in the formation of placer deposits of monazite, ilmenite, garnet, gold, cassiterite, diamond,

platinum etc. The dynamic agencies of hydrologic cycle act upon crustal blocks and bring about

concentration of heavy minerals. Examples of this type of deposits are the beach placers of Ilmenite-

magnetite bearing sand placers of Kerala - Konkan Coast, diamond placers in Madhya Pradesh and

Wairagarh, Tin placers of Bastar District,etc.

Another important example of exogenous deposits is coal. This is important source of energy

in the country. Large deposits of coal are found associated with Gondwana sediments. These are

formed by large scale deposition of vegetation materials entrapped in the alluvial sediments brought

in by the rivers which during the course of geologic time due to consolidation and lithification

transformed into coal beds.

As per the National Mineral Policy,2008, which emphasized for non-fuel and non-coal

minerals, that is, deposits locked at depth, mineral occurrences of India is presented in detail for

geologically potential areas in consonance with the national policy goals.Only significant

mineralization with possible economic significance have been described.

DIAMOND

India has the distinction of prducing many of the historically famous diamonds like the

Kohinoor (186 ct), the Great Moghul (787 ct), the Hope (67ct), Nizam (440ct), Pitt/Regent (410 ct),

Orloff(300 ct) and Daryainoor(185 ct).Till the discovery of the Brazilian diamond fields, India was

leading in diamond mining.

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Diamond occurrences in India are quite widespread. The known areas of occurrences of

diamond source rocks are broadly grouped into three diamond provinces, namely the South Indian

Diamond Province (SIDP), the Central Indian Diamond Province (CIDP) and the East Indian

Diamond Province (EIDP). Each of these Provinces extends approximately over an area of 100,000

km2 and includes both primary (Kimberlites/Lamproites) and secondary source rocks (conglomerates

and gravels) for diamond.

The SIDP is confined to the Dharwar Craton in the states of Andhra Pradesh, Karnataka and

Maharashtra, the CIDP to the Aravalli Craton in the states of Madhya Pradesh, Rajasthan and Uttar

Pradesh and the EIDP to the Bastar and Singhbhum Cratons in the states of Maharashtra,

Chhattishgarh, Orissa, Jharkhand and Madhya Pradesh.

Considering the Cratons and presence of diamonds and the source rocks, areas have been

prognosticated for kimberlite search in India.They are: (1) South Indian Diamond Province (SIDP)

including East Dharwar Craton and adjoining Dharwar Mobile Belt; (2) West Dharwar Province; (3)

East Bastar Craton including parts of Eastern Ghat Mobile Belt (EGMB); (4) West Bastar Craton;

(5) Southern part of Bundelkhand – Aravalli Craton ; (6) North of Central Indian Suture (CIS); (7)

Southern part of Singhbhum Craton including Singhbhum Mobile Belt; (8) Raigarh Mobile Belt; (9)

Structural Corridor of Son – Narmada rift zone; (10) Structural Corridor of Tapti Lineament Zone;

(11) Mahanadi Gondwana Graben and (12) Godavari Gondwana Graben.

The SIDP consists of both primary and secondary source rocks of diamond. The kimberlites

localised within the Eastern block of the Dharwar Craton are grouped into four kimberlite fields, viz.

Wajrakarur Kimberlite Field (WKF), Narayanpet Kimberlite Field (NKF),Tungabhadra Kimberlite

Field(TKF) and Raichur Kimberlite Field(RKF).Three N-S zones, viz. (i) the eastern zone of

alkaline syenites / alkali granites (1600–1400 Ma) extending from the eastern tectonic contact of

EGMB with DC to the eastern margin of CB, (ii) the middle zone of lamproites (~1350 Ma)

covering Nallamalai Fold Belt (NFB) and PGC along the northeastern and northern margin of CB,

and (iii) the western zone of kimberlites (~1100 Ma) covering PGC to the west of CB, are

recognised. The major lamproite dykes occurring along the eastern margin of the Craton i.e. within

the Nallamalai Fold Belt (NFB) and close to the north eastern margin of the Cuddapah basin are

included in the Chelima- Zangamrajupalle Lamproite Field (CLF) and Jaggayyapeta-Krishna

Lamproite Field (JLF) respectively.

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Until now, only the WKF is found to contain diamondiferous pipes.Twenty-one kimberlites

of WKF are distributed in three clusters viz., Wajrakarur-Lattavaram cluster (Pipe 1-13), Chigicherla

cluster (CC 1-5) and Kalyandurg cluster (KL 1-3). There are 34 kimberlite bodies in NKF distributed

in Kotakunda (KK1-7), Maddur (MK 1-11), Narayanpet (NK 1-10) and Bhima clusters (BK 1-5 and

RK-1). The lamproites are distributed in 12 clusters. Mineralogical composition of WKF indicates

their derivation from shallower depths above the diamond window in the inhomogenous mantle.The

diamond incidences (in carat per hundred tones-cpht) of Pipe 1 to 13 are 0.3, 3.5, 0.78 to 1, and 7.9

with the high value of 45 in the overburden of Pipe 7.

Secondary sourced diamonds in South India can be traced to the Proterozoic Cumbum

conglomerate (Cuddapah Supergroup), Banganapalle conglomerate (Kurnool Group) and Upper-

Tertiary Gollapalli/Malavalli conglomerate from the extensive old workings. The Banganapalle

conglomerate, explored by various agencies, has incidence of diamond – 0 to 35 cpht – with average

at 2 to 3 cpht. 75% of the diamonds recovered are gem variety and the largest one weighed 6 ct.

Though this diamond occurrence is rather localised, it assumes significance, in that, many of the

world famous diamonds were reportedly recovered from gravels of the area. Another localized

occurrence of old mining activity confining to the Mesozoic /Tertiary (?) sandstone is around

Mallavelli to the east of Vijaywada and south-eastern side of the Eastern Ghat Mobile Belt.

The basal conglomerate in the Banganapalle Quartzite Formation in the Kurnool Group is the

main diamond-bearing stratigraphic unit so far known in the Cuddapah basin (Table 6). The

conglomerate occurs as disconnected outcrops in a curved belt 250 km long in the western part of

the Cuddapah Basin and about 120 km long in the Palnad Basin.The conglomerate range in thickness

from 1 to 50 cm with an average of 10 cm, with clasts of chert and jasper and subordinate vein

quartz embedded in sand-silt matrix.The diamond-bearing conglomerates are subarkose and

classified as chert pebble-, oligomictic-, para-, conglomerates. The source of the conglomerates is

traced to the west comprising lower Cuddapah sequences, igneous intrusives and the basement.

Investigation for diamond bearing conglomerates has been revived recently from Banganapalle,

Vajragiri-Munimadugu, Tammarajupalle and Ramallakota-Viryapalle-Yerubayi.

Alluvial diamonds are known to occur in southern India along Krishna, Tungabadra and

Penner Rivers. Old workings in Krishna Valleys occur in T2/T3 terraces at Panchalingala, Kurnool

district near the confluence of Tungabhadra with Krishna River to Paritala down stream in Krishna

59

district , over a distance of > 400 kms.The Pleistocene-Holocene gravels of Krishna and

PennerRivers have been worked for diamond from different terraces (T2/T3 and T3) with probable

primary source from WKF and other unknown sources.The gravels mainly of Krishna river along

with those of the Pennar river, Sagileru, Kundair, Hundri and Ramileru yielded large quantities of

diamonds. Diamond occurrences in the Godavari gravels are sporadic.

The CIDP confined to the Aravalli Craton in the states of Madhya Pradesh, Rajasthan and

Uttar Pradesh also consists of primary and secondary source rocks. The NE-SW trending Panna

Diamond belt with established ancient mining activity is located within this province.This is the only

belt where active mining for diamond is presently carried out in the country. The National Mineral

Development Corporation Ltd is exploiting Majhgawan kimberlite/lamproite, the only diamond

producing mine, with an average annual production of 16,000 carats. The lamproite pipe at Hinota has low

diamond incidence and is not worked. NMDC also took up mining of a large gravel block at Ramkheria but

abandoned the work due to operational difficulties. The extension of Hatupur conglomerate block has been

explored by MECL. The occurrence of diamonds over such a long belt viewed in the light of only two known

diamond bearing pipes at one end of the belt strongly point to contribution of diamonds from more pipes.

A little amount of diamond is being recovered from placer occurrences. The kimberlites/

lamproites (~1100Ma) intruding into the Kaimur Group of rocks are found along the western margin

of the Vindhyan basin adjoining the Bundelkhand granite and are included in Majhgawan

Kimberlite/Lamproite Field. Kimberlitic rocks discovered in this province are only a few and

sporadic and are reported from the Bundelkhand granite terrain.

The main source of diamonds in the country is from Majhgawan with about 10 carats per 100

tonnes within the pipes, which have been producing about 15000 carats per year of which a third are

of the gem quality. The estimated reserve of diamond in this pipe is of the order of 1.3 million carats.

The Hinota and Jungel have low incidence of 0.7 and 0.6 carat per 100 tonnes, respectively.

The Vindhyan Supergroup of rocks host a major share of diamonds produced from the Panna

Diamond Belt in the form of three diamondiferous conglomerate horizons associated with the Itwa

sandstone, Jhiri shale, and Gahadra sandstone Formations of the Rewa Group of rocks of late

Proterozoic age. The conglomerates at Shahidan mine at the base of the Jhiri shale have been worked

for a long time and have a higher potential of 26 carats per 100 tonnes.

Diamondiferous alluvial gravels are found mostly along the banks of the Ken-Ranj-Baghain

rivers and lateritic gravels over the Baghain and Gahadra Sandstone Formations.The incidence of

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diamonds in Panna diamond belt from gravels of Baghain River (near Ramkheria village) and other

streams are good at 23 carats per 100 tonnes. Diamond is also reported from the river gravels and

alluvial caps at Chanda, Mahantola Salaia and Urdana.

The EIDP confined to the Bastar and Singhbhum Cratons in the states of Maharashtra,

Chhattishgarh, Orissa, Jharkhand and Madhya Pradesh is known for ancient diamond mining activity

at a few places only viz., Wairagarh area in Maharashtra, and Hirakud area in Orissa and Koel-

Sankh river areas inJharkhand. Kimberlite discoveries in the province are very recent and

investigations carried out in different parts of the Bastar Craton led to identification of two new

kimberlite fields (1) Mainpur kimberlite Field (MKF) and (2) Tokapal Kimberlite Field (TKF), both

in the state of Chhattisgarh. The kimberlites of the MKF intruded into the Khariar group of rocks and

those of TKF into the Indravati group of rocks of late Proterozoic age. Some of the kimberlites in the

MKF are known to be diamondiferous.Diamond-bearing pipes in the former field have been

identified from Payalikhand, Bahradih and Kodomali of Raipur district by GSI, DGM and private

enterpreneurs.

The recent discovery of kimberlitic / lamproitic rocks in Nuapada district of Orissa has

opened a new area of primary source rocks for diamond. A few lamproite dykes have been

discovered recently in adjoining Bargarh district, Orissa. A few of the Cretaceous lamproites

intruding into the Gondwana sediments of the Damodar valley

Coalfields and South Rewa Gondwana basin show similarities to that of lamproitic rocks.

Diamonds are also reported in the gravels of Maini, Ib, and Mand rivers in Chhattishgarh and

Tel-Mahanadi rivers in Orissa. The ancient workings in Wairagarh area appear to be in the

conglomerates as well as gravels. The conglomerates and grit are associated with either the middle

Proterozoic Sakoli group or the early Proterozoic Dongargarh Group of rocks.

Meaningful prospecting and exploration for diamond and kimberlites depend much on the

right type of prognostication. Prognostication for mineral search is essential at different stages of

prospecting from regional operations over large areas to detailed operations over narrowed down

target areas.

As a result of GSI's work several prospective blocks have been identified for further

investigation. Such blocks are listed below and short description on their status is enclosed.

A. LAMPROITE/ KIMBERLITES A.1 MAJHGAWAN KIMBERLITE/LAMPROITE DIATREME

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Geographic data:

Location: Majhgawan, Panna district,(24039': 80002'); Toposheet no. 63O/2

Extent: 515 x 330 m diatreme.

Access: Majhgawan pipe is located about 20 km south-west of Panna, the district Headquarters.

Since Majhgawan pipe is a diamond producing mine, it is connected to Panna by an all weather road.

Topography: The pipe intrudes into the Baghain sandstone, which forms a flat geomorphic surface

with a height of 360m to 400m above MSL. At present, the mine is approximately 80m deep with a

number of benches.

Geological setup:

The Majhgawan kimberlite diatreme identified as lamproite is a downward tapering, cone shaped body

measuring about 515 x 330 m in plan. The contact with the host rock dips at fairly constant angle of

7000inwards. The contact between the kimberlite diatreme and the Baghain sandstone is normally sharp. In the

western and southern periphery, however, the kimberlite is highly sheared and traversed by a network of

calcite veins.

The diatreme contains both cognate and accidental xenoliths. The yellow and blue grounds are well developed

with a capping of 5 to 6m of soil. The contact between the yellow and the blue ground is at an average depth

of 14 m from the surface.

Exploration :

The exploration programme was aimed at: (1) establishing offshoots of the kimberlite diatreme, (2)

deciphering the geometry of the body and study of different petrographic varieties at depth and (3)

establishing incidence of diamond in the 'extended arm' of kimberlite on the basis of surface sampling with

the help of deep pits.

A total of 2943.70 metres of drilling in 25 boreholes was done to study the pipe. During shallow

drilling, two prominent offshoots were delineated upto a depth of 40 m and an additional reserve of

kimberlite (0.14 Mt) has been established upto a depth of 40 m.

To study the behaviour of the Majhgawan kimberlite at depth, 5 boreholes were drilled from outside

the pipe area. The drilling has established the extension of pipe to a vertical depth of 330 m. The

wall of the pipe indicates an inward dip of about 700 to 800. As against the diameter of the pipe,

which is about 330 m on surface, it reduces to about 125m at a depth of 330m. The pipe continues to

further depth.

Treatment of about 1643.71t of kimberlite from offshoot yielded 14 diamonds weighing 7.20 ct

indicating an incidence of 0.43 cpht as against 10 cpht in the main pipe.

A.2 HINOTA KIMBERLITE DIATREME

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Geographic data Location: NNW of Hinota Village, Panna district, (24040': 80001'); Toposheet no. 63D/2

Extent: 200 x 180 m diatreme.

Access: Hinota kimberlite diatreme is located about 20 km WSW of Panna.

Topography: The pipe is emplaced into the Baghain sandstone which forms a flat geomorphic

surface with a height of 360m to 400m. The pipe forms a topographic depression.

Geological setup: The Hinota diatreme is emplaced into the Baghain Sandstone Formation of the Kaimur

Group (Vindhyan Supergoup). On surface, the diameter of the pipe is 200 x 180 m with a slight NW-SE

elongation. On the aerial photographs, the pipe is recognised by its high density of vegetation and negative

topography. It is well recognised on satellite imageries also. The pipe was discovered as a result of magnetic

and electrical resistivity surveys by GSI.

The drilling in the Hinota pipe indicated top 2.5m of detrital material, followed by about 25 m of earthy

yellow and greenish clayey matter and then blue ground upto a depth of 60 to 75m ending up in hard

kimberlite.

Exploration:

Atotal of 631.65 m of drilling was done in 3 boreholes, which indicated that the body extends beyond 160m

in depth.Shaft Sinking: One 18.50m deep shaft was sunk in the pipe.A total of 228.40 tonnes of material from

the shaft was treated and only two diamonds weighing 1.71 ct were recovered, which shows a very low

incidence of diamond

Recommendations: As diamond incidence is low, further investigation in this pipe is unwarranted.

Caution: The Hinota pipe falls in the Panna National Park area and to obtain prospecting lease, and

to carry out large scale operations or even preliminary surveys, a prior permission from the Ministry

of Environment, Government of India, is necessary.

B. CONGLOMERATES

B.1 HATUPUR BLOCK

Geographic data:

Location: Hatupur, Panna district,(240048': 80025') ; Toposheet no. 63 D/5

Extent: Hatupur block is 3 km x 3 km in extent; Hatupur, Rakhel and Damulua villages are located

within the block.

Access: The block is located about 23 km ENE of Panna on Panna-Paharikhera Road.

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Topography: The block fringes at Gahadara sandstone scarps in the southeastern part of the block,

with an elevation difference of about 70m .There is a small hill in the eastern part of the block with a

height of 440m.

Geological setup: The Jhiri shales are exposed on the surface in the entire block. At the base of the

Jhiri shale, a diamondiferous conglomerate horizon (Jhiri conglomerate), varying in thickness from 4

cm to 54 cm, exists. The Jhiri shale is underlain by Itwa Sandstone Formation. Towards the top of

the Itwa Sandstone Formation, another diamondiferous conglomerate horizon (known as Itwa

conglomerate) exists. The Jhiri and Itwa conglomerates are separated by 2 to 3 m thick sandstone

horizon. The Itwa Sandstone Formation and Jhiri Shale Formation (with conglomerate) show very

gentle dip towards SSE. The gradient is 1.5 to 2 m per 100 m.

Exploration :

The area has been mapped on 1:12,500 scale to demarcate conglomerate horizons, diamondiferous lateritic

and alluvial gravels and detailed mapping of about 5 sq.km on 1:2000 scale.

Drilling:In the western block the grid was laid at 200m intersection and in the eastern block at 250 m

intersection. A total of 3345.95 m of drilling was done in 108 boreholes. The drill hole data revealed that the

thickness of the Jhiri conglomerate ranges from about 1 cm to 70 cm. The depth of conglomerate varies from

4.55m to 36.35m.The Itwa conglomerate is separated from the Jhiri conglomerate by a non-diamondiferrous

shale /sandstone horizon, the thickness of which varies from 2 to 4 m. The thicker conglomerate horizons also

carry sandstone interbeds. The thickness of Itwa conglomerate varies from 1 cm to 2.42m and depth from

surface varies from 3.42 m to 62.28m. Core loss has also been recorded in a few drill holes. In view of this,

much thicker horizon of conglomerate is expected in the pits than in boreholes.

Isopach map for the Jhiri and the Itwa conglomerates indicates irregular distribution of conglomerate. Both

the conglomerates are thicker along palaeochannels than adjoining parts. The palaeochannels are oriented

along NE-SW and E-W directions. Isolated patches of thick conglomerate are also recorded. The stratum

contour plan of the base of the Itwa conglomerate horizon shows uniform and conspicuous south-easterly

gradient.

36 shafts (2.5 x 2.5m), ranging in depth from 5m to 34.75m, were sunk on a grid varying from 100 to 250m to

excavate the conglomerates. At the bottom of the shaft, where the Itwa conglomerate was encountered, two

east-west oriented drives (1.8m height, 2.1m width and 6m length on each side) were driven to win the

requisite quantity of conglomerate. The average thickness of conglomerate in shafts worked out to be 60 cm,

varying from 17cm to 1.40m. A total of 4746.92 t of conglomerate was obtained from 6494.50 cu m. of

excavation, which was treated at NMDC plant, Majhgawan.

Dimensions of explored prospects:

i) Sub-block A: The sub-block (area 0.3 sq.km) was proved to contain conglomerate reserves of

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about 0.45 Mt with a diamond incidence of 27.91 cpht. This block is open at both ends, indicating the

possibility of its further extension towards east and towards south-west. MECL has drilled in the eastern

extensions of the block, the results of which are yet to be received.

ii) Sub-block B: These sub-block measures 750 x 500m. Proved reserves of pure and diluted

conglomerate estimated are 0.53 Mt and 1.49 Mt, respectively. Treatment results of the samples drawn are not

available so far. The depth of the Itwa conglomerate varies from 20.95m to 29.10m

iii) Sub-block C: The block is along a NW-SE trending channel. Thickness of the Itwa conglomerate ranges

from 1.14 to 1.80m and depth varies from 6.45 to 21.65m. On the basis of the data of three pits (P-28, P-35

and P-36) and drives, about 0.31 Mt of undiluted and 0.74 Mt of diluted conglomerate of proved category

have been estimated. Probable reserves of 0.60 Mt of undiluted conglomerate and 2.72 Mt diluted

conglomerate have been estimated on the basis of drill hole data. The treatment results are not yet available.

iv) Sub-block D: It is a small block located in the northeastern corner of the Hatupur block. The thickness of

the Itwa conglomerate varies between 22 and 30 cm and depth varies from 8 to 8.5 m. Probable reserves of

the conglomerate have been estimated at 0.106 Mt. for the undiluted and 0.742 Mt for the diluted categories.

v) Sub block E: It is 1 km long, trending N-S and defined by drill holes. The thickness of Itwa conglomerate

varies from 10 to 77cm and depth from 12.70 to 25.15m. No pits have been sunk in this sub block. On the

basis of the drill hole data, probable reserves of the conglomerates have been estimated at 0.378 Mt of

undiluted and 1.49 Mt of diluted conglomerate.

vi) Sub-block F: It has a dimension of 500 x 500m and is a south-easterly extension of the subblock C. The

depth of the Itwa conglomerate varies from 23.40 to 26.05m and thickness from 29 cm to 1.70m. On the basis

of the drill hole and pit data, proved and probable reserves ofdiluted conglomerate have been estimated at

0.247 Mt and 0.495 Mt respectively.

Diamonds:

The percentage of gem quality of diamonds is very high (55%). Off-colour and industrial diamonds constitute

19% and 26% of the total diamonds. The largest sizes of diamonds recovered so far, during the exploratory

operations, are 3.38 ct (industrial variety), 2.27 ct (gem quality) and 1.68 ct (off colour). Average size of gem,

off-colour and industrial varieties is 0.6 ct, 0.45 ct and 0.63 ct, respectively.

B.2 SHAHIDAN BLOCK

Geographic data:

Location: 2.5 Km NE of Panna, Panna district.

Coordinates: 24044': 80012'; Toposheet no. 63 D/2;Extent : 2700 X 700 m

Topography: Gently rolling terrain.

Geological setup: Jhiri conglomerate occurs at the base and as interbeds within the JhiriShale and

siltstone of the upper part of the Rewa Group. It forms escarpment to the SW and NE of Panna. The

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conglomerate is coarse, pebbly or granular, with subrounded granules of jasper, chert, sandstone and

shale. It is rather well sorted with a sandy matrix.

Exploration: Shahidan area has the record of best and larger size diamond recovery. Data computed

from the operations of one of the large and systematically managed mines in Shahidan area indicated

diamond incidence of 43 cpht. During 1972-74, GSI drilled 20 boreholes which indicated that the

cumulative thickness of conglomerate to the SSE of Janakpur is above 30 cm. During 1980-85,

mapping (on 1:5000 scale) and drilling (62 boreholes by MECL) was done. Drilling showed an

average thickness of 20 cm of conglomerate. 10 pits sunk at drill hole sites indicated, on an average,

1.7 times greater thickness of conglomerate.The northern part of the area has a number of old

workings which are upto 15m deep and waterlogged, causing seepage problem. A part of the

northern section is in reserve forest, while the southern part is under cultivation.

B.3 GANJA - SHAHPUR BLOCK

Geographic data:

Location: Near Ganja - Shahpur village, Panna district. Toposheet: 63 D/5

Topography: Gently rolling terrain.

Geological Set up

Both Itwa and Jhiri conglomerates are encountered in the area. The Jhiri conglomerate is

both matrix as also clast supported. The matrix supported conglomerate has 15% to 40% of clasts set

in an argillaceous groundmass. The clasts are generally of granule size. These include white

quartzite, vein quartz, grey quartzite, green shale, cream quartzite, jasper, pink quartzite and chert.

Exploration: 16 holes drilled in the area encountered Jhiri conglomerate at a depth of 12.15m in the

northwest and at 49.30m in the southeast, down the dip. This is in conformity with the regional dip

of the formation.The Itwa conglomerate is intersected at a depth of 13.48m in the northwest and

50.50m in the southeast. Thickness of Itwa conglomerate varies from 6 to 70 cm.Drill hole data also

indicated that there is a rapid variation in the number of bands of Jhiri conglomerate from 1 to 6. The

Itwa conglomerate has generally one or two bands, except for southwestern side where 5 bands are

recorded. .

Reserve: On the basis of drill-hole data, indicated reserves of the Jhiri conglomerate is about 6.74

Mt and that of the Itwa conglomerate is about 4.44 Mt

C. RIVER GRAVELS

Geographic data:

Location: Itwa, Brijpur, Ramkheria villages, Panna district.

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Coordinates: 24047'- 24049': 80023'- 80030'; Toposheet no. 63 D/5

Extent: Gravel zone extends from Ramkheria (24049': 80027') in the east to Itwa (24047’: 800 23') in

the west.

Access: The area lies about 20 Km ENE of Panna and an all weather road between

Panna and Paharikeria runs through the entire length of gravel zone.

Topography: The area is practically flat, with the Baghain River incising into the flood plain

deposits.

Exploration :

Systematic mapping (1:50,000) of alluvial zone was done as part of regional mapping.The area

around and along the Baghain river was mapped on 1 : 12,500 scale as a part of delineation of

diamondiferous gravel zones.Geophysical survey of the gravel along the entire river section in Itwa-

Ramkheria section was done and the depth of bed rock was demarcated by taking cross traverses.

Dimension of the prospect: The area covers a length of approximately 15 km and width of 1 to 2

km.Diamondiferous gravel is restricted to the basal part of the alluvial pile and its thickness varies

from 30 cm to 4 m. It comprises boulders and pebbles of sandstone, shale and laterite, set in sandy

matrix.

Diamond Incidence: Bulk sampling by the GSI in 1956 in diamondiferous alluvial gravel of

Ramkheria indicated an incidence of 26 cpht. The exploration by NMDC proved a resource of about

1,15,000 ct with incidence of about 16 cpht.

Recommendations : Ramkheria gravel deposits indicate higher diamond incidence with higher

percentage of gem quality diamonds than the Majhgawan kimberlite. This prospect appears to be

quite promising provided prior exploration is done in the gravel. A few areas were delineated on the

basis of photogeological studies for detailed exploration along the Baghain River.

D. BUNDELKHAND BASEMENT

Several ultrabasic bodies are found in the Bundelkhand granite massif,emplaced after or along with

the granitic rocks. Preliminary exploration revealed diamonds, small in size. However, in view of

their possible regional relevance in the emplacement of diamond bearing pipe rocks, short

descriptions are given below.

D.1 ANGOR AND BANDHA ULTRABASIC BODIES

Geographic Data:

Location : 0.5 km north of Angor Village (24044':79025'; Toposheet no.54 P/6), on the Sagar-

Chhatarpur state Highway and 130 km SW of Panna,Chhattarpur district

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.Prospect : Angor Ultramafic prospect

Topography The granitic country is flat

Geological setup The ultramafic rocks are found in Bundelkhand granites exposed mainly on the

eastern side of the road but much of it has been levelled off to form cultivated land.

Exploration : :

Geophysical surveys indicated a 450 m long and 200m wide body, trending in NNW-SSE direction

and another 170m long and 30m wide body located 0.5 km NW of the first body. Drilling indicates

top 7 -12m weathered zones, underlain by brecciated carbonated pyroxenite, underlain by

harzburgite.7 boreholes totalling 792.35m were drilled in the main body, which continues beyond

289m depth.Six large pits reaching to a depth of 10m were put and two diamonds totalling 0.2

carats were recorded after treating 937.40 tonnes of excavated material. In course of another

excavation, 311.80 tonnes of treated material yielded five diamonds weighing 3.52 carats. NMDC

treated 1000 tonnes without any recovery of diamond.A similar body occurs near Bandha (240

39′:790 19'; 54 P/6) to the southwest of Gulganj. It is a dyke-like body, about 10m wide and covered

by soil at both ends. 86 tonnes of material treated yielded two diamonds weighing 1.62 ct (one gem

0.57ct and one industrial 1.05 ct).

. Recommendations In view of the diamond incidence, both the bodies could be subjected to further

investigation.

D.2 DONGRAHA ULTRABASIC ROCK

Geographic data:

Location : East of Dongraha (24051': 80008'), Panna district.

Extent: 10m long and 50cm to 1m wide; trends N 30 E - S 30 W.

Geological setup: The rock is intensely weathered, black in colour and porphyritic with

phenocrysts of altered olivine. Groundmass contains calcite and dusty opaques like ilmenite,

magnetite and possibly perovskite.

Exploration: No exploration was carried out.

D.3 ULTRABASIC ROCKS OF HARSA

Geographic data:

Location: 1.5 km north of Harsa village (24046':80006'), Panna district; Toposheet: 63 D/1

Extent: The outcrop measures 1 m long and 50 cm wide.

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Geological set up: The outcrop shows sharp contact with prophyritic pink granite; the other side is

covered by residual soil, rich in carbonate kankars. The rock has been identified as lamprophyre.

Exploration: No exploration for recovery of diamond was carried out.

D 4 ULTRABASIC DYKE NEAR BARIARPUR BARRAGE

Geographic data:

Location: East bank of Ken River, north of Barrage, Panna district

Coordinates: 24051': 80006'. Toposheet no.:63 D/1.

Geological set up: A dyke-like body, 5m to 10m wide trending N 50 E -S 50W, is well exposed

more than 1 km long in the west bank canal of the barrage, varying in thickness from 5 to 10m and,

ends covered under soil.The rock is grey, green to greenish brown, showing olivine, reddish mica

and opaques. The body cuts through Bundelkhand granite and shows contact metasomatism. The

rock is traversed by serpentine, carbonate and quartz veins. It continues under soil cover for 600m,

as proved by drilling three holes, spaced 200m apart; further extension possible.

Two pits were sunk in the eastern bank of the Ken River and treatment of 138 tonnes of material

from one of the pits yielded one diamond (off-colour) weighing 0.44 ct.

Recommendation: In view of large strike extension and diamond incidence, the body should be

further investigated.

D.5 BASALTIC KIMBERLITE OF BIHARPUR AREA

Geographic data:

Location: 0.7 km WNW of Biharpur, Panna district.

Coordinates: 24057’: 80031' - Toposheet no. 63 D/9

Extent: 600m long and 1 to 5m wide.

Exploration: Two boreholes, aggregating 298.43m, were drilled. No kimberlite was intersected in

any of the holes and it appears that this dyke pinches off at very shallow depth. About 33 cu m

excavation was done, and 55 tonnes of material treated but no diamonds were recovered.

PROSPECTS IN CHHATTISGARH

The Chhattisgarh State forms a part of Bastar Craton extending on west to Maharashtra and on east

to Orissa. It is of great significance that the Raigarh Mobile Belt, located between the Bastar Craton

on south-west and the Singhbhum Craton on north-east, is manifested by the presence of diamond in

all the streams of Ib, Maini, Mand and Sankh and their tributaries. The Archon of Bastar Craton is

bordered by Protons of Raigarh Mobile Belt and Eastern Ghat Mobile Belt and this tectonic scenario

is important in regional prognostication for diamond and kimberlite in Bastar Craton. In Bastar

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Craton there has been no major thermal activity after 2000 Ma. Hence, the Proterozoic platformal

belts over the cratonic area have been selected as first priority blocks for investigation of

kimberlite.The eastern and central parts of the craton are priority areas because they represent the

low heat flow and high permeability zones. The area is marked by presence of platform cover

sediments which protects the kimberlite diatremes from erosion. The prominent Proterozoic basins

are Chhattisgarh basin, Pairi-Khariar basin, Ampani basin, Indravati basin, Sabri basin and Albaka

basin.Considering all the positive features, the following target areas have been prognosticated in

search for kimberlites.

a) The Pairi-Khariar basin and surrounding granitic terrain, b) the Indravati basin and

adjoining gneissic complex on west and south, c) the Sabari basin and adjoining gneissic

complex, d) Saraipalli area comprising rocks of Chhattisgarh basin and the adjoining granitic terrain,

e) the Albaka and Abujhmar basins, f) the southern part of Chhattisgarh basin and adjoining granitic

terrain, g) the Raigarh Proterozoic crystallines bordering the Bastar Craton.

A total of 14 priority target blocks have been demarcated of which 11 are in Chhattisgarh and three

in Madhya Pradesh. The area of each block has been tentatively kept at 5000 Sq. Km.

In the Chhattisgarh State, so far, two Kimberlite fields have been identified which are

Mainpur Kimberlite Field in Raipur district and Tokapal Kimberlite Field in Bastar district.

A. MAINPUR KIMBERLITE FIELD (RAIPUR DISTRICT)

The Mainpur Kimberlite Field (MKF) is one of the three established diamond bearing

kimberlite fields in Peninsular India, the other two being Panna in northern Madhya Pradesh and

Wajrakarur (including Chigicherla and Kalyandurg kimberlites) in Andhra Pradesh. MKF is located

in the south-eastern part of the Raipur district of the state of Chhattisgarh in Central India, 135km SE

of Raipur city. Exploration activities by the GSI and the State Government have led to the

identification of five kimberlite pipes (including three diamondiferous pipes) and more than 40

kimberlitic indicator anomaly zones in the MKF, which are likely to be associated with kimberlitic

bodies.

Kimberlitic rocks: their occurrence and distributio n

Five kimberlitic diatremes have been located in a linear span of 12.5 km in the Mainpur

Kimberlite Field. The kimberlitic diatremes are Payalikhand-I (92010'10": 82021'00") (100m x 100m),

Payalikhand-II (50m x 50m), Jangra( (>50m across), Kodomali (300m across) and Bahradih (300m

x 200m).Most of the diatremes are circular in plan while Bahradih diatreme is elliptical. Amongst

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the diatremes only Kodomali exhibits fresh rock exposures while others have been weathered to

green earth at the surface.

A. 1. PAYALIKHAND DIATREMES

Geographical data:

Location: Payalikhand (20010'10: 82021'00", Toposheet No: 64 L/8), Raipur district; 169 km from

Raipur

Topography: 460m above MSL

Geological set up:

The Payalikhand area comprises a complex lithological assemblage represented by

metavolcanics and metasedimentary sequences of Sonakhan Group, rocks of Baya Gneiss Complex,

khondalite and charnockite suite of rocks of the Eastern Ghat Mobile Belt, intrusive Bundeli

granitoid and the sedimentary cover sequences of Pairi and Ampani Groups and Chhattisgarh Super

Group.

Exploration:

Two diatremes have been located along the slope of a foothill of the Khariar plateau.

Characteristics of the diatremes:

Number and name of kimberlite body: Payalikhand-I, MKF Field

Dimension Trend: 100m x100m

Emplacement control: Circular within granitoid rocks (64L/8)

Outcrop characteristics: Expressed as a break in slope, highly altered kimberlitic rock (green earth)

diatreme facies

Diamond contents/Heavy minerals: Diamondiferous and garnet, spinel, clinopyroxene

Number and name of kimberlite body: Payalikhand-II. MKF Field

Dimension Trend: 50m x50m

Emplacement control: Circular within granitoid rocks 64L/8

Outcrop characteristics: Along break in slope, highly altered kimberlitic rock as green earth.

Diamond contents/Heavy minerals: Diamondiferous`

A. 2. BAHRADIH DIATREME

Geographical data

Location: Bahradih (20012'30":82012' 00", ToposheetNo: 64L/4), Raipur district; 12 Km northwest

of Payalikhand

Topography: Approx 300m above M.S.L

71

Geological Set up: The geological set up is same as that of Payalikhand Block. The kimberlite pipe

located at Baharadih is elliptical in shape.Presence of xenoliths of consolidated shale and sandstone

within the weathered kimberlite indicate post Khariar age of diatremes. Since the kimberlite pipe

does not crop out above the Khariar cover sediments, it is therefore, presumed that it has only

intruded part of the sequence.

Exploration: The Bahradih diatreme is located in an ampitheatre like depression surrounded by

resistant granitoid rocks. Bahradih diatreme surfaces at an altitude of 560m from MSL.

Characteristics of the diatreme:

Name of kimberlite body: Bahradih

Dimension Trend: 300m x 200m;

Emplacement control: Sub circular within granitoid rocks (64L/4)

Outcrop characteristics: Ampitheatrical depression, highly altered kimberlitic rock (green earth),

diatreme facies

Diamond contents/Heavy minerals: Diamondiferous and garnet, spinel, clinopyroxene,

orthopyroxene, phlogopite

A. 3. JANGRA DIATREME

Jangra diatreme surfaces at an altitude of 500m from MSL.

Characteristics of the diatreme

Name of kimberlite body: Jangra (200 08′30″: 820 19’ 40”).

Dimension Trend: 50m x 50m

Emplacement control: Circular within granitoid rocks 64L/8

Outcrop characteristics: Ampitheatrical depression within granitoid

Diamond contents/heavy minerals: Not known/garnet and spinel

A. 4. KODOMALI DIATREME

Kodomali (20011' 10": 820 14' 08") kimberlite exposes as a dyke with WNW-ESE trend and is the

only diatreme with rock exposure visible at the surface, amongst the five known diatremes in

Mainpur Kimberlite Field. Like other diatremes, this diatreme is also surrounded by the granitoids.

The near surface alteration as green earth is not much as compared to other diatremes.

Characteristics of the diatreme

Dimension Trend: 300m x 300m

Diamond contents/Heavy minerals: Diamondiferous and garnet, spinel, clinopyroxene,

ilmenite and olivine

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Kimberlites of Mainpur kimberlite field have been classified into three volcanic facies,

viz. crater, diatreme and hypabyssal. Crater facies material has been preserved as xenoliths

within Payalikhand-I and -II diatremes. Bahradih, Payalikhand I and II and Jangra diatremes

have been classified as diatreme facies rocks. Only Kodomali rocks are classified as hypabassal

facies

Recommendation: The MKF has scope for further work to establish more kimberlite pipes and

evaluation of their diamond potentiality.

B. TOKAPAL KIMBERLITE FIELD (BASTAR DISTRICT)

The regional search for kimberlites in Indravati basin has located kimberlite clan rocks in

Tokapal, Duganpal, Bhejripadar and Parpa-Parakot areas and the Tokapal Kimberlite Field. The

area is occupied by the Archaean-Proterozoic rocks of Bastar Craton. The kimberlitic pipes have

intruded along NW-SE trending fracturers exhibited by mafic dyke swarms. The NW-SE trending

dyke swarms as well as major lineaments and faults possibly indicate reactivated mantle permeable

zones along which the kimberlitic pipes have been emplaced within the Proterozoic cover

sediments.The Indravati basinal area forms the east – central part of Bastar Craton.The Tokapal,

Duganpal and Parpa-Parakot kimberlitic rocks probably indicate multiple intrusions from a single or

multiple feeders covering an area with 5km length and 1 km width.

The borehole core samples indicate multiple intrusions at different levels with deposition of tuffs in

the upper part. The Bastar kimberlites are in the crater facies, without much erosion. It is also

interesting to note that in Bastar, there are kimberlitic flows in phases overlain and underlain by

Indravati sediments.

B.1. TOKAPAL KCR (KIMBERLITE CLAN ROCK) BODY

The Tokapal rock is exposed in pit section and the rock is greenish in colour and shows

typical kimberlitic clast-matrix texture and flowage structure within sediments (Jagdalpur

Formation) in the form of flows (65E/16).The rock shows crude banding and top portion is

lateritised and covered by black soil horizon.

Diamond content: Not known

B. 2. DUGANPAL KCR BODY

The Duganpal kimberlitic rock exposed in the Duganpal nala section has been exposed by drilling.

Diamond :content : Not known

B. 3. BHEJRIPADAR KCR BODY

The Bhejripadar kimberlitic body is located near village Bhejripadar (65 E/16). The body

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is exposed within the sandstone unit of Tirathgarh Formation.

Diamond content: Not known

B. 4. . PARPA – PARAKOT KCR BODY

The kimberlitic rock in Parpa – Parakot sector was observed from the borewell cores

drilled by the State Agricultural Department. The crater facies rocks are concealed under the soil and

laterite cover of >20m. The borehole data show the presence of kimberlitic tuffs and

pyroclastic rocks below 19.87m from the surface upto 36.67 m. From 36.67m to 62.69m

greenish black massive kimberlite was observed.

Diamond content: Not known

C.EXPLORATION FOR KCR IN RAIGARH MOBILE BELT

The exploration for KCR was also conducted in the Tapti Lineament Zone (TLZ) in parts

of Raigarh and Surguja districts of Raigarh Mobile Belt from 1994 to 2000 on the basis of

reported diamond incidences in the river gravels of Ib, Maini, Mand, Utial and Talda drainages.A

total of 6000 sq km area was covered by PGRS studies and stream sediment sampling, but no

primary source of diamond has been located except one grain of chromite falling in the edge of

kimberlite field.

D. SARANGARH SECTOR

The Sarangarh area falls in the north eastern part of Chhattisgarh basin. A major part of

the area forms a part of Bardwar sub basin of Chhattisgarh supergroup. Stream sediment

sampling in the area revealed presence of kimberlitic pyrope garnet which are found to be G-9 type

of lherzolitic derivative. In addition G-5 garnet has also been discovered from stream

sediment samples. Detailed sampling in this area is recommended.

PROSPECTS IN MAHARASTRA

Indicator mineral survey carried out in the western part of Bastar craton, falling in

Chandrapur and Garchiroli districts of Maharastra has revealed chrome diopside and G5 garnet.The

chrome pyroxenes show some similarity with the pyroxenes from the

Monastry kimberlite field, South Africa, in terms of their Ca/ (Ca + Mg) and Mg/(Mg + Fe)

ratio with chromium.

PALEOPLACER DIAMONDS OF WAIRAGARH, MAHARASHTRA:

Diamond incidence is known from conglomerates of Wairagarh area in Maharashtra. The Wairagarh

area exposes a narrow stretch of (10km x 6km), NNW-SSE trending low

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grade, highly deformed meta sedimentary belt within Archaean Amgaon Gneiss and forms a part of

the western part of Bastar Craton.

An octahedral diamond (3.5mm long and 2.5mm wide, 0.15 carat) was recently recovered

during the GSI investigations of the conglomerate unit of WMS. Along with diamond other heavy

assemblages identified include ilmenite, garnet (G-5 garnet, almandine, grossular and andraditic

garnets), pyroxenes, amphibole, staurolite, chrome spinel and rare tourmaline. This find has opened

up new vistas of diamond search in similar geological milieu in the western Bastar Craton.

PROSPECTS IN ORISSA

With Multisensor Twin otter aero-geophysical survey carried out by the Airborne Mineral Survey

and Exploration Wing (AMSE Wing) of Geological Survey of India during 1994-98 along E-W

flight lines at intervals of 500m with a mean terrain clearance of 80m covering an area of about

27,850 sq. km. from Mainpur Payalikhand area in the south to Raigarh-Sundergarh area in the north

around Chhattishgarh- Orissa border in search of kimberlite,.

NE-SW trending olivine lamproite dyke cross cutting a NW-SE trending dolerite dyke has been

discovered near Sakri village, Bargarh district, Orissa. Discovery of this lamproite has raised hopes

of finding more such dykes and main lamproite bodies along the ideal setting of the contact of Bastar

Craton and Eastern Ghat Mobile Belt. It may be mentioned here that this present setting is similar to

the Krishna lamproite field (KLF) on the eastern margin of Dharwar Craton just outside the NE horn

of Cuddapah Basin in Andhra Pradesh.

Discovery of a lamproite dyke on the margin of Bastar Craton and Eastern Ghat Mobile

Belt and incidence of several kimberlite indicators in Mainpur-Gariaband and Khariar road-

Paikamal area prove that the integrated strategy is well founded and worth continuing further to

utilize the vast amount of aero-geophysical data available with GSI pertaining to this area.

Recently State DGM has recovered diamond from a pipe in Kalmidadar.

The Cratonic domain of western Orissa lying in tectonic juxtaposition with circum

cratonic EGMB is a promising regional target of primary diamond exploration due to old diamond

panning records and recent discovery of kimberlite diatremes in adjoining state of Chattisgarh

having identical geological milieu.

KIMBERLITES AND LAMPROITES OF SOUTH INDIA

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Kimberlites and lamproites are located in about 270 x 180 Km area in Wajrakarur-Lattavaram-

Chigicherla-Kalyandurg area (WKF) in Anantapur district, Andhra Pradesh (A.P.), Narayanpet

Kimberlite Field (NKF) in Mahboobnagar district, A.P.and Gulbarga

district of Karnataka and Chelima-Zangamrajupalle area (CZLF) in Prakasam district,A.P. and

Jaggayyapeta Lamproite Field(JLF) also known as Krishna Lamproite Field of Krishna and

Nalgonda districts of A.P. These kimberlites and lamproites are known to occur only from the

Eastern Dharwar Cratonic block.

The WKF (14005'/ – 15003: 77018' – 77023'; Toposheet nos 57E/8 & F/5) measures 120kmx60km with

kimberlites emplaced into the gneisses and schist belt.A total of 21 kimberlites are distributed in 3

clusters, viz,

(i) Wajrakarur – Lattavaram cluster – 13 bodies (pipe – 1 to pipe-13)

(ii) Chigicherla cluster – 5 bodies (CC-1 to CC-5)

(iii)Kalyandurg cluster – 3 bodies (Kl-1 to Kl-3)

Majority of the pipes in WKF are diamondiferous.

During 2004, two new kimberlite bodies have been reported from Timmasamudram(TK-

1 & TK-2).

The (NKF) is located about 150 km southwest of Hyderabad and 200 km north of the WKF. It

measures 60 x 40 km in extent. The Kimberlites of (NKF), occur in four noticeable clusters, viz.,

(i) Maddur cluster – 11 bodies (MK-1 to MK-11)

(ii) Kotakonda cluster – 7 bodies (KK-1 to KK-7)

(iii)Narayanpet cluster – 10 bodies (NK-1 to NK-10)

(iv)Bhima cluster – 6 bodies (BK-1 to BK-6).

Incidence of diamond has not yet been reported from these bodies.

During 2001-02 inbetween NKF and WKF three new kimberlite bodies were discovered

near Siddampalle village (SK-1,SK-2&SK-3) in Gadwal district,A.P.

WAJRAKARUR KIMBERLITES

In Wajrakarur area, three kimberlite bodies (pipes 1, 2 & 6) are found over a length of 4

km in an E-W direction. The pipe 6 occurs in black soil area whereas the rest in the residual

brown soil area.

KIMBERLITE PIPE 1 (WAJRAKARUR PIPE)

The kimberlite reserves estimated for the southwestern part (400 x 150m) are about 6.94 Mt

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upto 60m depth with a diamond resource of 52,000 ct. Though the average incidence is less, large

majority of diamonds in general are gem quality and diamonds upto 9.45 ct were recovered.

KIMBERLITE PIPE-6 (WAJRAKARUR WEST PIPE)

Location: About 1.5 km west of Wajrararur and 300m north of Kottakunta tank.

Dimension: 260 x 240m – roughly circular in shape

Drilling: 19 boreholes. Deepest borehole upto 280m depth. The body is completely covered under

1.5m thick black soil. Yellow ground occurs upto a depth of 45m, followed by blue ground which

extends beyond 280m depth. A granite– kimberlite breccia raft (170m long and 30-80m wide) is

found in the centre of the pipe extending upto 35 to 40m depth. The kimberlite resources estimated

upto 60m depth are of the order of 5.99 Mt with a diamond resource of 40,000 ct.

KIMBERLITE PIPE -2 (WAJRAKARUR EAST PIPE)

Location: About 2.5 km east of Wajrakarur; Dimension: 380 x 70m

Drilling: 11 boreholes,Unaltered kimberlite at surface

The pipe is diamondiferous. Three diamonds were recovered after processing 278 tonnes of

kimberlitic material. Diamonds are of gem variety and range of weight is 0.04 to 3.26 ct.

LATTAVARAM KIMBERLITES

Four kimberlites (pipes 3, 4,8 and 9) are located in a radius of 0.5 km., about 1 to 1.5km

east of Lattavaram (14055': 77017'; 57F/5). Outcrops are scanty.

The results of exploration are as follows:

Pipe No. 3: Diamond incidence(cpht)- 0.28

Pipe No. 4: Diamond incidence(cpht)- 0.25

Pipe No. 8: Diamond incidence(cpht)- 0.33

Pipe No. 9: Diamond incidence(cpht)- 0.5

KIMBERLITE PIPE -5 (MULIGIRIPALLE PIPE)

Location: About 1.5 km east of Muligiripalle

Dimension: 240 x 45m

Sampling Five bulk sample pits ( 3 x 2 x 10m each). 276 cum of

excavation, 482t of processing. No diamonds recovered.

KIMBERLITE DYKE – 7 (VENKATAMPALLE KIMBERLITE)

Location: About 0.5 km east of Venkatampalle (14056:77021'; 57F/5)

Dimension: 1.2 km long x 0.5 to 30m wide – dyke like body.

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Av.Diamond incidence (cpht): 44.5

Kimberlite resources :About 0.5 Mt upto 90m depth (for the 600m length of dyke enlargements).

About 14000 t of overburden over the dyke enlargement.

Diamond resources: 48000 ct upto 90m depth in the kimberlite and 4700 ct in the

overburden over the dyke enlargements.

Diamond characteristics A large majority of the diamonds recovered from the

kimberlitres are gem quality. Till now, the pipes 1 and 6 and dyke 7 have yielded more number of

diamonds. In the pipes 1& 6, about 90% of the diamonds by weight are gem quality and in the dyke-

7, about 60% by weight. The largest diamond recovered from the area is 16.30 ct by weight (from

dyke-7) and is of gem variety.

KIMBERLITE PIPE – 10 (ANUMPALLE KIMBERLITE)

Location: 0.75 km west of Anumpalle village (14059' 40": 77030'55")

Dimension: 1200m long x 1000m wide pod shaped body.

Emplaced into the younger granitoids at the intersection of the ENE –WSW fracture with

the major NW-SE trending Singanamala fault. No outcrops, covered by 1.5m kimberlite

calcretre, rafts of granite float in the kimberlite – two linear disconnected satellite bodies noticed to

the west of the main body.

Pipe no. –P 10

Diamond recovery No/Wt.Ct.- 48/14.71

KIMBERLITE PIPE –11 (DIBBSANIPALLE KIMBERLITE)

Location 0.5 km SSE of Dibbsanipalle village (15002'00 : 77028' 00")

Diamond incidence (ct/100t): 0.78

Dimension: 143m long x 82m wide Bean shaped

Pipe no. –P 11

Diamond recovery No/Wt.Ct.- 2/2.15

Diamond incidence (ct/100t): 0.78

KIMBERLITE PIPE – 12 (CHINTALAMPALLE KIMBERLITE)

Location: 1 km west of Chintalampalle village (15002' 00": 77028' 00")

Dimension: 130m long x 40m wide

Pipe no. –P 12

Diamond recovery No/Wt.Ct.- Nil

Diamond incidence (ct/100t): Nil

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KIMBERLITE PIPE -13 (TUMMATAPALLE KIMBERLITE)

Location: 2.5km NE of Tummatapalle village (14049'55 : 77041' 00")

Dimension: 125m long x 100m wide

Emplaced into the TGA rocks along a ENE-WSW sinistral fault that displaces the

Manutla dome.Melanocratic outcrops and partly weathered and altered kimberlite capped by

calcretes.

A.2. CHIGICHERLA AREA (WKF)

Coordinates: 14031': 77041'; Toposheet no. 57F/10

KIMBERLITE PIPE CC-1 :

Dimension: 315 x 185 m – pear shapedA grab sample of 119 t from a well dump in the body yielded

4 diamonds weighing 0.44 ct. Subsequently 436 tonnes of material has been processed which yielded

5 diamonds weighing 1.31 ct averaging 0.30 cpht.

KIMBERLITE BODY CC-2

Dimension 200 x 175m

A total of 302 tonnes of kimberlite material was processed which yielded two diamonds weighing

1.02 ct averaging 0.35 cpht

KIMBERLITE BODY CC-4

Location: about 1.75km west of Golapalle

Dimension: 125m x 100m, nearly circular in outline

Incidence of diamond: 15 diamonds weighing 2.17 ct were recovered from 88 tonnes of kimberlite

material drawn from 5 trenches, indicating an average diamond incidence of 2.46cpht.

KIMBERLITE BODY CC-5

Location : This kimberlite body is located about 1km NE of Gollapalle.

Dimension : 220m x 70m

Incidence of diamond : 6 diamonds weighing 1.38 ct have been recovered from 175

tonnes material of pipe CC-5. All are gems ranging in weight from 0.05 to 0.51 ct, the

average weight of the stones being 0.23 ct.

A.8. CHELIMA-ZANGAMRA JUPALLE AREA (NALLAMALAI FOLD BELT )

A number of kimberlites/lamproites exists and lie undetected in the soil covered areas south, west

and north of the Cuddapah Basin and within the basin itself. The known source rocks tested so far

are not of much economic significance and therefore intensive efforts are needed to identify

additional primary host rocks for diamond.

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A.9 JAGGAYYAPETA (KRISHNA) LAMPROITE FIELD (JLF/KLF )

The JLF or KLF falls north of the Krishna River, along the eastern margin of Dharwar

Craton (DC) in Krishna and Nalgonda district spread over an area of about 160 sq. km. and

comprises 25 lamproite bodies located just outside the peripheral parts of the north-eastern horn of

Cuddapah basin. The lamproites occur as 0.5m – 5m dykes, mostly as clusters and run for lengths of

about 1m to 400m in close association with dolerite dykes mostly emplaced along the contacts

between granite gneiss and dolerite dykes.

A.10. SIDDAMPALLE KIMBERLITES

During 2001-02 three new kimberlite bodies were discovered near Siddampalle village in Gadwal

district, Andhra Pradesh. The first body (SK-1) measuring 100x65m is located about 2km N25E of

Siddampalle village and SK-2 measuring 110x50m is located about 1.5km N10W of Mallapuram

Tanda. The third body (SK-3) measuring 26 x 14m is exposed in a well section. SK-1 & SK-3 are

mainly ‘hardebank’ variety while SK-2 is a concealed body with calcrete cover.

B. CONGLOMERATES

B.1 BANGANAPALLE - NEREDUCHERLA AREA

Banganapalle - Nereducherla, Kurnool district.

Coordinates : 15012' -15020'; Long.: 77050'-78015';Toposheet no. 57 I/2 & E/16

Extent : 30 km long and 200 m to 2 km wide

Exploration: To assess diamond potential of the conglomerates (mainly basal) exploration was

carried out in 'two phases during 1980-87 by GSI in association with MECL and NMDC, in eight

selected blocks in the area, six in the Munimadugu-Allahabad plateau areas and two in the

Banganapalle-Rallakotturu-Lingambadi Plateau areas.

MUNIMADUGU BLOCK:

No. of diamonds/weight : 167/84,38 ct

Diamond incidence : 2.26 cpht

Average diamond weight : 0.50 ct

Conglomerate resource : 60, 700 t

Diamond resource : 2,000 ct

An average incidence of 8.32 cpht (spot values upto 35 cpht) was recorded. Average diamond

weight from this area is 0.87 ct.

ALLAHABAD WEST AND WEST EXTENSION BLOCKS:

No. of diamonds/weight : 221/71.24 ct

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Diamond incidence : 1.48 cpht

Average diamond weight : 0.32 ct

Conglomerate resource : 10,44,000 t

Diamond resource : 15,600 ct

Spot values for diamond are upto 7 cpht.

ALLAHABAD SOUTHWEST AND SOUTHWEST EXTENSION BLOCKS:

No. of diamonds/weight : 298/125.90 ct

Diamond incidence : 2.89 cpht

Average diamond weight : 0.42 ct

Conglomerate resource : 3,94,000 t

Diamond resource : 11,400 ct

An incidence of 8.23 cpht was

recorded over a length of 200m (with spot values upto 27.35 cpht)

RALLAKOTTURU - LlNGAMBADI BLOCK:

No of diamonds/weight : 104/51.67 ct

Diamond incidence : 2.59 cpht

Average diamond weight : 0.49 ct

Conglomerate resource : 21,37,00 t

Diamond resource : 26,600 ct

Of the total diamonds recovered, gem quality constitutes about 76% while the off colour and industrials, 8% and 16% respectively.

B.2 RAMALLAKOTA- YAMBAI AREA

The erratic distribution and lensoid geometry of the conglomerate beds warrant close spaced

pitting/shallow drilling to delineate the beds as well as estimate the conglomerate resources.

B.3 UNDUTLA-TAMMARAJUPALLE -CEMENTNAGAR AREA Area : Undutla-Tammarajupalle-Cementnagar, Kumool district.

Coordinates : 15030' –15025'.: 78010' – 78015'

The conglomerates from both the Undutla and Cementnagar Plateau have to be tested for diamond

potential.

Search for kimberlite in Buthpur and Achampet block in Mahbubnagar district, Andhra

Pradesh, yielded kimberlite specific minerals like picro-ilmenite and chrome-spinel in stream

sediment samples from Palkampally, Wattipalli and Kottapalli. Kimberlite specific minerals like

81

chrome spinel has also been recorded from Kalwakurthi and Charakunda block in Mahbubnagar and

Nalgonda districts.

GOLD

India ranked 6th in the world with a Gold production of 19.5 tonnes during the year 1905,

whereas the production of gold from primary source during the year 2007 is only 2.490 tonnes.

Kolar mine has produced more than 800 tonnes of gold before its closure in 2001. Presently gold is

produced from three mines viz Hutti, Uti, Hirabuddni (HGML) in Karnataka and as by product from

basemetal sulphide deposits of Khetri (Rajasthan), Mosabani, Singhbhum(Jharkhand), in public

sector and Kundrekocha in private sector in the decreasing order. In India, the total gold production

in the year (2006-07) was 12.82 tonnes, ( 0.5% of world production), of which 2.36 tonnes is from

primary source, 127 kg from basemetal mines as by product, and the remaining 10.34 tonnes

recovered from secondary source by smelting of imported copper concentrates by HINDALCO at

Dahej in Bharuch dist, Gujarat.

Kolar, the second deepest (3200 m) gold mine in the world, survived for 110 years and the

Hutti gold field witnessed four periods of widely separated exploration and mining Viz, Pre Asokan

+2000 years old, Nizam period 1886-1920; 1937 to 1947; and the present and most successful from

1947 onwards. The deepest (about 250m in length and over 195m in depth) known old working in

the world is located on the Main reef at Hutti gold mines.

The advent of worldwide gold rushes in 19th century laid the foundation for present day mining

activity. The gold boom was experienced in India with discovery and mining in Kolar, Hutti, Gadag,

Ramagiri, Honalli, Wynad, in the South and a few in North viz, Lawa, Mysara, Pahardia,

Kundrekocha, etc. Most of the old workings were closed due to dwindling production and prevailing

cost-benefits.

Geochronological data of gold metallogeny revealed major periods of enrichment as

Archaean and Proterozoic. Gold occurs in a variety of litho assemblages, and multiple geological

environments / settings such as greenstone belts, mantle derived intrusions, diaperic juvenile plutons

and granulites. In the Indian subcontinent, prominent granite greenstone belts of Peninsular Sheild

are located in Dharwar, Bastar, Singhbhum and Rajasthan cratons. The Dharwar craton, with two

blocks viz the eastern and western, hosts the maximum number of gold occurrences. The Eastern

block provides an important and favourable lithologic, structural and stratigraphic milieu for gold

mineralization and hosts major deposits like Kolar and Hutti.

In the northwestern Indian Shield, gold occurs in association with copper in the Archaean

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greenstone-like sequence (at Dhani Basri, in Mangalwar Complex) and Proterozoic

metavolcanosediments (at Bhukia and Dugocha, in Aravalli Supergroup) with enrichment in the

latter. Gold also occurs in Palaeo / recent river alluvium placers, laterite, soil and regolith. Puga

geothermal system is a “hot spring” type epithermal gold deposit in the making, in the Ladakh

region of Jammu and Kashmir.

In SGT, the primary gold mineralisation is recorded in three different geological settings

viz.(i) Archaean greenstone belts similar to Dharwar Craton, (ii) in Banded Iron Formations (BIF)

and amphibolite associated with granulites and (iii) in quartz-carbonate veins related to alkaline

magmatism. Among these, the gold mineralisation associated with the greenstone belts is quite

significant.

Kolar Gold Fields (KGF) had been the primary gold producer in the country. From the

position of a large producer in the world (790 tonnes since 1880 from a grade of about 16 gms/t), it

became an insignificant gold producer with grades lowered to about 3-4 gms/t to about one tonne per

annum in the mine.The KGF comprising the Champion, Nundydoorg, Mysore and Bisanattam mines

is located in the central part of the 80 km long Kolar Schist Belt. There are two zones of subparallel

lodes, sub-conformable to the meta-basite host rock viz., the Champion lode on the east and on the

west the Oriental and McTaggert lode.Gold-polysulphide association were identified in Champion

Reef and gold-pyrrhotite-arsenopyrite in McTagart lode with characteristic scheelite.The deposits

are vein type with wall rock alteration, especially in the eastern part of the belt.The economical

values of gold ore in the southern end of the Kolar Schist Belt came into limelight at the time the

KGF values were uneconomical to mine and is marked by a number of old workings.Gold

mineralization in the southern belt was established by GSI at Chigargunta, Mallappakonda,

Bisanattam, Kudithinapalle and Avulathinapalle.The Chigargunta mineralization in the south is in

non-conformance with that of the KGF to the north and is in distinct tectonised zones and post-dates

the major folding and amphibolite grade metamorphism.The 3 km long mineralized zone occurs in

the amphibolite and Champion Gneiss units as well as on their contacts, confined to shear zones.A

reserve of 4.19 Mt with grade ranging from 4.2 to 5.22 g/t of Au over widths ranging from 1.46 to

12.05m was estimated. The deposit is under exploitation by the BGML. In Mallappakonda Block,

auriferous zones associated with BIF are lensoid, parallel and enechelon occurring over a strike lenth

of 400m.A reserve of 0.65 Mt of ore with an average grade of 4.3 g/t was established.In Bisanattam

Block, both GSI and MECL carried out investigations for gold. The mineralized zones found in

fissile amphibolite are lensoid, parallel and en-echelon in disposition and vary in width from 1 to 3

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m. About 0.13 Mt of ore with a grade of 5.1 g/t was established.The deposit was mined by BGML

and since been closed.In Kudithinapalle Block, located 3 km south of Bisanattam Mine, gold

mineralization in quartz reefs is hosted by both hornblende schist and Champion Gneiss. The quartz

reef is about 100m long and 2 to 3 m wide. A reserve of 0.48 Mt ore with an average grade of 1.2 g/t

was established. Molybdenum is also found in the quartz veins.

Gold mineralisation is reported in the southern extension of the Kolar schist belt in

Veppananpalli and Bargur sectors in Krishnagiri district of Tamil Nadu. In Veppananpalli sector,

the southern continuity of the Kolar schist belt is traceable as two narrow linear strips, viz. the

eastern Maharajagadai strip and the western Adakonda strip representing synformal keels.

In the Maharajagadai block, eleven zones of gold mineralisation have been delineated

within the silicified zones in quartz-sericite schist (Champion gneiss) occurring in association with

amphibolite. The epigenetic gold mineralisation is mainly confined to the sheared and silicified

zones in the quartz-sericite schist. Gold is associated with sulphides, viz. pyrite, pyrrhotite,

sphalerite, chalcopyrite, arsenopyrite and galena of which pyrite is the most dominant. Exploratory

drilling in this block has indicated a potential reserve of 0.07 million tonnes of ore with 1 to 2 g/t of

gold upto 75 m vertical depth.

In the Adakonda Block, gold mineralisation is confined to sheared and silicified zone in

amphibolite and associated BIF. In this block, gold is associated with pyrite, pyrrhotite, arsenopyrite

and chalcopyrite. The surface exploration, by trenching and groove sampling, has indicated gold

values ranging from 0.2 to 2.57 g/t with an average width of 1.5 m over a strike length of 450 m.

Near Bargur (15 km SE of Maharajagadai block), gold mineralisation has been recorded in

the amphibolite band occurring within the gneisses. The mineralisation is traceable for a strike

length of about 75 m over a width of 0.65 to 4.45 m with gold assay values ranging from 0.2 to 0.96

g/t.

In the Hutti-Maski Schist Belt, gold mineralization is localized along the shear zones

developed parallel/subparallel to S1 schistosity in both basic and acid meta-volcanic rocks.The Hutti

Gold Mines located in the northern part of the belt produced 1048 Kg of gold during 1990-91.

Extensive and detailed investigations were carried out by GSI in Hutti mines area, Wandalli, Uti,

Hira-Buddini and Maski, proving sizeable gold reserves.

In the Gadag Gold Fields of Chitradurga district, ancient workings and mines are seen over

an area of 200 km2. All the known gold bearing lodes are confined to the western limb of an

overturned syncline over a strike lenth of 15 km.The prospects explored by GSI are-(i) Western

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Group comprising Hosur-Champion, Yelishirur and Venkatapur mines hosted dominantly in meta-

basalts and meta-andesites, (ii) Middle Group comprising Kabuliyatkatti-Attikatti, Mysore Mine and

Sangli Mine, hosted mostly in greywacke,and (iii) Eastern Group comprising Sankatodak Block and

a fewer prospects east of Nabhapur and Kabuliyatkatti villages, hosted in greywacke. In addition,

gold mineralization is also known from the area north of Nagavi hosted in BIF in contact with

tuffaceous rocks.

In the Anesidri-Ajjanahalli-Bellara area, Tumkur district, Karnataka, gold mineralization is

associated with meta-volcanics as well as sulphide banded iron formation of the Chitradurga Group.

In the Ajjanahalli block, 10 parallel zones of mineralization localized in shear zones in sulphidic BIF

along a fold have been delineated by GSI. The strike lenth of the block is about 1500 m. The

estimated reserves at 0.5 g/t cut-off grade are 0.77 Mt of ore.

Very recent exploration for gold by GSI in Ajjanahalli Block-C, Tumkur district, Karnataka

on.bedrock samples yielded gold value ranging from 0.10 g/t to 4.22 g/t. Analysis of trench samples

indicated gold value ranging from 0.36 g/t to 6.0 g/t. In Ajjanahalli block-F, three major auriferous

BIF bands have been delineated. Band-I (strike length 300m average width 3 to 4m) has recorded

1.02 to 2.2 g/t gold; Band-II (strike length 200m average width of 2m) has recorded 0.28 to 1.70 g/t

gold; Band III (strike length of 700m average width 4m) has recorded gold values from 0.03 to

0.70g/t.

The Ramagiri-Penakacherla Schist Belt extends over a strike lenth of 100 km with

number of gold prospects grouped into two fields viz. (1) Ramagiri Gold Field (RGF) and (2)

Bhadrampalle Gold Field (BGF). RGF has a reserve of 0.7 Mt with an average grade of 7 g/t in the

Om Pratima-Gantalappa Block. In Kottapalle Block, north of this mine, a probable reserve of 0.11

Mt withan average grade of 2.65 g/t over an average width of 1.41 m was estimated upto 165 m

depth. Auriferous lodes of BGF are of small length. A reserve of 0.023 Mt of ore with an average

grade of 4.13 g/t of Au over an average width of 1.21 m upto 75 m depth for the main lode and 0.36

Mt with 2.34 g/t of gold over a width of 1.00 m upto 80 m depth for the northern lode has been

estimated. In Ramapuram area, preliminary exploration has led to estimation of 0.07 Mt of ore upto

a maximum depth of 70 m for 4 lodes over width varying from 1.29 to 1.56 m and gold content

ranging from 1.28 to 1.39 g/t. Ancient mining activity is recorded in both the fields.

Another prominent area of gold mineralisation is located in Wynad gold field in Devala-

Pandalur, Cherambadi and Kotagiri sectors in Nilgiri district of Tamil Nadu and in the adjoining

parts of Kerala.

85

In Devala-Pandalur sector, gold mineralisation is confined to zones of intense shearing and

dislocation which have acted as loci for emplacement of auriferous quartz veins. The host rocks for

these quartz veins are biotite gneiss with interbanded hornblende granulite and magnetite quartzite.

The gold mineralisation is associated with intense wall rock alteration in the form of sericitisation

and chloritisation. The gold-bearing quartz reefs show a general trend of N-S. Two main types of

gold mineralisation have been recognised – one is sulphide-rich and the other is sulphide-poor type.

Alpha-Victoria, Nadghani, Solomon and Hare Wood mines near Devala and Phoenix,

Rosedall and Glenrock mines near Pandalur are the important old workings located in this sector.

Samples collected from this sector have analysed gold content of 3.06 to 15.2 g/t. The exploratory

drilling carried out in some of the old working areas reveal that in Alpha-Victoria mine, the gold

mineralised zone is traceable for a strike length of about 1000 m over a width of 1 to 3 m with an

average tenor of 1.98 g/t. In Hare Wood mine, the maximum strike length and width of the lode are

116 m and 30 m respectively. In Solomon mine, the lode is having a width of 2 to 5 m for a limited

strike length of 40 to 60 m with grade varying from 1.9 to 6.04 g/t.

In Cherambadi sector several old workings for gold are located in Mangorange,

Duraiswamikaradu, Went worth-I & II and Cherangode. Auriferous quartz veins occur in sheared

biotite gneiss showing intense sericitisation. In Mangorange tea estate, two quartz veins are

exposed. The first one occurring in the form of two detached en-echelon reefs trending in E-W

direction with 25 to 30º dip towards north. Among these two reefs, the prominent one is having a

strike length of over 1.5 km with a width of 2 m. The other reef is measuring 100 m x 2 m. Another

quartz vein has been traced for a strike length of 1.2 km with width varying from 1 to 3 m. In

Duraiswamikaradu area, a quartz reef with a thickness of 1 to 3 m over a strike length of 0.8 km has

been traced. This shows NE-SW trend with southeasterly dip in the southern part and N-S trend

with 60º dip towards east in the northern part. In Went Worth-I & II old workings, three quartz reefs

are exposed. The width of the individual quartz reefs varies from 20 cm to 5 m and traceable for a

length of about 60m. The gold assay values of the samples collected from this sector are not

encouraging.

Gold occurrences and ancient mining activities are also reported from Adathurai-Kotagiri

sector located in the eastern part of the Nilgiri hill ranges in Tamil Nadu. Preliminary sampling by

GSI in the year 1967, from the old inclines, drives and trenches has indicated an average gold value

of 2.41 g/t from 61 samples with 18.3 g/t being the highest value. Subsequent detailed studies by

GSI (2004-06) have brought out that the Adathurai area is traversed by a major brittle-ductile shear

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trending N-S to NNE-SSW. All along the shear / fracture planes, emplacement of auriferous quartz

veins is noticed.

Chemical analysis of the trench samples collected from this zone shows an average gold

values of 2.26 g/t over 2.5 m width and 6.2 g/t over 1.5 m width in two profiles. Similarly, the

samples collected from an gold incline have analysed a maximum gold value of 22.9 g/t thereby

indicating than this zone is a promising one for gold mineralisation. Four first level boreholes

drilled in this zone have indicated the depth persistence of the gold mineralised zone at 50 m vertical

depth. Although the assay values obtained for the core samples by AAS are not encouraging,

selected samples analysed by Fire assay method have indicated gold values upto 5.8 g/t.

In Gopanari-Velliyankadi sector in Coimbatore district, forming the eastern

extension of Attappadi valley in Kerala, gold minerlaisation is reported within the fractured and

sheared quartz veins emplaced along minor shears developed close to the major Bhavani Shear

Zone. The general trend of the quartz veins varies from NE-SW to ENE-WSW and occasionally

along NNW-SSE to NW-SE directions. The quartz veins occur as small stringers as well as thick

veins having a maximum width of about 5 m over 150 m length. The quartz vein contains sulphides

which are mostly pyrite and subordinate arsenopyrite. Limonitistion is seen along the fracture

planes. A total of five zones of gold mineralisation represented by lensoid auriferous quartz veins

have been delineated. These zones vary in length from 7 to 13.5 km. Samples collected from the

auriferous quartz veins have shown gold values ranging from 0.03 to 3.5 g/t. This prospect falls

within the Gopanari Reserved Forest area.

Old workings for gold are also recorded in Bensibetta-Modikadavur -Inbakombai

sector in parts of Erode and Coimbatore districts. Auriferous quartz veins are found within the

sheared granitic gneisses which occur in association with charnockite, pyroxene granulite and minor

meta-sedimentaries of Sathyamangalam Group. These lithounits show intense shearing marked by

cataclasites, mylonites and phyllonites. Preliminary sampling by GSI has indicated gold values from

0.1 to 0.8 g/t.

Wynad gold field is one of the earliest known gold fields in the country, where gold

is found in quartz reefs. Placer deposits of gold are known from Nilambur valley in Malappuram

district.

In Kottathara block of Attapadi valley, Palaghat district, Kerala, 60000 tonnes of

gold ore with an average grade of 13.6 g/t has been established. In Maruda area of

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Malappuram district, are estimated reserve of 0.55 million tonnes of primary gold ore with an

average grade of 4 g/t over a strike length of 350 m upto a depth of 100 m has been worked out by

KMEDP.

Preliminary exploration carried out by GSI by test drilling has indicated six parallel

lensoid zones in en echelon pattern in Kappil prospect and two lensoid lode zones in Mankada

prospect. Gold mineralisation is restricted to the highly sheared and fractured quartz vein within the

biotite-hornblende gneiss and amphibolite. The grade of the mineralisation in Kappil prospect

ranges from 1.28 to 4.58 ppm and preliminary estimate indicate 0.462 m.t. of ore with a gold content

of 1726 kg in Kappil prospect.

Gold mineralisation has been reported by GSI in epigenetic quartz veins emplaced

within amphibolite / granite gneiss in Puttumala in Attapadi valley in Palakkad district. A

structurally controlled mineralised zone with an average width of 1.75 m has been traced with a

value of 7.3 g/t gold.

Besides, preliminary gold occurrences are also known in Meppadi, Chundale,

Vayittiri, Tariode, Vattam, Kuthimada, Karumsanthod, Thavingal, Venmani, Kakkarikunnu and

Manathoddy areas of Wynad district in Kerala. The tenor of gold bearing reefs in Wynad Gold

fields is generally 2 to 3 g/t.

ii) Gold mineralisation associated with Archaean BIF in granulite terrain

Numerous bands of Banded Iron Formation (BIF) occur in association with

charnockite and pyroxene granulite within the granulite terrain in northern Tamil Nadu in parts of

Dharmapuri, North Arcot, Tiruvannamalai, Villupuram and Salem districts. The BIF shows

transition from quartzite (oxide phase), magnetite-orthopyroxene bearing quartzite (silicate phase) to

silicified sulphide rich quartzite (sulphide phase). These BIF show intense shearing, brecciation and

minor drag folds. Gold bearing quartz veins occupy the shear zones and fracture / foliation planes

within the BIF.

Preliminary prospecting of the BIF occurring in Melchengam-Attipadi-Thirthamalai belts

and in Vediappanmalai-Kavuthimalai-Uchchimalai areas of Tiruvannamalai district has indicated

gold values ranging from < 0.1 to 0.6.5 ppm. Samples collected from Kannakadu Malai and east of

Ravathanallur in Villupuram district have assay gold values ranging from 0.28 to 0.6 g/t.The

samples collected from the BIF of Nainar Malai, Idaiyappatti, Rasipuram, Kariyampatti and other

areas have analysed 0.1 to 0.9 g/t of gold.

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The available data indicate that gold mineralisation in BIF is sporadic and the higher

values of gold are mainly from the silicified zone in BIF.

iii) Gold mineralisation associated with Neoproterozoic alkaline-carbonatite complex

In northern part of Tamil Nadu, an array of alkaline-carbonatite complexes is found within

the major NNE-SSW trending Dharmapuri shear zone. This zone is marked by intense shearing,

hydrothermal alteration of the charnockite and the associated quartzofeldspathic gneiss with profuse

development of epidote and carbonates and emplacement of several quartz veins. The Harur-

Uttangarai molybdenum prospect is located within this shear zone.

A few occurrences of gold are reported in the quartz veins as well as in the ankerite-

siderite bearing quartzofeldspathic gneiss within this shear zone. The prominent among them are in

Nekkundi area near Vaniyambadi and in Andipatti-Elavadai-Ammapettai and Vellakkal west sectors

within the Harur-Uttangarai molybdenum belt in Dharmapuri district.

In Nekkundi area, gold mineralisation occurs in the quartz veins emplaced within the

sheared epidote-hornblende gneiss containing quartz-carbonate and ultrapotassic veins. The major

quartz vein trending in NE-SW direction is traceable for a strike length of about 1 km with a width

varying from 1 to 20 m. Chip samples collected from the sheared quartz vein with perthosite have

analysed gold values ranging from 01. to 4.35 g/t with sporadic high values upto 10 g/t.

In Andipatti area, a major quartz vein is traced for a strike length of 600 m with width

varying from, 5 to 27 m. Out of 42 groove samples collected from the entire length of the quartz

vein, six samples have analysed 1.05 to 1.25 g/t of Au, fifteen samples showing gold values from 0.2

to 0.8 g/t and five samples giving 0.04 to 0.15 g/t of gold.

In Elavadi area, the auriferous quartz vein is 1 km long and 4 to 12 km wide trending in

N20ºW-S20ºE to N-S. Out of 87 groove samples collected from this vein, two samples have

analysed 2.46 to 3.10 g/t of gold, eighteen samples have analysed 0.11 to 0.73 g/t and six samples

analysed 0.03 to 0.09 g/t. The remaining samples have shown < 0.03 g/t of gold.

The 1.4 km long quartz vein traced in Ammapettai area shows a general trend of N20ºE-

S20ºW with 20º to 40º dip towards southeast. The width of the quartz vein is 5 to 17 m. It shows

intense shearing and wall rock alteration. Out of 117 groove samples collected from this quartz vein,

five samples have analysed 1.1 to 5 g/t of gold and six samples analysed from 0.13 to 0.3 g/t. The

remaining samples have shown gold values <0.3 g/t.

In Vellakkal west area, a feebly carbonated quartz vein is traced for a strike length of

800 m with width varying from 5 to 15 m. Out of 62 groove samples, only three samples have

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analysed 1.39 to 3.0 g/t of gold. Twenty seven samples have shown gold values ranging from 0.03

to 0.08 g/t and the rest of the samples give only < 0.03 g/t of gold.

In Velampatti block, the sheared quartz vein have analysed 0.2 to 1.0 g/t of gold in

association with molybdenum in several boreholes drilled upto 320 m vertical depth.

Besides these primary gold occurrences, placer gold is reported from several parts of

Tamil Nadu in Singiliyankombai and Iswaramurthipalaiyam area in Salem district, Veppanapalli

area in Dharmapuri district and in Arakkadavu-Gudaiyur-Velliyankadu-Bhavanisagar sector in

Coimbatore and Erode districts.

In the Proterozoic metavolcanosediments of the northwestern Indian Shield, the major

reserves of gold are from the Jagpura-Bhukia belt in Banswara district of Rajasthan. Five parallel

zones extending over a strike length of 2 km is delineated. Minor occurrences are noted in Hinglaz

Mata area (Dungarpur district), Ladera area (Jaipur district), and from associated copper ores of the

Khetri copper belt. Besides, gold is also noted to occur in Pindwara-Watera belt, which is about 20

km long. On the basis of analytical result a resource of 22.97million tonnes of gold ore with 1.81 g/t

Au has been estimated in Delwara West block, Rajasthan by GSI. The total gold resource of Bhukia

gold prospect has been augmented from 60.58 million tonnes to 83.55 million tonnes with average

grade of 1.87g/t Au. The stage of exploration corresponds to G-3 of UNFC system.

Primary gold prospects occur in shield areas of Uttar Pradesh in Lalitpur and Sonbhadra

districts. A tentative resource of 0.053 million tonnes gold ore with an average grade of 3.03 g/t Au

has been estimated in the Proterozoic rocks of Sonapahari area, Sonbhadra district, Uttar Pradesh.

The stage of exploration corresponds to G-3 of UNFC system.

Au mineralization of Gulaldih : Extensive old workings occur over a strike length of about

10 km from Gulaldih Detailed geological mapping and examination of old workings have revealed

presence of a N85°W-S85°E trending shear zone in the volcanosedimentary sequence of Agori

Formation. The mineralisation occurs in the quartz veins and is associated with sulphides of lead,

copper, iron, etc. Clusters of quartz veins form detached lenticular bodies. Gossan zones are well

developed and are marked by boxwork with limonitic coatings. The prospect is divided into Bhiwa

and Gulaldih block.Prospecting by Geological Servey of India in Bhiwa block indicated that, the

shear zones occur in two sub parallel zones in Agori Formation. The northern zone extends for about

2.4 km with width varying from 0.30 m to 2.0 m The southern zone is in arenaceous phyllite

with width varying from 0.40 m to 2.0 m. Chemical analyses of samples have analysed gold upto

3.87 ppm with background value of 0.3 ppm and threshold value of 1.3 ppm.

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The known gold deposits of the Central Indian Shield includes Sleemnabad in Jabalpur MP,

Parsori West, Kitari-Marupar deposits of Nagpur district, Maharashtra, BIF hosted gold deposits of

Sonadehi, Bastar district, Pandripani deposit of Raigharh district Chhatisgarh .The estimated gold

resources of the region is of the order of 2.69mt.This is likely to yield of 4.5 tonnes of yellow metal.

Investigation for gold mineralization in Sonadehi gold prospect Chhattisgarh, revealed a resource of

2.28 million tonnes with 0.699 g/t gold. The stage of exploration corresponds to G-3 of UNFC

system.

In the Eastern Indian craton, one of the important metallogenic provinces of India, gold is

obtained as important by-product during the extraction of copper (and other elements) from the

copper ores of the Singhbhum copper-uranium belt. Gold occurs in these ores as discrete grains.

Auriferous quartz reefs are commonly found in the low-grade metasediments and

metavolcanic rocks of ultramafic to acidic composition belonging to Iron ore Group and Singhbhum

Group and volcanics of Dhanjori-Dalma affinities. Among the important areas Kunderkocha deposit

is considered to be highly potential.Reserve of gold in Kunderkocha as on 1.4.1990 was 0.1 ton.

Another prospective area is the Tomka -Daitari region, south of the Jamda - Koira valley. The Lawa-

Maysara deposits and quartz-pebble-conglomerate located at the base of Dhanjori basin is equally

potential in view of its multi-metal association in the latter. Decades back gold was mined from

Lawa and Mysera, north of the Dalmas. The other notable occurrences in this area are Pahardia,

Ankua, Sausal, Bhitardari and Digarsai. The one at Sonapet is also quite significant. . ln north

Singhbhum, gold is reported from a number of places located to the north and south of Dalma range.

Chaibasa Formation forming the lower part of the Proterozoic Singhbhum Mobile Belt hosts

occurrences of gold at Pahardia, Rungikocha, Ankua, Sausal. At Pahardia a gold ore resource of 0.25

mt with 3.85 g/t gold at 1 ppm Au cut off has been estimated up to 65m vertical depth. At Parasi

work by Geological Survey of India revealed an estimated gold resources of 0.11 million tonnes of

3.84 g/t Au (at cut off 3 g/t), 0.62 million tonnes of 1.83 g/t Au (at cut off 1 g/t) and 1.6 million

tonnes of 1.07 g/t Au (at cut off 0.5 g/t).Recently the intensely fractured quartzite underlying the

Dhanjori volcanics and the quartz pebble conglomerate (QPC) have shown significant gold values.

The average grade of gold revealed from matrix-supported QPC bands of Haludbani sector is around

0.75 g/t. The bulk sample from Haludbani and Baruniya revealed 1.28 g/t and 0.306 to 0.66 g/t Au

respectively. Primary gold mineralization in reef quartz is noted intersecting pelitic and volcanic

sedimentary sequences at Babaikundi and Birgaon along Tamar- Porapahar Shear Zone traversing

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Chhotanagpur Gneissic Complex. Auriferous quartz vein extending for about 500m shows gold

values from 0.30 to 1.54 g/t with thickness varying from 0.15 to 3.0m.

Gold has been traditionally obtained from the sands of the rivers and streams of southern

Chhotanagpur. Alluvial gold in Sonapet valley of Ranchi district varies from 0.045-0.68 g/cu.m in

gravel. One placer sediment near ichagarh and another 1.5 km south of Ichagarh indicated 1200 ppb

and 555 ppb of gold respectively. Estimated tonnage of gold from placer along Sona nala and

Karkari nala are about 0.4 million tonnes with a maximum tenor of 20 ppb. Placer gold is also

known from Ankua. Recoverable resource of gold in Bihar & Jharkhand has been estimated to be

128.88 Mt (IBM, 2005).

Gold occurrences of Orissa are confined to mainly placers, though there is evidence of old

mining activity in the northern parts of Orissa, especially in Keonjhar disrtict adjoining Bihar.

Occurrence of alluvial gold has been recorded in almost all the districts of Orissa and panning of the

stream sediments in the major rivers has yielded gold.

Occurrences of native placer gold have been recorded from a few places in rivers of Upper

Assam, of which the Subansiri riverbed was the best gold producing area in Assam in older days.

Small grains of native gold were won by panning alluvial sand. In view of insignificant quantity of

gold, commercial exploitation of gold, is not possible. The placers presumably have been derived

from auriferous quartz veins in the metamorphic rocks of northeastern Himalaya.

Presence of sporadic gold placers, traces of silver and platinum are reported from Kupwara,

Leh, Kargil and Doda districts, Jammu & Kashmir. Placer gold has been reported from Bijnor;

Gonda, Lalitpur, Morabad distts of U.P and Nainital & Pauri Garhwal districts of Uttarakhand.

BASE METALS

The major discoveries of copper, lead, zinc deposits of India are in Khetri Copper Belt and in

the Dariba-Rajpura area in the Aravalli Supergroup of rocks in southern Rajasthan, in the Cuddapah

basin, Andhra Pradesh, in Malanjkhand, Madhya Pradesh, in the Singhbhum Copper Belt, Bihar, in

Sargipalli, Sundergarh district,Orissa, in Himalayan region and in the Darjeeling Himalaya.Potential

occurrences are summarized tectonic betlwise:

Deposits/Occurrences in Dharwar Craton:

Two small deposits, one at Ingaldhalu located in the Chitradurga schist belt and the other at

Kalyadi located in Dharwar schist enclave within the Peninsular Gneissic Complex of Karnataka are

being worked on a scale of about 200 tonnes per day by the Chitradurga Copper Company which is a

subsidiary of the Hutti Gold Mines Co., Ltd.

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A belt of polymetallic sulphide mineralisation with copper, lead, zinc, antimony, arsenic,

gold and silver values has been traced over a strike length of about 40 km along the eastern part of

the Chitradurga Schist Belt. This mineralised belt (designated as the Chitradurga sulphide belt)

extends from Chikkanahalli (14°26: 76°22') in the north to Yarahalli (14°04: 76°26') in the south.

Copper mineralisation mostly occurs in quartz veins emplaced along shear zones occurring within

the metavolcanics. Pyrite mineralisation with galena and occasional quartz veins is seen in chert

bands and quartz reefs occurring within

the metavolcanics.

Copper mineralisation is prominent in the Belligudda-Ingaldhalu-

Kunchiganahalu sector over a strike length of about 5 km. Galena mineralisation with silver values is

seen in the Kurubamaradikere-Madikeripura area over a length of 10 km. Galena occurrences have

also been reported further to the north, near G.R. Halli. In addition, arsenic, antimony, and gold

mineralisation occur along the Gonur-G.R.Halli-Chikkananahalli stretch (about 16 km).

Ingaldhalu copper deposit, Chitradurga district:

The Ingaldhalu (14°11': 76°27'; 57 B/8) copper deposit which is now being mined by the

Chitradurga Copper Company is located in the Belligudda- Ingaldhalu-Kunchiganahalu sector. This

sector has been explored in detail by the GSI and the DUG. For purposes of exploration, this sector

has been divided into 5 blocks, (from south to north) viz., Ingaldhalu

South Block - strike length about 1.3 km; Mines block - strike length about 1.1 km ; Ingaldhalu

North/West Block - strike length about 1.8 km ; Ingaldhalu North block - strike length about 750 m

and Ingaldhalu Northeast block - strike length about 260 m. The mines of the Chitradurga Copper

Company are located in the Mine block and the North block.

The sulphide mineralisation is localised in quartz veins occupying narrow shear zones in the

metabasalts and is of polymetallic type containing copper, zinc and lead with some silver and gold

values. The principal sulphide minerals are chalcopyrite, pyrrhotite, pyrite and sphalerite with minor

galena.

The Mines block has been explored by 45 boreholes drilled by GSI and the Department of Mines

and Geology, Government of Karnataka. Mine development has been done to a vertical depth of

about 300 m in 12 levels.On the basis of the borehole data, the reserves in the Mine block have been

estimated to be 1.4 million tonnes with a copper content of 1.2% of

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which about 0.27 million tonnes have been blocked out by the mine development. The silver values

in the ore mined ranges from 6 to 85 g/t with occasional higher values of upto 950 ppm. The gold

content is generally between 0.1 to 0.2 g/t with occasional values upto 3 to 5 g/t.

Ingaldhalu North block : This block has been investigated by 24 boreholes drilled by GSI. The

mineralisation is similar to that in the Mines block. The copper lodes range in width from 0.44 to 4.3

m. (mostly less than 1 m). The grade ranges from 0.75 to 2.25% Cu, mostly around 1%. Appreciable

zinc and lead are also present in the mineralised zone.A reserve of about 0.22 million tonnes with an

average copper content of 1.46% has been estimated for this block over a strike length of 450 m and

a vertical depth of 120 m. The mineralised zone does not appear to persist to deeper levels.

Ingaldhalu North West block :This block lies in the area intervening between the Mines block and

the North block and has been explored by 37 boreholes drilled by GSI. The total strike length of the

block is 1.8 km. Significant concentrations (>0.5% copper) are confined to 4 discontinuous zones

varying in length from 70 to 440 m. The cumulative strike length of the 4 zones is about 1380 m.

The width of these zones range from 0.35 to 3.03 m (average 1.36 m) and copper content from 0.5 to

1.53% Apart from these, a parallel mineralised zone has also been established over a strike length of

about 350 m. The width of this zone ranges upto

1.55 m and copper content ranges from 0.35 to 1.77%.On the basis of borehole data, the reserves

estimated in this block are as follows :

Indicated - 77,180 tonnes with 0.95% Copper and 9.31 g/t silver.

Inferred - 314,150 tonnes with 0.95% Copper and 9.31 g/t silver.

Total = 391,330 tonnes.

Ingaldhalu North-east block : the copper content varies from 1.14 to 3.38%. The reserves estimated

in this block are of the order of 0.16 million tonnes with a copper content of 1.79%.

Ingaldhalu South block :In this block, copper mineralisation has been traced over a strike l length of

about 750 m. The copper content in the sulphide zones vary between 0.1 and 2.2%. Zinc ranges from

0.32 to 10%, generally between 2 and 6%,and lead from 0.3 to 9%, generally between 0.5 and

2%.Reserves have not been estimated from this block, since the average copper content is <0.5% and

the mineralised zones are very narrow.

The overall pattern of the distribution of copper, lead and zinc values indicate zoning of the metals;

copper with minor lead and zinc in the central part with the zinc and lead contents increasing

laterally both towards south and north of the Ingaldhalu Mines block. On the whole, the gold and

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silver contents of the mineralised zones in the Belligudda-Ingaldhalu-Kunchiganahalu sector are also

quite high. Some boreholes core samples have indicated upto

12.2 g/t gold and 950 g/t silver.

The economic viability of the Ingaldhalu operations can be improved marginally, if the recoveries of

gold, silver and zinc associated with the ores can be substantially increased from the present level of

less than 50%.

Madikeripura (14°13'30'': 76°26'30'') - Kunchiganahalu (14°12': 76°27'), Chitradurga district:

Geochemical sampling identified a few parallel en echelon quartz veins showing intense shearing

and presence of sulphides such as chalcopyrite,galena, sphalerite and stibnite, malachite and

cervantite and indicated multi-elemental anomalies (for lead, zinc, copper,antimony, arsenic and

silver) scattered over an area of about 2.5 sq.km. The quartz veins traversing acid and mafic-

volcanics have analysed 0.6% Cu, 3.2% zinc, 0.88% arsenic, 0.62% Sb and upto 410 ppm silver and

0.11 to 10.2 g/t gold. A few scout boreholes are being drilled in this block to evaluate the anomalies.

G. R. Halli Northwest block (14°16': 76°25'):

This block is located in the northern part of the Chitradurga Sulphide Belt with a well marked shear

zone trending NW-SE over a strike length of about1 km.Geochemical sampling has indicated

anomalous zones with values upto 0.66% copper and 0.30% zinc coinciding with I.P. anomaly zones

indicated by geophysical survey. Scout drilling to evaluate the anomaly is in progress.

Kennedlu Southeast block (14°07'45'': 76°30'), Chitradurga district : In this block, regional geochemical surveys have indicated high values of copper, lead and zinc in

rock samples. Samples of quartz veins have analysed upto 12% lead, 3-5% copper and 2% zinc. This

anomalous zone is also proposed to be evaluated by drilling.

Musturu (14°28': 76°26'), Chitradurga district : Two brecciated quartzose/cherty zones (250 to 800 m) within the Peninsular Gneissic Complex

contain disseminations of sulphides, viz., pyrite, chalcopyrite, galena and sphalerite. Three shallow

boreholes intersected only narrow, lean zones of copper, lead and zinc viz., 0.50 to 1.90 m with

0.16% -0.3% Pb, 0.11 - 0.52% Zn and 0.34 - 1.14% Cu.

Summing up, it can be stated that geochemical sampling and geological work carried out in

various parts of the 40 km long Chitradurga sulphide belt has identified a few small deposits over a

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strike length of about 5 km. The overall geological setting and indications of mineralisation warrant

further detailed work in the other parts of the 40 km long Chitradurga sulphide belt and its possible

extensions towards north and south.

The known evidences of mineralisation in Chitradurga Schist Belt are within the volcanic

sequence and are mostly proximal to the volcanic sources for emplacement of the metal. The

possibility of finding deposits located distally in the overlying metasedimentaries is to be critically

evaluated.

Garimanipenta (14°59'30'' : 79°33'10'' - 57 N/9) Nellore District :

The area exposes gneisses and schists of the Peninsular Gneissic Complex in the eastern part

and Dharwar schists in the western part. The rocks trend NW-SE with steep dips (55 to 75°) towards

south-west.Copper mineralisation is associated with vein quartz and pegmatites

intruding the amphibolites and mica schists. Out of 10 boreholes drilled in the area, only one

intersected sporadic copper mineralisation.

Sporadic occurrences of malachite, pyrite and chalcopyrite associated with vein quartz and

pegmatites in mica schists and amphibolites have been reported from a number of locations -in

Nellore District.

Jonnagiri (15°44': 77°31' - 56 E/11) Kurnool District: The area is made up of Peninsular Gneisses, granites, Dharwar schists (chlorite schists and

hornblende schists) basic dykes and quartz veins Old workings with extensive coatings of malachite

and azurite are seen over a strike length of 2 km in chlorite schist. Two bands of gossans are exposed

along the old workings. Drilling data indicates that the zone of sulphide mineralisation is essentially

made up of pyrrhotite and pyrite with subordinate chalcopyrite

and sphalerite. The zones of copper mineralisation are narrow with copper contents of 0.1 to 0.5%.

Only in one borehole a richer zone of 6.45 m thickness averaging 0.8% Cu and 2.20% Zn was

intersected. In one borehole, massive pyrite zone of 9 m thickness was intersected. This zone is

traceable over a strike length of about 300 m. The average sulphur content is about 23.12% over a

width of 5.24 m. Reserves of 0.9 million tonnes of pyrite ore with 2.3% sulphur are estimated down

to a depth of 100 m.

Sandur Schist Belt :

Yeshwantnagar (15°32'30' : 76°30'00''), Sandur taluk, Bellary district :

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Copper mineralisation occurs in the form of disseminations and stringers of chalcopyrite, chalcocite

and bornite associated with pyrite and pyrrhotite, within silicified metabasalts of Krishnanagar

formation of Sandur schist belt.Integrated surveys by GSI has indicated that the sulphide

mineralisation is very poor, highly scattered and erratic in nature. The chemical analysis of the

borehole cores from 32 shallow boreholes have given low copper values ranging from 10 ppm to

0.24% Cu, 70 ppm to 0.15% Ni, and 20 ppm to100 ppm Co, 10 to 20 ppm Pb and 30 to 100 ppm Zn.

The area is largely covered by soil. Evidences for mineralisation are seen in the well cuttings only,

Mailaram (17°43': 80°38') Deposit, Mailaram Belt, Khammam District : The area comprises quartz-chlorite schist, biotite gneiss intruded by amphibolite, granite, pegmatite

and quartz veins. The schists and gneisses (of the Sargur Supergroup) trend NE-SW and dip at 50 to

85° towards south-east. The quartz-chlorite schists is traversed by numerous veins of black, grey and

white quartz. Blue and grey quartz carry sulphide

mineralisation, whereas the white quartz is barren. The copper mineralisation is localised in a NE-

SW trending shear zone. Chalcopyrite is the principal ore mineral and is associated with

pyrite, pyrrhotite and molybdenite. Sericitisation is developed in the vicinity of the copper

mineralisation. The Mailaram block extends over a strike length of 1100 m and has been explored by

20 boreholes drilled by GSI. The deposit is now being mined on a small-scale by the Andhra Pradesh

Mining Corporation Limited. Exploration by drilling indicates that there are three orebodies in the

area. Viz., Main Oreshoot (400 m), Central oreshoot (140 m) and

Northern oreshoot (l60 m). The oreshoots are narrow and range in width from less than a metre to a

maximum of 12 m. The average width is around 2 to 3 m. At a cut-off of 0.3% Cu, reserves are

estimated to be 0.812 million tonnes with 1.07% Cu.

Deposits associated with sheared quartz veins and metabasic rocks traversing granitoids : Kallur (16°08'30': 77°12'25''), Raichur district:

The area, mostly under soil cover, comprising granite, diorites and pink porphyritic granite has been

investigated by 30 boreholes by the Department of Mines and Geology. The orebody is reported to

consist 4 sub-parallels to parallel zones ranging in length from 450 to 1100 m and in width from 5 to

40 m.The ore zones are lenticular with the maximum width in the central part. Copper mineralisation

in the area consists of disseminations of chalcopyrite and pyrite, native copper occasionally seen as

specks and flakes along joints and associated with specularite and haematite. A reserve of 2.47

million tonnes with 0.85% Cu has been estimated by the DMG.

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Machanur (16°15'50'': 72°42'30"), Raichur district :

Specks of chalcopyrite associated with malachite and azurite with minor specularite and pyrite are

noticed in the shear zone.The area has been explored by 6 boreholes drilled by DMG. These

boreholes have tested a strike length of 430 m. the deepest intersection being at about 210 m. On the

basis of drilling data, four lodes have been delineated.The lodes range in width between 2 and 30 m

with copper contents of upto 3.14%. Majority of the values lie between 0.12 and 0.97% Cu.

Reserves of 1.91 million tonnes with 0.95% Cu has been estimated.

Tinthini (16°23': 76°31') Gulbarga district : Copper mineralisation is seen in the sheared and brecciated hanging wall contact of the metagabbro

dyke over a strike length of 5 km. The mineralised zone extending over a strike length of 1.25 km

with width of 4.5 to 14 m contains on an average, 0.15 to 0.33% Cu. The deposit has been explored

by 26 boreholes drilled by DMG. Reserves of about 1.84 million tonnes with about 0.6% Cu have

been inferred. Subsequently, the deposit was taken up by exploratory mine development by the Hutti

Gold Mines Company Limited. 250.80 m of shaft sinking and 1879.60 m of level developments in

two levels were carried out over a strike length of 300 m in the central part of the block. The mine

development indicated that there is no improvement in the grade at depth. The work, was therefore,

concluded in view of the low grade ore.

The Kallur, Machanur and Tinthini deposits are located close to eachother and can probably be

worked as a cluster with common facilities for milling,beneficiation etc. Although the width of these

ore bodies and total reserves are fairly large (6.23 million tonnes), the average grade is again

marginal (0.80%). The economic viability will depend on the cost effectiveness of the mining and

beneficiation techniques.

Sowanahalli (12°08': 76°48' - 57 D/16), Mysore district:

In this area of high grade granulite rocks, the Konkanhundi layered complex, covering an area of

about 50 km2 and consisting of a rhythmic, layered (and concentrically arranged) sequence of

gabbro, norite and anorthosite, along with conspicuous non-layered norites occurs as an oval shaped

body within the Peninsular Gneissic Complex. Sulphide mineralisation is noticed in the northwestern

part of the complex in the form of gossans and malachite encrustations along fractures in a dolerite

dyke trending N18°W - S18°E. The gossan zone is traced for a strike length of 400 m intermittently.

Old workings are also present. 13 boreholes drilled by the DMG indicated mineralization consisting

of veinlets, stringers and disseminations of pyrrhotite, pentlandite, chalcopyrite and pyrite,

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intersected over narrow widths in 7 boreholes, with copper values of 0.14 to 0.37% over 0.20 to 3.50

m widths and Ni values of 0.10 to 0.42% over widths of 0.20 to 2.9 m..

Kaiga (14°51': 74°26' - 48 J/3) - Mothimakki (14°45: 74°34' - 48 J/9) area,North Kanara district: The rock formations in this area consist of rnetasediments, ultramafics and metavolcanics of

Dharwar Supergroup surrounded by granitic gneisses and traversed by dolerite dykes. Sulphide

mineralisation of the disseminated and occasionally massive type is found in the pyroxenite,

peridotite and gabbro which constitute the ultramafic complex in the area. Pyrrhotite is the dominant

sulphide with pyrite (cobalt bearing) and chalcopyrite in subordinate amounts.Marcasite, pentlandite

and bismuthinite and rarely native gold are also recorded.Exploration by drilling in the Kaiga area

has delineated a zone of copper

mineralisation over a strike length of 300 m. Reserves are placed at 0.32 million tonnes with 1.23%

Cu and about 0.2% Ni.

Deposits associated with schist belt enclaves in Peninsular Gneissic Complex : Kalyadi Copper Deposit (13°14': 76°09' 57 C/4), Hassan district:

The Kalyadi copper deposit is located in a supracrustal Dharwarian schist band relict in the

migmatite terrain of the Dharwar Craton. The rock types in the schist belt comprise hornblende

schists, quartzites, quartz-sericite schist which are the host rock of the copper mineralisation and

ultramafic rocks,quartz diorite and gabbro which occur as intrusives. The mineralised quartzite

exhibits sinistral drag folds and is involved in intense shearing, slickens-siding and puckers folding.

Copper mineralisation is confined to the sheared and folded quartzite, quartz-chlorite schist and to a

minor extent to amphibole-biotite schist. 34 boreholes drilled by GSI and Department of Mines and

Geology, Government of Karnataka. indicate that the orebody ranges in width from 5,60 to 26.31 m

(average 14.34 m). The average copper content in the various levels range from 0.59 to 1.03% with

an overall average of 0.89% for the 6 levels.Drill indicated reserves are placed at 3.8 million tonnes

and blocked out reserves at 1.2 million tonnes.

The reserves are adequate to support a 500 t.p.d. mine and the width of the orebody (average 14.34

m) is also adequate to permit larger scale operations. But the average grade of the ore is marginal,

and economic viability will depend largely on the feasibility of major reductions in the cost of

mining, milling and beneficiation.

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Kalasapura (I3°17': 75°56': 48 O/15), Chikmagalur district:

The area forms the southeastern part of the Chikmagalur schist belt and consists of Precambrian

metavolcano-sedimentary suite of rocks belonging to the Bababudan Group. The basal part of the

Bababudan group comprises conglomerate (quartz pebble) and current bedded quartzite and quartz-

sericite schist which are the host rocks for sulphide mineralization. Nine boreholes drilled in the area

by GSI have indicated zones ranging in width from 1.10 to 8 m (average 3.27 m) with copper

contents of 0.13 to 0.43% (average 0.25%). The mineralisation is conspicuously restricted to the

uppermost contact of the quartzite with amygdular amphibolite. Reserves of 0.16 million tonnes with

an average grade of 0.25% has been estimated over a strike length of 240 m. Uranium mineralisation

is also associated with the quartzite and conglomerate.

It may be worth while to explore for mineralisation of the type associated with the conglomerates at

Kalasapura.

Aladahalli (13°08': 76°21'; 57 C/8), Hassan district :

This is a narrow NW-SE trending schist belt within the Peninsular Gneissic Complex. Sulphide

mineralisation comprising pyrite, chalcopyrite and pyrrhotite occurs as disseminations in micaceous

chlorite schist. Several discontinuous NW-SE trending gossan zones are seen near Aladahalli,

Balehalli, Dasapura, Bhaktarahalli, Mangalapura and Ugranahalli. The gossan zones listed above

have been tested by drilling – 20 boreholes in Aladahalli Main block, 17 boreholes in Balehalli East

and Main block, 7 boreholes in Aladahalli West block, 10 boreholes in Dasapura block,3 boreholes

in Bhaktarahalli block, 5 boreholes in Mangalapura block and 1 borehole in Ugranahalli block. In

Aladahalli Main block, the following reserves have been estimated :

1% Cut-off with 1.6 million tonnes with 1.24% Cu.

0.8% cut-off with 1.757 million tonnes with 1.03% Cu.

0.5% cut off with 3.186 million tonnes with 0.75% Cu.

In the Aladahalli West block, two zones of mineralisation are present but no significant sulphide

zone was intersected.In the Balehalli block the copper content seldom exceeds 0.1%. The sixth

borehole drilled to test the eastern zone intersected a 16 m wide sulphide zone out of which a width

of 2.1 m yielded 0.48% Cu.The ten boreholes drilled in the Dasapura block have Reserves of 0.34

million tonnes with a copper content of 0.83% at 0.5% cut-off. The

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five boreholes drilled in the Mangalapura block also did not indicate any appreciable copper values.

Zinc values in the sulphide zones in Bhaktarahalli and Mangalapura East block were found to range

upto 1.36% over 4.15 m and 1.04% over 8.8 m respectively. Mineralisation

Exploitation of the deposits in the Aladahalli area can be done on small scale of about 300 t.p.d.

subject to economic viability.Occurrences similar to Aladahalli sulphide zone is also recorded from

Ramanahalli (13°23':6°20'), Kadikengalbetta (13°20': 76°16'), Hassan district.

Deposits / occurrences associated with ultramafic complexes:

Sulphide mineralisation (pyrite with subordinate pyrrhotite and chalcopyrite) associated with

titaniferous magnetite bands is seen near Nuggihalli (13°01': 76°28'), Belagumba (13°14': 76°18')

and Tagadur (13°26': 76°26'). In Nuggihalli the average copper in the individual borehole ranges

from 0.19 to 0.5% and nickel from 0.17 to 0.2%. In the Belgumba area, the drilling data indicate

copper values of 0.3 to 0.48% over widths of 1.8 to 5.8 m in two boreholes. In the Tagadur area,

sulphide mineralisation (pyrite, pyrrhotite, pentlandite and cubanite) is indicated in gabbro and

titaniferous magnetite bands over an area of 600 m x 200 m. The overall copper content is estimated

to be around 0.4% with occasional high values over narrow widths.Occurrences of basemetal

mineralisation with ultramafics have also been recorded from Ranganahallibetta (13°03' :

76°26'40''), Idagondanahalli (12°39': 76°19').

Masanikere (13°51': 75°59'), Tavarekere (13°51'30' : 75°57'30''),Magyathhalli (13°53'30': 75°57'00'') areas (48 O/13), Shimoga district : In these areas, the metasediments (quartz-chlorite-carbonate schist with quartzite bands) of the

Chitradurga Group are intruded by a gabbro anorthosite complex. The basemetal mineralization

(pyrite and chalcopyrite) is seen in the magnetite gabbro occurring in the basal part of the complex.

Copper is concentrated in the magnetite gabbro and vanadiferous titaniferous bands. Copper values

in these rock types range from 0.3 to 1.56% whereas the copper content in the other rock types is

less than 0.1%. Reserves of 6,38 million tones of titaniferous-vanadiferous magnetite with a copper

content of 0.36% has been estimated on the basis of the 1st and 2nd level boreholes. The copper

values were mostly less than 0.1% in the third level borehole. On the basis of drill hole data, reserves

of 8.2 million tonnes of

vanadiferous titaniferous magnetite with 0.34% Cu has been estimated. The copper content in the

ferrogabbro ranges from 40 ppm to 0.18%.

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Base Metal Deposits/Occurrences in SGT:

Kollegal (12°09': 76°07') area, Mysore district:

In this area located in high grade granulite terrain, two types of sulphide mineralisation are noticed -

syngenetic, stratabound pyrite and pyrrhotite associated with pyroxene granulite and magnetite

quartzite along Talbetta-M.M.Hills Ghat section and M.M.Hills-Palar Ghat section and the second

type of mineralisation consisting of pyrite, pyrrhotite and chalcopyrite occurring in the fenitised

gneiss and associated quartz veins related to alkali syenite-carbonatite emplacement near

Tomyarpalya . Old workings for copper are seen on the northern slope of the ridge near Hadabanatta

village.

In SGT of Tamil Nadu, only one basemetal deposit, Viz., the multimetal copper-lead-zinc

deposit at Mamandur is so far known. In addition, there are a number of reported occurrences of

copper and copper-nickel-sulphide mineralisation from a number of locations. These occurrences are

mostly associated with calc-granulites, pyroxene granulites, pyroxenites and maficultramafic rocks.

Quartz barytes vein with galena and molybdenite have been recorded from the Alangayam area.

Mamandur Deposit (12°02':79°02' - 57 P/4) South Arcot District :

This deposit lies in the Peninsular Archaean complex in the transition zone between

charnockites on the west and migmatites on the east. The Mamandur area is made up of migmatites

and charnockites with bands of garnetiferous biotite sillimanite gneiss, magnetite quartzite and a

suite of ultrabasic rocks comprising pyroxenite, gabbro, norite and anorthosite. The general trend of

foliation is NNE-SSW to NE-SW with dips of 60 to 65° towards SE. Galena from the mineralised

zone has given an isotope age of 2581 to 2600 Ma.

The Mamandur area has been extensively explored by large scale geological mapping,

geochemical soil sampling, geophysical surveys and drilling by the GSI and the Directorate of

Geology & Mining, Government of Tamil Nadu under a collaboration programme with UNDP.

Exploratory mining consisting development of an adit level and the first and second levels have

been carried out by the BGML. A total of about 30 boreholes were drilled and 607.46 m. of mine

development was carried out.

The exploration work has shown the presence of two zones of mineralisation, Viz., the multimetal

lode with lead-zinc-copper and silver values and a parallel lode on the foot wall side with

disseminated copper mineralisation. The multimetal lode comprises zinc, lead, copper, silver and

cadmium and the other disseminated copper sulphides and is considered to be of the stratiform

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exhalative volcanogenic sedimentary type. Part of the zinc values in the lode are in the form of the

zinc spinel gahnite. This mineralised zone has been traced over a strike length of 760 m. by drilling.

Of this, the northern part of about 300 m is relatively better mineralized and the sphalerite rich ore

body extends over a strike length of about 300 m with an average width of 3.15 m and persist to a

depth of 280 m in the dip plan ; the southern part being generally poorly mineralised and containing

mostly chalcopyrite. The reserves in this ore body are estimated to be 0.66 million tonnes with a

metal content 5.53% Zn; 1.15% Pb and 0.45% Cu. The chalcopyrite rich ore body, which extends

over a strike length of 180 m with a width of about 7 m and a depth persistence of 34 m, is estimated

to contain 0.13 million tonnes of ore with a metal content of 0.62% Cu, 0.69 Zn, 0.12% Pb and 37

g/t Ag.Drilling data indicate that the multimetal orebody does not persist beyond a depth of 280 m.

Drilling and exploratory mine development data indicate that the width of the multimetal orebody

ranges upto about 9 m. in some sections with an average of about 3.15 m.

Exploratory mine development shows continuity of the orebody: the adit level of the BGML

exposing the ore zone continuously over a strike length of 182 m. The range in metal contents in the

orebody are as follows :

Copper 0.17 to 1.04 %

Lead 0.16 to 1.86 %

Zinc 2.23 to 14.0 %

The second zone comprising essentially of chalcopyrite is located about 10 to 15 m. to the

foot wall (western) side of the multimetal lode. It has been traced over a strike length of about 460

m. Appreciable concentration of chalcopyrite of possible economic significance is found only over a

strike length of about 180 m. The depth persistence of the lode is also limited to about 35 m. below

the surface. The average width of the lode is about 8 m. On the basis of the drilling and exploratory

development data, the ore reserves available in the orebodies are estimated to be as follows :

A: Multimetal Lode Reserves Average Grade (million tonnes) % Cu % Pb % Zn Ag (g/t) Cd% Proved 0.20 0.54 1.13 5.88 39.92 0.13 Probable 0.46 0.37 1.16 5.19

_____ _____ _____

0.42 1.14 5.40

_____ _____ _____

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B: Footwall Lode 0.13 0.62 0.12 0.69 37.0

IBM carried out Ore beneficiation tests and showed that the recoveries of metal, particularly

zinc are only partial, as part of the zinc is present as gahnite.

Regional geochemical surveys in an area of about 350km2 falling along the strike extensions

of the Mamandur deposit has not brought out any significant mineralisation.

Thus the Mamandur Cu-Pb-Zn-Ag deposit is the only one multimetal deposit, so far known

from Tamil Nadu. This also is a small deposit with 0.66 million tonnes of ore averaging 0.42% Cu,

1.14% Pb, 5.40% Zn and about 40 g/t silver. Normally, it should be possible to operate a small scale

mine of about 150-200 t.p.d. on a deposit of this size. But because of the presence of part of the zinc

values as gahnite and consequent low recoveries during beneficiation and its isolated location, its

economic viability will be adversely affected.

Satyamangalam area (11°15'- 11°28':76°54'-77°15; 58 A/15 & E/3) Periyar and Coimbatore Districts : In the Satyamangalam Group of rocks lying between the Moyar-Bhavani-Attur lineament in the

north and Noyil Cauvery lineament in the south and forming a part of the Cauvery suture zone

(transform fault?) which extend right across the Tamil Nadu State in an east-west direction from its

western border with Kerala to the boundary of the Cretaceous sedimentary basin on the east,

Sulphide mineralisation occurs in sheared, silicified zones occurring within the metagabbros or close

to the metagabbro hornblende-biotite gneiss contact. These zones contain pyrite, pyrrhotite and

chalcopyrite with some nickel and gold values. In addition, sulphide mineralization with copper-

nickel-cobalt and marginal PGE and gold values also occurs in sheared ultramafic bodies occurring

within hornblende gneiss.

During regional geochemical survey and mapping by GSI, numerous sulphides in well dumps with

copper-nickel-cobalt etc., values and as many as 15 silicified zones with development of in situ

limonite after sulphides have been delineated. The silicified zones range in strike length from 100 -

200 m to about 6500 m, as seen in the Nadukavundanpudur and Ballepalayam and other areas. The

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width of these silicified zones ranges from 0.5 m to about 8 m. Data of a few boreholes indicate that

the sulphide content ranges from sparse

disseminations of less than 0.1% to as much as 50% total sulphides in some sections, Analytical data

of core samples yielded less than 0.2% Cu and less than 0.1% Ni.

Sulphide mineralisation associated with the ultramafic bands occurring within the hornblende

biotite gneiss country rock is seen in well dumps at several locations in toposheets 58 A/15 and

E/3.Minor chalcopyrite, pyrrhotite and molybdenite occurrences were noticed in pyroxenite and

amphibolite near Godepalaiyam and Maranur.Outcrops are rare due to soil cover. On the basis of

geophysical surveys and a few boreholes, it is inferred that these ultramafic bands are of limited size

ranging in strike length upto 200-300 m and in width from 2-15 m. The well dumps at a few

locations indicate appreciable pyrrhotite and pyrite with subordinate chalcopyrite. A few grab

samples have analysed upto 2.1% Cu, 0.9% Ni, 0.65% Co, 2 g/t gold and 0.3 g/t Pt.Though the

results of exploration so far have not indicated appreciable nickel and copper values in the various

silicified zones and sulphide shows in ultramafic fragments from well dumps the over all geological

setting is considered favourable to warrant further search.

A similar geological setting prevails over large areas to the East of Cauvery river in Salem

and Tiruchirapalli districts in Toposheet Nos. 58 I/2, 3, 4,6,8,10,12 and 16. In these areas also values

of greater than 1000 ppm nickel and copper have been reported in association with ultramafic rocks.

Several bands of banded magnetite quartzite and sillimanite bearing gneisses are also present in

these areas indicating that there may be

possibilities of locating copper-lead-zinc deposits of the Mamandur type.

Chalk Hills area (11°43': 78°10': 58 I/12) Salem District :

Some of the major magnesite deposits of the country are located in this ultramafic complex.

Incidence of pentlandite, pyrrhotite and chalcopyrite have been recorded from Chalk hills and Red

hills area and the nickel content is fairly high in the limonitised peridotite/dunite suggesting the

possibility of locating copper-nickel sulphide mineralisation associated with mafic - ultramafic

complexes. No copper deposits of possible economic significance have so far been established in

Tamil Nadu. But potential areas for search for copper-nickel sulphide mineralisation associated with

mafic-ultramafic complexes are large.The possibility of locating Cu-Zn-Pb mineralisation in the

alkaline-carbonatite province of northern Tamil Nadu also needs examination

Arumanullur (8°19'15'': 77°24'35'' - 57 H/7) and adjacent areas,Kanyakumari District:

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In this area, sulphide mineralization has been recorded from a number of meta-norite bands

occurring in the Arumanullur area and in the areas lying about 3 to 10 km to the north and north-east

of Arumanullur.

The occurrence near Arumanullur is by far the best known and contains the maximum

concentration of sulphides. Here, the sulphide zone has been traced over a strike length of about 135

m., in a NNE-SSW direction in a shear zone in metanorite. Trench sample data have indicated

copper values of 0.12 to 1.94% (average 0.44%) and nickel values of 0.12 to 0.72% (average

0.34%). The drilling carried out by the DGM indicated that the orebody is highly lenticular and

discontinuous. The concentration of sulphides in the other meta-norite bands ranges from less than

0.5% to about 5% in some bands. Analytical data of samples with fresh sulphides have indicated that

the copper and nickel contents are very low; copper upto 0.12% and nickel less than 0.1%. However,

gold values of 0.10 g/t to 1.16 g/t with an average of about 0.5 g/t for 7 samples have been recorded

from the sulphide zones. The strike length of these bands range from about 50 m to over 500 m. and

the width of the sulphide bearing zones from less than a meter to about 50 m. (true width about 12 to

15 m., as the dips are moderate - about 20 to 25°).

A similar occurrences of pyrite - pyrrhotite – chalcopyrite mineralisation within meta-norite

band is also reported from Pattankadu (8°37': 77°34'), Tirunelveli district. Groove samples indicated

only 0.02 to 0.12% Cu.

Josiar Alangulam (9°53': 77°58': 58 G/13) Madurai District:

Lead-Copper-Zinc mineralisation in calc-sillicate rocks was traced over a discontinous strike length

of 200 m in a 3 m wide zone in this area.This strike length has been tested by 13 boreholes.On the

basis of the drilling data, resources of 0.36 million tonnes copper ore with 0.4% Cu are estimated.

The thickness of the mineralized sections with a relatively better concentration of chalcopyrite

ranges upto 4 m. The nickel values in the area are 0.05%.

Thaniar area (12°25' - 12°40': 78°57' - 79°05') North Arcot Dist.:

Massive concentration of pyrite -pyrrhotite occur as thick bands in association with the pyroxene

granulite and BMQ bands of this SGT terrain. Five parallel bands with thickness upto 7.9 m.and

strike length upto 3.5 km have been mapped. Since zoning of iron, copper, lead, zinc, with iron at the

base and copper-lead-zinc at higher levels is common the world over, the possibility of locating

Mamandur type of copper-lead-zinc deposit in this area is considered worth examining.

Alangayam - Harur - Bhavani belt, North Arcot & Dharmapuri Dists. :

106

A large number of quartz baryte veins with galena have been recorded from the Alangayam area and

galena is a common association with molybdenite bearing zones ores which occur along shear zones

in a number of areas in this alkaline carbonatite belt. Incidence of pyrite has also been recorded

from a number of locations and in association with the quartz-barytes

and molybdenite mineralisation. Since copper-lead-zinc-baryte zoning is reported from a number of

areas the world over, the possibility of copper zinc mineralisation in the vicinity of quartz-baryte

veins and other sulphide mineralisation will be worth evaluating.

Near Narayanapuram in Thiruvallur district, a 380 m long 5.2 to 9.1 m wide quartz vein in a

faulted and fissured zone, carrying specks of pyrite, chalcopyrite and pyrrhotite was emplaced along

the contact of norite body with country rocks. Chip samples have analysed Cu content between

0.0005 and 0.04%.

Vettilaimalai (10°27: 77°41' - 58 F/11) Madurai District:

In this area, sulphide mineralisation (pyrite, pyrrhotite and chalcopyrite) hosted in pyroxenite has

been recorded. The area comprises charnockites with pyroxene granulite, pyroxenite, anorthosite and

quartzofelspathic gneiss. The pyroxenite body is about 50 m wide and extends for a strike length of

290 m. Trench samples have indicated 0.18 to 0.48% Cu (average 0.30% and upto 0.37% Ni

(average 0.09%).

Base Metal Deposits/Occurrences in Central Indian Craton:

In Madhya Pradesh, basemetal deposits and occurrences have been recorded from Malanjkhand

granitoid belt, Bhundelkhand granite complex and the Mahakhosal and Vindhyan Groups of rocks.

Of these, the Malanjkhand copper deposit is by far the best known. It is the largest single copper

deposit known in Peninsular India.

Malanjkhand Granitoid Belt:

Malanjkhand copper deposit:

The Malanjkhand (22°02': 80°43' - 54 B/12) copper deposit located in the Balaghat district is

presently under exploitation by open cast mining by M/s. Hindustan Copper Limited. The copper

mineralisation is localised in the quartz reefs, associated with the granites and also seen within the

granites near its contact with the quartz reefs. The ore zone extends over a strike length of about 1.9

km with an average width of about 65 m. On the basis of the drilling carried out by GSI, MECL and

the mine development by HCL, reserves available in the deposit upto –8 m. R.L.(i.e. about 600m

below the surface) at a cut-off 0.45% copper are estimated to be as follows:

Proved:145.7 million tonnes

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Probable:50.4 million tonnes

Possible:40.3 million tonnes

Total : 236.4 million tonnes of 1.28% copper.

During open cast mining, low grade copper ore beyond the main ore body is also likely to be

excavated. The quantity of such ore is estimated to be about 93.03 million tonnes with an average

copper content of 0.29% (cut-off 0.2% copper). About 3 million tonnes of oxidised ores with 0.18%

copper is also likely to be produced during mining.

Significant molybdenum values are associated with the ore. The copper concentrates are expected to

yield 1.24 g/t of gold, 70 g/t of silver and 0.04% molybdenum.

The areas with a similar geological set-up surrounding Malanjkhand copper deposit have

been investigated. The work has not, brought out any significant copper deposit, but a number of

occurrences for copper have been recorded. They are : Bhaunra Pahar (22°04' : 80°48') – Taregaon

(22°03' : 80°51' – 56 B/16) area; Parewa Dongri (22°02'35'' : 80°45'30'' – 64 B/15); Bodapahadi

(22°03' : 80°53'' – 64 B/15); Pathratola (22°00' : 80°55' – 64 C/13);

Manegaon (21°58' : 80°48' – 64 C/13); Gidori (21°52' : 84°43' – 64 C/9), and Dhorli (21°52' : 80°46'

– 64 C/13).

Exploration to search for Malanjkhand type of deposits adjacent to Malanjkhand has

indicated only sparse mineralisation. But some of the mineralised quartz reefs have sizeable widths

and strike lengths. Considerable scope for further search in the Malanjkhand belt as also other belts

exists.

Deposits / occurrences in Mahakhosal Group :

A number of basemetals occurrences mostly localised in the zones of shearing and faulting have

been recorded from different parts of this belt.

Imalia (23°36': 80°16'), Bhula (23°37': 80°20'), Nawalia (23°39' : 80°28') area. Toposheet No.

64 A/6, Jabalpur district :

In the Imalia area 0.075 million tonnes of copper ore with 1.12% Cu over a strike length of 240 m

have been estimated. If lower grade ore are also taken into consideration, reserves are

of the order of 0.12 million tonnes of 0.82% Cu. In addition, 0.044 million tonnes of lead ore with

1.19% Pb, 6.58 tonnes of Ag metal at an average of 17.32 gm/tonne from 0.38 million tonnes of ore

have also been estimated from this zone. In addition, presence of bismuth and arsenic has also been

established in the sulphide ores of Imalia block there by suggesting

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polymetallic nature of mineralisation. The drilling results have proved the depth wise (60 m)

extension of the silver mineralisation with a gradual widening of the zone with depth. Deeper

drilling will be necessary to get a complete picture regarding the potentiality of the silver

mineralization.

Bahera - Baheria Shear Zone (24°20' - 24°31' : 81O52' - 81°56' ; 63 H/15), Sidhi district :

Sulphide mineralization confined mostly to the silicified shear zones has been intersected below 200

m depth in the boreholes. There are indications of a thin zone of supergene

enrichment. Besides copper, lead, zinc, cobalt and nickel occur as traces in the mineralised zone.

Few samples gave silver values of 1 to 50 ppm. Only 2 boreholes intersected copper zones averaging

0.50% Cu viz., SD/1 - 0.50% Cu x 9.0 m and 0.51% Cu x 6.5 m; SD/6

– 0.50% Cu x 2.5 m. The remaining boreholes intersected zones averaging less than 0.2% Cu. The

possible strike extension of the zone with +0.5% Cu is about 600 m.

BUNDELHKAND GRANITE GNEISS

Quartz reefs and veins traversing granite bodies revealed sulphide mineralization, at Salaiya (24°40':

79°45') - Jamtoli (54 P/10, 13 & 14) area, Chhatarpur district, and Antri (26°03' : 78°15') and

Bhageh (26°31' : 78°26') - Gijora (26°04' : 78°28') areas, Gwalior district .

The copper values in the borehole cores varied from 50 to 500 ppm . and sporadic galena

near Andar (25°42' : 78°06'), Shivpuri district,

Copper and fluorite mineralisation localised in silicified fault breccia, quartz vein and

epidiorite has been recorded from Chichola (21°04': 80°40'), Durg district. Lead-zinc and fluorite

mineralisation occurs in quartz veins, silicified fault breccia, pegmatite and epidiorite emplaced

along N-S to N10°E - S10°W shear zones in Chandidongri (21°05' : 80°38'), Dura district. The

maximum metal contents in core samples were 2.5% Pb, and 1.20% Zn (mostly traces to 0.5% Zn).

Bhawratekra (N21°57'40'': E78°21' - E78°22'30'' in Toposheet No. 55 K/5)

Zinc deposit, Multai Tehesil, District Betul, M.P.

Massive sphalerite ore studded with chalcopyrite, galena, pyrite and pyrrhotite occur within the

mineralised zone established over a strike length of 265 m. The grade varies from 2 to 16% Zn. Zinc

is the predominant metal with minor Cu, Pb, Cd, Ag and W. Cadmium and tungsten values increase

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with the increase of Zinc values and silver values increase with Pb values and attains maximum of

115 ppm. The reserves estimated at 2% and 4% Zn cut

off upto a depth of 180 m are as follows :- 1.At 2% Zn cut-off of 5.10 m average width - 1.58

million tones of 4.52% Zn, 85 ppm Cd, and 3.5 ppm Ag. 2.At 4% Zn cut-off of 5.83 m average

width - 0.85 million tones of 6.48% Zn, 120 ppm Cd and 3.4 ppm Ag.

The Bhawratekra deposit (Reserves 0.85 million tonnes of 6.48% Zn) can perhaps be exploited on a

small scale of about 150 – 200 t.p.d. But since a part of the zinc values are in the form of gahnite, ore

beneficiation aspects will have to be critically evaluated, before decisions regarding feasibility of

mining the deposit can be taken.

Five copper deposits and one zinc deposit have so far been delineated in Maharashtra as summarised

below :

__________________________________________________________________________

Deposit Reserves Grade Average thick

Million tones % -ness(m)

__________________________________________________________________________

1. Kolari Zone III 8.272 6.79% Zn 51-6.65 m

2. Thutanbori

0.4% Cut-off 1.909 1.18% Cu 2.03-4.58 m

.0% Cut-off 0.845 2.24% Cu 1.35-3.23 m

3. Ran Mangli

0.4% Cut-off 0.829 0.81% Cu 1.77

.0% Cut-off 0.344 1.25% Cu 1.73

4. Pular Parsori 0.119 1.76% Cu

_________________________________________________________________________

Total 2-4 (1.0% Cut-off) 1.308 1.47% Cu

__________________________________________________________________________

5. Thanewasna 4.7 0.80% Cu 5.0

6. Dubarpeth 1.38 1.19% Cu 3.52

__________________________________________________________________________

Total 5+6 6.08 0.89% Cu

__________________________________________________________________________

110

The Kolari (Zone-Ill) zinc prospect is located at 2 km S57°W of Kolari Village (20°48' : 79°31', 55

P/5) about 75 km from Nagpur on State Highway No.78; in Umrer Tehsil, Nagpur district,

Maharashtra.The reserves and grade of ore in the Kolari Zone III deposit appear to be adequate

enough to sustain economically viable operations on a scale of over 500 tonnes per day.Pular

(20°51': 79°30'; 55P/9) and Parsori (20°50' : 79°33'; 55P/9) are located about 30 km to the east of

Umrer, a Tehsil headquarters of Nagpur district, Maharashtra. Ran Mangli (20°48' : 79°27'; 55P/5)

prospect lies at 58 km from Nagpur on State Highway No.78 in Nagpur district, Maharashtra.

Thutanbori (20°51' : 79°35'; 55-P/9) prospect is located at about 15 km on the fair weathered road

from Pauni, the Tehsil town, Nagpur district, Maharashtra.The Pular-Parsori, Ran Mangli and

Thutanbori deposits close to each other and to the Kolari Zone III zinc deposit. The combined

reserve in these deposits works out to 1.308 million tonnes with 1.47% Cu. They can perhaps be

mined as a group of small deposits, on a scale of 200 - 300 tpd. if a common infrastructure can be

established for all the four deposits, viz. Kolari, Pular - Parsori, Thutanbori and Ran Mangli. The

Thanewasna (19°51': 79°44'; 56-M/9), Chandrapur district) and Dubarpeth (19°40': 79°30'; 56-

M/10), Chandrapur district) deposits also occur close together in adjacent parallel zones. The

combined reserves at 6.08 million tonnes are fairly large, but the grade (0.89% Cu) is marginal.The

feasibility of mining them will largely depend on economic considerations.

Base Metals in Eastern Indian Craton

Singhbhum copper belt extends over a strike length of 128 km in the Singhbhum district of Bihar.

Exploration to-date has established copper mineralisation of possible economic significance in 3

sectors over a cumulative strike length of about 30 km in the central and eastern part of the belt.

They are:

(i) The Turamdih Sector (strike length - 5 km)

(ii) The Tamapahar-Rakha Mines-Roam Sideshwar-Chapri-Kehdadih-Surda-Mosabani-Badia-

Mainajharia Sector (strike length - 21.5 km) and

(iii) The Baharagora Sector (Strike length - 3.5 km)

Over 150 occurrences of copper, lead and zinc have been recorded from eight districts of

Bihar and Jharkhand, viz. Singhbhum, Hazaribagh, Ranchi, Palamau, Bhagalpur,Santhal Parganas,

Shahabad and Gaya. Almost half of them are copper occurrences located in the Singhbhum Copper

Belt of Singhbhum district. Some of the deposits in Singhbhum are very large and are being mined

since 1908. Till 1970, the Mosaboni Group of mines were the only copper mines in the country.At

111

present copper mines in the Mosaboni and Rakha-Roam Sideshwar areas are being operated by

Hindusthan Copper Limited.

Copper-lead-zinc mineralisation appears to be confined to Hazaribagh and the adjacent

Santhal Parganas districts. The lead-zinc mineralisation is widely distributed in the western part of

Singhbhum district, southern and eastern parts of Ranchi district and in southern Bhagalpur district.

Except 2 occurrences of lead with some copper in Palamau district which are associated with

sedimentary rocks of Lower Vindhyans, the remaining occurrences are found in Archaean rocks.

In Singhbhum Copper Belt ,Chalcopyrite and pyrite are the principal sulphides in the mineralised

zone. The copper lodes have been emplaced principally along shear fractures developed within the

shear zone.. The Mosabani mines have been developed to a depth of about 1250 m, below the

surface. In the Tampahar-Rakha mines-Roam Sideshwar sector the lodes have been tested by drilling

to depths of about 600 m and have been found to persist without signs of bottoming.

Tamapahar-Rakha Mines-Roam Sideshwar Sector: (22°36'N to 22°38'50''N :

86°21'08''E to 86°24'E)

This sector carry very significant copper mineralisation.The entire strike length of about 5,400 m is

continuously mineralized. The Rakha Mines block was worked by M/s Cape Copper Company

between 1908 and 1923. An evaluation of the Mine assay plans, and drilling data of M/s Cape

Copper Company, indicated that the Rakha Mines block and adjacent areas constitute a highly

potential prospect.

The estimates of insitu ore reserves for the three blocks are furnished.

______________________________________________________________________

Proved Probable Possible Total

Cut-off Reserves Grade Reserves Grade Reserves Grade Reserves Grade

Grade (in m.t) (% Cu) (in m.t.) (% Cu) (in m.t.) (% Cu) (in m.t.) (% Cu) % Cu 1.5 14.94 2.24 15.15 2.100 . 90 1.74 30.99 2.10 1.0 40.17 1.53 35.99 1.54 2.86 1.38 79.02 1.54 0.8 60.55 1.27 49.59 1.33 4.52 1.16 114.66 1.30 0.5 105.16 0.95 85.05 0.99 10.28 0.79 200.49 0.96

Besides copper, a number of other elements such as molybdenum, nickel, etc., are associated with the copper lodes. The average content of these elements in the lodes of the area is as follows:

112

Nickel 0.80%

Cobalt 0.011%

Molybdenum 0.025%

Bismuth 0.008%

Arsenic 0.007%

Sulphur 2.10%

Selenium 0.0025%

U308 0.02%

P205 0.55%

Silver 1 g/t

Gold 0.1 g/t

Copper concentrates with over 24% copper with recoveries of +96% were obtained.

The Rakha mines and Roam-Sideshwar blocks were taken over by M/s.Hindusthan Copper Limited

in 1974.

Sideshwar-Chapri-Kendadih-Surda sector:

The ore reserve potential of this sector is very high and is yet to be fully assessed.

Chapri-Sideshwar-Kendadih area :

This area extends over a strike length of 5 km. The potential reserves over the mineralised strike

length of 3068 m down to a depth of 300 m is about 8.24 million tonnes with +1.60% Cu. The

maximum reserves potential down to 600 m depth at a cut-off of 1% Cu can be of the order of 20

million tonnes per km, i.e. about 100 million tonnes over the 5 km stretch.

In the Chapri area, the ore zones are fairly wide and reserves of 14.71 million tonnes of 0.73% Cu

may be available for open cast mining.

The Sideshwar/Chapri zones have been investigated over a strike length of about 2.3 km by 66

boreholes (total meterage 20703 m) by MECL. These boreholes have tested the depth persistence of

the lodes upto 300 m. vertical depth. The drilling carried out by the MECL indicates that there are

several ore lenses ranging in strike length from 100 to 500 m localised mainly in quartz-chlorite

schist. Probable reserves of 7.25 million tonnes with 1.74% Cu have been estimated.

Kendadih mine area :

Several rich lodes have been developed in the mine workings.There are six copper lodes occurring in

an en-echelon pattern. The reserves estimated in this area are as follows :

113

Proved 2.61 m.t.

Probable 1.24 m.t.

Possible 1.47 m.t.

Drill indicated reserves of 5.32 m.t. with 2.01% Cu

Surda-Mainajharia Sector :

This sector extends in a NW-SE direction over a strike length of about 8.5 km. The Mosaboni,

Pathargora, Surda and Badia Mines and Dhobani (old mine) of M/s. Hindusthan Copper Limited are

located in this sector. A few other mineralised areas, viz. Tamajhuri, Mainajharia and Chirudih-

Somaidih are also present.

Surda (22°33' : 86°26') - Pathargora (22°32' : 86°27') – Mosaboni (22°31' : 86°23') - Badia

(22°29' : 86°28') - Dhobani (22°31' : 86°27') Mines area :

In this sector, the mineralisation is distributed in a much wider zone of shearing (upto 5 km) than in

the Rakha Mines sector. The mineralisation is hosted in biotite-chlorite schist occurring in sheared

soda granite. A strike length of about 3.2 km has been investigated by GSI. Probable reserves are

estimated to be:

At 1% Cu cut-off 0.798 m.t. with 3.13% Cu

At 0.5% Cu cut-off 1.41 m.t. with 2.4% Cu

There is therefore considerable scope for further exploration and increasing the rate of ore

production from this 21.5 km stretch of Tamapahar-Rakha Mines-Roam Sideshwar Sector.

Tamajhuri (22°32': 86°26') area:

The area has been explored by 18 shallow series boreholes (total drilling 2,653.6 m) spaced 150-200

m apart drilled by GSI. A number of mineralised zones ranging in width from 0.1 to 2.25 m were

met with in most of the boreholes. Probable reserves upto 100 m depth are estimated to be:

Cut-off Reserves Grade

1.0% Cu 0.27 1.70% Cu

0.5% Cu 0.59 0.91% Cu

Chirudih-Samaidih area :

9 shallow boreholes were drilled by GSI. These boreholes have intersected several thin zones with 1

to 5% copper alternating with low grade zones. A probable reserve of 1.47 m.t. with 1.39% Cu has

been estimated at 0.5% Cu cut-off. At 1% cut-off, the probable reserve comes to 0.46 m.t. with

2.58% Cu.

Khadandungri (22°26': 86°32') area :

114

The rock formations in the area belong to the Chaibasa stage. The total length of mineralised zone is

about 1 km. The mineralisation is confined to amphibolite. Drilling in the area has established

mineralisation over a length of 630 m. The average thickness of the zone is about 1 to 3 m and the

average copper content is 1.3%. Molybdenum, vanadium and titanium are seen associated with

mineralisation.

Baharagora (22°16'15'': 86°43'00'') Sector : This sector lies in the Singhbhum district of Bihar near the trijunction of Bihar, West Bengal and

Orissa States. Copper mineralisation is closely associated with the metabasics and their derivatives

and is co-folded with the host basic schists. The area has been sub-divided into six blocks for

purposes of exploration.The total strike length of about 3500 m has been investigated by 45

boreholes (total depth 7823.22 m).

Kharkari River - Rajdah Sector :

A cluster of significant copper deposits with an aggregate reserves of about 30 million tonnes and

lying close to each other have been identified in this sector. They are :1.Turamdih (22°43'2'' -

22°43'53'' : 86°10'47'' - 86°11'43'');2.Nandup (22°44'30'' : 86°14'15''); 3.Ramachandra Pahar (22°43'

: 86°13');4.Bayanbil (22°44'00'' : 86°14'30''); 5.Dadkidih (22°44' : 86°10').Of these the Turamdih

deposit is the largest. Besides these a few other

significant occurrences are also located in this sector viz., Mohuldih (22°44' :

86°09'); Hitku (22°42' : 86°15'); Rajdah (22°41' : 86°17'); Garadih (22°43' : 86°14') and Keruadungri

(22°44' : 86°11').Uranium and apatite deposits are also found in this sector. The uranium

mineralisation occurs on the hanging wall side of the copper lodes in the Turamdih deposit and in

the Narwa Pahar (22°42' : 86016').

Turamdih area :

The deposit has been explored in detail by close spaced drilling and exploratory mine development.

Copper mineralisation of varying intensities is seen to persist over the entire strike length of 1320 m

explored in detail. Zones of richer concentration constituting the lodes occur as lensoid bodies

predominantly within the chloritequartz schist. The drilling has established the mineralised zone

upto a depth of 200 m.

Turamdih Sector:

115

(i)A cluster of deposits viz., Turamdih, Nandup, Ramachandrapahar,Bayanbil and Dhadkidih occur

close to each other extending over a strike length of about 5 km. The reserves in these 5 prospects at

1.0% Cu cut-off are:

___________________________________________________________________________

Prospect Reserves in Grade (% Cu)

million tonnes

___________________________________________________________________________

Turamdih 17.85 1.59

Nandup 4.00 1.29

Ramachandrapahar 1.70 1.50

Bayanbil 1.36 1.74

Dhadkidih 3.18 1.42

___________________________________________________________________________

Total 28.09 1.52

___________________________________________________________________________

(ii) Of these deposits, only the Turamdih prospect has been investigated.

The deposit has been explored in detail by close spaced drilling and exploratory mine development.

Copper mineralisation of varying intensities is seen to persist over the entire strike length of 1320 m

explored in detail. Zones of richer concentration constituting the lodes occur as lensoid bodies

predominantly within the chloritequartz schist. The drilling has established the mineralised zone

upto a depth of 200 m

A summary of the probable in situ ore reserves for different cut-off grades

estimated on the basis of drill hole data is as follows :

___________________________________________________________________ Cut-off grade Total Reserves Reserves in major lodes (Lodes 1A, 2A & 2B) Million Grade Million Grade tonnes % Cu tonnes % Cu 1.5% Cu 7.270 2.15 4.371 2.25 1.2% Cu 12.100 1.81 7.434 1.87 1.0% Cu 17.850 1.59 10.992 1.59

____________________________________________________________________

A bulk sample drawn by the MEC was beneficiated by the IBM.

116

The average grade of the sample treated was 1.15% Cu which on flotation yielded a good

concentrate analysing 25.11% Cu with a recovery of 90%.

Nandup Prospect :

Inferred reserves of about 4 million tonnes with a copper content of 1.29% have been estimated upto

a depth of 200 m, of which 1.77 million tonnes upto a depth of 145 m may be workable.

Ramachandrapahar :

Drill indicated reserves in an area of 540 m x 480 m down to a depth of 130 m below the surface are

estimated to be 1.7 million tonnes with a copper content of 1.5% at 1% cut-off.

Bayanbil:Copper mineralisation occurs in magnetite bearing quartz-chlorite schist as

disseminations, blebs and locally as thin stringers. The zone of intense shearing where ore is

localised is about 3 m wide.

Probable ore reserves down to a depth of about 140 m (10 m R.L.) have been estimated to be as follows: __________________________________________________________________________ Cut-off Reserves in correlatable Reserves in grade lodes (lodes 1 and 2) uncorrelatable lodes Million Grade Million Grade tonnes % Cu tonnes % Cu 1.5% Cu 0.81 2.12 0.60 2.31 1.2% Cu 1.09 1.90 0.98 1.95 1.0% Cu 1.36 1.74 1.69 1.64

Dhakidih :

The host rock for the mineralisation is quartz-chlorite schist, impregnated with apatite and

magnetite. Five lodes with width ranging from 1 m to 5.2 m and copper content from 1.06 to 2.98%

have been identified. Inferred reserves upto a depth of 100/120 m are placed at 3.18 million tonnes

with 1.42% Cu, 0.03 to 0.08% U3O8 and 0.03% Ni at a cut-off of 1% Cu.

In view of the sizeable total reserves in these prospects and the average grade of 1.52% Cu it

should be feasible to open a group of mines with a total capacity of about 2000 - 3000 tpd in this

sector. In case the average grade of 1.52% is marginal, it will be feasible to mine a higher grade at a

cut-off of 1.2% or 1.5% Cu.

Galudih:

The host rocks in the area are silicified quartz-chlorite schists. Data of 6 boreholes (total drilling 610

m) indicated that copper mineralisation occurs as several detached en-echelon lenses over a strike

length of 160 m. The grade of the individual occurrences ranges from 1 to 15%.

117

Sankhadih:

The area around Sankhadih-Kharswan is predominantly covered by alluvium.Three of the 11

boreholes drilled to test this zone intersected two en-echelon copper lodes. The mineralised zones

intersected vary in thickness from 1 to 2.17 m and in copper content from 0.89 to 2.49%.

Rajdah-Tamapahar Sector:

No significant copper mineralisation has been recorded, but some uranium deposits are located near

Bhatin and Jadugoda. Some copper and molybdenum values are associated with the uranium

mineralization.

Hazaribagh district, Bihar :

There are many occurrences of copper, lead and zinc in this district. The main zone bearing these

minerals extend from Baraganda (24°04': 86°04') to Parasia (24°09': 85°47') over a length of 30 km.

Old workings are found at several places between Baraganda and Parsabera (24°04': 86°03').

Charkipahari-Toolsitanr area:

Copper-lead mineralisation extends over a strike length of 4 km in this area and is indicated by the

presence of malachite and azurite stains, disseminations of Chalcopyrite, chalcocite and galena, old

workings and mine spoils. Mineralisation is restricted to lenses of tremolite-actinolite schist within

the granite gneiss. The lens dimensions vary from 1 x 0.5m to 22 x 12 m in Toolsitanr area and from

3 x 1 m to 30 x 8 m in Charkipahari area.There are several old workings in the area about 2 km SSE

of Bhairukhi village (24°36'00'' : 86°36'15''). Small occurrences of copper have been reported at

Phaga (24°46': 86°56'),Bhagro-Bajra-Jhibra area (24°48'45'' to 24°49'55'': 86°32'45'' to 86°37'15''),

Bhusi-Bhandaria-Duarsar (24°50'20'' to 24°51'40": 86°35'45'' to 86°39'45'') and Baghmari (24°47':

86°45') in Bhagalpur district.

Baghmari mineralised pockets (maximum extent 150 m x 50 m) are associated with dolomite marble

and tremolite-actinolite schist. Four boreholes were drilled. The maximum values obtained were

only 1.21% Pb x 0.50 m and 0.41% Cu x 0.11 m.

Amjhore Pyrite Mine Area: (24°35' - 24°45': 83°50' - 84°00'), Shahbad District:

The stratiform Amjhore pyrite deposit (thickness 0.55 to 1.04 m; sulphur content about 40%) occurs

in the uppermost part of the Bijaigarh Shale horizon of the upper Vindhyans over an area of about

100 sq.km.The incidence of strata-bound lead-zinc mineralisation in the form of a thin seam varying

in thickness from 0.11 to 1.77 m (average 0.77 m) and metal content from 0.22% to 1.17% Pb + Zn

(Average 0.44% Pb + Zn) has been established by drilling over an area of 5.21 sq.km. This zone

occurs about 6 to 10 m above the pyrite horizon and dips northward at low angles.

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Two main mineralised belts are known in Orissa. They are:

1.The southern extension of the Singhbhum Copper belt (of Bihar) for a strike length of about 15 km

in the Kusumbari (22°04' - 86°42'), Kesarpur (22°06' - 86°41') area of Mayurbhanj district hosting

copper mineralization, and

2.The Sargipalli shear zone in the Gangpur basin of Sundargarh district extending discontinuously

over a distance of 35 km. from Lokdega (22°02' -83°55') in the east to Amatpari (22°12' - 83°38') in

the west hosting lead mineralisation with subordinate zinc, copper and silver in dolomitic marble and

mica schist. The Sargipalli deposit is being mined by M/s.Hindustan Zinc Limited on a scale of 500

t.p.d.

Exploration of the Sargipalli deposit has indicated that these areas mostly comprise iron

sulphides.The Kesarpur deposit is of marginal grade and reserves are low (2.81million tonnes with

1.49% Cu at 0.8% cut-off).The Adash prospect in Sambalpur deposit is also a small, marginal one:

Reserves 0.93 million tonnes with 1.46% Cu.

Apart from the above mineralised belts, a number of scattered occurrences of galena are

reported from Bolangir, Sambalpur and Mayurbhanj districts with one significant zone in between

Ampali (20°25' - 83°20') and Chormaria (20°18'- 83°17') over a length of 29 km in the Bolangir

district.

Base Metal Deposits/Occurrences in Western Indian Precambrian Shield:

Deposits in BGC:

Rampura-Agucha Zinc-Lead Deposit:

This deposit is a major recent discovery in the basement rocks – the BGC, which are devoid of

mineralization except for these deposits.The stratiform and stratabound mineralization includes

sphalerite and galena as major minerals with minor pyrrhotite, pyrite, and arsenopyrite occurring in

the core of a synform in the basement (BGC) rocks.The ore occurs in garnet-graphite-sillimanite

bearing biotite schist and gneiss, calc-granulite and amphibolite.

Pur-Banera-Rewara Copper-Lead-Zinc Deposit:

This polymetallic sulphide deposit of Bhiwara area occurs in metasediments with mineralization of

Cu-Pb-Zn-Fe sulphides.

Surwas-Lakhols-Satdadia Copper Deposit:

This mineralized zone of copper sulphide occurs in metasediments of Bhilwara area with magnetite-

quartzite, calc-silicate and amphibolite.

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Copper sulphide occurrences in the metasediments of Bhilwara area are known from Wari-

Lunera.Other oocurrences include the pyrite-chalcopyrite mineralization near Bajta, Ajmer district in

the Sawar-Bajta metasedimentary belt of Sawar Group of Bhilwara Supergroup and the carbonate-

hosted sphalerite-galena mineralization of Sawar Group.

Aravalli Supergroup

Rajpura-Dariba-Bethumni (Zinc-Lead-Copper) Belt:

This 17 km long belt of polymetallic sulphide mineralization in Aravalli Supergroup consists of ores

of zinc, lead, copper,silver,cadmium,arsenic,phosperous,fluorite and sulphur with minor gold,

molybdenum, indium and mercury.It occurs as a broad conformable Lead-Zinc-Copper sulphide

clusters to bedding in graphite mica schists and calc-silicates.Zoned copper-lead-zinc and iron-rich

minerals characterize Dariba mineralization. The major ores are are sphalerite, galena, chalcopyrite,

pyrite, and pyrrhotite with minor arsenopyrite, cubanite.

Other major Lead-Zinc-Copper mineral deposits in Aravalli Supergroup occur at Mochia,

Zawarmala and Borai.The ores are synchronous with the second phase of Aravalli deformation

resulting in localizing the spahalerite, galena and pyrite mineralization.

Angeni Copper Deposit, Udaipur district:

The metabasic chlorite schist bands in the basal Aravalli hosts thin discontinuous lenses of

chalcopyrite, pyrite, pyrrhotite lenses, upto 5 cms thick with minor covellite and magnetite parallel

to pervasive schistosity in a zone of basement-cover interaction. This is characterized as a

Proterozoic mélange zone (ductile shear zones).

Delhi Supergroup

The Khetri and Kho-Dariba copper sulphide ore mineralization and the polymetallic sulphide ore

mineralization along Ajari-Basantgarh-Ambaji –Deri are the two major sulphide deposits.

Khetri Copper Belt

This 100 kms long belt has dominant stratabound copper deposits confined to chlorite schist and

amphibolite at Madhan-Kudhan, Kolihan, Akwali and Satkui-Dhanota.Ore minerals are

chalcopyrite, pyrrhotite, pyrite, cubanite, magnetite, sphalerite, arsenopyrite, cobaltite, pentlandite.

Massive stratiform copper-zinc ore deposits occur along Ajari-Basantgarh-Rohera-Pipela

section in southwest fold belt confined to chlorite-mica-quartz schists and amphibolite. The zinc-

lead-copper deposits of Ambaji and Deri are massive stratiform types located in the southwestern

part of the Delhi Fold Belt.Pyrite, sphalerite, galena and chalcopyrite with minor pyrrhotite occur as

tabular and lensoid bodies in cordierite-anthophyllite-chlorite rocks and amphibolite.

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The base metal deposits of Gujarat are mainly located in Amba Mata deposit in

Banaskantha district where the main prospect is 2 km long and 600-800m wide with mineralisation

of mainly lead and zinc with subordinate copper. The other base metal deposits are located in Kui-

Chitrasani belt falling in Gujarat-Rajasthan.

Base Metal Deposits/Occurrences in Purana Basins:

As many as 70 of the 84 deposits/occurrences recorded from Andhra Pradesh are located in

the rocks of the Cuddapah Supergroup. The bulk of the basemetal mineralisation is localised in the

Nellamalai sub-basin.

At present, only the lead deposit at Bandalamottu in Cumbum formation of the Cuddapah

Supergroup is being worked on a small scale by M/s. Hindustan Zinc Limited.

Agnigundala belt:

The Agnigundala belt is located in the north-east corner of the Cuddapah basin. Over 30 copper-lead

and zinc occurrences are located in this belt in the calcareous quartzites and dolomites of the

Cumbum formation. The only working lead mine of H.Z.L. Viz., Bandalamottu deposit (16°13'30'' :

79°34'45'' - 56 P/12) of Guntur district is located in this belt. This area comprises dolomite and

dolomitic limestones interbedded with phyllites and quartzites of the Cumbum formation of the

Nallamalai Group. Zones of lead-copper mineralisation occur mainly in the upper part of the

dolomite. The mineralisation is generally poor where the dolomites are associated with chert bands.

The regional structure is an anticline plunging at low angles towards north. Concentration of the

mineralisation is better along depressions between the anticlines.

Galena is the dominant sulphide mineral with minor chalcopyrite and occasionally sphalerite and

pyrite.The deposit has been investigated by 92 surface boreholes and a large number of underground

boreholes and mine development by Hindustan Zinc Limited (HZL). The lead orebody is being

exploited by the HZL at the rate of 240 tpd.

As a result of the drilling and mine development, the mineralized zone in the Bandalamottu hill has

been established over a strike length of about 1200 m with a down dip extension of about 500 m.

(about 20°dip). Three ore bodies,Viz., Main, Eastern and Western have been

identified. The Main orebody is developed on the northwestern flank of an anticlinal structure and

consists of five overlapping lodes over a strike length of 400 to 600 m. The thickness of the

orebodies ranges from 1 - 11 m and the average thickness of the individual lodes from

1.5 to 6.5 m.The Eastern orebody is located on the eastern flank of the anticlinal

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structure which extends over a strike length of about 320 m. and comprises the No. I lode only.The

Western orebody is located to the west of the main orebody.It extends over a strike length of 150 m

and comprises only lode No. I.In addition there is a zone of copper mineralisation below lode No.I of

the main orebody in the lower part of the upper dolomite horizon. This ore body extends over a

strike length of about 900 m.The reserves estimated by the GSI for the various orebodies are as

follows:

__________________________________________________________________________

Average Grade Reserve (thickness) Pb % (m.t.) __________________________________________m_________________________

Lead Orebody:

Main Orebody 2.84 to 4.29 to 7.899 (Lodes I, II, III, IV, & V) 6.36 8.99

Eastern Orebody 5.12 5.58 1.059 Grade - A (Lode - I)

Western Orebody 3.15 6.45 1.100 (Lode - I)

Main Orebody 1.49 3.10 0.650 (Lode –

Grade - B Eastern Orebody 1.60 3.08 0.180

Western Orebody 3.48 3.18 0.571 (Dolomite zone)

_______

11.459

_______

Copper Ore:

Grade - A Main Orebody 1.5 - 3.0 1.71% Cu 0.775 Grade - B 0.5 - 1.6 Cu 0.261 _________ Total : 1.036

_________

The reserves estimated by the HZL (over a strike length of 700 m) are of the order of only 2.46 million tonnes with an average lead content of 4.98% (at 2% cut-off). The lead deposits are being mined by HZL (about 240 tpd).

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Dhukonda (16°13'30": 79°43'30" - 56 P/12) Deposit, Guntur Dist : The geological setting in this area is similar to that of Nallakonda.The rocks are intensely

folded.Copper mineralisation is dominant and confined to coarse–grained quartzite. Lead

mineralisation is subordinate and is localised in dolomites.

The area has been explored by 79 boreholes.The orebodies are spread over an aggregate strike length

of 2 km. in the southern and southeastern slope of Dhukonda peak and adjoining

areas. Due to structural complications it has not been possible to clearly establish the exact nature of

correlation of the orebodies. Drilling data indicate that the orebodies occur as parallel en-echelon,

lodes of limited depth persistance and that the orebodies are repeated due to folding.

The drilling indicated reserves are as follows:

Block Copper ore Grade Lead Ore Grade Reserve % Cu Reserve % Pb

(m.t) (m.t)

___________________________________________________________________________

NE Dhukonda 1.59 1.39 0.22 9.94

SW Dhukonda 0.04 2.60 - -

Central 0.13 1.48 0.17 8.00

Western Dhukonda 0.40 1.91 0.07 7.06

Total 2.16 1.51 0.46 8.98

Nallakonda (16°13' - 79°42' - 56 P/12) deposit - Prakasam District:

The area comprises chlorite phyllites and grey argillites with intercalations of quartzites and

dolomite of the Cumbum formation. Copper mineralisation is localised in coarse grained calcareous

quartzites. The better zones of mineralisation are seen along the nose of major anticlinal drag fold

plunging towards north-east. The deposit has been explored by 72 boreholes drilled by GSI and

exploratory mine development at 4 levels by Hindustan Copper Limited (HCL).

The GSI drilling indicated the presence of mineralisation over a strike length of 1300 m and a

vertical interval of about 60 m. The orebody appears to have a gentle pitch of about 10 to 15°

towards north-east.The downdip extension of orebodies ranges from 90 m to 400 to 450 m.

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The orebody comprise a series of parallel en-echelon lodes with sinistral shifts. The lodes pinch and

swell both along strike and dip.

Reserves of the order of 3.14 million tonnes with copper content of 1.82% were estimated on the

basis of the drilling data by GSI. But the reserves estimated by HCL after exploratory mine

development over a strike length of about 150 m. are of the order of 0.35 million tonnes with 1.50%

copper only. This downward revision of the reserve estimate is mainly attributed to the limited strike

and depth persistance of the oreshoots as revealed from exploratory mine development.

Vummidivaram (16°09'19'': 79°25'3'' - 56 P/8) area, Prakasam Dist.:

The area comprises quartzite, and dolomitic breccia intercalated with thick phyllites of Cumbum

formation. The beds trend NE-SW with southwesterly dips of 35 to 60°. Lead mineralisation is

hosted in dolomitic quartzite breccia and quartzite.The area is divided into two blocks, Viz.,

Gabbilagavi and Ittammakuvva. The Ittammakuvva block has been explored by 5 boreholes.

Reserves of 0.3 million tonnes with 2.69% lead are estimated. In the Gabbilagavi block, several

breccia zones of 0.5 m. to 30 m. thick are seen on the surface over a width of 800 m. Exploration by

4 boreholes has not indicated the persistance of breccia zones beyond 70 m. depth probably due to

pinching/faulting of the mineralised zone. Lead values range between 0.3 and 0.8% the highest value

being 1.40% Cu over0.77 m.

Karempudi : 16°23'30" : 79°40'40'' - 56 P/11) area, Guntur Dist.

The area comprises phyllites interbedded with dolomite and quartzite of the Cumbum formation. The

dolomite host rock is folded into an anticline plunging gently towards east and is partly sheared.The

mineralisation is predominantly/in dolomite in the form of veinlets,

stringers, pockets and streaks of galena and sphalerite with stray specks of pyrite and

chalcopyrite.Fifteen boreholes have been drilled. The mineralised zone has a strike length of 600 m.

in the northern limb and 200 m. in the southern limb. The average width of the mineralised zone is

2.43 m. At a cut off of 2.0% Pb + Zinc, reserves of 0.5 m.t. with 1.38% Pb + 0.96% Zinc has been

estimated upto a depth of about 150 m. below the surface.

Peddagavalakonda (16°16'30'' : 79°39'30'' - 56 P/11) area, Guntur Dist : The area comprises phyllite, slaty phyllite and argillite with interbeds of dolomitic limestone and

quartzite of the Cumbum formation. The beds strike NE-SW with dips of 40 to 60° towards south-

east.Old workings in mineralised dolomite are seen over a strike length of about 1000 m. The area

has been explored by 18 boreholes. Four of these boreholes intersected significant zones of lead

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mineralisation in the lower dolomitic horizon with lead values of upto 8.99% over widths of 1.60 to

3.19 m. These zones do not appear to have dip or strike continuity. Anticipated reserves are of the

order of 0.18 million tones with 4% Pb.

Other occurrences in the Agnigundala area:

Veerappakonda (16°12': 79°42' - 56 P/12) area. Guntur District : In this area specks of chalcopyrite and galena are seen in sheared and silicified dolomites of the

Cumbum formation. At the surface a persistant leached zone is seen over a strike length of 400 m.

Two boreholes drilled in the area intersected highly limonitised zone with malachite and specks of

chalcopyrite.

Papayapalem (16°22': 79°38' - 56 P/12) Guntur District: In this area galena mineralisation is seen in brecciated dolomite of the Cumbum formation. Old

workings are seen over 500 m. Out of 8 boreholes drilled, only 2 boreholes intersected mineralised

zones: 0.45m x 3.04% Pb and 1.30 m x 2.02% Pb + 0.55% Zn.

Kanchugavi (16°12': 79°24' - 56 P/11) Prakasam District: Disseminations of galena are reported to occur in breccia zones in

quartzites of the Cumbum formation. Old workings are seen over a strike

length of 150 m.

Other reported occurrences are:

1. Sarikonda (Cu), located 3.6 km NW of Bandalamottu, 2. Balam Devlam (Pb) located east of

Bandalamottu, 3. Mella Vagu, 4. Ling-alakonda (Cu) located along the NE continuity of

Dhukonda Block, 5. Yerrakuppukonda (16°12': 79°42'), 6. Sakalavonikuvva (Pb-Cu),

7. Currapusala (Cu), 8. Tadivaripalle (Cu-Pb), 9. Ramasamudram (l6°01': 79°24'),

10. Gajjalakonda (15°45' : 79°24'); Copper, 11. Basuvapuram (15°24': 78°38'): Lead,

12. Koilkuntla (15°13': 78°19'); Lead, 13. Chityale (15°28': 77°47') Lead.

Varikunta - Zangamarajupalle belt:

This belt is located in the south-central part of the Cuddapah basin and stretches over 50 km (N-S).

Lead zinc ores are localised in dolomites enclosed within Cumbum slates. Dips are moderate and

rolling.

Zangamarajupalle (14°46': 78°53' - 73 J/13) deposit, Cuddapah Dist:

The area comprises variegated slates and phyllites interbedded with dolomites and quartzites of

Cumbum formation. Dolomites are the host rocks. Three dolomite bands are interbedded in the

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slates. The upper dolomite is 3-8 m thick with chert band at the top. It is developed all along the

strike length of 2 km. The middle dolomite (30 to70 m) carries the mineralisation and is a

finegrained, light to dark grey rock with argillaceous, arenaceous and carbonaceous intercalations.

The lower dolomite (10 to 20 m) is impersistent and merges with the middle dolomite in the

southern part. The Zangamarajupalle area forms the western limb of a doubly

plunging major anticline. Zones of shearing and brecciation occur in dolomite.The mineralisation is

mostly stratiform and confined to the transitional zone between dolomites and cherts and the

overlying carbonaceous slates.The area has been explored by 22 boreholes at intervals of 200m. On

the basis of the borehole data, three better mineralised zone Viz.,

Central Section (400 m) Southern Section (600 m) and Northern Section (200 m) have been

identified.There are 5 lodes (I-V in the main dolomite and one in the upper dolomite. The lodes I to

V in the main dolomite are lead-rich whereas the lode-V in the cherty dolomite is zinc

rich.Subsequently, four series of boreholes spaced at intervals of 50 to100 m along the strike to test

the mineralised zones at 50 m., 100 m.,150 m and 200 m. vertical depths were drilled by the MECL.

These boreholes indicated the persistence of the mineralised zone both along strike and depth.

The reserves estimated on the basis of MECL data are as follows:

Reserves Grade

At 3% Lead + Zinc cut-off 1.34 m.t. 2.63% Zn

1.91% Pb

At 2% Lead + Zinc cut-off 2.42 m.t. 2.74% Zn

1.3% Pb

Golapalle: (14°45'00'': 78°54'00'' - 57 J/13) deposit, Cuddappah Dist.:

The area comprises greyish green slate, grey dolomite and black pyritiferous carbonaceous slates of

the Cumbum formation. Thin chert bands occur interbedded with the dolomite. The mineralisation

mostly occurs in the grey dolomite.Sphalerite and galena with minor chalcopyrite occur in

association with pyrite at the chert bearing brecciated contact of the dolomite with carbonaceous

slates. The sulphides occur as continuous to semi-continuous beds /lensoid bodies in cherty dolomite

with finegrained (stratiform) layers of sulphides along bedding planes.

The total strike length of the block is 3.3 km divided into Golapalle East block, Kothapalle block and

Chikativaripalle block. 33 boreholes have been drilled in the Golapalle block, 2 in the Kothapalle

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block and 5 in the Chikativaripalle block. In the Gopalpalle block, continuous mineralisation has

been established over a strike length of 1.33 km. The mineralisation is weak in the other two blocks.

The reserves estimated in the Golapalle block are as follows:

Cut-off Reserve Grade Width Total Pb + Zn% m.t. Pb% + Zn% (m) Pb + Zn%

5 0.46 2.88 2.03 2.55 4.91

4 0.50 3.83 1.87 2.23 5.70

3 1.22 1.61 1.76 3.94 3.37

2 1.89 1.36 1.50 4.30 2.86

__________________________________________________________________

The entire deposit falls in the submersion zone of the proposed dam site of Telugu - Ganga project. Varikunta (15°11: 78°46' - 57 I/16) area, Cuddappah Districts : This area is located along the northerly strike extension of the Zangamarajupalle belt and comprises

mainly Cumbum slates interbedded with dolomites and dolomitic quartzites. The strike trend is

NNW-SSE with dips of 10 to 35° to east or west. Old workings in the area appear to be along a shear

plane in dolomite as also along axes of minor folds in the dolomite. The mineralisation appears to be

of the pitches and flats type presumably pitching at 10° to 20° towards north, some of the old

workings are very extensive with large open stopes. The old workings indicate a series of lenticular

ore zones of 100 to 200 m strike length and 5-20 m. thickness. Random samples of oxidised zones

analysed 0.34 to 3.59% Pb, 0.25 to 0.85% Zn and 0.23 to 0.63% Cu. Two mineralized zones have

been identified. An upper zone associated with cherty dolomite with mostly sphalerite and minor

galena and a lower zone of chalcopyrite with minor galena. Six boreholes drilled in the area

indicated that the mineralization is impersistant and lensoid. The metal content in the mineralised

zones

was found to be less than 2% Pb+Zn (0.88 to 3.72%) over widths of 1.20 to 4 m.

Karredukuppa (14°51'30" - 78°49'30" - 57 J/13) Cuddappah District: This area is located about 21 km south of Varikunta and has a similar geological setting. Drilling of

6 boreholes indicated only sporadic specks of galena and sphalerite.

Chinnelupatti area, Cuddappah District: This area forms the northwesterly extension of the Zangamarajupalle-Kareduppan belt. Galena-

sphalerite-chalcopyrite mineralisation within dolomites is noticed over a strike length of about 2.5

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km. Geochemical surveys have indicated several linear anomalous zones for zinc and occasional

spot values for Pb and Cu.

Ambavaram : Preliminary geochemical surveys indicate an anomalous zone of Cu-Zn over an area of 200 m x

4000 m. The country rock is green grey shale which carries dolomite lenses and quartz barytes veins

with galena.

Gani-kalava belt - Kurnool District: This belt extends over 16 km in the northwestern part of the Cuddapah basin. Copper ore occurs in

quartz reefs (nearly vertical) cutting through the Tadapatri shales and traps of the Kurnool

formation.The Gani-kalava copper belt comprises Vempalle limestone and

Pulivendla quartzites of the lower Cuddapah Supergroup have overlain byTadapatri shales of the

Kurnool Groups. There is a marked angular unconformity between the lower Cuddappahs and the

Tadapatri shales.The Cuddappahs and Kurnools in the area are intruded by sills and

sheets of metagabbro and metadolerite. Mineralisation is confined to WNW-ESE trending shear

faults occurring in the Tadapatri shales. It is in the form of disseminations, stringers and pockets

associated with breccia and quartz vein in traps or at the contact of the trap and shales.

Gani (I5°40'70'': 78°19'57'' - 57 I/6) block, Kurnool District: The mineralisation in the Gani block consists of an eastern sector of strike length 1100 m and a

western sector of strike length 950 m with a gap of about 350 m. in between. The mineralisation in

the western sector is highly lenticular though old workings are extensive. Some borehole

intersections have shown values of 1.31 to 2.7% Cu over 1.25 m. thicknesses.

But the strike persistence of these values is very limited. Drilling in the eastern sector over a strike

length of 500 m has indicated the probability of a significant and persistent zone of copper ore over a

strike length of at least 300 m. On the basis of borehole data, reserves of 0.43 million tonnes

with1.37% Cu are inferred to be available over a strike length of about 550 m and a depth of 100

m.Copper occurrences have also been recorded from Somayazulapalle (15°35' : 78°11')

Kommamarri (15°12' : 77°53') and Gummankonda

(l5°38'30' : 78°18'00'') in the Gani-Kalava belt.

Chelima (15°30': 78°40' - 57 I/11) Kurnool District:

The area is made up of Byrankonda quartzite and cherty quartzites with dolomite, green shales, slaty

and phyllitic shales of the Cumbum formation. These are intruded by dykes of kimberlitic

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carbonatite. Surface indications of mineralisation are seen over an aggregate strike length of 1 km.

The mineralisation is more conspicuous in the nose of the fold where the mineralised dolomite has a

thickness of 10 m. Mineralisation is found mostly in the zone of brecciation and dolomites. Three

groove samples from trenches indicated values of 2.15 to 6.96% Pb, and 6.36 to 8.32% Zn. But

drilling of 5 boreholes did not intersect any mineralisation of significance.

Ahobilam (15°08': 78°40'30'' - 57 I/12) Kurnool District: Copper-lead-zinc mineralisation in this area is hosted in dolomites o the Cumbum formation.

Drilling of 12 boreholes indicated only weak mi neralisation with 0.14 to 2.15% Pb, over widths of

0.30 to 4 m.

Pacherla (I5°23': 78°42' - 57 I/11) Kurnool District: Galena and sphalerite and occasionally chalcopyrite and pyrite re seen in dolomite intermittently

over a strike length of about 2 km.Two samples indicated 3.10% Pb+Zn over 0.97 m. thickness.

Basavapuram (15°24': 78°43'): Lead mineralisation associated with barytes is noticed in quartz veins traversing slaty rocks

Pulivendla belt : Cuddappah District : Copper mineralisation associated with barytes occurring along shear zones in the Tadpatri formation

have been recorded from Venkatapuram (14°24': 78°13'), Vemula (14°22': 78°14') and Midipenta

(14°19': 78°19'). The mineralised zone contains barytes, chalcopyrite, pyrite and galena. Six

boreholes drilled in the Venkatapuram area did not indicate any significant zones of mineralisation.

Geochemical surveys in the Vemula area indicated an anomaly zone with lead contents of 300 to

1000 ppm. The zones of high values coincide with the known shear fractures in the area.

Mallapuram (15°30'35'' : 79°10'30'' - 57 M/2) (Marakapur belt) Prakasam Disrict: The area comprises rocks of the Cumbum formation, Viz., slates, phyllites with quartzite, limestone,

dolomite and chert trending NNE-SSW to SW-SW with variable dips of 10 - 80° towards SE. Eleven

boreholes have been drilled, of which 3 intersected mineralised zones with upto 3.73% Pb over a

width of about 5 m. In a fourth borehole a 0.85 m. thick zone with 5.30% Cu was intersected. The

strike length of the mineralised zone is about 600 m

Venkatapuram (17°46': 80°47') area, Khammam district: The area comprises phyllite, quartzite, dolomite and ferruginous phyllite of the Pakhal Supergroup.

The Venkatapuram block is situated on the western limb of an anticline. The chalcopyrite

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mineralisation occurs as disseminations and stringers in quartzite and dolomite. Old workings are

seen over a length of 120 m. Drilling of 8 boreholes has indicated two en-echelon zones of copper

mineralisation with a cumulative strike length of about 150 m.

The average grade of the mineralised zone ranges from 1.27 to 1.58% Cu over widths of 1.5 to 5.40

m.

Yellambailu (17°41': 80°40') area, Khammam District : This area is located 8 km south-east of Mailaram, and comprises quartz-chlorite schists and biotite

gneisses (Sargur Group) intruded by pegmatite and quartz veins and quartzite, tremolite, marble,

dolomitic limestone, phyllite, and quartz veins of the Pakhal Supergroup. The strike trend is NE-SW

with steep dip towards north-west.

Copper mineralisation is seen in quartz-chlorite schists traversed by grey quartz veins and the Pakhal

quartzite and dolomitic limestone. Excavations are seen over a strike length of 370 m. close to the

Archaean and Pakhal contact, but within the Pakhal quartzites and limestones.

Three boreholes drilled in the area indicated two zones of mineralisation, one corresponding to the

line of old workings and the other in the underlying quartz-chlorite schists. The zone corresponding

to the old workings analysed 1.83% Cu over a width of 0.68 m.

Venkatapalem: (17°16' : 80°13'), Khammam District : This area comprises cherty dolomites interbedded with phyllite and cherts and quartzites of the

Pakhal Supergroup. Baryte is often associated with cherty quartzites. Disseminations of chalcopyrite,

pyrite and galena are associated with dolomites.

Drilling of 15 shallow boreholes indicated that the mineralization occurs as lensoid bodies with

limited strike and depth persistance. Only three boreholes indicated significant values. They are :

1) 2.68% Pb, 2.88% Zn and 0.38% Cu over 2.24 m.

2) 0.97% Pb, 0.2% Zn and 0.2% Cu.

3) 2.65% Pb, 0.35% Zn and 0.13% Cu.

Ragaboyingudem (17°31': 80°22') Khammam District : The area comprises dolomite and phyllite with sheared quartz veins. Three boreholes were drilled of

which only one intersected 0.61% Cu over 2.08 m.

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Sarakal : (17°43' : 80°42'- 65 C/10) In this area some old workings in felspathic quartzites and ferruginous quartzites (of Pakhal Group)

are seen. Six boreholes were drilled. One borehole intersected oxidised zone with 1.10% Cu over

1.55 m. width at 80 m.depth. A deeper borehole was negative.

Incidence of copper mineralisation has been recorded from two locations in the Kaladgi basin

of Bijapur district. Traces of copper on talcose laminae in limestone has been recorded at Khajjidoni

(16°10' : 75°31' ) and north of Gaddankere (16°11' : 75°37'), show specks of malachite and

occasionally chalcopyrite. Although these two occurrences are of sporadic nature, the possibility of

finding economically viable deposits for copper in the Kaladgi basin cannot be ruled out

OTHER DEPOSITS

.

In Uttar Pradesh, base metal mineralisation is located in the large hilly tracts covered by the

Garhwal Group of rocks, in the Vindhyans and in the shear zones crossing the Bundelkhand granites.

There are a number of reported base metal occurrences in the State, the most important one being the

Askot deposit which is described below.

Askot (Copper-Lead-Zinc) Deposit (29°46': 30°20'), Pithoragarh district

The sulphide mineralisation is confined to the northern limb of the Askot syncline near its south-

eastern closure. The surface indications of mineralisations are seen in the form of a small outcrop -

unaltered, hard, silicified epidoteactinolite biotite-quartz rock.

The southern ore body, (the most important one), which had been explored by the GSI by drilling at

50 m strike interval, at two levels (1015 m RL and 985 m RL), covering some 150 m, was opened up

by two adits by the MECL at 1015 m RL. The exploratory mining carried out exposed the ore at 985

m level with 1.68% Cu, 4.39% Pb, 4.77% Zn (10.83% TMC) along with 1.68% As, 0.10%

Sn,0.062% Sb. The GSI has estimated reserves of about 0.77 million tonnes of ore averaging 2.32%

Cu, 2.64% Pb and 3.95% Zn in the area.

The other explored occurrences are Dudhi (copper-lead-zinc) in Mirjapur district, Khanayun-

Galpakot-Kimkhet area (copper-lead-zinc) in Nainital-Pithoragarh districts and Tons Valley in

Dehradun district.

Base Metal Occurrences in Himalaya

At the foothills of Himalaya, in West Bengal, only one basemetal deposit has so far been

identified viz., the Gorubathan lead-zinc deposit. The total reserves of 3.70 million tonnes with

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3.77% Pb + 3.87% Zn in this deposit may be adequate for opening a small mine of 300 to 500 tpd.

But the reserves are distributed over a number of orebodies in several blocks. These orebodies have

only limited strike persistences of upto 240 m. This is not a very favourable factor, but the average

width of the orebodies (3.27 to 4.30 m) is a favourable factor. However, the fact that magnetite is the

principal gangue mineral in the orebodies can favourably influence the economics of mining.

Recoveries of about 90% of the magnetite are reported.

Two other shear zones viz., Purulia-Bankura and Chirugora-Kutni-Beldih, are known from

the state. But the results of exploration to date have not indicated any mineralisation of possible

economic significance in these shear zones.

The Sikkim-Darjeeling area is dotted with as many as 40 base metal occurrences confined essentially

to the Daling/Darjeeling Group of rocks with biotitic granites occurring as tongue like bodies. The

important copper-lead-zinc prospects are: Bhotang (Copper-Lead-Zinc) (27°10'30'': 88°32'00''),

Rangpo, East Sikkim district ; Dikchu (Copper-Zinc), (27°23' : 88°35'), North Sikkim district;

Peshok (Copper) (27°04' : 88°24'), and Pedong (Copper) (27°09' : 88°37'). Drilling encountered poor

mineralisation in Bhotang. The IBM estimated following reserves for the Dikchu ore body.

Proved reserves: 1.62 lakh tonnes with 3% Cu and 1.53% Zn

Probable reserves:1.23 lakh tonnes with 2.91% Cu and 1.59% Zn

Total: 2.85 lakh tonnes with 2.97% Cu and 1.56% Zn (2.90 lakh tonnes)

Peshok (Copper) grades between 0.5% and 2.5% Cu (VE).In Pedong the richer zones have a grade

of about 2.5% Cu (VE).

Palaeo to Meso-Proterozoic Polymetallic mineralization : The Bomdila Group of Lesser

Himalayan sequence in Ranga Valley of Lower Subansiri District of Arunachal Pradesh hosts

polymetallic (Fe, Cu, Pb, Zn with Ni, Co, Sn and W) mineralization of Palaeo- to Meso-Proterozoic

age. The mineralization is confined to the magnetite bearing schistose units of the Potin Formation.

Two copper-rich zones with a possible reserve of 1.55mt with an average grade of 0.33%Cu with

appreciable amount of lead and zinc has been tentatively estimated in the Ranga Valley (Potin-

Yazali area). In the Lesser Himalayan sequence of West Kameng District of Arunachal Pradesh,

Proterozoic grey dolomite of Mukatung Formation of of Shergoan Group hosts lead-zinc

mineralization in the form of galena and sphalerite. The mineralized belt extends for a distance of

about 9 Km on which four explorations blocks are located.. The deposit is patchy, highly erratic in

depth persistent; but so far as age (Proterozoic), host rock (dolomite), metamorphic grade (lower

amphibolite) and character of mineralization (strata bound) is concerned, the deposit is similar to

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that of Rajpura-Dariba Group of Rajasthan, where more than 300 mt of lead and zinc been

discovered by G.S.I.

Deccan Traps:

Native copper as thin films along joints, vesicular in fillings and disseminated grains have been

reported from the Deccan basalts near Handigund (16°25': 75°05'), Belgaum district. Magnetite,

haematite and maghemite are other associated minerals.

Nagavand (14°20': 75°35'), Dharwar district: The metasedimentary-volcanic suite consist of andesite flows, tuffs, carbonaceous shales and

ferruginous cherts. Gossanous bands have assayed 0.64 to 12.80% copper. Further exploration is

required to assess the nature and intensity of mineralisation.

Late Palaeozoic metallogenic epoch mainly associated with volcanic rocks.

1)Pb-Cu mineralisation in the epiplatform carbonate sequence around Bora Agar, Rain Agar,

Shisakhani and Dhanpur in Uttarakhand Himalaya and Sirban Limestone around Sersandu in

Jammu Himalaya.

Strata bound sulphide occurs in the carbonate rich formations of the volcano – sedimentary sequence

of the Garhwal Group in U.K. Himalaya. Though a good concentration for and economic deposit has

not yet been demarcated, these occurrences contain a number of old workings

2)Kwanu lead-zinc-copper belt in Uttrakhand in Deoban group of rocks:

The Kwanu lead-zinc-copper belt extends over a strike length of about 1km from Chamri in the

southeast to Anyar in the northwest. Amtiyargad and Chamri prospects of this belt are in

Uttarakhand, whereas, Anyar is located in the adjoining state of Himachal Pradesh. Old workings,

slag heaps and gossans scattered throughout the area are indicative of base metal mineralisation. The

base metal mineralisation in this area is associated with Sauli Formation of Deoban Group. The

principal host rocks for mineralisation are dolomite, shale, carbonaceous and/or calcareous slates and

tuffs. Mineralisation occurs mainly in the form of stringers, disseminations, vug fillings, veins and

patches of metallic sulphides, mainly pyrite, galena, sphalerite and chalcopyrite. Traces of

mercurous sphalerite and argentite are also present. Fractures and shears, parallel to the axial planes

of tight folds are the main locales of mineralisation.

BARYTE

The largest baryte deposit in the world with a reserve of 74 Mt is located in Mangampeta in

Cuddapah District. This deposit occurs in the Pullampet Shale of the Cuddapah Supergroup.

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Baryte occurring as lenses in pegmatites occurs near Kurichchi, Coimbatore District. The

mineral is associated with quartz veins near Alangayam, Vellore District. In central India,baryte

occurs in the septarian nodules in the concretionary zones overlying the Gunderdehi Shale near

Dotapur in Raipur district, Gairi (Dewas District), Dhar area (Dhar district), Sunehra, Manehra

(Jabalpur district), SW of Kerua Village near Harsi Reservoir (Shivpuri district), Andhiri Kho, Bari

(Sidhi district) and around Bhoiron in Tikamgarh district. Baryte veins occur south of Phutana and

NNW of Thanewasna, Mahadwari and Dewada areas in Chandrapur District of Maharashtra. In this

state minor occurrences of baryte are noticed near Kopela and Jingaanur areas of Gadchiroli District

and north of Ran Mangli in Nagpur district. Barytesoccur as very thin vein along foliation planes in

Musnota in Mahendergarh district and from Haripur in Ambala district of Haryana. Baryte deposits

of the order of 15,000 tonnes are located in Kaami, Tatyana, Batwari and Kheel in Sirmaur districts

of Himachal Pradesh and in Kinnaur district, 1425 tonnes of barytes are located in Aarsomang. In

Askot copper-lead-zinc deposit, Pithoragarh district, Uttarakhand, the total reserves of barytes have

been inferred to be about 20, 0000 tonnes.

PLATINUM GROUP OF ELEMENTS (PGE) AND CHROMITE

The ultramafic – mafic suite of rocks are considered to be the potential host for PGE, nickel,

chromium and copper mineralisation. The world's largest deposits of PGE are located in the

Bushveld Layered Complex in South Africa and in the Stillwater complex in U.S.A. The PGE

mineralisation is generally concentrated in the basemetal sulphides and in the chromites.

In the Granulite Terrain of Tamil Nadu, several ultramafic-mafic -anorthosite complexes

occur in Sittampundi, Mettuppalaiyam, Torappadi, Manmalai, Tenmudiyanur, Kadavur and

Oddanchatram areas. Among these, the major Sittampundi and Mettuppalaiyam complexes

represent layered or differentiated sequences of dunite, meta-pyroxenite / chromiferous meta-

pyroxenite, chromitite, garnet-pyroxene granulite, meta gabbro ±garnet, amphibolite, gabbroic

anorthosite and anorthosite. These complexes, dated to be ca.2900 ma, are emplaced within the

amphibolite facies gneisses and the associated supracstals of Archaean age within the E-W trending

Cauvery Shear Zone.

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PGE mineralisation in Sittampundi Anorthosite Complex was first identified by GSI in the year

1984 when one of the seven chromitite samples analysed in U.S.G.S. has given 0.929 ppm of total

PGE. Close-spaced sampling carried out subsequently has resulted in delineating two zones of PGE

mineralisation in the Karungalpatti block – one in the chromitite band No.III with an average grade

of 1.56 ppm of Pt + Pd over 3 m width and the other in the chromiferous meta-pyroxenite band

no.IV with 2.45 ppm of Pt + Pd over 1.60 m width.

Based on detailed mapping and close-spaced sampling in the adjoining Chettiyampalaiyam

block, a significant zone of PGE mineralisation has been delineated for a cumulative strike length of

1.4 km with total PGE values ranging from 1 ppm to a maximum of 18 ppm in the chromitite

chromiferous meta-pyroxenite bands. The average grade of PGE mineralisation in this zone works

out to be 1.8 ppm of Pt + Pd over 1.5 m width.

In Tasampalaiyam block, located at the western part of the Sitampundi Complex, two zones

of chromitite / chromiferous meta-pyroxenite have been delineated. Among these, the western zone

shows significant PGE mineralisation with Pt + Pd values ranging from 0.7 ppm to as high as 6.7

ppm over 0.25 to 1 m width, with sporadic high values upto 16.43 ppm of Pt + Pd.The depth

persistence of these PGE mineralised zones is being tested by scout drilling.

Similarly, a significant zone of PGE mineralisation (1-4 ppm of total PGE) extending for a

strike length of about 1.1 km has been delineated by G.S.I. in the meta-pyroxenite of Solavanur

block in Mettuppalaiyam Ultramafic Complex. The PGE mineralisation with an average grade of

1.8 ppm of Pt + Pd over a width of 2.5 m is found within the meta-pyroxenite band showing

malachite-azurite encrustations.

In Mallanayakkanpalaiyam area, preliminary sampling of the chromite-bearing meta-

pyroxenite band has indicated 0.97 ppm of Pt + Pd.

In Karappadi block, two linear bands of chromitite and chromiferous meta-pyroxenite have

been delineated for a cumulative strike length of about 500 m with a maximum width of 3.5 m. Chip

samples collected from these bands have shown Pt + Pd values ranging from 0.47 ppm to 1.70 ppm.

The depth persistence of these PGE mineralised zones is being tested by scout drilling.

Recent exploration (2007-2008) by GSI indicated the presence of PGE mineralisation in the

form of Sperrylite (PtAsS), Braggite (PtS) and stibiopalladinite (PtAsS) reported alongwith

pentlandite (NiS) and chrome-spinel within the chromitites in Chettiyampalayam Block of

Sittampundi Anorthoste Complex.

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The weathered profile over the Bhuvanagiri Ultramafics, Coimbatore District has yielded

0.10 to 0.43% Ni. Peridote / dunite from Chalk Hills, Salem District has yielded upto 0.40% Ni and

occasional composite grains of Pentlandite + Pyrrhotite + Chalcopyrite have been recorded from the

Red Hills. Nickel values upto 0.12% have also been recorded from the Torappadi ultramafic body,

Vellore District.

Chromite :

The region south of the Singhbhum Cu-U belt is very rich in Cr mineralisation. More than

90% of India’s reserve of about 150 mt. of economic grade Cr-ores occurs in this region. The

mineralisation occurs in two locale:(1) Jojohatu — Hatgamaria (Singhbhum district) and (2) Sukinda

(Jajpur - Dhenkanal districts) - Baula Nuasahi (Keonjhar district).Deposits in (1) were much smaller

and already mined out. Ore mineralisation at Sukinda is more intense than at Baula Nuasahi.

Important chromite occurrences are reported from Sittampundi and Mettuppalaiayam

ultramafic complexes in Tamil Nadu. Several linear parallel bands and lenses of chromitite occur

within the anorthosite gneiss in Sittampundi Complex for a total stretch of 12.8 km between

Sittampundi in the west and Karungalpatti in the east. These chromitite bands, varying in width

from 8 cm to a maximum of about 3 m, are made up of chromite (50-60%), amphiboles (30-35%)

and rutile and other accessories (5%). At places, massive chromitite with 70-80% of chromite

showing cumulate texture is also noticed. These chromitite bands analyse 21.72 to 28.20% of

Cr2O3, 24.04-41.31% of Al2O3, 10.20 to 25.59% of Fe2O3 and 10.10–13.20% of FeO.The reserves

are estimated at 0.221 million tonnes upto a depth of 6 m.

In Mettuppalaiyam ultramafic complex, three occurrences of chromite are reported at

Karappadi, Mallanayakkanpalaiyam and Solavanur areas in Erode district. Chromite occurs as

bands, lenses and disseminations within the meta-pyroxenite-gabbro-anorthosite sequence extending

for a strike length of about 1 km with a width of about 250 m. The chromitite samples collected

from Solavanur and Karappadi areas have given Cr2O3 values ranging from 20.14% to 30.78% and

total iron as Fe-varying from 16.50 to 19.30%.

Only minor chromite mineralisation is reported from Central India. The known deposits are in

Maharashtra in Sindhudurg and Nagpur-Chandrapur districts. The estimated deposits are of 0.53 mt.

Chromite generally are of podiform nature associated with ultrabasic intrsuives in the gneissic terrain.

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Chromite mineralization is reported from Kyun Tso-Shurok Sumdo, Leh district and Sanko

area. The inferred reserves have been estimated at 14000 tonnes

Late Mesozoic Ophiolites of Northeast: The belt with Ophiolite suite’of rock extends for about

200 km from Moreh in Manipur, in south to north-east of Chiphur in Nagaland in north. Chromite is

the main economic mineral of the ‘Ophiolite suite’ of rock that is similar to those of the Alpine type

in their mode of occurrence, physical (podiform) and chemical characteristics (high Cr2O3 content

(>45%) and low TiO2 content).

Meso-Cainozoic mineralisation epoch associated with Indus ophiolites.

Cr mineralization occurs in Ladakh in the form Chromite lenses in ophiolitic suits of rocks

represented by basic and ultrabasic rocks which have been emplaced within flyschoid sediments.

Copper in the form of disseminated chalcopyrite and native specks is associated with Dras volcanic

in Tal and Spiti area.

INDIA’S RESOURCES AND PRODUCTION : 1. Archean Greenstone Association

a. Sukinda and Nausahi in Orissa

b. Sinduvalli and Byrapur in Karnataka

c. Bhandara and Ratnagiri in Maharashtra

d. Roro and Jojohatu in Bihar

e. Ponda and Dudsagar in Goa.

2. Proterozoic Granulite Association

a. Kondapalli in Andhra Pradesh

b. Sittampudi complex in Tamilnadu.

3. Tertiary Ophiolite Association

Chromite occurrences of Manipur, Nagaland, Andaman and Nicobar Islands and

Jammu & Kashmir.

[ Important resource occurrences in India are shown in Plate – 1]

Resources :

Total recoverable reserves of chromite in the country as on 01.04.1995 were assessed at

86.23 million tonnes in which the shares of proved, probable and possible reserves are 30%, 36%

and 34% respectively. Over 97% of the total recoverable reserves are found in Orissa State. Out of

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the total recoverable reserves of all grades about 34% is of Metallurgical grade and 29% is of charge

Chrome grade. As per UNFC system, total resources of chromite in the country as on 1.4.2000 are

179 m.tons comprising 47 m.tons of insitu reserves (26%) and the remaining 132 m.tons of resources

(74%). Category-wise, grade-wise and state-wise break up of recoverable reserves are given in

following table.

RECOVERABLE RESERVES OF CHROMITE (In thousand tonnes) ______________________________________________________________________________ State / Grade Recoverable Reserves ( as on 1.4.2000) Proved Probable Total Metallurgical (>48% Cr2O3) 8072 3464 11535 Refractory (>40% Cr2O3) 407 448 855 Charge Chrome (>44% Cr2O3) 14381 7057 21,439 Low - - - Beneficiable 5876 6923 12799 BY STATES Karnataka 523 648 1170 Maharashtra 2 0 2 Orissa 28227 17263 45490 Manipur - - - Tamilnadu - - - _____________________________________________________________________________________ ALL INDIA 28752 17910 46,663 _____________________________________________________________________________________ [Source : IBM Year Book, 2004]

B. Production :

Orissa continued to be the leading producing State of chromite, accounting for 99% of

the total production in 2003-04. Production of chromite in Karnataka, Maharashtra accounts for the

remaining 1% production.Major share (98.6%) of chromite resources in the country are located in

Orissa. The chromite deposits occur in number of localities along NE-SW belt associated with

ultramafic complexes of Sukinda, Baula-Nausahi and similar occurrences of ultramafic rocks at

Bhalukasoni and Ramgiri. Chromite occurs as persistent thick bands, seams, lenses within ultramafic

complex. Six seams have been delineated with thickness varying from 10 to 50 m. These are friable

in nature and described as brown ore. The chromite deposit of Sukinda belt is mainly stratiform type

and can be classified into the categories like lumpy ore, granular ore, friable ore, ferruginous ore,

disseminated ore and banded ore.

BAULA – NAUSAHI BELT :

Nausahi ultramafic complex covers a surface area of 5 sq km and a detached segment

occurring at a distance of 50 km to the ENE of Sukinda area. Mining of chromite in Nausahi area

started during 1942-43. Ore bodies in Nausahi sector are spread over a strike length of 3 km in N-S

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direction.The width of individual band as revealed from borehole data, varies from 15 m to as thin as

10 cm. The Nausahi ores are inferior charge chrome grade. Iron and silica are higher than in Sukinda

sector. Reserve of 3.40 million tonnes of chromite of all grades have been estimated in Baula-

Nausahi sector. Bhalukasuni chromiferous ultramafic body is the only known occurrence of its kind,

east of famous Nausahi chromite fields. The DGM, Orissa estimated a total reserve of the order of

1550 tonnes for both massive and spotted variety of chromite with Cr2O3 content from 25.77 to

54.76%.

Ramagiri can be approached from Jeypore, which is connected with NH No.43.5 channel samples

collected from pits showed the following analytical results :

Cr2O3 - 24.07 to 27.49%

Fe(t) - 8.10 to 14.24%

IRON ORE

Major iron ore deposits in India, distributed in five zones designated as Zone – I to Zone-V, have

been identified in the country on commercial ground .Zone-I group of iron ore deposits occur on the

Bonai Iron Ore Ranges of Jharkhand and Orissa states and in the adjoining areas in Eastern India,

Zone-II group comprises the iron ore deposits in the 225 km. long North-south trending linear belt in

central India comprising the states of Chhattisgarh and Maharashtra (East), Zone – III deposits occur

in Bellary-Hospet Regions of Karnataka while the Zone – IV deposits cover the rich magnetitic

deposits of Bababudan-Kudremukh area of the same state in south India,Zone – V deposits cover

iron ore of Goa state. In addition, in south India, magnetite rich banded magnetite quartzites occur in

parts of Andhra Pradesh near the East Coast while in Tamilnadu good deposits of magnetite occur in

Salem district and in neighbouring areas.

Banded Iron Formation of Pre-Cambrian Age :

Extensive outcrops of BIF, iron formation which is seen confined to granulite terrains, are found in

the states of Jharkhand, Orissa, Chhatisgarh, Maharashtra, Karnataka, Goa and Tamil Nadu. The

most common names used in India to designate BIF are Banded Haematite Quartzite (BHQ) and

Banded Magnetite Quartzite (BMQ).This is a weakly banded magnetite- quartzite forming part of a

supracrustal sequence of quartzites, mica schists, marbles, metavolcanics and amphibolites

completely engulfed in a voluminous mass of a tonalitic gneiss. The formation is highly folded and

metamorphosed under granulite facies condition. Typical examples are iron formation from the

granulite regions of South India (Tamil Nadu, parts of Andhra Pradesh, Karnataka and Kerala) that

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is different from those of the Archean schist belt.Thus the iron ore formation within the Indian shield

can be divided into two main types :(i) those lying within the high grade region and (ii) those

confined to Archean schist belt.Among these, the first type occurs as narrow, highly deformed and

metamorphosed belt within Archean granulites and gneisses and represents formation of an older age

group (>3000 Ma.) formed in distinct tectonic environment and later incorporated within high grade

mobile belt.The second and the more extensive type having characteristic of both Algoma and

Superior type, is the one confined to the schist belts formed during the period 2900-2600 Ma. These

types of deposits are confined to states of Jharkhand, Orissa, Karnataka, Maharashtra, Chhattishgarh

and Goa. These form important repositories of rich iron ore deposits in India. The major ore minerals

are haematite and magnetite. Important accumulations are in Singhbhum district (Jharkhand),

Keonjhar district (Orissa), Bellary district (Karnataka), Bastar district (Chhatisgarh) and in Goa.

Magnetite ore deposits are mainly confined to Chikmagalur district in Karnataka and Salem and

North Arcot district in Tamil Nadu and Prakasam district of Andhra Pradesh.

Sedimentary iron ore deposits of siderite and limonitic composition:

These ores are also known as Bog iron deposit. These ores of siderite and limonitic compositions are

found associated with the iron stone shales of lower Gondwana age occurring in the coal fields of

Jharkhand and West Bengal and the ferruginous beds in the Tertiary formations of Assam and the

Himalaya.In upper Assam such deposits occur in Lakhimpur and Sibsagar districts and are mainly of

two types: clay iron stone and impure limonite.In Ranigunj area the sedimentary iron ores occur in

the form of thin beds of ironstone of variable thickness and frequently in the Ironstones shale Group

of the Damuda series in Ranigunjcoalfield.

Titaniferous and vanadiferous magnetites:

The vanadiferous-titaniferous magnetite deposits of south eastern Singhbhum (Jharkhand),

Mayurbhanj and Keonjhar (Orissa) and Hassan districts( Karnataka) are associated with gabbroid

and ultrabasic rocks. The larger and rich iron ore deposits are mainly concentrated in Jharkhand,

Orissa, Chhatisgarh, Karnataka and Goa. Comparatively small deposits are situated in Maharashtra,

Andhra Pradesh, Tamil Nadu, Kerala and Rajasthan.The occurrences of iron ore deposits are also

reported from Assam, Meghalaya, Nagaland, West Bengal, Himachal Pradesh, Uttar Pradesh and

Jammu-Kashmir. But these deposits are not economically significant. Detail description of the

deposits belt-wise and sectorwise has not been enumerated.

MANGANESE

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Karnataka has the largest recoverable reserves (64.55 million tones) of manganese ore in the

country. Managanese ore minerals occur in close association with haematite and carbonates as

stratiform, lenticular, patchy or pockety deposits of varying dimensions, within various greenstone

belts. Andhra Pradesh contributes about 90% of the manganese ore production in the country. The

manganese ore here is mainly associated with kodurites of the Khondalite Group in Eastern Ghats

and Penganga beds in the Pakhal Basin.Orissa accounts for one third of the country’s annual

production of manganese and possesses the second largest recoverable manganese reserve in the

country i.e. 50.36 million tonnes of all grades, next to that of Karnataka. Manganese ores are mined

in Singhbhum district in between Noamundi and Gua and from south of Chaibasa. The ore minerals

are mostly psilomelane, braunite, cryptomelane and pyrolusite. Deposits have also been rcorded

from Lada Buru and from Lanji. The total recoverable reserve of manganese ore of all grades is

estimated to be 2.3 Mt .

Goa possesses 83.1 Mt of manganese which constitutes 22.4% of the total resources

estimated for the country.

Madhya Pradesh is India’s foremost source of high-grade manganese ore. The largest and

richest deposit is located in Balaghat district. Other small deposits and occurrences are in

Chhindwara, Jabalpur, Jhabua, Khargone and Seoni districts.Maharashtra possesses about 10% of

the country's total estimated resources of Manganese ore, which are of the order of about 22.186

million tonnes. Maharashtra was the second largest producer of manganese ore, sharing 26% of

mineral production. The manganese belt in Nagpur and Bhandara districts extends for 100 km from

west of Gumgaon to Ghanor in the east and passes through Paraseoni, Kandri, Mansar, Guguldoh,

Alsalpari, Dongribuzurg and Chikla with a maximum width of 20 km in the central part, near

Mansar. The major share of manganese ore of this sector comes from Sausar Group Manganese ore

deposits occurring in the lower part of the Sausar Group. There are about 20 deposits spread over a

length of 45 km and with an outcrop width of about 15 km. The ore occurs in two forms viz. (1) as

bands intercalated with gneisses, schists and quartzites associated with spessartite-quartzite rock

(gondite), rhodonite rock or both and (2) as lenticles of bands of nodules in crystalline limestone.

There are as many as 55 known manganese deposits in this district. Manganese ore in Sindhudurg

district occurs as secondary enrichment deposits associated with lateritised Dharwarian meta-

sediments. Other small deposits and occurrences are in Chhindwara, Jabalpur, Jhabua, Khargone and

Seoni districts. Manganese minerals are found scattered on the eastern slope of a hill 1.5 km

northeast of Ratanpur near Newasa and Kamarakhol area of Bilaspur district of Chhattisgarh.

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MOLYBDENUM

Molybdenite mineralisation occurs in two different geological settings - one associated with the

alkaline group of rocks occurring in Harur-Uttangarai Belt, Dharmapuri and Alangayam, Vellore

Districts of Northern Tamil Nadu and the other in a graphite pegmatite intrusive into migmatitic

gneiss of Karadikuttam area of Dindigul District, Tamil Nadu.

In Harur-Uttangarai Belt, the mineralisation is confined to the shear zone within which

emplacement of quartz and carbonate veins are present. In Velampatti South Block, detailed work

was carried out by GSI by drilling upto the fourth level over a length of 1.38 km, which proved the

depth persistence of molybdenite mineralisation upto the vertical depth of 320m. The resources

estimated in this block are of the order of 2.74 million tonnes with an average grade of 0.102% Mo

at 0.03% cut-off or 5.75 million tonnes of ore with an average grade of 0.064% Mo at 0.01% cut-off.

In the other blocks of Harur sector, a tentative resource of 12.68 million tonnes of ore with an

average grade of 0.032% Mo has been estimated.

In the Velampatti Central Block, the extension of the above said mineralized zone has been proved

further north over a strike length of 0.50km. A reserve of 0.336 million tonnes with an average

grade of 0.079% Mo at 0.05% cut-off and 0.723 million tonnes with the average grade of 0.059%

Mo at 0.03% cut off is established. The other nine blocks existing north of Ponnaiyar River in

Uttangarai Sector are being explored, some of the borehole core samples show values as high as

2000 ppm of Mo.

The Alangayam area falls in the northeastern part of the Gudiyattam Bhavani Belt and mainly

consists of epidote - hornblende gneiss occupying the valley between the Yelagiri Hills in the west

and the Javadi Hill range in the east. A number of quartz - baryte vein bearing pyrite, galena and

molybdenite and occasional chalcopyrite are emplaced within epidote - hornblende gneiss. Detailed

prospecting including scout drilling by GSI, has revealed a number of low dipping parallel quartz

veins, some of which assayed significant molybdenum values (0.01% to 0.51%). The maximum

thickness of the mineralised zone is one metre. A probable reserve of 86,314 tonnes and possible

reserve of 6,33,408 tonnes with the average ranging from 0.0125 to 0.04% of Mo has been

estimated.

Near Karadikuttam in Dindigul District, molybdenite occurs in the form of disseminated and thin

stringers in a graphite pegmatite, intrusive into migmatitic gneiss. Exploratory drilling has

established about 0.28 million tonnes of ore with average grade 0.0285% of Mo.

TIN, TUNGSTEN

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Extensive deposits of wollastonite are located in Khera Uparla and Bel ka Pahar areas of Pali-Sirohi

districts, and in Gola-Alipura area of Ajmer district of Rajasthan. Tosham prospect, Bhiwani district

of Haryana contains appreciable quantity of casseterite and wolframite with tin ore (0.15% tin) of the

order of 30.33 million tonnes. In the state of Chhattisgarh, tin is found in the form of cassiterite

mineral in the pegmatites and in alluvial soil being derived from these pegmatites in Bastar district.

Stratiform zinc-scheelite mineralisation in Sakoli belt represents the earliest phase of metallogeny in

this belt In the state of Madhya Pradesh, sporadic occurrences of cassiterite have been noticed within

Aravalli Supergroup intruded by granitoid rocks of Jhabua district. Disseminations, streaks and patches

of scheelite are seen in the calc-granulite band occurring within pegmatoidal granite/granite body in the

Karungalagudi area, Madurai District, Tamil Nadu. Significant concentrations, upto 2% W, are seen near

Kambalipatti, Somagiri and Rayarpatti. At Kambalipatti, the mineralised zone has been traced over a strike

length of about 270m with a width upto 40m. In the Somagiri also the mineralised zone as a width of about

40m or more and is inferred to have a strike length of about 1km. Several ore shoots (at the cut-off grade of

0.05% W) are inferred. On the basis of trench sampling 4 or 5 ore shoots upto 5 m wide are inferred. Ore

shoots are estimated to comprise about 20 to 30 % of the total width of the mineralised zone and are expected

to have an average W content of 0.10 to 0.15%. In the Rayarpatti area, the mineralised zone extends over a

strike length of about 1800m but the mineral content is rather low, about 200 to 300 ppm.Tin values (upto

1800ppm) are associated with the mineralised zone in the Kambalipatti. Tin values of 200 to 500 ppm are

reported from three grab samples of quartzite from Vaiyampatti, Tiruchirapalli District.Tungsten are known

from Pauri and Almora in Uttarakhand & Sonbhadra & Hamirpur districts of UP.

URANIUM

Singhbhum district in Jharkhand has so far remained the only place in India, producing uranium ore.

Uranium in Singhbhum district was first reported in 1921 by GSI. At Jagduguda, uranium occurs

associated with hard compact and somewhat mylonitised chlorite-sericite schist and granular

metasedimentaries. Indicated ore reserves at Jaduguda have been estimated at 2.8 Mt with an

average grade of about 0.08% uranium oxide. Uranium is found associated with copper

mineralisation in Chamoli district, Uttarakhand and Lalitpur district, Uttar Pradesh.

BAUXITE

The deposits in AP and Orissa with a total reserve of about 1650 Mt constitute one of the largest

bauxite deposits in the world. Orissa continues to be the leading state accounting for 59% of the total

bauxite production of the country Jharkhand is rich in bauxite deposits. It occurs in the high

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hilltops of the Chhotanagpur plateau as residual deposits. Bauxite occurs as segregated sheets,

pockets, patches and lenses within laterite cappings over the traps and gneisses Extensive deposits of

bauxite are found in the western Chhotanagpur plateau area falling in Lohardaga and Gumla

districts and adjoining Palamau district. The reserves of high-grade bauxite, containing above 50%

Al 2O3 were tentatively estimated to be about 9 mt in the erstwhile Ranchi district and 1.7 mt in

Palamau district. The exploration at Amtipani area (23º20' to 23º23' : 84º16' to 84º19') established an

estimated reserve of 4.95 mt analyzing 48.47% Al2O3 and 5.59% SiO2 in five blocks covering 1.75

sq km. Occurrences of bauxite with laterite in Kharagpur hills, Munger district are known since

long. Deposits occur on the hills at Khapra (25º10' : 86º27'), Maruk (25º11' : 86º28') and Maira

(26º14' : 86º22'), of which the deposit at Maruk is the most promising bauxite occurrences.Bauxites

are also reported in the high level laterite, capping the highly dissected plateau tops of Rajmahal trap

rocks in the Santhal Parganas district. Bauxite with laterite occurs as capping over the Dhandraul

Quartzite of the Vindhyan Supergroup near Adhaura (24º41'15": 83º37') in Rohtas district

(erstwhile Shahabad district).The reserves of bauxite estimated from Andhra Pradesh are placed at

565 Mt.

Bauxite occurs in association with laterite capping on Deccan Traps on the high plateaus, east of

Kolhapur and Satara districts and along the low lying plateaus of the Konkan terrain in Kolaba and

Ratnagiri districts. It also occurs in Kolhapur district, Raigad district, Ratnagiri district, Satara

district Sindhudurg district and Thane districts of Maharashtra. The important occurrences of bauxite

are located in Rakti Dadar, Nanhu Dadar, Jamuna Dadar (Mandla) , Tikuri and Tikaria (Jabalpur),

Mundi Dadar, Touri Dadar, Kauwajhar Dadar (Balaghat) and also in Shahdol, Rewa, Satna, Guna,

Shivpuri and Vidisha districts of M.P. High grade bauxite occur between Keshkal and Amabera

(Bastar district), Phutka Pahar (Bilaspur district), plateau laterite in Khuria (Raigarh district), Bodai,

Daldali, Kesmarda (Rajnandgaon district) , atop Deccan trap in Mainpat-Jamirapat and Joka-

Luchupat (Surguja district) and also in Durg district of Chhattisgarh state. Bauxite occur as irregular

lenses / pockets and high-level laterite cappings over charnockite in the Nilgiri Hills, Shevroy Hills,

Kollimalai Hills, and the Palani Hills of Tamil Nadu.

The diasporic bauxite is extensively found in Jammu region. It belongs to Jangalgali Formation. The

aggregate reserves of 13.40 million tones were estimated for these deposits. In recent years GSI has

investigated bauxite deposits of (1) Triyath-Krul,Ransuh-Khori areas of Chakkar (192000 tonnes

bauxite, 345600 tonnes alumunous clay) (2)Saro-da –Bas-Malhad area of Sangarmarg (13,26,430

tonnes pisolitic/non pisolitic bauxite,aluminous clay and kaolinite) (3) Panhasa area(total 2432000

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tonnes) (4) Heimna-Gura area (219980 tonnes) and (5)Karthal-Simnigali-Lodra, Jangalgali,

Sukhwalgali, Chhaparbari, Kotla areas and Mohogala areas(1.33 million tones).

NON METALLIC AND INDUSTRIAL MINERALS

Magnesite

Prominent deposit of magnesite is located on Chalk Hills as criss-cross veins traversing dunite /

peridotite in Salem District, Tamil Nadu with estimated reserves of 44 million tonnes. High grade

magnesite reserve in Paintahl, near Katra are 2.5 million tonnes while 45,330 tonnes magnesite

occur in Kyun tso-Shurok, Leh district. 3.48 million tonnes magnesite has been reported from Agar

– Girechhina deposit, Almora district with 38% MgO; 7.9 million tonnes from Dewaldhar depoist

with 38% MgO ;6.7 million tonnes from Kanda – Masauli deposite with 39.67% to 44.50% MgO;

0.01 million tonnes from Areapani prospect; 43.45 million tonnes of grade 1 magnesite deposit and

3.14 million tonnes of grade II magnesite from Pithoragarh district, UP. A reserve of 9.2 million

tonnes magnesite deposit with Mg O from 37% to 44% has been reported from Bora – Agar,

Pithoragarh district, UP.In Alaknanda valley, a possible reserve of 2.65 million tonnes with MgO

between 38% to 41.61% from Dwing – Tapowan depoist; 6.45 million tonnes with MgO more than

43.5% from Gulabkoti- Pagnao- Mamolta- Molta deposit;1.38 million tonnes with MgO from 38%

to 43.5 % from Helang deposit; 1.54 million tonnes with Mg O from 38% to 43.5% from Palla –

Jhakhola – Kimana deposit; 1.31 million tonnes with Mg O 42.348% to 45.96% from Mandra –

Taraktal deposit and in Nandakini valley area 5.45 million tonnes with MgO 38% to 43.5 % from

Ramini deposit have been reported.

Limestone

Extensive deposits of cement grade limestone occur in the Himalayan states. Huge deposits of

limestone of differenet industrially exploitable grades occur in Jammu and Kashmir. Extensive

deposits of limestone occur in various part of the state. Reserve in these districts are - Anantnag 671

million tonnes, Baramulla 180 million tonnes, Srinagar 7.5 million tonnes, Ladakh .53 million

tonnes, Kathua 45.45 million tonnes, Rajouri 12.26 million tones (probable reserve), Poonch 6.5

million tonnes and Udhampur 3.03 million tonnes. Cement grade limestone reserve of 117 million

tonnes (CaO:45.22 to 47.80% and MgO:0.91%) occur in Jamkhal and Gangta Hill in Bilaspur

district of Himachal Pradesh(H.P.). In Kangra district, H.P.,3 km north of Dharamshala, 17.6 million

tonnes cement grade limestone of CaO 42.52% and MgO 2.04% are reported. In Mandi district 550

million tonnes reserve of cement grade limestone with CaO 34.40 to 52% and MgO 0.2 to 9.1 % are

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reported. In Shimla district, H.P., tentative reserve of 1020 million tonnes is estimated in Drawal,

Kariali, Jutog Thench and Suma. Cement garde limestone deposits of the order of 50.25 million

tonnes are located in Ambala & Mahendergarh districts of Haryana. From Rihuita, Kolgadaiya,

Sidhpur & Hanuman dhara blocks, Banda district, U.P.the limestone reserves are reported to be 66

million tonnes. From Barkot – Nutiya, Lambidhar- Hathipawn and Song valley deposits, Dehradun,

limestone reserves of 38.2 million tonnes, 7 million tonnes and 146.4 million tonnes respectively,

have been estimated.Substantial limestone deposits occur in Tamil Nadu both as crystalline and non-

crystalline (amorphous) varieties besides corals. The bulk of limestone deposits are mainly

distributed in parts of Salem, Tiruchirapalli, Karur, Madurai, Virudhunagar, Ramanathapuram,

Nagapattinam, Tirunelveli, Tuticorin and Coimbatore Districts. The total reserves of crystalline

limestone are 200 million tonnes of ‘Proved’ category and about 25-30 million tonnes of ‘Inferred’

category. Non-crystalline limestones are located in parts of Tiruchirapalli, Tirunelveli and Tuticorin

Districts with reseve base of about 670 million tonnes of both 'proved' and 'inferred' categories.Coral

limestone is found in a series of islands in Gulf of Mannar, Palk Bay and Rameswaram.

From Rihuita, Kolgadaiya, Sidhpur & Hanuman dhara blocks, Banda district, the limestone

reserves are reported 66 million tonnes. This is high in Mg O content. From Barkot – Nutiya,

Lambidhar- Hathipawn and Song valley deposits, Dehradun, limestone reserves of 38.2 million

tonnes, 7 million tonnes and 146.4 million tones respectively, have been estimated. From Deoban-

Bazmara area, Chakrata tehsil, Uttarakhand a probable reserve of 478.43 million tonnes with 45% to

46% Ca O has been estimated. In Deoban sector, Durari Dhar deposit has 80 million tonnes with

CaO ranging from 51.38 % to 53.34%, Kanasar deposit 62.5 million tonne with CaO from 47.08% to

53.05%, Deoban deposit 125 million tonnes with CaO from 45.91% to 51.22%, Aun chak deposit

98.43 million tonnes with Ca O from 49.33% to 53.1% and Osmar deposit 18 million tonnes with

CaO 52.53%. In Bazmara sector, Bazmara deposit has 50 million tonne limestone with CaO from

50.56% to 53.17%, Bazmara Lani deposit 25 million tonnes with CaO from 52.27%to 53.04 %. In

Pithoragarh district, Dharchula deposit has cement grade lime stone of 6.591 million tonnes with Ca

O from 40.97% to 49.75% , Gangolihat deposit 91.89 million tonnes with Ca O from 46.80% and

46.40%, Rorgaon deposit 7.8 million tonnes with Ca O from 39.38% to 51.43%. In Nainital district,

Betalghat – Jaurasi deposit has a reserve of 10 million tonnes with 44.% Ca O. A large deposit of

limestone has been reported near Nagni in Tehri Garhwal district and 3.6 million tonnes cement

grade limestone around Garur chatti area, Pauri Garhwal district. A reserve of 161.22 million tonnes

with 60 million tonnes of cement grade and 30 million tones of blast furnace grade limestone has

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been reported from Kajrahat limestone belt; 48.90 million tonnes with Ca O from 38.1% to 48.3%

from Gurmah – Patwadh block, Rohtas limesote belt; 49.60 million tonnes with Ca O from 42% to

45% from Kanach block, Rohtas limestone belt; 26 million tonnes with Ca O from 42.23% from

Susnai Mahona block and 70.90 million tonnes with CaO from 43% to 44% from Chandi –

Basuhari block, Sonbhadra district,UP.

Limestone deposits in Bihar and Jharknand are mainly associated with two different groups of rocks,

viz., Vindhyan rocks in Rohtas and Palamau districts, and Chhotanagpur Gneissic Complex in

Hazaribagh, Ranchi, Munger and Palamau districts. Besides, some fine-grained, non-crystalline

limestone is also found within the rocks of Kolhan Group in Singhbhum district. The total

recoverable resource of limestones of all categories and all grades has been estimated to be 1450.84

million tones in the whole of Bihar & Jharkhand

Apatite and Rock Phosphate/Phosphatic nodules:

Apatite is found in East and West Singhbhum district as veins emplaced in the Singhbhum Shear

Zone and also as a constituent associated mineral in mica pegmatites of Bihar Mica Belt, in parts of

Gaya, Hazaribagh and Munger districts. In Singhbhum district, apatite occur in a 60 km. long belt in

the eastern part of shear zone, between Ichagarh (22º45':85º42') and Khejurdari (22º41' : 85º34'). . A

total possible reserve of 178 million tones (Mt) atite of all grades in the whole of Singhbhum Shear

Zone has been estimated by IBM (1998). In Pathargora, a reserve of 0.45 mt. of apatite with 15%

P2O5 was estimated in 1989 by IBM. However, later work in (1992) Pathargora has indicated a

possible reserve of 3.73 Mt. of apatite with average grade of 11.89% P2O5 at 4.0% P2O5 cut-off.

Recoverable probable reserve of apatite in Jharkhand has been estimated as 7.27 Mt.

Small crystals of apatite have been noted in hybrid rocks (syenite-pyroxenite) in the Hogenekal area,

Dharmapuri District,Tamil Nadu .In the carbonatite near Sevattur, Vellore District, apatite crystals

are disseminated and a reserve of 190,000 tonnes of apatite has been estimated with P205 content of

27.48 per cent.

Phosphatic nodules occur in association with gypseous clay and shale of Karai Formation of Uttattur

Group of Cretaceous age, along a belt extending from Neykulam to Siruganpur covering an area of

27.5km in Tiruchirapalli District, Tamil Nadu. A total probable reserve of 127,000 tonnes of these

nodules upto a depth of 15.24m was estimated. The P205 content of the nodules varies from 21.14

to 26.50%. Upto 1960, about 100 to 150 tonnes of nodules were produced annually, but no

production is reported at present.

Asbestos

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Asbestos occurrence in Jharkhand are almost entirely confined to the East and West Singhbhum

districts and are associated with Precambrian basic and ultrabasic rocks, especially where the latter

have been serpentinised. Although both crysotile and amphibole varieties are found, the majority of

the occurrences are mainly of amphibole variety. Tremolite type being the most common crysotile

variety occurs at Roro (22º39'30":85º30'30"), Nurda (22º20':85º44'), Kalimati (22º16'00":85º35'30"),

Bichaburu (27º17'30":85º48'00") and Manpur (22º36':86º16'). A total reserve of all categories of

asbestos in whole of Jharkhand has been estimated to be of the order of 0.155 Mt.

Amphibole asbestos has been noted near Bargur and Muddampalayam in Coimbatore District, 13km

south of Namakkal and Allanganathan in Namakkal District and at Kargudi in Karur District of

Tamil Nadu. Asbestos occurs at Goreghat (Balaghat District), Badagaon and Khemra (Betul district

), Dhantalab (Dewas district) Abdia (Hoshangabad district ) and in minor quantity in Mandsaur,

Narshingpur, Schore Sconi and sidhi district of Madhya Pradesh. Minor occurrences of asbestos

have been reported between and Kolgaon in Sindhudurg District; near Tumkhera khurd in Bhandara

District, near Wenganur and Kandodi in Garhchiroli District of Maharashtra.

Borax

The net reserves of crude borax in Puga valley have been estimated 5423 tonnes. Other occurrences

of borax have been noted at Chumathang, Chusul, Yang and Mahe areas of Leh district.

Stibnite

Stibnite reserve of the order of 10,582 tonnes (1.65% Sb) occur at Bara Shingri in Lahaul & Spiti

districts of Himachal Pradesh.

COAL, LIGNITE, OIL and GAS (FOSSIL FUEL)

Jharkhand, the leading State in the Indian subcontinent in respect of its solid fossil fuel content,

bears the testimony of classical development of the Permian coal measures. Out of different

Gondwana basins of Peninsular India, the newly redefined Jharkhand State of erstwhile Bihar

occupy the most important Damodar-Koel valley basin belt along with a subsidiary basin chain to

the north of it and the Rajmahal group of basins (a part of Rajmahal-Purnea master basin). The

coalfields like Raniganj (western part, to the west of Barakar River and a small area in trans-Ajay

part), Jharia, Bokaro, Ramgarh, Karanpura, Auranga and Hutar from east to west are included in E-

W trending Damodar-Koel valley basin belt. Coal Resources of Bihar is 160 milliom tones and

Jharkhand is 74313.64 million tonnes as on 01.01.2007.

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Raniganj coalfield of West Bengal holds the earliest known coalfield of the country. During the last

10-12 years, the Birbhum coalfield has been discovered. Besides these two large coalfields, there are

a few minor coalfields and/or outliers of coal bearing rocks, like Darjeeling, Barjora, Hetampur and

Tangsuli in West Bengal. Till date, Raniganj coalfield is the only coal producing area of the

State.The total Coal resourse of West Bengal is 28334.84 million tones.

Important coalfields of central region include coalfields of Mahanadi basin, Satpura-Son basin, and

Wardha valley basin .The coal is generally non-coking and high in moisture. The important coal

fields are 1) Wardha Valley Coalfield (Chandrapur District) and Kamthi-Saoner Coalfield (Nagpur

District) of Maharashtra state; 2) Korba coal field, Hasdo-Arang coal field, Sendurgarh coal field

(Bilaspur and Korba districts), Mand-Raigarh coal fields (Raigarh-Jashpur districts), Sohagpur coal

field, Chirimiri coal field, Jhilmili coalfield, Sonhat coalfield (Koriya district) and Bisrampur

coalfields, Lakhanpur coalfields and Tatapani coalfields (Surguja district) in Chhattisgarh state; 3)

Pench-Kanhan-Tawa coalfields in Betul-Chhindwara and Hoshangabad districts, Mohpani coalfield,

Johilla coalfield, Umaria and Korar coalfields of Narsinghpur district, Singrauli coalfield of Sidhi

district in the state of M.P.Semi-anthracitic coal deposits are located in various part of Udhampur &

Rajour districts of Jammu region. Estimated reserve are at Jangalgali (4.7 million tones), Chinkah

(3.9 million tonnes), Metka (2.25 million tonnes) and Jigni-Kura (0.18 million tonnes). Few deposits

of lignite of the order of 7.26 million tonnes are reported in Nichahom and Chowkibal, Baramulla

district.

Recently, the Geological Survey of India carried out an exercise for prognostication of possible gas-

in-places reserves (Coal Bed Methane) in selected areas of few coalfields containing high rank coal

under cover of younger sediments. Attempt was made to make the estimate more realistic by

reconciling empirical calculations of methane content with actual gas emission, gas desorption data,

published or otherwise, wherever available. Thus prognosticated gas-in-place reserves of 281 Billion

cubic meter (BCM) (at equilibrated pressure under saturated reservoir condition) were derived from

prospective areas of Bihar and Jharkhand coalfields.

The lignite belt in the Cauvery Basin of Tamil Nadu, about 130km long and 5 to 15km wide, extends

from Bahur in the north, through Neyveli, Srimushnam, Jayamkondacholapuram and up to

Mannargudi in the south - falling in parts of Union Territory of Pondicherry and Cuddalore,

Perambalur, Nagappattinam and Thanjavur Districts of Tamil Nadu. The lignite occurs as a sub-

crop at depth ranging from 50m to 500m below ground level. Down dip extension of this lignite

zone is reported from ONGC boreholes from 500m to 1800m depth in Tiruvarur, Kamalapuram,

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Kovilkalappal and Mayiladurai. Lignite zone is 1 to 25 m thick with an average of 12m, north of

Kollidam River whereas, 1 to 90 m thick (cumulative thickness) in the Mannargudi area, south of

Kollidam River. The estimated reserve of lignite is about 6500 million tonnes and 18,000 million

tonnes in the area north and south of Kollidam River, respectively. It is being mined by Neyveli

Lignite Corporation Limited and the mined lignite is utilised in thermal plants I&II, respectively,

which has 600 and 1470MW generation capacity.

Rajasthan has good deposits of lignite in Bikaner, Nagaur and Barmer districts. Sustantial deposits

of lignite occur in the Tertiary formations of Middle Eocene area in the Barmer – Jaisalmer Palana

and Nagaur basins of Barmer/Jaisalmer, Bikaner – Nagaur districts. Exploration of these deposits are

being carried out by GSI, NLC, MECL & DMG Rajasthan.Major occurrences of Lignite in Gujarat

are in the Panandro Lignite field and adjoining areas of Kachh district and in the Bhuri – Rajpandi

area of Bharach district. The lignite occurs within Tertiary formations of Eocene age. Exploratory

work by ONGC indicated possible occurrences of lignite at 800m – 1400m depth level in the Kalol

basin. Sizeable deposits of Lignite are reported from Hundwara tehsil of Baramulla districts. GSI has

proved 4.5 million tonnes of lignite reserves upto a depth of 36.5 m in Nichahom and Chowkibal

areas of J & K.

Significant prospects of oil and natural gas have been identified over an area of about 40,000 km2

on-shore and off-shore in the Krishna-Godavari basins in parts of East and West Godavari and

Krishna districts.

GRAPHITE

Graphite occurrences are reported from Sindhudurg, Bhandara and Gadchiroli districts of

Maharashtra. In the Bastar district of Chhattisgarh state, graphite occurs associated with quartzite

and diopside gneiss on the west bank of Sabari river. Flaky ghaphite is noted near Borakonde and

SW of Kamaram. Specks of graphite are reported from Palachelama and Bote Tongu. Graphite is

also reported from the khondalites near Kartpadar and Limpara (Raipur district) and as lenses in

association with quartzites and schists at Kennapara, Manikpur, Kobi and Tolkipara areas of Surguja

district. Flaky graphite has been noted near Borakonde and Kamaram in Bastar district, Kartpadar

and Limpara in Raipur district of Chhattisgarh state.Graphite occurrence is located in Puvandhi in

Sivaganga District, Kurinjankulam in Tirunelveli District, Palakottai Hill and near Pudupalaiyam in

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Vellore District and Tirumangalam,Ponnamangalam in Madurai District. Reserves are estimated of

over 0.6 million tonnes of graphite concentrate in Tamil Nadu.In the state of Madhya Pradesh,

graphite is found associated with graphite schist and phyllite of Tikari, Maramjhiri, Chiklar,

Gauthana, Bhopali, Junawani and Golighat areas in Betul district, in the graphite schist from Jobat,

Tampura, Jowari Moti and Kalapan areas of Jhabua district and in carbonaceous shale of Morar

Formation near Chalgaon and Chattgurhi near Behat of Gwalior district.Graphite also occurs in

Doda and Baramula districts (probable reserve of 16 million tonnes)ofJ& K.Graphite is reported

from Almora and Pauri Garhwal districts in the Himalaya and Hamirpur district in Uttar

Pradesh.From Kalimati and Sirar areas of Almora district, a possible reserve of 10.7 million tonnes

graphite has been estimated upto a depth 3 m.

Ilmenite, Rutile, Monazite and Garnet sands:

Tamil Nadu has major heavy mineral deposit (Ilmenite, Rutile, Monazite and Garnet sands)

associated with the beach sands spread along its vast coastal tracts; major concentration of these

heavy minerals occur along east coast between Kolachal and Kanyakumari in Kanyakumari district

with reserves of 45,75,605 tonnes, as reported by Atomic Minerals Division (AMD). Apart from

these, 93,60,093 tonnes of heavy mineral deposit have been estimated between Periaswamipuram

and Vembar Naripaiyur in Ramanathapuram District. In the Union Territory of Pondicherry, ilmenite

and garnet sands occur along the coast of Karaikal with reserves of 17,26,862 tonnes (AMD).

The heavy mineral deposits of Kerala are mostly dominated by ilmenite and monazite confined to

sandy beaches of coastal stretches of Varkala and Chavara in Kollam District. The Chavara heavy

mineral deposit extends in the north to sandy beach west of Nirkunnam to south of Trikkunnapuzha

in Alappuzha District. These deposits are being worked by the Kerala Minerals and Metals Ltd. and

Indian Rare Earths Ltd. In Malappuram District, the coastal tract between south of Ponnani to

Balangod is endowed with 9,15,000 tonnes of ilmenite, 1,80,000 tonnes of magnetite, 2,30,000

tonnes of garnet and 4000 tonnes of zircon. The Thiruvananthapuram District deposit of ilmenite and

monazite in beach sands are found in Vizhinjam, Kovalam and near Veli and Varkala. The AMD has

estimated a reserve of 3.33 million tonnes of heavies from these areas out of which ilmenite

constitutes a reserve of 2 million tonnes. Apart from these GSI has proved the probable resources of

Ilmenite-0.9 million tonnes, Rutile- .07 million tonnes, Zircon-0.06 million tonnes and Sillimanite-

0.3 million tonnes in the inner shelf areas of Kollam-Varkala sector.

Gypsum

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Rajasthan accounts for about 90% of total production of gypsum in the country, and it is located

mainly in Bikaner district (Jamsar, Dhirera, Kaoni, Bharru, Lunkaransar areas), Nagaur district

(bhadwasi, Dhakoria areas), Barmer (Utarlai, Kavas, Thob, Chittar ka Par areas), Jaisalmer (Sri

Mohangarh, Hamirwali Wadi, Lakha, Nachna, Bhaddara, Phalsund, Satta Sunde and Nokh areas),

Sri Ganganagar district ( Siramsar, mahala, Pallu, Borasar Malkisar, Karnisar, Raghunathpura,

Suratgarh, Desli, Hanumangarh, areas), and Churu district (Bhallan, Deogarh, Shethon areas) of

Rajasthan. Large gypsum deposits of the order of 100 million tonnes occur between Liwa Thach and

Kapus in Kinnaur district of Himachal Pradesh.Gypsum deposits are located in Uri, Baramulla

district (63.83 million tonnes), and Ramban-Batote–Assar belt (41 million tonnes) of J & K. Gypsum

reserves of 15.60 million tones are reported from Perambalur in Perambalur District and Lalgudi

Taluk in Tiruchirapalli District, Tamil Nadu. Gypsum occurs as lump in Ambala district, Haryana.

Gypsum deposits are known from Dehradun, Nainital, Pauri Garhwal and Tehri Garhwal districts of

Uttarakhand & Hamirpur & Jhansi districts of Uttar Pradesh. Gypsum reserve from Manjhara area

(13209 tonnes), Deradun district, upto a depth of 15 m., Kharari chatti area (1.585 lakcs tones), Pauri

Garwhal district, Uttarakhand, Garur chatti area (1.066 lakhs tones), Tehri Garhwal district,

Uttarakahd,Gugthani (5080 tonnes), Mahipur (2032 tonnes) and from Rangargaon (30481 tonnes)

have been estimated.

Apatite

The important apatite occurrences are located in Beldih and Mednitanr in the western part and

Chirugora, Purtaha Kutni and Dandodih-Gamardih in the eastern part of West Bengal. At Beldih

reserve of 4.56 million tones of ore containing an average grade of 13.17% P2O5 has been estimated

up to a depth of 150 m which includes high grade reserve of 1.56 million tones of ore with an

average grade of 21.62% P2O5. The apatite ore contains high Nb-content which may be recovered as

by-product. The lensoid apatite zone has been delineated over a strike length of 350 m in Mednitanr.

Apatite-quartz rock occurs on surface only as float ore boulders. A probable reserve of 0.19 million

tones of ore with an average grade of 7.00% P2O5 has been estimated for a vertical depth of 50 m. At

Chirugora, a reserve of 1,862 million tones of ore with an average grade of 10.58% P2O5 has been

estimated up to a vertical depth of 50 m and in the eastern sector 0.521 million tones of ore with an

average 7.33% P2O5 has been estimated up to a vertical depth of 100 m. At Purtaha, a probable

reserve of 0.74 million tones of ore with average grade of 7.26% P2O5 has been estimated up to a

vertical depth of 50 m. This reserve also contains 0.25 million tones of ore with average grade of

10.39% P2O5. In Kutni, a total of 4.26 million tones of ore with average 8.87% P2O5 have been

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estimated up to a vertical depth of 100 m. In Dandodih-Gamardih, a total of 4.48 million tones of ore

with average grade of 8.04% P2O5 have been estimated up to a vertical depth of 50 m. The reserve

also includes 1.29 million tones of ore with 12.22% P2O5 and 0.11 million tones with 25.04% P2O5.

Along the North Purulia shear zone, apatite-magnetite-quartz rock is reported to occur at Pankridih

in the northern part of Purulia district. The apatite mineralisation appears to extend over a strike

length of around 300 m.

Precious and Semi-precious Stones

A number of occurrences of precious and semiprecious stones are known from gemstone belt in the

Eastern Ghats, distributed in East Godavari, Visakhapatnam and Vizianagaram districts.