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Romanian Journal of Romanian Journal of MINERAL DEPOSITS MINERALOGY
continuation of
DARI DE SEAMA ALE SEDINTELOR INSTITUTULUI DE GEOLOGIE SI GEOFIZICA
COMPTES RENDUS DES SÉANCES DE L’INSTITUT DE GÉOLOGIE ET GÉOPHYSIQUE (1. Mineralogie, 2. Zăcăminte)
Founded 1910 by the Geological Institute of Romania
ISSN 1220-5648 vol. 83 ISSN 1220-5621
THE SOCIETY OF ECONOMIC THE SOCIETY OF MINERALOGY
GEOLOGY OF ROMANIA OF ROMANIA
SIXTH NATIONAL EIGHTH NATIONAL SYMPOSIUM SYMPOSIUM ON MINERALOGY ON ECONOMIC GEOLOGY
“Rocksalt and other nonmetalliferous deposits”
4td - 6th September 2008, SOVATA ROMANIA
Institutul Geologic al României
Bucureşti - 2008
GEOLOGICAL INSTITUTE OF ROMANIA
General Director: Dr. Ştefan Marincea The Geological Institute of Romania is publishing the following periodicals:
Romanian Journal of Mineralogy Romanian Journal of Petrology Romanian Journal of Mineral Deposits Romanian Journal of Paleontology Romanian Journal of Stratigraphy
Romanian Journal of Tectonics and Regional Geology Romanian Journal of Geophysics Anuarul Institutului Geologic al României Memoriile Institutului Geologic al României
Editorial Board: Gheorghe Udubaşa (chairman), Şerban Veliciu (vice-chairman) Tudor Berza, Paul Constantin, Emilian Roşu, Ioan Stelea, Mircea Ţicleanu.
Sixth National Symposium on Economic Geology Eighth National Symposium on Mineralogy
Honorary Committe Presidents: Theodor Atavasiu - President of AVAS
Dr. Bogdan Găbudeanu - President of the National Agency for Mineral Resources
Prof.dr.eng. Moise Ioan Achim, Rector of “1Decembrie 1918" University
Eng. Liviu Necşulescu, General Manager of S.C. Jidvei Company
Members: Prof.dr.eng. Nicolae Dima Dr. Laurenţiu Bogatu Dr. Ştefan Marincea Eng. Mihai Sorin Găman Eng. Nicolae Tandrău Eng. Pompiliu Craiu Eng. Ec. Gergey Olosz Dr.eng. Sorin Vătăjelu Dr. John Menzies Dr. Gary O’Connor
Organizing Committee Co-presidents: Prof.dr. Gheorghe Popescu
(SEGR President) Prof.dr. Gheorghe Udubasa (Member of the Romanian Academy) Vice-presidents: Marcel Octavian Nicolescu Dr. Laurenţiu Bogatu
Conf.dr. Nicolae Luduşan Members: Prof.dr. Corina Ionescu Prof.dr. Titus Murariu Ing. Andrei Minciunescu Dr. Ştefan Marincea Conf.dr. Gheorghe Ilinca Prof.dr. Gheorghe Damian Prof.dr. Grigore Buia Ing.geol. Irina Müler Secretary: Lect.dr. Antonela Necşu
Lect.dr. Sorin Udubaşa
Scientific and Editorial Committee Chairman: Prof.dr. Gheorghe Udubaşa
Prof.dr. Gheorghe C. Popescu Members: Lect.dr. Sorin Silviu Udubaşa
Conf.dr. Lucian Petrescu Lect.dr. Antonela Neacşu
Rom . J. Mineral Deposits is also the Bulletin of the Society of Economic Geology of Romania
Rom . J. Mineralogy is also the Bulletin of the Mineralogical Society of Romania
©GIR 2008 ISSN 1220-5648 (Mineral Deposits) Classification index for libraries 55(058) Printed by "1 Decembrie 1918" University Alba Iulia
Printed by “1 Decembrie 1918" University Alba Iulia
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CONTENT Foreword (Gh.C.Popescu - President of SGER, Gh. Udubaşa - President of SMR).......................... 5 Invited lectures: ....................................................................................................................... 7 GĂBUDEANU Bogdan, BOGATU Laurentiu - Nnon-energy mining industry – current status in Romania......................................................................................................... 9 POPESCU C. Gheorghe, NEACSU Antonela - Tellurium mineralogy, resources, energetic implications ............................................................................................................ 19 UDUBAŞA Gheorghe, UDUBAŞA Sorin Silviu - Rrock salt in Romania: a powerfull pillar of the national mineral triad gold-oil-rock salt ...................................................................... 27 ZAMFIRESCU Florian, GIURGIU Nicolae, POPESCU Viorel, COPAESCU Sorin - present – day situation of ocnele mari wellfields following 48 years of the salt exploitation by dissolution already, close to be and approaching solved problems ............. 31 Extended abstracts: ............................................................................................................... 37 ANASTASIU Nicolae, POPA Marius, MAN-VIZITIU Luisa - Evaporite Facies in the Badenian Formations from the Teleajen Valley ............................................................. 39 BORCOS Mircea, UDUBASA Gheorghe, SANDULESCU Mircea, LUPU Marcel, Bogdan GABUDEANU - Mmap of mineral resources – scale 1:500.000. I. Metalliferous, non-metalliferous and radioactive substances............................................ 43 BUZGAR Nicolae - Tthe raman study of certain K-Na dioctahedral micas ..................................... 45 CONSTANTINA Ciprian, MOXON Terry - Mmicroscopical and xrd study on the gems from the area within Gurasada locality (Hunedoara county).......................................................... 49 DAMIAN Gheorghe, DAMIAN Floarea - Tthe zeolitic resources in Bbârsana zone, possibilities of use.................................................................................................................. 54 HIRTOPANU P., ANDERSEN J.C., CHUKANOV N., PETRESCU L. - Cymrite from Bălan sulphide deposit, East Carpathians, Romania ........................................................................ 58 HIRTOPANU P., ANDERSEN J.C., HARTOPANU I., UDUBASA S.S. - Iilvaite from the Cavnic deposit, Romania ....................................................................................................... 62 IATAN Elena Luisa - New data concerning fluid inclusions and cathodoluminiscence petrography of some quartz samples from Rosia Montana epithermal deposit, Metaliferi Mountains, Romania ............................................................................................. 66 IONESCU Corina, HOECK Volker - Genesis of brucite deposits in the Apuseni mts. (Romania): pt-constraints....................................................................................................... 70 JUDE Radu - Vitrophyric facies of the magmatic rocks exemplified by some neogene volcanites of East-Carpathians arc .......................................................................................................... 71 JURAVLE Doru-Toader, FLOREA Florinel Fănică , ANDRONE Delia Anne-Marie, BOGATU Laurenţiu - The Kliwa sandstone formation from the area between Suceava and Moldova valleys (eastern carpathians). Economic considerations........................................................ 77 LUCA Anca, BARZOi Sorin, ROBAN Relu - Some geological data used for rating of the stage of preservation of rupestral church “Corbii de Piatră” ................................................. 81 LUDUŞAN Nicolae, DIMEN Levente - Salt exploitation and transport from the Ocna Mureş saline.................................................................................................................. 85 MÁRTON István, MORITZ Robert - Geochemical characteristics and the evolution of the mineralizing fluids within the Eastern Rhodopian sedimentary rock-hosted low-sulpidation epithermal gold systems, Bulgaria............................................................... 89
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MARUNŢEANU Cristian, NICULESCU Victor, MAFTEIU Mihai - Evaluation and zoning of ground instability risk in salt mining areas (Ocna Dej case study) ............................................... 93 MILU Consuela, CATIANIS Irina - Gas – chromatography – a modern physico-chemical method of investigation for polluted sites with petroleum products...................................... 97 MURARIU Titus, RĂILEANU Maricel, CALCAN Cristina - Rb/Ba ratio in K – minerals of the granitic pegmatites as a metallogenic indicator ................................................................... 101 MUREŞAN Mircea - Ccontexte tectonique et lithostratigraphique des minéralisations logées dans la partie méridionale du compartiment Tisa-Ciuc de la zone critallino-mésozoïque des Carpates Orientales .............................................................................................................. 105 NEACŞU Antonela, DUMITRAŞ Delia Georgeta - Comparative physico-mineralogical study of Romanite and Baltic amber; preliminary FT-IR and XRD data...................................... 109 PINTEA Ioan - Liquid inclusions microthermometry in the Badenian halite and actual evaporite salt crust from Romania ....................................................................................... 115 POPESCU C. Gheorghe, ILINCA Gheorghe, NEACŞU Antonela - Mineralogy of Vivianite from Roşia Poieni; metallogenetic significance................................................................... 119 PRIDA Toma, SUCIU Gabriela, GIURGIU Nicolae Emanuel - Live cycle assessment for a salt mining project ...................................................................................................................... 123 ŞABLIOVSCHI Victor, BALINTONI Ioan, RĂILEANU Maricel, MURARIU Titus - Contributions at the study of complex utilization of the nepheline syenites on hydrothermal way .......................................................................................................... 127 SCHOLZ Ricardo, KARFUNKEl Joachim, BERMANEC Vladimir, DA COSTA Geraldo Magela, HORN Adolf Heirich, CRUZ SOUZA Luiz Antônio & BILAL Essaid - Amblygonite- montebrasites from divino das laranjeiras - mendes pimentel pegmatitic swarm, Minas Gerais, Brazil. I. Geologic setting............................................................................ 131 SCHOLZ Ricardo, KARFUNKEl Joachim, BERMANEC Vladimir, DA COSTA Geraldo Magela, HORN Adolf Heirich, CRUZ SOUZA Luiz Antônio & BILAL Essaid - Amblygonite- montebrasites from divino das laranjeiras - mendes pimentel pegmatitic swarm, Minas Gerais, Brazil. II. Mineralogy .................................................................................. 135 SCHOLZ Ricardo, KARFUNKEl Joachim, BERMANEC Vladimir, DA COSTA Geraldo Magela, HORN Adolf Heirich, CRUZ SOUZA Luiz Antônio & BILAL Essaid - Amblygonite- montebrasites from divino das laranjeiras - mendes pimentel pegmatitic swarm, Minas Gerais, Brazil. III. Secondary phosphates................................................................ 140 UDUBASA Sorin Silviu, UDUBASA Gheorghe, Paulina HÎRTOPANU, CONSTANTINESCU Şerban, a POPESCU-POGRION Nicolet, POPESCU V. Ion, STIHI Claudia, PETRESCU Lucian, How to detect submicroscopic minerals and their bearing on the extension of the mineral parageneses ............................................................................................................. 148 URECHE I., ONESCU D., PAPP D.C. - Designing dacite quarry developing options .................. 153
FOREWORD
The symposia of the Society of Economic Geology of Romania became already a
tradition. The sixth edition is dedicated to the rock salt, one of the major mineral commodities in
Romania, ranging in value and persistency with gold and oil.
The decision has been made to continue the organizing of joint symposia with the
Mineralogical Society of Romania (MSR) (the first joint symposium being at Albac, two years
ago). The MSR is an “older sister” among the geosciences “federation” of Romania, born in
1922 at Cluj - Napoca. The joint symposia have been proven to be welcome, due to interfering
topics presented at both joint symposia. In fact, mineralogy is common place for all the
geosciences, especially for the economic geology. The ore deposits consist of minerals, the study
of which gives keys for the understanding their genesis.
The topics to be presented at the joint symposium include of course the rock salt, be its
environment-related problems (Mărunţeanu et al.; Zamfirescu et al.; Prida et al.), be its
exploitation issues (Ludusan & Dimen). Mineralogy is also present, both descriptive concerning
rare and interesting minerals, i.e. cymrite and ilvaite (Hîrtopanu et al.), brucite (Ionescu &
Hoeck), vivianite (Popescu et al.), amber (Neacşu & Dumitraş), moganite as first occurrence in
agates (Constantina & Moxon), Raman spectra of some phyllosilicates (Buzgar), zeolites as used
in environmental problems (Damian & Damian), fluid inclusions in halite (Pintea) or quartz
(Iatan), submicroscopic minerals in some ores (Udubaşa jr. et al.). Cathodoluminiscence used in
depicting oil-related environments is presented by Milu & Catianis. A method to hydrothermally
process the Ditrau syenites is presented by Sabliovschi et al.
A special plenary lecture is devoted to tellurium. Both richness of some Au-Ag deposits
in the Metaliferi Mts. and the perspective of recovery of the Te for use in producing a new
energy source, i.e. the solar cells with CdTe are presented by Popescu & Neacşu.
Last but not least we are happy to acknowledge the participation of collegues from
France, Switzerland and Brazil (Bilal and his many colleagues from Brazil, Márton & Moritz
from Switzerland). Rare minerals bearing pegmatites from Brazil and pegmatites from Romania
(Murariu et al.) are therefore important topics to tackle with at the symposium.
As usual, petrography is also present through the papers of Jude and Ureche et al.
(igneous) and Anastasiu et al., Juravle et al. (sedimentary), Muresan (metamorphic) and Luca et
al. (applied petrography).
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The present day state of non-energy mining activity will open the symposium
(Găbudeanu & Bogatu).
Finally, there is a paper of Udubaşa & Udubaşa jr. concerning the mineral triad of
Romania gold-oil-rock salt and a short presentation of the new map of mineral resources scale
1:500,000 by Borcoş et al.
We hope to use the opportunity given by this symposium to further cooperate in order to
contribute to the progress of the most active geosciences domains in Romania, i.e. economic
geology and mineralogy.
Prof. dr. Gheorghe C. Popescu
President of the Society of Economic Geology of Romania
Prof. dr. Gheorghe Udubasa Member of the Romanian Academy
President of the
Mineralogical Society of Romania
NON-ENERGY MINING INDUSTRY – CURRENT STATUS IN ROMANIA
Bogdan GĂBUDEANU, Laurentiu BOGATU National Agency for Mineral Resources; [email protected], [email protected]
The National Agency for Mineral Resources (NAMR) was established in 1993, under
Government’s subordination, and is the competent authority according to the Mining Law No.
85/2003 and the Petroleum Law No. 238/2004. NAMR has 112 staff in the main offices and its 19
territorial inspectorates.
Territorial units of NAMR
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Main responsibilities
Administration of the mineral resources, public property of the State
Setting up norms, regulations and technical instructions
Keeping records on the fund of mineral resources/ reserves
Administration of the geological data fund, public property of the State
Monitoring the mining concessions, including the payment of mining royalties and fees
Regulatory Framework
Mining Law No. 85/2003
• The mineral resources are the public property of the State
• The right to carry out mining activities for exploration/ exploitation is granted based on
prospecting permits/exploration licenses/ exploitation licenses or permits, as the case may be
• The initiative regarding the concession belongs to NAMR or the interested legal entities
• Concessions are granted following a competition of offers and making proof of the technical and
financial capabilities;
• NAMR negotiates and concludes the licenses and permits in relation with the mining activities
(prospecting, exploration, exploitation)
• Exploration licenses enter into force at the time of the Order issued by the President of NAMR
on the approval of the license is published in the Official Monitor
• Exploitation licenses enter into force after their approval by the Government
• The Title Holder of an exploration license may obtain directly the exploitation license, through
negotiations with NAMR, based on the documents provided by the Law
• The term of the exploitation license is maximum 20 years, with the possibility of successive
renewals for periods of 5 years
• The Title Holder is obliged to establish a financial guarantee for environmental rehabilitation
• Consultation with the affected stakeholders and the local communities
• Obligation to submit an initial mining activity cessation plan before starting mining activities
• Tax/ Royalties type of concession
• International UN classification for resources/ reserves is used
• Regulations regarding the management of the mining waste in accordance with the EU
legislation
• Appropriate conduct of mining activities , including closure, environmental rehabilitation and
post-closure monitoring
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Statistics on the type of licenses
Type of license / permit Under approval In force Terminated
Exploitation licenses 358 513 36
Exploration licenses 0 153 304
Prospecting permits 0 48 474
Exploitation permits 0 1653 6737
Statistics on groups of non-energy materials
Category Exploitation Licenses/ permits
Prospecting Permits
Exploration
Gold and Silver Ores 14+11 94 45
Al ores and rocks 9+1 2 0
Rare earth and dispersed minerals 9 26 1
Ferrous ores 10 3 1
Non-ferrous ores 36 68 10
Non-metallic minerals 38+27 13 17
Metallic minerals 0 2 2
Bitumen rocks 1 0 1
Ornamental rocks 42+131 4 24
Useful rocks (sand, gravel, aggregates) 643+8320 101 253
Salt 9 4 2
Peat and therapeutic mud 11 0 5
Industry policy objectives as regards non-energy mining sector in Romania
• Business environment based on a stable and coherent legal framework: Mining Law No. 85/2003,
as subsequently amended and supplemented;
• attracting foreign investment;
• accelerating privatization process;
• environmental protection.
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Business oportunities
• Participation in the competitions of offers organized by NAMR in order to obtain concessions for
exploring for/exploit non-energy mineral resources;
• The right to propose new perimeters located in free areas in order to be included in the list of areas
for the following public competitions of offers which will be advertized by publishing a notice in
the Official Monitor of Romania;
• Possibility to start the exploitation phase in certain perimeters where exploration has been
finalized.
Keeping records of the mineral resources/ reserves fund
There are centralized data starting with the ’60s. Currently, we have data for approximately
1.900 deposits of non-energy minerals:
- Annual data: production, resources/reserves on categories according to the classification for
each deposits, and centralized data on types of minerals, total at national level.
- Each Title Holder is obliged to annually fill in and submit the data based on a form.
Main minerals included in the mineral resources/ reserves fund
Ores Industrial minerals Industrial rocks / construction rocks/ ornamental rocks
• Iron
• Iron and Manganese
• Copper
• Polymetallic
• Gold and Silver
• Molybdenum
• Bentonite
• Diatomite
• Feldspar, feldspar
pegmatite
• Salt
• Peat
• Talcum
Hard rocks
• Limestone, chalk, dolomite, quartzite and
sanstone
• Volcanic rocks: basalt, andesite, dacite,
rhyolite, diabase, tuff
• Plutonites: diorite, granite, granodiorite,
serpentinite etc.
Ornamental rocks
• Marble, travertine, ornamental limestone,
ornamental andesite, etc
Soft rocks
• Quartz sands, silts, sands, sand and gravel,
loess, gypsum, etc.
Mineral Resources in Romania
Non-ferrous ores : • Measured resources 549,337 103 t; • Indicated resources 593,017 103 t; • Possible resources 2,212,300 103 t.
Salt : • Measured resources 5,912,919 103 t; • Indicated resources 10,372,908 103 t; • Possible resources 16,965,228 103 t.
Ferrous ores : • Measured resources 90,189 103 t; • Indicated resources 93,389 103 t; • Possible resources 58,617 103 t.
Non-metallic : • Measured resources 277,542 103 t; • Indicated resources 137,687 103 t; • Possible resources 292,877 103 t.
Construction Rocks :
Sand and Gravel : • Measured resources 1,078,941 103 t; • Indicated resources 38,035 103 t; • Possible resources 456,902 103 t.
Other : • Measured resources 7,224,875 103 t; • Indicated resources 941,532 103 t; • Possible resources 2,025,814 103 t.
Ornamental Rocks : • Measured resources 81,139 103 t; • Indicated resources 12,820 103 t; • Possible resources 34,513 103 t.
Out of which: Marble:
• Measured resources 19,467 103 t; • Indicated resources 8,206 103 t; • Possible resources 6,395 103 t.
The evolution of the mining production during the period 1990-2007
0
100
200
300
400
500
600
700
1990
1996
1997
2000
2001
2002
2003
2004
2005
2006
2007
Evolutia productiei miniere in perioada 1990-2007
CUPRU ÎN CONCENTRATE
ZINC ÎN CONCENTRATE
PLUMB ÎN CONCENTRATE
CONCENTRATE CUPROASE
CONCENTRATE ZINCOASE
CONCENTRATE PLUMBOASE
MINEREU Fe – Mn
NĂMOLURI AURIFERE
CONCENTRATE AURIFERE
SARE
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The value of the mining production of non-energy minerals extracted in Romania (million lei):
The amount of mining royalty for the non-energy minerals extracted in Romania (million lei)
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The royalties for non-energy minerals compared with total royalties
The value of the production of non-energy minerals compared with the value of the total production
Mineral Resources Administration
• Development and implementation of a database system for the mining sector, a tool for
monitoring and implementing the Mining Law, which enables data gathering, storage,
administration, modification and analysis regarding licenses, permits, etc.
• Development of a geographic visualization system (GIS) for the mining exploration/
exploitation perimeters, support for the promotion of mineral resources concessions
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Technical assistance for the development of a database system
• Open
• Mining
• Activity & Software
• Geoscience
• Information Centre
• Development of the OPEN MAGIC application
• Software acquisition
• Professional training programmes for NAMR staff
Project team:
LANDMARK EAME LTD. (UK)
- Project coordination
- Analysts
- Oracle Programmers
INTERGRAPH COMPUTER SERVICES (Romania)
- GIS Analysts
- GIS Programmers
GEUS (Denmark)
- Specialists in geology and mining
NATIONAL AGENCY FOR MINERAL RESOURCES
- benefficiary
System functionality - OpenMagic modules:
• perimetres
• contracts
• deposits
• mines
• geological index
• mining cadastre
• resources and reserves
• financial – payments
• reports
• administration
OpenMagic: - Developed based on ORACLE technology, in which a geographical visualisation
system (GIS) has been embedded based on INTERGRAPH technology.
- Enables creating, editing and visualizing spatial data (maps)
- 120 screens for data loading and viewing
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Natura 2000 – Protected areas:
Future activities
• Administrative process simplification by ‘better regulation’
• Mining Law amendment: shortening the timing for exploitation licenses approval and removing
mandatory approval of the Government level
• Development of norms and instruction in compliance with the harmonized European legislation
• Stimulating projects dealing with the recovery of the resources from the old tailing ponds and
waste dumps
• Stimulating the use of new technologies, the reevaluation of the mineral potential, Romania
being an old mining province
• Improving access to data, data sharing and interoperability
• Integrating the information from the old archives, taking over and loading the data in the
OpenMagic system
• Interest for community projects, partnerships, networking
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TELLURIUM MINERALOGY, RESOURCES, ENERGETIC IMPLICATIONS
Gheorghe C. POPESCU, Antonela NEACSU
University of Bucharest, Faculty of Geology and Geophysics, 1, N. Balcescu Ave., 010041 Bucharest [email protected], [email protected]
Tellurium is an emblematic element for our country. This is the place where it was described
for the first time as a chemical element and a native mineral, back in 1798. It is also the place where
many tellurium minerals have been discovered to later generate the expression „Romania – the
country of tellurides” and where the most numerous telluride minerals in Europe occur, usually
associated with gold-silver ore deposits. As a consequence, the research focused on the mineralogical
features of this element, as proven by the large number of minerals firstly described at Sacaramb:
krennerite, muthmanite, nagyagite, petzite, stutzite, museumite; at Baia de Aries: sylvanite and at
Fata Baii: native tellurium and tellurite.
A relatively recent scientific and technological event, that is, the perfection by „First Solar”
Company of a new method to manufacture photovoltaic cells based on CdTe, has determined
tellurium to be approached as a potential mineral resource, not only as a substance of mineralogical
interest. Little attention has been given to this newer facet of tellurium, and one can thus explain the
lack of data concerning the tellurium resources in Romania. Hence, we are left only to speculate on
tellurium’s geological and economic features.
Fig. 1 The First Solar module (www.firstsolar.com)
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In Romania, tellurium deposits are known especially within the so-called „Golden
Quadrilateral”, where it occurs in association with gold and silver, within a variety of minerals, most
of them tellurides.
Before everything, when speaking about tellurium, one must bear in mind that its name
derives from the Latin word „tellus” meaning „fruit of the earth”. It was discovered by Muller v.
Reichenstein, between 1783 and 1785, in Sibiu, after examining some samples (probably hosted by
Brukenthal Museum), originating in Fata Baii, Metaliferi Mts. He demonstrated that it was a new
semi-metal which he called „metallum problematicum”. We owe its actual name to Klaproth, who
managed to chemically separate tellurium as a self-standing element, in 1798.
Geological and economical research carried out worldwide, indicate that many mines and
potentially waste rock piles (tailings dams) contain economic amounts of tellurium. There is a
similar situation in the Metaliferi Mts.
Metaliferi Mts. represent the gold richest unit in the entire Neogene volcanic area in the
Carpathians. It is this very feature that makes these mountains unique.
There are no sound analytical data on the tellurium content in various ores, so that only
several speculative assessments on the tellurium resources can be brought up front. An indication
might be the Au:Te ratio which is about 1:2 in the most frequent tellurides present in our country:
nagyagite and sylvanite. It may thus be inferred that in the bulk ores, the ratio might be similar. For
instance, approximately 60 tons of tellurium have been mined to date from Sacaramb ore deposit
(Udubasa & Udubasa, 2004).
On the basis of published data and of filed assessments carried out by World Industrial
Minerals, the following observations came out in relation with tellurium ore deposits:
1. Most frequently, tellurium is associated with alkaline igneous rocks, especially with calc-
alkaline volcanics and with alkaline intrusives.
2. There is no age limit for the tellurium ore deposits which span from Quaternary to
Precambrian (<1 Ma to 2500 Ma).
3. Gold and silver telluride ore deposits may be found in all epithermal types: low sulphidation,
high sulphidation, etc., but most frequently they belong to the low sulphidation type.
4. Many tellurides are associated with copper, Cu-Mo or porphyry ore deposits, and are located
within or at the outskirts of intrusive bodies.
Also on the basis of to date research, seven types of ore deposits with significant tellurium
content (as either by- or secondary product within other metals or metalloids), may be separated:
1. Gold and silver telluride and quartz veining ore deposits.
2. Bismuth and telluride ore deposits
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3. Pyrrhotite-chalcopyrite-pentrlandite-telluride ore deposits
4. Pyrite-telluride ore deposits
5. Polymetallic ore deposits with galena-sphalerite-telluride
6. Fahlore (As-pyrite and tetrahedrite) and telluride ore deposits
7. Skarn-related ore deposits with tellurides
Tellurium also occurs in numerous other types of ore deposits, such as porphyry copper or palladium
in PGM, but in such low concentrations that it does not bear any economic interest.
Gold (silver) tellurides in quartz veining
Gold (silver) telluride bearing quartz veining is by far, the most important tellurium ore
deposits in the world. Common telluride in such ore types are calaverite and sylvanite, whereas gold
tellurides are represented by krennerite and petzite. In pure calaverite and sylvanite, the Au:Te ratio
is 1:1. In the case of petzite and krennerite, the ratio is 2:1. At the Emperor mine (Fiji) the Au-Te is
10 ppm for Au and 10 ppm for Te.
The Au:Te ratio represents an important factor in assessing gold-silver telluride ore deposits.
For example, in the Lone Pine ore deposit (Mexico), the ratio of Au (4.5 ppm) to Te (4500 ppm)
becomes 1:1000. In the case of Bambola ore deposit, the same ratio is of 1:176. Such values suggest
the presence of tellurium in native state as well as of numerous Te oxides. A comparable situation is
found in Metaliferi Mts., at Sacaramb, where the average Au content over 250 years of mining is
estimated at 10 g/t (Udubasa & Udubasa, 2004). In 1941, Ghitulescu & Socolescu estimated a total
mined quantity of Au and Ag of 85000 kgs, that is 30000 kgs. Au and 55000 kgs. Ag. No data are
available on the Te content in the ore deposit or on the total Te quantity mined. However, based on
the Au:Te ratio of 1:2 in some of the most frequent telluride occurring in the deposit – nagyagite and
sylvanite – one can infer a Te content 20 g/t, and a total amount of 60 t of tellurium mined until
1941, from Sacaramb ore deposit alone (Udubasa & Udubasa, 2004).
The presence of such significant amounts of tellurium in this ore deposit has highly
influenced the ore processing as it rendered gold to be unamenable by cyanidation. This is but
another reason to plead for a thorough research of gold-telluride ore deposits and for the separation
(extraction) of tellurium, even if no use of this element can be envisaged.
Tellurides associated with galena and sphalerite in polymetallic mineralization
This type of ore deposit occurs in south-eastern Europe (Romania, Bulgaria and Russia). The
mineralization takes the form of veins, lens-shaped and metasomatic bodies within granites,
volcanic-sedimentary, acid granites and alkaline derivatives. The main economic mineral is altaite.
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Fig. 2. The distribution of main elements and economic minerals in Sacaramb ore deposit
(Ghitulescu & Borcos, 1969)
In Russia, the most representative ore deposit is Zyryanovsk with galena containing 150ppm
Te in the oxidation zone, where altaite has been recognized. The same type of mineralization occurs
at Baia de Aries, Romania, where the telluride field occurs in the western part of the metallogenic
area, as vein bodies located to the east and south-east of the Afinis structure.
Fig. 3 Simplified geological map of the Baia de Aries deposit (Ciofica et al., 1999)
22
Geological and economic considerations
The economic assessment of Te and Te-Bi ore deposits may be carried out based on three
important factors:
1. The Au-Ag-Te and the Te-Bi mineral assemblages may be an indicator for the size of the
ore deposit. When gold occurs exclusively as tellurides (calaverite or Au-Ag tellurides (sylvanite,
krennerite) at the intrusion outskirts, as in the case of Au-Ag Emperor Mine, calaverite precipitates
in fissures on the margins of the igneous body, followed by later Au-Ag tellurides.
2. The economic feasibility is also indicated by the Bi and Te content; for instance, when
such contents are around or below 10 ppm, the mineralization is economically uninteresting. When
concentrations span between 10 and 300 ppm, the ore deposit is economic, subject to the reserves
and mining capacity. Values over 300 ppm are economically interesting regardless of mining
capacity.
3. The zoning of Te-Bi ore deposits is less known to many geologists. Two aspects of zoning
should be underlined; one refers to the vertical zoning with respect to the intrusive bodies, as in the
case of Larga ore deposit in Metaliferi Mts., where the Au-Te zone is located in the upper part,
whereas the Te-Bi zone occurs at 1 km in depth, marginal to the intrusive body. In Henan province,
China, the Au-Te mineralization lies between 2 and 10 km lateral to the intrusive body. It should be
stressed that Chinese ore deposits span between 99 and 179 Ma, whereas the Romanian ones,
between 10 and 12 Ma.
Energy considerations
“First Solar” Company uses a technology to automatically produce solar panels with
extremely fine semiconductor films, at the lowest costs in the world. The price of energy is
compatible with the price of conventional energy, thus reducing the dependency on the fossil
combustibles, the CO2, NO2, SO2 emissions and the constraints related to overcharging
consumptions. In 2005, First Solar produced 330,000 modules equivalent to 20+ MW.
23
Fig. 4. Volume production of module shipments between 2005-2009, First Solar Inc. (www.firstsolar.com)
CdTe is a semiconductor obtained from elementary metals brought to a stable form. Cd is
recovered from Zn smelting processes. The recycling of Cd is beneficial not only for electricity
production, but also for diminishing the toxic effects of fossil combustibles and for preventing the
potential environmental pollution with Cd.
Fig. 5. Environmental benefits of the replacing of energy generated from fossil fuels in Thuringen and California (www.firstsolar.com)
Conclusions of the US Department for Energy
CdTe panels do not produce pollution and moreover, they are beneficial to the environment by replacing the fossil combustibles. Large scale usage of CdTe panels poses no risk to human health and to the environment, whereas the recycling of modules at the end of their life-cycle do not raise any environmental issues. Finally, we consider that the research of telluride bearing geological structures, and especially of gold-silver telluride ore deposits such as Sacaramb, Larga-Fata Baii and Baia de Aries, is a must. Following the mineralogical data, these structures are potentially economic for tellurium extraction.
24
25
References Ciobanu, Cristiana, Găbudeanu, B., Cook, N.J. (2004): Neogene ore deposits and metallogeny of the
Golden Quadrilateral, South Apuseni Mts., Romania, in Gold-Silver-Telluride Deposits of the Golden Quadrilateral, South Apuseni Mts., Romania, IAGOD Guidebook Series 12, 25-88, 31st
August – 7th September, Alba Iulia Cioflica, G., Jude, R., Lupulescu, Berbeleac, I., Lupulescu, M., Costea, D., Costea, A.(1999):
Epithermal gold mineralizations of low-sulfidation type from Baia de Aries Mine, Southern Apuseni Mts., Romania. Rev. Roum. Geol., 43:3-18
Cook, N., J., Ciobanu, Cristiana, Damian, Gh., Damian, Floarea (2004): Tellurides and sulphosalts from deposits in the Golden Quadrilateral, in Gold-Silver-Telluride Deposits of the Golden Quadrilateral, South Apuseni Mts., Romania, IAGOD Guidebook Series 12, 25-88, 31st August–7th September, 111-114, Alba Iulia
Ianovici, V., Giusca, D., Ghitulescu, T.P., Borcos, M., Lupu, M., Bleahu, M., Savu, H. (1969): Evolutia Geologica a Muntilor Metaliferi Ed. Acad. Rep. Soc. Romania, 741p.
Popescu, Gh. & Simon, Gr. (1992): New tellurides from Sacaramb, Metaliferi Mts., Romanian Journal of Mineralogy, v. 75, Supp. Nr. 1, IGG Bucuresti, 37-38 First National Symp. on Miner., 15-21 October 1992, Cluj Napoca
Popescu, Gh. & Simon, Gr. (1993): Tellurantimony from Sacaramb gold-silver telluride deposit, first occurence on the romanian territory, Terra Nova, v. 5, EUG VII, Strasboug, France, 4-8 April, p.30
Szakall, S., Udubasa, Gh., Duda, R., Kvasnytsya, V., Koszowska, Ewa, Novak, M. (2002): Minerals of the Carpathians, Ed. Granit, Prague
Udubasa, Gh. & Udubasa, S.,S. (2004): Au-Ag telluride deposits in the Metaliferi Mts.: effects of local geology or of a „hydrothermal ichor”, Romanian Journal of Mineral Deposits, v. 81, Fourth National Symposium on Economic Geology „Gold in Metaliferi Mts.”, 3rd-5th September 2004, Alba Iulia, 39-46
www.article.pubs.nrc-cnrc http://firstsolar.com http://nitro.t2i.info http://ro.wikipedia.org/celulasolara
ROCK SALT IN ROMANIA: A POWERFULL PILLAR OF THE NATIONAL
MINERAL TRIAD GOLD-OIL-ROCK SALT
Gheorghe UDUBASA, Sorin Silviu UDUBASA University of Bucharest, Faculty of Geology and Geophysics, 1 N. Balcescu Blvd.,
The territory of Romania displays a high diversity of mineral occurrences both as concerns
the genetic and compositional types. Their number is also great, of about 1500, but the size of
mineral bodies is small and medium, as in all the areas with Alpine deformation processes.
Kimberlites are typically lacking, as in the whole alpine Europe. Among the numerous types of
mineral occurrences a number of three types are of outmost importance, i.e. gold, oil and rock salt.
Several years ago G. Udubasa named them as the typical “mineral triad” of Romania. The triad
strongly contributed to the economic development of the country in the last two centuries. However,
at least two pillars, i.e. the gold and the rock salt, were known and locally used beginning with the
first years of the first millennium. Some data are given in the papers by Haiduc (1940) and Popescu
et al. (2007) for gold, and by Stoica and Gherasie (1981) and Pîrşcoveanu-Apostolide (1963) for salt.
Many historical data for the Ocnele Mari salt deposits are contained in a nice book by Marinoiu
(2006).
Officially, the exploitation of oil started in 1857 (first oil well production in the world), but
Mihalache (2005) has identified many proofs concerning the use of crude oil early in the XVth and
XVIth centuries, mostly at celebrated oil occurrence at Lucăcesti.
The distribution of gold, oil and rock salt occurrences seems to be complementary (Figs. 1-
3). Only the oil and rock salt occurrences appear to overlap in some areas. In fact, the link between
the rock salt and the oil has been envisaged already by Mrazec in 1907; in that time he defined the
diapir folds, of great importance in the oil migration processes.
Amazingly enough, there is a nearly perfect coincidence of natural gas fields in Transilvania
and the celebrated vineyards in the Târnave-Mureş area. If there is a pure coincidence or not, it is a
difficult question. Some overlappings seem also to exist between the oil fields and the vineyards in
the Subcarpathians.
27
Rock salt – halite
The two terms define the rock and the mineral respectively. Their names are quite different
in different languages, i.e.:
Romanian: sare gema – halit
French: sel gemme – halite
German: Steinsalz/Kochsalz/Bergsalz – Halit
Russian: Kamennaia sol’/Solianoi şpat - Galit
Rock salt – halite priorities
(1) The relatively simple structure of NaCl, cubic, Fm3m, ao = 5.6404 Ǻ was the first to be
solved by using XRD (Bragg, 1914),
(2) The main player in the development of the diapir folds, defined as early as 1907 by L.
Mrazec. The explanation is quite simple. The halite structure has numerous translation planes, i.e.
011, 110, 001, 111, which enable a high solid state mobility of rock salt masses.
(3) At least in Romania, the rock salt mines, e.g. Slanic Prahova, Praid etc. were the first
which hosted underground museums.
The age of the rock salt deposits practically covers all the geological epochs, but with
marked concentrations in Permian and Tertiary (mainly Miocene) sedimentary deposits. Less
common is the occurrence of rock salt/halite as veinlets in diabases in a gold deposit in Ontario
(Searls, 1956). Presence of halite in fluid inclusions is a common place.
Crystals of halite may reach 100 cm in Thüringen, 40 cm in the Wieliczka deposits and 31
cm in a salt mine in the Braunschweig area. In the rock salt deposits in Romania limpid crystals up to
10-15 cm were reported.
The rock salt resources in Romania are huge, reaching over 43 billions of tons. The biggest
mines are Gura Slanic (14 mil. t), Ocnele Mari (12 mil. t), Cacica (10 mil. t), Ocna Mures and Praid
(9 mil. t) (Calinoiu and Harosa, 1989). Some rock salt deposits are deep, reaching even 2000 m (57
deposits of 193) (Calinoiu and Harosa, 1989).
In the last decades underground solubilisation of rock salt (theoretical solubility of halite at
20˚C is of 35.7 g/100 cm³) has been proved to be an efficient method of extraction but with many
consequences producing collapse phenomena on large areas (see Marunteanu et al., Zamfirescu et
al., this volume). In addition, holocarst development is widespread in many salt areas, involving also
collapse risks, as shown by Ticleanu et al. (2006).
28
The huge amount of rock salt in Romania can assure exploitation for many years, provided
the limitations of risks will be taken into consideration. Anyhow, the mineral triad gold (annual
production of about 1 t; the National Bank of Romania has already reached its 106 t of pure gold
reserves), oil (annual production of about 6 mil. t) and rock salt still provide a sustainable economic
development of Romania. No other European country show to be “equipped” with such a powerful
mineral triad.
Fig. 1. Gold deposits and occurrences in Romania.
Fig. 2. Distribution of oil industry in Romania.
29
Fig. 3. Distribution of salt industry in Romania.
References:
Bragg W.L. (1914) Proc. Royal Soc. London, 89A, 468.
Brana V., Avramescu C., Calugaru I. (1986) Substante minerale nemetalifere. Ed. Tehnica,
Bucuresti.
Calinoiu M., Harosa S. (1989) Consideratii asupra patrimoniului national de sare gema. CDG Bul.
inf.-doc. teh.-st. 4, 5-14.
Marinoiu C. (2006) Civilizatia sarii. Copacel la 510 ani. Ed. Offsetcolor, Rm. Valcea.
Mihalache I.M. (2005) Evolutia industriei extractive de petrol si artizanii ei. Ed. Asociatiei SIPG,
Bucuresti.
Pîrşcoveanu-Apostolide Ana (1963) Noua stralucire a unei bogatii stravechi. Ed. Stiint., Bucuresti.
Popescu Gh.C., Tamas-Badescu S., Bogatu L., Tamas-Badescu Gabriela, Neacsu Antonela (2007)
Geologia economica a aurului. Ed. Aeternitas, Alba Iulia.
Searls F. (1956) Econ. Geol. 51(2).
Stoica C., Gherasie I. (1981) Sarea si sarurile de potasiu si magneziu din Romania. Ed. Tehnica,
Bucuresti.
Ticleanu M. et al. (2006) An. Inst. Geol. Rom. 74/1, 241-245.
30
PRESENT – DAY SITUATION OF OCNELE MARI WELLFIELDS FOLLOWING 48 YEARS OF THE SALT EXPLOITATION BY DISSOLUTION
ALREADY, CLOSE TO BE AND APPROACHING SOLVED PROBLEMS A TEHNICAL SOLUTION FOR THE COLLAPSE FRAGMENTATION OF THE FIELD
2 CAVERN OCNELE MARI, ROMANIA
Florian ZAMFIRESCU1, Nicolae GIURGIU2, Viorel POPESCU3, Sorin COPAESCU4 Research & Design Consortium including: 1 Bucharest University – Research Department of
Environmental Geology and Geophysics (DC-GGA), [email protected]; 2 SC ICPM MINESA SA Cluj Napoca, [email protected]; 3 SC ICSITPML SA Craiova; 4SC Conversmin SA,
The main causes of the instability process:
An insufficient knowledge of site geological and structural conditions: the presence of sterile
intercalation; the diapiric process effects.
Technical working conditions: large work pressures which led to the hydraulic fracture of the
sterile intercalation; the link of dissolution chambers – explotation by doublets and groups boreholes;
The weak survey of the dissolution process during the exploitation period.
Estimation of the SOCON cavern stability (fig. 1):
31
The analysis of the roof stability
in crossing sections lined-up from
East to West can provide a realistic
estimation of the system’s stability.
The geometrical modifications
of the roof between 1993 and 2002,
as well as the head variations are
sufficiently well known.
The analytical method proposed
by W. Ritter was adapted to the
particular conditions of the SOCON
cavern.
Fig. 1 - CAVERN ROOF STABILITY
412900 413000 413100 413200 413300
41070
0410
800
41090
0411
000
411
4113
00
100
411
200
S362S363
S364
S365
S366
S367
S369
S376S377
S378 S379
S381
crater 26.11.2002
sec 0
sec6
sec 7
sec 17
sec13 sec 14
sec15
sec 1
sec 2
sec 3
sec 4 sec 5
sec 8
sec 9
sec 10
sec11
sec 12
sec 16
crater 15.09.2001fault
SOCON cavern
tabularvoids
sec 5-6
sec 3-4
crater 04.11.2004
disolution bloc
I
II
III
IV
Ritter’s analytical methods adaptation (fig. 3):
It was introduces the notion of volumetric weight (e) of the salt floor; the e (tf/m2*m) parameter
is a correct estimate f the stress levels in the salt roof (fig. 4);
The ultimate equilibrium in cross-section having the span (d) and th height (h), is a given by :
where t is the ultimate tensile strength.
Cavern zoning from the stability point view:
Zone I: is an unstable zone;
Zone II: is temporally stable, because the cavern
span is reduced with about 100m;
Zone III: has the maximal span of 480m.Raises
major issues on the whole cavern stability;
Zone IV: covers approximately the southern half
of the cavern. It is a stable zone.
Defining processes. Causes and effects for Zone I:
The development of a breach at the salt/sterile contact at the Northern limit of the cavern, before
1991.
Mechanical yielding of the remnant pillar between 365 and 367 wells.
Conclusions: Zone I was subjected to the coupled geomechanical processes which have led to:
The 12 September 2001 accident when the crumbling chimney reaches the morphological surface;
The yielding of the zone corresponding to Section 1 in January 2002. The crater formed in
September 2001 will be strongly enlarged East- and Westward respectively;
The overburden of the zone corresponding to the Section 2 which yielded in July 2004.
32
412900 413000 413100 413200 413300410
70
04
10
800
410
90
04
110
00
411
100
411
20
04
11
300
S362S363
S364S365
S366
S367
S369
S376 S377
S378 S379
S381
Fig. 4 - ECHIVALENT VOLUMETRIC WEIGHT
crater 15.09.2001
crater 04.11.2004
03248 22
2 d
ht
et
e
EV
300
60
90
120
150
180
210
240
270
Fig. 3 - CROSS SECTION 5-6
Ritter arch 2002
balance arch 2002
Ritter arch 1993balance arch 1993
0 100 200 300 400
sterile
salt
cavern
Elements of additional uncertainty
An additional element of uncertainty is due to the further dissolving of the roof by the water
coming from the sterile deposits pierced through after September 2001 (200 – 250 l/m3). Thus, for a
volume of about 2 million m3 of sterile, it results 0.4 – 0.5 millionm3 of water, which could have
dissolved 0.12 – 0.15 million m3 of salt in the higher parts of the roof. These observations and the
stability analyses for the northern slopes led to an evaluation according to which had the relief level
resulting from the 2004 collapse decreased by another 20-25 m, the northern slope would have lost
its equilibrium and about 4 million m3 of mud could have moved to the hill foot.
In view of the above results, the following conclusions were derived:
The collapse of the SOCON cave roof is imminent, the obvious end of an undergoing process;
To avoid another uncontrolled collapse, with potentially devastating consequences for the town
of Ocnele Mari, a fragmentation of the collapse process must be done that will not affect that the
morphological levels around the region of the collapsing chimney;
The fragmentation process can be carried out by cutting a ”window” in the salt cave roof of zone
III while keeping the entire system at a constant hydraulic level. The sterile penetration in the
cave will then ensure the stability of the deposits entering from the north. Thus, the overall
stability of the northern slope is also guaranteed;
The employed technologies should not introduce additional risk factors into the geomechanical
phenomena that take place in the region.
Main activities
A set of inclined wells was drilled, starting from outside of the risk zone, using a
hydraulically controlled drilling technique. First, two wells were drilled, which intercepted the cave
at the highest roof levels. Through these drillings a volume of over 1000 m3 of diesel was
gavitationally extracted. Based on a numerical modelling of the salt’s dissolution process along an
inclined well, their position was determined, so that through the spatial interference of the resulting
chambers a ”window” could be cut in the salt roof. Ten more wells were drilled with lengths between
130 and 230 m. Their shallower part was cased and cemented as it run through sterile and at least 20
m of salt, while the lower part run freely 50 to 60 m deep into the salt before intercepting the cave.
By transmitting through each well about 10l/s depleted brine with an initial concentration of 100-110
g/l, taken directly from the return pipe of a chemical plant, a kinetic dissolution cell was created,
which allowed the cutting out of a block of at least 40 m x 70 m room the salt roof (fig. 7).
33
S363
S366
413000 413050 413100 413150 413200
41
0800
41
0850
410
900
410
950
S1
S2S3
S4
S5
S6 S7 S8
S18
F1
F2
E1
S11
S16
Fig. 7 - CONTROLLED WELL-DRILLING LOCATION
S1 S2 S3
S4 S5
S6 S7 S8
Working Floor III
sec-VE1-I
secVE2-I
sec-NS1-I
sec-NS2-I
sec-NS3-I
sec-NS4-I
sec-NS-5-I
sec-NS-6-I
secVE3-I
E2
dissolution void contours
Working Floor I
SOCON cavern contour
The dissolution fluid introduced via the recharging/dissolution wells was evacuated in the
form of concentrated brine through two wells with a larger diameter (8 5/8”) and about 250 m long,
under constant hydraulic level in the cave. Water pressure in the return pipe was high enough to
recharge the well system directly. From a hydraulic point of view, the recharge and return well
system worked gravitationally. For a continuous monitoring of the stress change around the cavern
and in the surrounding areas, a micro-seismic system was installed. Geophones were located in 12
vertical boreholes of 63 to 326 m long, three sensors per hole. A system of topographical enchmarks
was also implemented to carry out a remote measurement of the sinking process.
34
crater 28.12.2005
crater 28.07.2005
Fig. 9 - CRATER EVOLUTION AFTER 14 DECEMBER 2005 EVENT
SOCON cavern 04.10.2005
SOCON cavern
sec S-N
443700 443800 443900 444000 444100 444200
3989
00
3990
00
399
100
399
200
399
300
399
400
399
500
362363
364
365
366
367
369
376377
378 379
381
crater 12.01.2006
lake 08.04.2006
crater 03.03.2006
S NFig. 10 - ACTUALE SITUATION, CROSS SECTION ON S-N DIRECTION
Results:
Through the 10 dissolution wells, 1.5 million m3 of partially saturated brine (100-110 g/l) was
introduced while more concentrated brine (308 - 310 g/l) was evacuated through two extracting wells
and sent to a chemical plant. An amount of 1.3 millions € was cashed, which fully covered the cost
of the drillings and pipe system necessary to transport the brine.
The Socon cave in the Field II of Ocnele Mari was transformed in a depression with a
partially saturated brine lake at its Southern zone. One and half year later the process of rearranging
the depression slopes has practically come to an end (figure 9). The ecological reconstruction of the
area will follow. The morphology of the hillside in the zone of the chimney formed in September
2001 remained unchanged. The overall stability of the northern hills incline was preserved.
35
0 50 100 150 200 250 300 350 400 450 500 550 600
100
150
200
250
300
350
100
150
200
250
300
350365
379
377
12.01.2006200503.03.2006
2001
03.2001
09.1993
11.2001
07.2005
salt
sterile
cavern
EVAPORITE FACIES IN THE BADENIAN FORMATIONS FROM THE
TELEAJEN VALLEY (PERICARPATHIAN UNIT, THE EASTERN CARPATHIANS)
Nicolae ANASTASIU 1, Marius POPA 1, Luisa MAN-VIZITIU 1
1 University of Bucharest, Faculty of Geology and Geophysics; [email protected] In the uppermost Langhian, below the boundary with the Kossovian, and above the cineritic sequence, evaporitic formations are known in the Tarcau and Subcarpathian Nappes. They are represented by gypsum and/or salt formation. The differences between the Langhian and the Burdigalian salt formations concern not only the age but also the origin of the detritic material involved in their matrix. In the Langhian Salt Formation the “Green Schists”, debris is absent, which is abundant in the Burdigalian one. The discontinuous area development of the Langhian evaporitic formation may be determined by a discontinuous development of the sedimentary basins and/or by slight erosion processes occurring before the deposition of the Kossovian deposits. The Upper Badenian rocks show, generally, two lithofacies: arenitic (sandstone and sands) or pelitic (marls). In some areas (south sector of the Carpathian Belt area) two sequences can be distinguished; a low sequence - the "Radiolaria Shales" Formation (sand and sandstones with more or less developed intercalations of siltic shales rich in radiolarians) and an upper sequence - the “Spirialis Marls” (predominantly pelitc with subsequent inter-calations. of sandstones or sands).
The evaporitic sequences from the Carpathian Fore deep are parts of Lower-Middle Neogene "formations", and we can analyse bellow “Radiolaria |Shales”.
Fig.1. The location of the evaporite outcrops (red point) and it chronostratigraphic position.
The "Upper Evaporite Level" at Teisani (Teleajen Valley) shows distinctive facies
characteristics which recommend it as an evaporitic "megasequence" that comprises 4 units ("mesosequences"): rhytmites with intraclastes; slumps; algal mat/laminated sulphate rhytmites; massive clastorudite evaporites. These units display a wide range of postdepositional (diagenetic) transformations (fig.2).
39
Sequence description. a) The mesosequence of "rhytmites with intraclasts level" comprises centimetric couplets and consists of laminated algal mats gypsum laminae in which the frequency of black porphyroclasts-relict secondary gypsum from the anhydrite - is greater. b) The mesosequence of "slump": convers erosional or dissolution surfaces and includes brecciated intraclasts in a convolute arrangement that covers (or is covered by) the algal facies. c) The mesosequence of "algal mats/laminated sulphate rhytmites": is clearly developed and constitutes the central part of the megasequence. It comprises 10-30 couplets of algal mats/sulphates in an individual thickness of 5-20 cm. d) The mesosequence of "massive clastorudite evaporites": may be regarded as the upper unit of the megasequence and comprises a thickness range of maximum 12 m. Its planar boundaries are subaequeous dissolution surfaces that limit its irregular body by the "Radiolarian Shales and Spirialis Marls Horizon"(level B, fig.2).
Fig. 2. Expose of the megasequence with Evaporite Fm. (A), Radiolaria Shales (B), and Spirialis Marls Fm. At Teisani, Teleajen Valley Basin.
Facies interpretation.
The facies of algal mats/laminated sulphate rhytmites suggests a shallow-water setting, been accumulated within a marginal basin ("salinas type") probably installed on a tectonic depression, behind a costal barrier.
Stromatoliths may grow in protected shallow water setting a photic zone, but other organic matter could be derived from seasonal phytoplankton blooms within the photic zone (fig.3).
The active subsidence and the short-term cycles (of Vth - VIth order) controlled the rhythmic deposition of algal mats/gypsum couplets and, consequently, the increase in sequence thickness.
The upper facies (clastic debrites), showing a deep-water setting, have been accumulated- by gravity- flow processes - at the base of a high-energy paleorelief, become submerged during eustatic rises; the source area - placed in an arid climate - have comprised suspended evaporitic beaches and plains, at that time affected by weathering.
40
Fig.3. The facies interpretation (F1-F4) – environmental terms.
Depositional evolution
The evolution of depositional area toward a "transgressive-stand" basin may be argued - in adition- by the central basin facies represented by the overlying megasequence of "Radiolarian Shales and Spirialis Marls".
The presence of clastic dykes and the irregular thickness emphasize the real overload within the frame of the basin after the debris-flow deposition and also, the high grade of consolidation existing in the overlying units.
41
Fig.4. The depositional and postdepositional processes which controlled the evolution of Evaporite Sequences
Evaporites deposited in low-relief basins are similar to shelf evaporites; they are
exclusivelly composed of shallow or mud flat facies. In basin that had high relief shallow water/subaerial facies may have formed on basin
marginal shelfes, beeing the terminal phases of the basin fill (after depositional relief was eliminated). Near basin edges they may pass laterally into an intermediate facies belt of slope deposits, characterized by reworked evaporites, mass flow deposits, slumps. Economic considerations
The thickness and the quality of evaporitic megasequence at Teisani (as part of the Lower Neogene evaporites) recommend it as sustainable for economic exploitation in quarry. References Anastasiu N. (1998), Sedimentologie şi petrologie sedimentară, Ed.Univ.Bucureşti. Anastasiu N., Popa M., Roban R-D., 2007, Sisteme depozitionale- Analize secventiale in
Carpati si Dobrogea. Editura Academiei Romane, Bucuresti. 605pp. Frunzescu, D, Anastasiu N., Popa M., 1995. Clastic evaporitic events in the Lower Neogene
of the Pericarpathian Unit, Rom. Journ. of Stratigraphy: 7. Kendall, A.C., 1992, Evaporites, in James ed. Facies Models. Geological Ass.of Canada, p.
375-409. Pauca, M., 1978. Evaporitele din Romania. Aspecte genetice, paleogeografice si tectonice,
An. Muz. St. Nat..Ptra Neamt., nr.5. Sãndulescu M., Micu M., Popescu B., 1980, La structure et la paleogeographie des
formations miocenes des Subcarpathes Moldaves; Mat. XI, Congr. Karpat.-Balk. Assoc., Kiev, Tektonika, 184-197;
Warren J., 1999, Evaporites. Blackwell Science Oxford. 438 pp. * * * 1976, Carbonate Rocks and Evaporites - Guidebook Series nr. 15, Institute of Geology
and Geophysics, Bucharest 1976.
42
MAP OF MINERAL RESOURCES – SCALE 1:500.000 I. METALLIFEROUS, NON-METALLIFEROUS AND
RADIOACTIVE SUBSTANCES
Mircea BORCOS1, Gheorghe UDUBASA1,2, Mircea SANDULESCU1,2, Marcel LUPU1, Bogdan GABUDEANU3
1Geological Institute of Romania, Caransebes Str. No. 1, Bucharest; 2University of Bucharest, N. Balcescu Blvd. No. 1, Bucharest; 3National Agency for Mineral Resources,
Bucharest.
This map is intended to show up to date informations about the mineral resources –
metalliferous, non-metalliferous and radioactive, by using a geological background in line
with the new acquired knowledge. It is a direct continuation of the map on the 1:1.000.000
scale (edited by GIR in 1984), keeping its main features, however with much more details
and without coal and oil (gas) fields. These last substances will probably be included in a
separate map on the same scale.
About 1.000 occurrences and deposits are displayed on the map, exceeding the
corresponding items of the 1:1.000.000 scale map. As usual, areas with a high density of
occurrences and deposits were separately represented, sometimes with details of the
geological structures.
Several new data are included in this map:
(1) Size of deposits, wherever possibly, in order to make easier the comparison with the
maps of other European countries.
(2) Probably the biggest achievement of the map is the inclusion of the radioactive
substances, till now ranging as secret and thus impossibly to be published. We therefore
acknowledge the efforts made by the colleagues from the Uranium National Company
(F. Baciu et al.) for delivering to us convenient data to publish.
(3) The representation of some ore-bearing formations with significant deposits and
occurrences hosted by some metamorphic rock piles. Several ore-bearing formations are
shown both on the main map and on the detailed insert maps.
Many new data are included in the explanatory text, rather extended (about 300
pages), both in the tables and in the text itself. In addition to the usual geologic data, i.e. age
(wherever known), morphology etc., there are given: size, operational stages (still active,
43
44
under conservation, abandoned, exhausted), as well as survey stage (explored, identified only
etc.).
Some data on the mining industry related pollution problems are also shown, both on
a special insert map and in a discussion in the text.
A special time-related column gives an idea about the main mineral-producing
events, beginning with the oldest deposit (Fe, Palazu Mare) and ending with the heavy
minerals concentrates in the Holocene sands of Danube Delta.
The map and the accompanying text are intended to give an overview on the mineral
potential of Romania, to eventually help the decision-maker in Romania in evaluating any
future chance of mining industry.
The map (4 sheets) and the text (about 300 pages) will be published by the
Geological Institute of Romania (GIR) late this year and will be delivered both as hard copies
and (mainly) in electronic format.
The text (book) include and extensive bibliography (both published papers and
books and unpublished reports mostly existing in the Archives of the GIR), reminding all
types of maps at various scales, i.e. metallogenetic (1:1.000.000), of mineral resources
(1:1.000.000 and an unpublished version of limited circulation of a map on the scale
1:200.000), geological maps on the scales 1:200.000 and 1:50.000, which have been of high
interest in the final editing of the 1:500.000 map of mineral resources. A simplified map of
radioactive substances on the scale 1:1.000.000 was also used in their localization. Some
examples from the geochemical map of Romania on the scale 1:3.000.000 are also given,
both as fingerprint of eventually undiscovered deposits/occurrences and as areas highly
polluted by mining and related industries.
A long list of acknowledged persons is given at the end of the text, from the
Geological Institute of Romania, S.C. PROSPECTIUNI S.A., the former Geological
Enterprises for Geological Prospecting and Exploration (IPEG’s), FORADEX, National
Company of Uranium, etc. etc.
Thus the map and the accompanying text is in a way a collective works.
Nevertheless, the authors are only responsible for collecting, selecting and interpretation of
data, as an effort to produce an unitary final product.
THE RAMAN STUDY OF CERTAIN K-Na DIOCTAHEDRAL MICAS
Nicolae BUZGAR
University „Al.I.Cuza” Iaşi, 20A Carol I Blv., 700507 Iaşi, [email protected]
Four samples of muscovite, one sample of chromian-muscovite (fuchsite) and one
sample of paragonite have been used for this Raman study. The muscovite samples come from
pegmatites from the Cataracte region, the Gilău and Lotru Mountains, and the Rebra Valley. The
paragonite sample is from the Rebra II Formation in Rodnei Mountains (data courtesy of
Murariu Titus). The Cr-muscovite sample originates from Mari, Norway.
The Raman spectra of micas were obtained using a Jobin Yvon transportable HE532
Raman system. The analyser is optimized to work with 532nm laser excitation. The HE
instrument obtains spectral information from the sample via a single fibre-optic probe. The laser
is also connected to this probe by a fibre. Peak intensity is, however, lowered by filter absorption
for wavenumber <~200cm-1. The detector is a CCD multichannel matrix detector (1024x256
pixels, pixel size 26 x 26 microns), MPP selected chip (size 26.6 x 6.7mm), spectral range: 400
to 1050nm. The power of illumination on the sample was 35mW. Twenty to fifty accumulations
of 0.5–8s were typically used to record the spectra. In undertaking a curve fit of the Raman
spectra, the linear baseline was subtracted using LabSpec software. A Lorentzian shape was
assumed for all Raman lines. Some technical obstacles were encountered when recording mica
samples (e.g. high backgroud noise in the case of paragonite).
The Raman spectra of muscovite samples are almost identical (Fig. 1). According to Tlili
and Smith (1989), the spetra of micas are sub-divided as follows: (i) a low wavenumber region,
50 – 300cm-1, and (ii) a high wavenumber region, 300 – 1250cm-1. In the first region, Raman
spectra of muscovite show two peaks: ≈219cm-1 and 265.8cm-1. The last peak is the strongest
peak in muscovite. The two peaks were attributed by Loh (1973) and Tlili and Smith (1989) to
asymmetrical and symmetrical stretching of the “isosceles triangle O-H-O” where the two
oxygens are adjacent apical oxygens and not the oxygens of the (OH) group. Nakamoto (1997)
shows that normal modes of vibrations in H2O are 1595cm-1 (ν2) and 3657cm-1 (ν1). Wang et al.
(2001) propose that peaks in the 200-400cm1 range belong to the lattice vibrations. We believe
45
that the two peaks do correspond to the lattice vibration, since they are identical for all the
samples of muscovite, Cr-muscovite (Fig. 2) i paragonite (Fig. 3).
Fig. 1. The Raman spectra of muscovite samples (a – Rebra Valley; b – Cataracte region; c – Gilău Mountains; d – Lotru Mountains).
In the high wavenumber region, Raman spectra show two strong peaks: ≈412cm-1 and
703.9cm-1. The first peak involves the octahedral site and is assigned to the Al-O-Al vibrations
(symmetrical stretching vibrations are the stongest vibrations). The second band involves the
tetrahedral sites and is assigned to the Si-O-Si vibrations (acording to Tlili and Smith, 1989,
Wang et al., 2001). Furthermore, Raman spectra display a few bands of lower intensity, the
values of which slightly differ among spectra because of background noise and overlaping.
These peaks are assigned to asymmetrical stretching of the Al-O-Al and Si-O-Si vibrations, and
symmetrical stretching of the Si-O-Al vibrations (acording to Tlili ad Smith, 1989).
The Raman spectrum of Cr-muscovite is very similar to that of muscovite (Fig. 2). An
additional strong band appears at 468,9cm-1, corresponding to the symmetrical stretching of the
Cr-O-Al. Another difference between the muscovite and Cr-muscovite spectra consists in the
≈635cm-1 peak for muscovite and the 615,4cm-1 peak for Cr-muscovite respectively. These
46
bands are caused by the asymmetrical streatching of the Al-O-Al and Cr-O-Al. The Cr-O bond is
more polarized than the Al-O bond, which is probably the reason why the 615,4cm-1 peak masks
the 635cm-1 peak in muscovite.
Fig. 2. The Raman spectrum of Cr-musovite.
The Raman spectrum of paragonite (Fig. 3) is very similar to that of Cr-muscovite. The
presence of a single band at 442,4cm-1 may be a consequence of the overlapping bands at
≈412cm-1 and 468,9cm-1. This implies the presence of a small amount of Cr3+ (which would also
account for the green hue of paragonite). The presence of Cr3+ is also suggested by the 611.5cm-1
peak (as with Cr-muscovite).
47
Fig. 3. The Raman spectrum of paragonite.
All Raman spectra show a weak peak at 2330cm-1. This is due to OH vibrations.
48
49
Acknowledgements
This project was financed by the Romanian Academy (grant no. 96/2008).
References
Nakamoto K. (1997) – Infrared and Raman Spectra of Inorganic and Coordination Compounds
(5th ed.). John Wiley & Sons, Inc.
Tlili A., Smith D. C. (1989) – A Raman microprobe study of natural micas. Mineralogical
Magazine, Vol. 53, pp. 165-179.
Wang A., Jolliff B. L., Haskin L. A., Kuebler K. E., Viskupic K. M. (2001) - Characterization
and comparison of structural and compositional features of planetary quadrilateral pyroxenes
by Raman spectroscopy. American Mineralogist, Vol. 86, pp. 790–806.
MICROSCOPICAL AND XRD STUDY ON THE GEMS FROM THE AREA WITHIN GURASADA LOCALITY (HUNEDOARA COUNTY)
Ciprian CONSTANTINA 1, Terry MOXON 2
1 „Romaltyn Exploration”Baia Mare, [email protected]; 2 Department of Earth Sciences, University of Cambridge, UK
Geological background
Gurasada locality is situated north from Mureş culoir, in South Apuseni Mountains,
and from an administrative point of view belongs to Hunedoara County.
The rocks making up this area are represented by laramian volcanic rocks (lava flows,
pyroclastic breccia and rare levels of tuffs) and were radiometric-dated as Senonian age
(Constantina, 2008). There is a bentonite deposit, near Gurasada, which resulted from the
argillization of a volcanic tuff having an age older than that of the previously mentioned
rocks.
The area is crossed by Gurasada valley, which together with its tributaries,
concentrates miscellaneous gems from the silica group (agates, chalcedonies, jasper, silicified
wood and opal).
Microscopical study
Usually, agates and chalcedonies are lightly coloured, with the central part most
frequently represented by white-milky crystalline quartz that grades into microcrystalline and
fibrous silica of grey and red colours. Microscopically, the quartz microcrystals have been
classified according to their structure; the granular one prevails, and in addition, fibrous and
lamellar varieties have been identified. The microscopic structures evidenced in our samples
were represented by: granular structures, structures based on long fibres, fan-like structures,
rosette-like structures, hematite interlayers (fig 1).
As regards the jasper, the colour is mainly given by oxides and iron hydroxides
(hematite).
The microscopic study of silicified wood highlights the vegetal (cellular) structure
of the wood fully replaced by silica (fig. 2).
49
Fig. 1. Chalcedony consisting of fibrous silica (rosettes) and microgranular and fibrous (rosette-fan type) silica
(Microphotograph, N+, 35 X); Tisei V.
Fig. 2. Silicified wood with visible vegetal structure – cross section (Microphotograph, 1N, 35 x);Câmpuri Brook .
X-ray diffraction study of the gems
Besides the identification of the mineral species, we have also tried a novel
interpretation for Romania, which connects the age of the agates (with possible implications
on the age of their host rocks) to the quartz crystallinity degree. Thus, we have applied the
calibration method proposed by Moxon (2002), tested and completed in further studies
(Moxon and Rios, 2004; Moxon and Reed, 2006; Moxon et al., 2006).
The mineralogenetic mechanism that explains the basis of this interpretation is related
to the transformation, at geologic scale, of moganite into microcrystalline quartz. The
correlation of these evolutionary trends, evidenced in a large number of representative
samples, carefully selected from world wide occurrences, allowed the elaboration of a
quantitative work hypothesis concerning the agate formation and evolution, schematically
presented in fig. 3.
The first set of measurements was taken for moganite identification in the 17 – 250 2θ
interval, at 0,010 for 20 sec/step. In the investigated samples we have noticed a moganite
doublet around 20o 2θ. It is worth noticing that all the diffractograms on our samples display
an additional phase of approximately 21.90 2θ, which does not allow a semi-quantitative
routine assessment for the moganite content. Nevertheless, by comparing them with other
diffractograms of the same type, we estimate a moganite concentration of around 5%.
50
Early stage Intermediary stage Final stage
Age of the host rock: ~ 275 My > 400 My
The amount of “internal water” decreases due to the “internal water” “free water” conversion
Free water (constant) Free water (constant) Free water (constant) + + +
Internal water (~ 1 %) in defect centres
moganite ( ~ 13 %) +
microcrystalline quartz (~ 86 %)
Fig. 3. Scheme for the quantitative evaluation of the agates age based on the content of internal water, microcrystalline quartz and moganite, and crystal.
Si internal standard and measurements in the 16 – 520 2θ interval, at 0,020 for 10
sec/step were used at the the second set for the identification of the mineral phases.
In samples Ro 156wh and Ro 158wh – representing the white areas of the
corresponding chalcedonies, the peaks of an additional phase have been noticed, around the
values of 22 and 36o 2θ. We assume that this phase is represented by cristobalite, which has
the main peak at 21.98o 2θ, followed by three less intense peaks at 28,32; 31.46 and
respectively 36,08o 2θ (according to the ICDDD - International Centre for Diffraction Data
on synthetic cristobalite). The values for the natural opal-C are close to these reference ones
(fig. 4).
15 20 25 30 35 40 45 50 55
0
200
400
600
800
1000
1200
Co
unt
s
2 theta (deg)
Ro 156 wh
Cr
Si
Si
Cr
Internal water (~ 0.7 %) in defect centres
moganite (~ 6 %) +
microcrystalline quartz ( ~ 93 %)
crystal size: ~ 470 Ǻ
Internal water (0.4 %) in defect centres
moganite 0 % +
microcrystalline quartz (~ 99 %)
crystal size: ~ 550Å
Fig. 4. Diffractogram of the white sample Ro 156 with Si addition.
crystal size: ~ 320 Ǻ
51
14 16 18 20 22 24 26 28 30 32
0
200
400
600
800
Cou
nts
/ 1
0 se
cs
2 theta (deg)
Ro 155
Mog + Q
Cris
Q
Si
Calc
Fig. 5. Diffractogram of the chalcedony sample Ro 155 consisting of -
quartz (Q), moganite (Mog), calcite (Calc) and cristobalite (Cris).
The brownish, chocolate-like chalcedony Ro 155 (N.B. the vein chalcedony described
in situ from the intensely altered pyroclastic breccia from Şcolii Valley, Gurasada) has
indicated a minimum amount of -quartz, a large concentration of moganite besides which
calcite and cristobalite have been identified. It is worthy to mention that the Si addition
represents only 13 % of the sample mass, but in the diffractogram it appears as dominant
phase (fig. 5).
We state that these mineral phases of gems from Gurasada were also noticed by
RAMAN spectroscopy analyses (Pop et al, 2004).
The third set of measurements, using scans in the 16-300 2θ interval, at 0,010 for 10
sec/step, with a view to calculate the quartz crystallites sizes based on the 26,640 2θ peak,
was performed for the calculation of the quartz crystallites sizes based on the peak width at
half-heights of the main quartz peak at 26,640 2θ that was subsequently used for evaluating
the age of the agates and chalcedonies under study. The dimension of quartz crystallites
Cs(101) from our samples are tabulated further on.
Table 1. Size of quartz crystallites in the agates and chalcedonies from Gurasada
Sample Crystallite size Cs(101) / Å
Ro 151 417 Ro 152 462 Ro 153 506 Ro156 555 Ro158 624 Ro159 627 Average 567 (72)
52
53
As compared to the values obtained by Moxon and Rios, (2004), the average value of
567 Å obtained for our studied samples would suggest a geological age in the interval 30 and
40 My.
The difference of about 35-40 de million years between the formation of the silica
gem varieties (30-40 My) and the radiometric ages obtained for the host rocks by using the
K-Ar method (76-80 My) suggests, as in the case of the agates from Brazil, that the agates
and chalcedonies from the area under study have formed in a subsequent stage of the volcanic
activity, in relationship with the bentonitization processes that have affected the pyroclastic
rocks.
Conclusions
The theory connecting the transformation of moganite into quartz in chalcedonies and
agates at geological scale, corroborated with the increase of the quartz crystallites size was
applied in a study of this type for the first time in Romania; based on this method we could
estimate ages of 30–40 million years (Lower Eocene) for the agates. These values, to which
the nature of mineral phases is added, may suggest that, in the area, the agates and chalcedonies
were the outcome of exogenous processes (bentonitization of the pyroclastic rocks).
References
Constantina, C. (2008) – Studiul complexului vulcanoclastic paleocen din regiunea Sârbi-Gurasada-Burjuc (Valea Mureşului), cu privire specială asupra mineralelor cu valoare gemologică. PhD thesis 135 p. Univ. Babeş-Bolyai, Cluj-Napoca.
Moxon, T. (2002) – Agate: A study of ageing. European Journal of Mineralogy 14, p. 1109-1118, Stuttgart, Germany.
Moxon, T., Rios, S. (2004) - Moganite and water content as a function of age in agate: an XRD and thermogravimetric study. European Journal of Mineralogy 16, p. 269-278, Stuttgart, Germany.
Moxon, T., Nelson, D. R., Zang, M. (2006) – Agate recrystallisation: evidence from samples found in Archaean and Proterozoic host rocks, Western Australia. Australian Journal of Earth Sciences (2006) 53, p. 235 – 248.
Moxon, T., Reed, S.J.B. (2006) – Agate and chalcedony from igneous and sedimentary hosts aged from 13 to 3480 Ma: a cathodoluminescence study. Mineralogical Magazine, 70(5), pp. 485–498.
Pop Dana, Constantina, C., Tătar, D., Kiefer, W. (2004) – RAMAN Spectroscopy on gem-quality microcristaline and amorphous silica varieties from Romania. Studia Univ. UBB, Geologia, XLIX, 1, 41-52, Cluj-Napoca.
THE ZEOLITIC RESOURCES IN BÂRSANA ZONE,
POSSIBILITIES OF USE
Gheorghe DAMIAN 1, Floarea DAMIAN 1 1North University of Baia Mare, Dr. Victor Babeş Street, no. 62/A, 4800 Baia Mare [email protected] 1. Introduction
The zeolitic tuffs are used in various activity domains (Bedelean and Stoici 1984), especially
due to their cation exchange capacity. The high cation exchange selectivity of the clinoptilolite for
the ammonia ion has recently been demonstrated, (Leggo 2000). In the last 40 years studies have
been made regarding the use of natural zeolites in various domains including the environmental
protection (Mumpton 1999).
2. The Geology of Maramureş Basin
The tuffs in the Bârsana zone (Maramureş Basin) are developed in badenian formations. The
Badenian is discordantly disposed over the paleogene deposits. Within these deposits, Antonescu et
al. (1979) has separated the following formations: the tuffs and globigerina marls formation, the salt
breccia formation, the sandstone-marl formation. The tuffs in the Bârsana zone are parallel to the Dej
tuff, (Antonescu et al. 1979).
The first complex of tuffs in the base of the lithologic column is represented by the lapilli
tuffs with pumices of about 40-50 m in thickness. Over these there are fine vitroclastic and vitro-
crystalloclastic tuffs. There are green, yellow-rusty tuffs, very little stratified, with a thickness
between 50 and 60 m, which can also be of 170 m. The sandstone complex with interbeded clay
contains black clays in the lower part and medium and coarse grained sandstones disposed in the
upper part of the complex. The second complex of tuffs contains at base a level of 30-40 m of
crystalloclastic coarse grained tuffs with passing towards sandstones with volcanic material. The
upper part of the lithologic column is ended with tuffs which are finely laminated parallel with a low
content of volcanic material.
3. The Mineralogical and Petrographical Characterization of the Zeolitic Tuffs
Previous data regarding the mineralogy, petrography and geochemistry of the zeolitic tuffs in
the Maramureş Basin have been published by Damian, et al. (1990), (2002), (2007).
The lapilli zeolitic tuffs represent a basal sequence of the fine tuffs (vitroclastic) and
sometimes of the crystalloclastic tuffs and have a high percent of the pumices fragments, which can
be up to 50%. The pumices are up to 5-6 mm in size and are substituted by clay minerals, celadonite
54
and zeolites. The crystalloclasts appear in small quantities and are represented by quartz, feldspar,
biotite, and muscovite. Lithoclasts are quite frequent (7-14%) and are represented by sedimentary
rocks (fine sandstones, siltstones, marls, clays) and eruptive rocks (andesites, dacites). Vitroclasts (6-
23%) are disposed between the pumices and are substituted especially by zeolites. Diagenetic
products have a high percent, of up to 70-80% and are represented by: smectites, celadonite, zeolites,
carbonates, and the iron oxyhydroxides. The presence of the celadonite as a substitute of pumices
emphasizes the psefitic structure of these rocks.
The crystalloclastic tuffs develop in the superior level. They appear as levels with a
thickness of 10-20 m. The crystalloclasts have a participation between 45% and 70% and they are
represented by: quartz, feldspar, together with biotite, muscovite, ilmenite. Many crystalloclasts are
angular, thus demonstrating their magmatic source. The prevailing of the quartz and feldspar crystals
fragments and that of the large glass fragments demonstrates a hydraulic sorting during the
deposition. The quartz crystals that are sub-rounded and sometimes rounded represent material of
sedimentary origin. Vitroclasts are partially or completely substituted by zeolites. Together with the
glass fragments, there also appear rare pumice fragments of small sizes, below 3 mm. Lithoclasts are
quite often, but they do not exceed 5% and they are represented by sedimentary rocks fragments: fine
siltstone sandstones, clays, all of them rolled, thus demonstrating their exogene origin. Together with
these, there appear metamorphic rocks fragments (quartzite and quartz-sericite schists) and magmatic
rocks (andesites, dacites, microdiorites). The diagenetic components are represented by: zeolites,
smectites, autigene calcite, celadonite and chalcedony.
The vitroclastic zeolitic tuffs are made of volcanic glass (about 90%), which can be
distinguished under the microscope especially when they are covered with a fine film of clay
minerals. Vitroclasts are present as curved angular, globular, filiform fragments, with sizes below 0.5
mm in general. Vitroclasts are devitrified producing zeolites, smectites, celadonite. Crystalloclasts
have a participation in volume estimated of below 10% and they are represented by feldspar
crystalloclasts, quartz, micas (biotite and muscovite). Lithoclasts appear sporadically and are
represented by quartzite and the eruptive rocks. Diagenetic products have a considerable percent, up
to 90-92% of the rock volume and are almost totally represented by zeolites. Smectites appear as
micro-aggregates or especially as films that cover vitroclasts.
4. Zeolitic Minerals
The presence of the following members from the zeolitic group: clinoptilolite, mordenite and
heulandite has been emphasized, by using special analyses, X-ray diffraction, electron microscopy,
absorption spectroscopy and IR transmission, thermic analyses.
55
Clinoptilolite appears as a devitrification product of the cineritic groundmass and of
vitroclasts. Clinoptilolite is well crystalized, constituting aggregates of idiomorphic or xenomorphic
crystals, limited in the vitroclast’s or pumices’ outline, with sizes between 40-60 microns and present
a medium to high idiomorphism degree. If the fine material is completely substituted by the zeolites,
the fine glassy mass is homogenous and welded. By substituting the glass masses of high
dimensions, there appear zeolites nests that do not exceed in dimensions the shape of the grains and
of the volcanic glass vacuoles. In these vacuoles, the zeolite crystals are disposed perpendicularly on
the glass wall. The central zones are occupied by celadonite and by clay minerals. Fiammes are only
partially substituted by zeolite.
The X-ray diffraction analyses have emphasized the presence of the clinoptilolite in large
quantity. All spectres correspond to the diffraction data present in the literature for clinoptilolite and
the 8.91 Å, 2.96Å, 3.96Å reflexes are well marked. The X-ray diffraction spectres show an advanced
grade of crystallinity of the clinoptilolite.
The thermic curves are characterized by a single endothermic effect, with a maximum at
about 200oC, corresponding to a continuous and progressive loss in weight, due to water elimination.
The total weight loss is of about 11%, which is close to the theoretical water content from the
clinoptilolite formula. The absorption and IR transmission spectrum has been useful for separating
clinoptilolite from heulandite, through the absorption band at 610 cm-1, as heulandite compared with
that of 700 cm-1. The electron microscopy analyses have identified the presence of crystals of
prismatic plate form, very homogenous. Tabular crystals, similar to the heulandite appear frequently.
Heulandite has been emphasized through the diffraction analyses made on thermically
treated samples that indicate a strong decreasing of the clinoptilolite’s reflexes, due to the presence
of heulandite.
Mordenite appears associated with clinoptilolite as fine fibrous acicular crystals and has been
emphasized by electron microscopy analyses.
5. The Chemistry and the Physical Properties
The chemistry of the vitroclastic zeolitic tuffs is very important in order to emphasize the
possible exchangeable cation. The vitroclastic clinoptilolitic tuffs are rich in calcium, potassium and
sodium. The variation limits of the chemical composition are the following:
SiO2 % Al2O3 % Fe2O3 % FeO % MnO% MgO% CaO % Na2O% K2O % 66,68 12,47 0,73 0,42 0,05 1,09 2,37 2,14 2,29
TiO2 % CO2 % H2O+ % H2O- % Total% 0,14 0,62 7,02 3,73 99,76
56
57
The cation exchange capacity varries from one sample to another and it is between 8.05-
118.49 mvali/100g for Na+, 16.55-40.7 mvali/100g for K+, 20.9-87.70 mvali/100g for Ca2+ and
0.49-13.93 mvali/100g for Mg2+.
The values of the specific surface are between 12.3 – 20.4 m2g, with an average of 15.85
m2g. The reactive silica shows very large limits, i.e. 5.10-16.43%. It is extremely curious that
exactly the fine zeolitic tuffs have low values, which negatively correlate with the high values of the
cation exchange capacity.
6. Criteria for Using the Zeolitic Volcanic Tuffs
In order to appreciate the quality of the zeolitic tuffs, some criteria must be used, based on
which the use possibilities in the environmental protection domain and in the industrial activities are
going to be selected. A first criterion is the zeolites content. An average content between 45-50% of
zeolites in the primary rock allows the use in the industrial activity. In order to use the zeolites in the
environmental protection domain, the content must be higher than the previous, of minimum 60%.
The crystallinity of the zeolites is also an important criterion, which can determine the high cation
exchange capacity. The chemical composition can be another use criterion of these materials. The
contents in Ca ± Mg, K and Na can be used as parameters. The cation exchange capacity and the
specific surface are properties used for the exchange or absorption of the substances and it depends
very much on the zeolites content. The zeolitic tuffs in the Bârsana zone can be used in the following
domains:
- products for retaining the heavy metals;
- zeolitic products for the waste waters treatment;
- gases purification and other domains;
- materials for retaining Cs and Sr from nuclear waste;
- materials used for barriers at the biodegradable municipal waste.
We conclude that in the future it will be possible to obtain viable commercial products from
natural zeolites deposits in Bârsana, which can be used in various domains. An obstacle in using the
natural zeolites is represented by the high costs. References Antonescu Fl., Mitrea Gh. & Popescu Al., (1979),. D. S., Inst. Geol. Geof., Bucureşti, v. LXVI, p. 5-23. Bedelean I. & Stoici S. D. (1984), Zeoliţii, Ed. tehnică Bucureşti, p. 227. Damian, Gh., Pop N. & Kovacs Palfy P., (1991), In special Issues: The Volcanic Tuffs from the
Transylvanian Basisn, Univ. of Cluj Napoca, 233-243. Damian Gh., Bud I., Damian F. & Macovei Gh., (2002), Bull. St. Seria D V. XVI, p. 109-118 Damian Gh, Damian F., Macovei Gh., Constantina C., & Iepure Gh., (2007), Carpth. J. of Earth and
Environmental Sciences Vol. 2. no.1, p. 59-74. Leggo J. P., (2000), Plant and Soil, 219, p.135-146. Mumpton F. A., (1999), Proc. Natl. Acad. Sci. USA, vol. 96.
CYMRITE FROM BALAN SULPHIDE DEPOSIT, EAST CARPATHIANS, ROMANIA
HIRTOPANU1 P., ANDERSEN J.C. 2, CHUKANOV N. 3, PETRESCU L. 1
1University of Bucharest, Faculty of Geology and Geophysics; [email protected]; 2University of Exeter, Camborne School of Mine, UK
3Institute of Problems of Chemical Physics, Moscow, RAS The rare mineral cymrite, a barium aluminium silicate hydrate, was determined recently in
the Balan sulphide deposit, situated in retromorphic rocks of Cambrian Tulghes Group, East
Carpathians, Romania. This is a second occurrence of cymrite in Romania. The first occurrence was
identified in sphaleritic ore of Blazna Valley stratiform pyritic Pb-Zn deposit, localized in medium
grade metamorphic rocks of the Precambrian Rebra Series, East Carpathians (Udubasa, 1986). In the
Balan sulphide deposit cymrite is an important constituent of gangue minerals, after quartz. Most
probably, until now it was confused with chlorite. The Balan polymetallic sulphide ores form lenses
(strata-bound) of massive compact pyritic ore (dominantly fine grained) with sphalerite and galena.
A disseminated sulphides ores are also present. The main component minerals of the parageneses
are: pyrite, sphalerite, galena, chalcopyrite, arsenopyrite and tetrahedrite with minor other
components like magnetite, bournonite, jamesonite, cosalite, native Ag, native Au, chalcopyrite-
cubanite, bornite, calcosine, covellite (Petrulian et al., 1971, Popescu, 1974). The gangue minerals
until now were cited quartz alone, different carbonates and chlorites. Among gangue minerals we
determined Ba-feldspars (celsian and hyalophane) in association with quartz, Ba-micas in association
with cymrite and baryte. The cymrite is more widespread than the chlorite. It is frequently in host
rocks of ores, being an important constituent near quartz, carbonates, Ba-K-Na feldspars and
different micas. Also, the cymrite was determined in all sulphides deposits of the Tulghes Group,
which form an alignment of 200 Km, from NW to SE (Baia Borsa, Mestecanis, Puiu, Lesul Ursului,
Isipoaia, Paltinu, Holdita, Brosteni, Paraul Caselor, Borca) that will be discussed in other paper, as
well as the presence of cymrite in the Bistrita manganese belt.
Cymrite was originally described by Smith et al. (1949) from the Benalt manganese mine,
Rhiw, Carnarvonshire, Wales, Great Britain. The name comes from the old Welsh name for Wales,
Cymru. The cymrite is apparently restricted to veinlets which cut across the hydrothermal-derived
manganese silicate ore being associated with ganophyllite. Many of the occurrences reported later
are associated with low and medium grade metamorphic rocks: Bonanza Creek, Alaska (Brosgé,
1960); Brook Range Alaska (Runnells, 1964; Carron et al., 1964); Franciscan Group, California
(Essene, 1967); strata-bound Ba-Zn deposit in the Scottish Dalradian (Fortey and Beddoe-Stephens,
58
1982); high pressure metamorphosed Mn-rich rocks from the islands of Andros (Reinecke, 1982);
the Foss celsian-barite-sulphides deposit at Aberfeldy, Scotland (Moles, 1985); Nevada cymrite
(Winter, 1991); Sedex barite deposit of Zamora, Spain (Moro et al., 2001); Pelagonian massif,
Nežilovo mine, Macedonia (Bermanec et al., 1993); many pollymetallic ores in Russia; Kola
Peninsula, in carbonatite for the first time (Sorokhitina et al., 2007).
Physical and optical properties. The Balan cymrite forms white cm sized bands in pyrite
ore and is folded togheter. Macroscopically cymrite has a massive or fibrous texture composed from
an elongate parallel white prisms or needles with a satiny to vitreous lustre. These small
prisms/needles have a few mm in length, sometimes more. The mineral is translucent. The cymrite
was studied in thin sections (fig.1) where it appears as a colourless easily light yellow or to
colourless (when it is pure); could be green or brown due to inclusions of alteration products. It has
two prismatic cleavages crossed at right angles, perfect on (001) and good on (110). The extinction is
direct with respect to elongation direction. The refringence is about n≈1,608. The mineral is uniaxial
(pseudouniaxial) or nearly so (2V=0-50), with negative optical character and has a low birefringence.
The cymrite differs from others phyllosilicates by the low birefringence and the two prismatic
cleavages. In polished sections the ilvaite has a low reflectivity (<sphalerite), grey colour, strong
bireflectance from grey to blue and strong anisotropy from pink to bluish grey. The crystal structure
of the mineral went through a series of revisions. Smith et al (1949) report that cymrite has
hexagonal symmetry. Runnells (1964) described the crystal system of Brooks Range, Alaska
cymrite as hexagonal. In the later structural determination, Drits et al (1975) proposed that cymrite
has a monoclinic symmetry (space group P2) with pseudoxehagonal nature and that those crystals
previously studied that yielded hexagonal symmetry were triplets and those that yielded
orthorhombic symmetry were twins.
Fig.2. IR spectrum of cymrite from Balan deposit, sample Bln4.
Fig.1. Thin section of cymrite from Balan deposit.
In the fig. 2 is presented the IR spectrum of cymrite from Balan. It was obtained with two-
beam SPECORD 75 IR spectrophotometer at resolution of 2 cm-1 for the range 400-1400 cm-1.
Polystyrene and gaseous ammonia were used as probe standards. The assignment of the bands is
59
following: 3550 cm-1 -O-H-stretching vibrations; 1660, 1627 - bending vibrations of H2O molecules;
1177 cm-1 - stretching vibrations of Si-O-Si bridges connecting tetrahedral silicate layers; the range
400-650 cm-1 - bending vibrations of tetrahedral layers combined with Al-O-stretching modes.The
X-ray diffraction powder data for Balan cymrite: 2.96(100), 3.96(90), 2.67(70), 7.71(50), 2.24(40),
2.21(40), 1.850(40). The chemical composition of Balan cymrite analysed by microprobe (wt%):
SiO2=31.30; Al2O3=26.10; BaO=38.00; H2O+=5.10 (theoretical added) ∑=100.50.
Genesis of cymrite. For establish the genesis of cymrite, we started from the natural
association of cymrite in Balan sulphide deposit (with quartz, sulphides, Ba-micas, celsian,
hyalophane, barite) and from the experimental phase relations between these minerals. Phase
relations between cymrite and celsian, especially of the bulk composition of BaAlSi3O8-OH (Seki
and Kennedy, 1964) indicated that cymrite is stable at pressures above 18Kbar at 3000C and above
20Kbar at 5000C. This pressure is inconceivably high in view of its natural occurrence. More recent
experimental work on the bulk composition of BaAl2Si2O8-H2O (Nitsch, 1980) has shown that
cymrite equilibrates with celsian at pressures above 4.3Kbar at 3000C and above 6.7Kbar at 5000C.
Hsu (1994) using the conventional hydrothermal techniques indicated that cymrite can be stable at
much lower pressures than those previously reported. The replacement of barite by cymrite was
experimentally demonstrated in an alkaline solution as shown by the reaction: BaSO4+2OH-
+Al2O3+2SiO2=BaAl2Si2O8.H2O+SO42-. The stability field of cymrite confirms that this mineral
can be stable in low P-low T metasedimentary environments (Moro et al., 2001). The first Ba
minerals from Balan sulphide deposit were probably like a Ba-Al-Si gel corresponding to
harmotome, BaAl2Si6O6.6H2O, or an unnamed hydrous Ba silicate, BaAl2Si2O8.4H2O, (Jakobsen,
1990). These phases reacted to form cymrite (BaAl2Si2O8.nH2O) and finally celsian (BaAl2Si2O8)
by a series of essentially dehydration type reaction (Jakobsen, 1990). Ba and SiO2 were supplied to
the basin by the hydrothermal activity (the same source and of sulphides) and they were kept as a
silica gel on the sea floor (Large, 1980) and during later diagenesis, under relatively reducing and
calcareous conditions, barite and Ba silicates (simultaneously with sulphides) formed. The textural
relations show that the cymrite from Balan deposit was formed at the expense of the celsian and
barite, as a late stage. The first (earlier) cymrite could represent an intermediate phase in a prograde
diagenetic sequence of minerals, for example at the expense of harmotome (with a content of 6H2O)
through a stage of hydrated Ba silicate (with a content of 4H2O) to cymrite, and ending to celsian
with increasing P-T conditions. Assuming rapid reaction between cymrite and celsian, as observed
by Nitsch (1980) in his hydrothermal experiments, all the cymrite should have reacted to celsian
+H2O. Later, this celsian was partially hydrated again to form cymrite (the second one, that now we
see it on microscope), as indicated by the textural relationships described above. The relics of celsian
60
61
are present when the P fluids are higher than the PH2O; when the PH2O are higher than the Pfluid the
celsian completely disappeared. We appreciate that the physical conditions which prevailed in the
formation of the cymrite in Balan deposit may have been above 6kb water pressure and cca 5000C. In
conclusion, the cymrite was determined for the first time in massive sulphides belt of Tulghes Group,
in the all rocks of these group as well as in the Mn belt. It occurs as an important constituient both of
gangue minerals and of the Tulghes Group rocks. It appears as a secondary mineral, substituting the
primary minerals (pyrite, sphalerite, baryte, Ba-feldspars, Ba-mica), but the first cymrite could be an
early crystallization product of barium phase (like Ba-Al-Si gel, harmotom?), and later it could be
transformed by dehydration in Ba-feldspars and the Ba-feldspars by hydration past in present
secondary cymrite again. The mineralogy of Tulghes Group is very simple being formed from five
important mineral constituents with variable proportions: quartz, carbonates, cymrite, K-Ba micas
and B-K-Ca-Na feldspars, chlorite. A revision of the mineralogy of Tulghes Group seems to be
necessary as well as of the all sulphide massive deposit belt contained in it, because of the new Ba-
minerals occurrences in them.
References Bermanec V. et al., Eur.J.Mineral., 1993, v.5, p.957-960. Brosge W.P., 1960, U.S.Geol.Survey, Prof.Pap., 400-B, p.351-352. Caron M.K. et al., 1964, Geol.Soc.America, Spec.Pap., v.82, p.26. Drits V.A. et al., 1975, Soviet Physics and Crystalography, v.20, p.171-175. Essene E.J., 1967, Am.Mineral., v.52, p.1885-1890. Fortey N.J. and Beddoe-Stephens B., 1982, Mineral.Mag., v.46, p.3-72. Jakobsen U.H., 1990, Mineral.Mag., v.54, p.81-89. Large D.A., 1980, Geol.Jarhrb., v.40, p.59-129. Moles R.N., 1985, Journal of Geological Society, v.142, issue1, p.39-52. Morro Maria Candelas et al., 2001, Can.Mineral., v.39, no.4, p.1039-1051. Nitsch K.H., 1980, Fortschr.Mineral., v.58, p. 98-100. Petrulian N. et al., 1971, St. cerc. geol., geof., geogr., Seria Geologie, t.16, nr.2, p.343-352. Popescu C. G., 1974, Studiul formatiunilor cristaline cu sulfuri din zona Balan (M.tii Haghimas-
Ciuc), Oficiul de documentare si publicatii MMPG, Bucuresti ReineckeT., 1982, Contrib. to Mineralogy and Petrology, v.79, p.333-336 Runnells D.D.,1964, Am.Mineral., v.49, p.158-165. Seki Y. and Kennedy G.C., 1964, Am.Mineral., v.49, p.1407-1425. Smith W.C, Bannister F.A., Hey M.H., 1949, Min.Mag., v.28, p.676-68. Udubasa G.,1986, Crystal chemistry of minerals, IMA Meeting, Varna 1984, p.717-727.
ILVAITE FROM THE CAVNIC DEPOSIT, ROMANIA
HIRTOPANU P.1, ANDERSEN J.C. 2, HARTOPANU I. 1, UDUBASA S.S. 1 1University of Bucharest, Faculty of Geology and Geophysics, RO, [email protected]
2University of Exeter, Camborne School of Mine, Cornwall, UK,
The Cavnic deposit is located in the East Baia Mare metallogenetic district which belongs to
the Neogene volcanic belt from East Carpathians, Romania. The Neogene volcanic belt is
characterized by presence of many precious/base-metal hydrothermal ore deposits of low
sulphidation type, like Ilba, Nistru, Sasar, Suior, Dealul Crucii, Baia Sprie, Cavnic and Herja. The
hydrothermal activity was related to the presence of an underlying magmatic pluton of 65 Km length
and 15Km wide, established by geophysical data. This is considered as the source of ore metals
(Borcos, 1994). The Cavnic deposit was considered a typically carbonate base metal gold system,
with rare Au-Ag concentrations and mined in the past. The mineralization is principally of vein type
and is developed on the fractures oriented NE-SW. Fourteen veins 400-1500m long, 1-8m thick and
900m vertical development are known, hosted by Neogene volcanics. In the deeper and the midle
part of the deposit the host rocks are Paleocene-Miocene sedimentary and Pannonian age dioritic
bodies. At the deposit scale, four main mineralisation stages were distinguished at Cavnic (Piantone
et al., 1999): (1) Fe-+W (hematite-pyrite-quartz-magnetite-sheelite), T=3200C; (2) Cu-Fe,
(chalcopyrite-pyrite), T=3000C; (3) Zn-Pb-Fe-Cu (sphalerite-galena-pyrite-chalcopyrite), T=2600C;
(4)Mn silicates and carbonates (rhodonite-rhodochrosite-kutnahorite-bournonite–tetrahedrite, T=
2000C. The earlier stage (1) was a higher temperature mineralization, the stages (2) and (3) are rich
in chalcopyrite and the late stage is rich in carbonates. Our samples, collected on the mine dump are
rich in Fe and W belonging, most probably to early stage (1). Until now, the Fe richness of stage (1)
was linked with magnetite, hematite and ferberite. Now, we determined in the Cavnic deposit for the
first time the ilvaite, the mixed valence iron and calcium silicate and that it is frequently recognized
as a type mineral of the skarn deposit. The name “ilvaite”of mineral comes from the old name of
Elba Island, on which the type locality is situated. The type locality is Torre de Rio-Santa Filomena
area (Monte della Torre) Rio Marina, Elba Island, Livorno Province, Tuscany, Italy (Lelievre,
1807).First occurrence of ilvaite in Romania has been mentioned in Ferdinand Mine, Dognecea
(Dogneczka), Banat (Scheerer, 1893). llvaite has been identified in the polymetamorphic iron ores
from Ruschita as a recrystallisation product of the banatitic contact metamorphism with increase in
Si content. Ilvaite occurs in magnetite hedenbergite skarnes formed from regional metamorphic
volcanic-sedimentary iron carbonate ores (Krautner and Medesan, 1969). Ilvaite occurs in the
62
banatite skarns from Baisoara (Popescu, 1973). The ilvaite was identified in Ghezuri deposit of the
Oas neogene metallogenetic district, in the high temperature paragenesis with magnetite, pyrrhotite,
chalcopyrite, cubanite, pyrite, and native gold (Jude, 1986). Ilvaite was determined in calcic skarn
deposits at Dognecea – Ocna de Fier related to Upper Cretaceous – Paleocene banatitic intrusions
developed in the Banat Mountains (Vlad, 1997) and in the Herja epithermal ore deposit related to
neogene magmatism (Damian, 1996). Also, Clain and Haake (2006) mentioned the ilvaite in Turt
Mine, Maramures. First occurrence of manganilvaite, a new mineral, was identified in the skarn
deposit at Dognecea, southwestern Banat (Ilinca et al., 2006) in association with Mn-hedenbergite
and magnetite. Its chemical composition, crystal structure and cation ordering have been presented.
Although the ilvaite is a rare mineral, in the last years were mentioned many occurrences in the
world. Between them we mention some recent occurrences. In the USA, ilvaite occurs in the
Fortitude Au skarn deposit, Nevada, the first reported occurrence in an Au skarn deposit. At
Fortitude, ilvaite is present as resinous, black grains with quartz, ferroactinolite, and sulfides
(pyrrhotite-arsenopyrite-bismuthinite). Ilvaite occurs as a late-phase replacing prograde pyroxene
(Hd91–96 Jo3–5) in magnetite-rich exoskarn near the skarn-marble contact and replacing calcite grains
at the marble front (Franchini et al., 2002). An occurrence of ilvaite layers in the Cinco Villas
metasomatic rocks, Western Pyrenees, Spain (Pesquera and Velasco, 1986), in the Artikutza area,
near the contact with the southern Aya granite, skarns containing hedenbergite, grandite, epidote,
quartz, calcite, actinolite, idocrase and magnetite occurs. This is the second reported occurrence of
ilvaite in Spain, where the monomineralic ilvaite lens intercalation developed by hydrothermal
alteration of hedenbergite in a second stage of skarn formation. Ilvaite occurs in Permian veins
transecting Proterozoic granitic gneisses on the southwestern flank of the Late Paleozoic Oslo
Graben, Norway. The mineral occurs in hydrothermal quartz-magnetite veins in association with
hedenbergite, andradite, fluorite and calcite. Ilvaite as an accessory mineral in hydrothermal veins is
a very unusual mode of occurrence (Larsen and Dahlgren, 2002). Also, ilvaite occurs in some
typical contact deposits within the region. These ilvaites are generally much richer in Mn (varying
from 8.60 % MnO to 15.03 % MnO) than the ilvaites from the hydrothermal veins. This is a new
mineral, manganilvaite, that was determined for the first time in Pb-Zn skarn deposits in the
Rhodope Mountains, Bulgaria as a product of retrograde alteration of the early skarn pyroxenes
(Bonev et al., 2005).
The Cavnic ilvaite is associated with sphalerite, galena, magnetite, hematite, pyrite, chalcopyrite,
ferberite, native gold and native Bi. The sphalerite has a yellow color in transmitted light (low Fe
content) and frequently is zoned; also, it could be red in the same thin section having a high Fe-
content proving a high chemical variability. The native gold grains have an isometric shape of
63
micronic to mm dimensions and it can see easy on optical microscope. On the microprobe image one
can see many grains of native gold forming a little “veins” on the fine crack in the ilvaite (Fig 1).
Also, the native gold surroundins the pyrite grains. This location of native gold could be explain the
forming of gold after ilvaite and pyrite. The composition of native gold determined by microprobe
shows a some silver, ca 1% (Fig 1). The gangue minerals are: quartz, siderite, phillosilicate with Zn
(?), chlorite, rhodochrosite, rhodonite. The quartz presents a hexagonal idiomorphic shape on which
grow radiary others fibrous quartz grains. The carbonate directly associated with ilvaite has a
mixture composition, with Fe, Mn, Ca and little Ba, Mg (determined by microprobe). The yellow
phyllosilicate (with Zn) is intimately associated with sphalerite and was probably formed from it by
hydrothermal alteration. The chlorite(?) don’t looks like a phyllosilicate; it has not any cleavages, has
isometric, round shape and very light green color. Because of the Mn richness mentioned before (the
occurrences of rhodonite and rhodochrosite as gangue minerals) and because of the ilvaite and the
manganilvaite form a continuous solid-solution series and gradations between them can be observed
even in a single crystal (Bonev et al., 2005), it is very probably for manganilvaite to occurs in the
Cavnic deposit. To prove this supposition will need to continue this study, especially need
microprobe analyses. The chemical composition of ilvaite determined by microprobe (mass%):
SiO2=31.313; MnO=4.917; FeO=49.956; CaO=14.064; 2.9118; TiO2=0.047. Electron microprobe
analyses show that the Cavnic ilvaite is similar in composition to ilvaite from skarn Fe-deposit, both
having high iron and relative low manganese. The high Fe content in ilvaite from Cavnic deposit is
consistent with the high Fe activities and low FO2 conditions that characterize both skarn types and
their associated intrusions. The X-ray diffraction powder data for the Cavnic ilvaite: 3.856(40),
3.246(40), 3.102(90), 2.859(60), 2.823(100), 2.699(100), 2.660(60), 2,250(25), 2.350(25),
2.450(30), 2.230(30), 1.807(25), 1.621(60), 1.445(30).The Cavnic ilvaite presents a large prisms of
few mm until 1cm long, forming a compact texture. It is translucent, with iron black, dark grayish to
black colour, brittle and present a submetallic luster. The cleavage is distinct on (001) and (010). In
thin sections the ilvaite has a intense pleochroism: X=dark green; Y=yellow red brown to dark
brown; Z=dark brown. In reflected light, the pleochroism is from light gray to bluish gray, pinkish
red to violet, being strongly anisotropic. The ilvaite is associated with sphalerite, hematite,
magnetite, pyrite, chalcopyrite, galena, ferberite, native Au and Bi and also with quartz, Fe-Mn-Ca
carbonates, rhodochrosite, rhodonite, chlorite and apatite as gangue minerals. By isotopic study
Piantone et al. (1999) calculated the crystallization of sphalerite/galena assemblages from Cavnic
between 234-2900C, this being thus a epithermal deposit. According with the mineral association of
relative high temperature, including magnetite, chalcopyrite, cubanite, pyrite, ferberite, the
mineralisation has a pneumatolitic character. The native gold of Cavnic is included in ilvaite, similar
64
to Turt Ghezuri deposit, where the crystallisation of ilvaite took place at ca 4000C (Jude, 1986). The
presence of rhodonite as mineral gangue, is according to a T higher than 4000C. The forming and
stability of rhodonite in the hydrothermal experimental conditions are situated at ca 7000C (Momoi,
1974), but in natural conditions the T could be lower. The rhodonite Cavnic could be rather a result
of manganiferous skarns and the formation of ilvaite is associated with it later retrogression.
Fig 1. The association gold (white)-ilvaite (grey)-pyrite (cream)-quartz (black) from Cavnic deposit (left); the chemical
profile of the ilvaite (up) and the chemical profile of the gold (bottom) (right).
References
Bonev I.K. et al., 2005, Canadian Mineralogist, v.43, p.10027-1042. Borcos M., 1975, Revue Roumaine de Geologie, v.19, p.23-35. Clain E. and Haake R., 2006, Mineralien-Welt, 17(5), p.52-64 (in German). Damian G. et al., 1996, Studia Universitatis Babes-Bolyai, Geologia 1-2, p.201-214.
Editura Academiei Romane, p.132. Franchini Marta B. et al., Economic Geology, 2002, v.97, no.5, p.1119-1126. Ilinca Gh. et al., 2006, Mineralogica-Petrographica, Abstract Series 5, p.47, Szeghed. Jude R., 1986, Metalogeneza asociata vulcanismului Neogen din NV Muntilor Oas, Krautner H.G. and Medesan A., 1969, Miner. and Petrol., v.13, no2, p.157-164. Larsen A.O. and Dahlgren S., 2002, Neues Jahrb Mineral-Monatshefte, v.4, p.169-181. Lelievre M., 1907, Journal des Mines, v.21, p.65-74. Momoi H., 1974, Min.Journ., v.7, p.359-373. Pesquera A. and Velasco F., 1986, Mineral. Mag., v. 50, no.358, p. 653-656. Piantone P. et al., 1999, Mineral Deposits: Processes to Processing, Stanley et al.(eds), v.1, p.79-82. Popescu M., 1973, Stud.Cerc.Geologie, v.18, nr.1, p.101-107. Scherer Fr., 1893, Studien am Arsenkiese, Z.K., v. 21. Serban V., 1997, Mineralium Deposita, v.32, no.5, p. 446-451.
65
NEW DATA CONCERNING FLUID INCLUSIONS AND CATHODOLUMINISCENCE PETROGRAPHY OF SOME QUARTZ
SAMPLES FROM ROSIA MONTANA EPITHERMAL DEPOSIT, METALIFERI MOUNTAINS, ROMANIA
Elena Luisa IATAN University of Bucharest, Faculty of Geology and Geophysics ([email protected])
The epithermal Au-Ag deposit of Rosia Montana is located in the historical mining
district known as “Golden Quadrilateral”, within the Metaliferi Mountains, in western Romania.
Rosia Montana is a breccia-hosted epithermal system, associated with strong phreatomagmatic
activity related to the shallow emplacement of the Rosia Montana dacite. The hydrothermal
alterations are extremely well developed. The mineralization consists of an epithermal
intermediate-sulfidation assemblage (quartz, adularia, carbonates, pyrite, sphalerite, galena,
chalcopyrite, tennantite-tetrahedrite, tellurides and native gold) and occurs in stockworks, veins
and disseminations within the dacite, different type of breccias and epiclastic and sedimentary
rocks.
A reconnaissance study of primary fluid inclusions from the hydrothermal prismatic
quartz and magmatic quartz phenocrysts was carried out to asses the spatial and temporal
evolution of the ore forming fluids.
Based on phase proportions at room temperature and the homogenization behavior, three
major types of two-phase (liquid and vapor) fluid inclusions have been identified in the
hydrothermal quartz in breccias from Carnic and Cetate Hills, as follows:
Type I fluid inclusions is liquid rich and homogenize by disappearance of the vapor
phase. The measured homogenization temperature (Th), range widely between 234°C-379°C
(Fig.1);
Fig. 1: Frequency histogram showing microthermometric measurements of type I fluid inclusions from hydrothermal quartz.
66
Type II fluid inclusions is vapor rich which homogenize also by vapor disappearance
showing two distinct populations, first between 259°C-277°C and the second between 401°C-
443°C (Fig.2);
Fig. 2: Frequency histogram showing microthermometric measurements of type II fluid inclusions from hydrothermal quartz.
Type III fluid inclusions which are vapor rich and homogenize by expansion of the vapor
faze at temperatures between 523°C-535°C (Fig.3).
Fig. 3: Frequency histogram showing microthermometric measurements of type III fluid inclusions from hydrothermal quartz.
The magmatic quartz phenocrysts from the Rosia Montana dacite contain inclusions of
minerals, melt and fluids. Microthermometric measurements of fluid inclusions, revealed two
phase fluid inclusions which are vapor rich and show a well-defined bimodal distribution of Th
with values between 458°C-493°C and 542°C-549°C (Fig.4).
67
Fig. 4: Frequency histogram showing microthermometric measurements of fluid inclusions from the magmatic quartz phenocrysts.
All the melt and mineral inclusions are arranged along growth surfaces of the quartz
crystal (Fig.5A, B) and they have Th >6000C. The mineral inclusions found in the magmatic
quartz samples are represented by zircon crystals (Fig.5C), apatite (Fig.5D) and some
unidentified green long crystals (Fig.5E).
Fig. 5: The melt and mineral inclusions found in the magmatic quartz samples: A. the distribution along the growth surface of the melt inclusions in the quartz phenocrysts; B. melt inclusion; C. zircon
crystal; D. apatite crystal; E. unidentified green long crystals.
The cathodoluminiscence (CL) petrography revealed three different generations of
hydrothermal prismatic quartz. The first generation of quartz is euhedral and appears dark
luminescent with no internal zonation (Fig.6 A,B). The second generation is also euhedral,
shows internal zonation with light grey-dark grey luminescence colors (Fig.6 A,C,D). The third
generation of quartz is anhedral and shows very weak dark grey luminescence (Fig.6 A,C).
68
Fig. 6: Different generations of hydrothermal quartz revealed by the CL petrography study: A. the quartz vein studied; B. the first generation of quartz; C. the second and the third generation of quartz
pointed; D. a close up view of the second generation of quartz, showing the internal luminescent zonation; 1st-first generation; 2nd-second generation; 3rd-third generation.
The magmatic quartz crystals show a weak luminescence. The melt inclusions trapped in
the quartz phenocryts are light luminescent and shows a concentric pattern. They are trapped
along the growth zones of the crystal (Fig.7).
A B
Fig. 7: CL response of the magmatic quartz and the melt inclusions: A. light luminescent melt inclusions arranged along the growth surface of the crystal; B. zonated light luminescent melt inclusion
The CL response might be related with composition changes of the quartz-forming fluids
(temperature or pH changes and variability in the trace elements content during mineral
formation.
69
GENESIS OF BRUCITE DEPOSITS IN THE APUSENI MTS. (ROMANIA): PT-CONSTRAINTS
Corina IONESCU 1,2, Volker HOECK 2,1 1Department of Geology, Babes-Bolyai University, 1 Kogalniceanu Str., RO-40084 Cluj-Napoca, Romania. [email protected]; 2Geography-Geology Department, Salzburg University, 34
Hellbrunner str., A-5020 Salzburg, Austria. [email protected].
Various hornfelses, skarns, and hydrated metasomatic rocks formed at the contact between
Mesozoic sedimentary rocks and two large Late Cretaceous-Early Paleogene granodioritic intrusives
(banatites) in the Apuseni Mts. (NW Romania). Among these, large brucite-bearing zones occur in
the Anisian calcitic-dolomitic marbles forming two main deposits: Budureasa in the north and
Pietroasa in the south. The irregular, sometimes lens-shaped brucite-bearing zones range from
several meters up to tens of meters in width and from tens to hundreds of meters in length. The bulk
chemical analyses of the brucite-bearing dolomitic limestones point to an inhomogeneous
distribution of brucite, ranging from brucite-rich (up to 40%) to brucite-poor domains (less than 5%
brucite).
Brucite occurs mainly as small thin lamellas, grouped in three types of clusters: a) small,
isometric clusters, rarely containing relics of periclase; b) large, irregular-shaped clusters, often
containing carbonate relics; c) oval-shaped clusters, with brucite associated with forsterite relics ±
antigorite. Microprobe investigations show 86.05-86.51% of MgO in brucite, and the presence of the
same mixture of calcite + dolomite grains inside the brucite cluster as in the surrounding carbonate
mass.
The formation of brucite reveal a model of heating and cooling sequences under an assumed
pressure of 0.1 GPa for the contact metamorphism, inferred from the field relations. The brucite-
bearing assemblages can be described in the system: CaO-MgO-SiO2–H2O-CO2 and the following
minerals are considered: calcite-dolomite-periclase-brucite-forsterite-antigorite. The phase diagrams
show that the stability field of brucite is restricted to the very low XCO2 in a wide range of
temperatures. The upper temperature stability limit of brucite is near 600-610oC, according to a
prograde reaction, which generated periclase: dolomite periclase + calcite + CO2. It was followed
by a retrograde reaction, which generated brucite by the decomposition of periclase: periclase + H2O
brucite. The direct decomposition of dolomite into brucite and calcite can take place over a wide
range of temperatures, from 600 down to ~350oC. Lower temperatures, close to 400oC, can be
estimated from the decomposition of forsterite into brucite and antigorite.
70
VITROPHYRIC FACIES OF THE MAGMATIC ROCKS EXEMPLIFIED BY SOME NEOGENE VOLCANITES OF EAST-CARPATHIANS ARC
Radu JUDE
University of Bucharest, Faculty of Geology and Geophysics, Mineralogy Department, 1 N. Balcescu Bulevard, Bucharest
The vitrophyric varieties of magmatic rocks have a wide spread within the Neogene volcanic products of internal part of the Carpathian Arc. They may be found as massive outcrops of hyalovolcanites and (or) as fragments of pumices or scorias and shards of glass within volcanoclastic deposits.
The vitrophyric facies of the volcanic rocks are significant from volcanological and petrological point of view, as well as for sources of industrial raw material (perlites, bentonites, zeolitised tuffs, etc.), even as building stones.
Panto (1969) distinguished, on the Hungarian territory, a volcanism related to “the Mantle Dome” in the inner side of the Pannonian Basin that generated important volumes of products – most of ignimbritic feature – generally of rhyolitic and dacitic composition and, on the other hand, a dominantly andesitic one (andesites, dacites, rhyolites) in the Northern part: the Cserhart, Matra, Bück and Tokaj massifs; farther, to the North the Neogene volcanites continue to Preshov, Eperiesh, Kremnitz and Shemnitz massifs in Slovakia and to N.E., in Bregovo and Vihorlat areas in the Transcarpathian Ukraine and in Oaş-Gutâi Mts. on the Romanian territory.
Recently investigations point out that the subduction tectonism and related volcanism of the Carpathian Arc evolved in connexion with the “Miocene diapiric uprise of the asthenospheric mantle of Pannonian Basin, with a back-arc role (Kovač et al., 2002).
It is known that the vitrophyric facies is more frequent and characteristic to the felsic-silicic volcanites than those of basaltic compositions. The refringence of the volcanic glass “N” varies directly (systematically) with the content of SiO2 in the analyzed samples: a rapid mode of estimation of the nature of rock. But the refringence is modified by the degree of hydration of the material that may be discerned in this section; the perlitic variety has a lower refractive index than the obsidian one.
The vitreous state is explained as a “sub solidus”, metastable kind of rocks; he alters and crystallizes in geological time. Some variable as: viscosity versus fluidity of the silicatic melts, composition of the lavas, a.s.o., have an essential role in the mechanism of the volcanic phenomena. Dissolved water has a notable effect to render magma less polymerized. These variables, inclusive the content of volatiles (CO2, Cl, F, B, P) and alkaline substances make explainable the great diversity of the textural features of the vitrophyric volcanic rocks (Fig.1).
Oaş-Gutâi volcanic zone. At the NE border of the Pannonian Basin, on Romanian territory, the succession of the
Neogene volcanites begin with a rhyolitic – dominant of ignimbritic facies of Badenian age (15.6 ± 0.2 M.a.) which occur beneath Sarmatian pyroxenic andesite in the Ilba, Nistru and Băiţa Valleys, to western part of the Gutâi Mts. This is an equivalent term of the Low-Badenian tuff named “Dej Tuff
71
complex” (Complexul tufului de Dej) with a regional spread in the Transylvanian Basin (Giuşcă et al. 1973; Szakács, 2001; Fullop, 2002 – PhD Thesis, Bucharest University).
Fig.1. Relationship between viscosity and temperature for the main lava types. From Murate T. and M. Birney A.R., 1973, in Francis P. (1993), p.107-108.
Generally, the main Neogene volcanism of Oaş
and Gutâi Mts. may be characterized by a recurrence of three or many episodes of pyroxene andesites and /or basaltic andesites during 13.4 – 7 M.a (Kovacs et al., 1988) interchanged by sequences of amphibole andesites, qz-andesites and dacites, with related subvolcanic intrusions.
The “Şindileu dacite” (Rădulescu, 1958) from Nistrului Valley has a pyroxenic aspect – massive, dark-grey in a small quarry, whereas on the adjacent effluents the outcrops exhibit an eutaxitic texture, with vitrophyric compact bands and vesiculated ones.
In thin sections the phenocrysts of plagioclase (25–55 % An.) subordinate hyperstene and, occasionally, quartz are incorporated into glassy groundmass (Rădulescu, 1958, p.171). The lava flow covers the Seini-Sarmatian pyroxenic andesites. Plot of the chemical analyze in the total alkali-silica diagram of Le Bas et al. (1986) reveal the qz-andesite nature of the rock (Fig.2).
The Oraşu Nou petrographic entity. There is an extrusive dome of hyalovolcanites southwards of the Oaş segment of the Neogene volcanites, at junction with the Gutâi unit (10 km of Seini). The volcanic structure, approx. 20 km2 in extensions, traverses and covers Sarmatian mollasic deposits. It consists of massive and vesiculated felsic rocks with a marked flow foliation and pyroclastic material. The volcanoclastic products more vesiculated – pumiceous – here and here, occur as interbanded with vitrophyric lavas. These petrographic mixtures were used (proved) by Barlea (1969) to postulate the ignimbritic feature of the Oraşu Nou volcanites. In thin sections the phenocrysts of plagioclase (22–25 to 55 % An), some solitary quartz and Fe and Ti oxides are incorporated in a glassy groundmass. The grains of quartz, with a dispersed extinction seem to be a “restite” (xenocryst) mineral. Spherulitic concretions of alkaline feldspars and lithophyses of trydimite may be seen, also, in thin sections. Pyroxene andesite, as enclaves in lava flows of rhyodacite or as clasts in piroclastic matter was reported by Bârlea (1969). The mean value of the refractive index of the perlitic glass, N = 1.503, correspond to 68% SiO2, that denote a dacitic composition. The chemical data, published by Bârlea (1969) reveal a dacitic composition of the fresh perlitic samples, close to the rhyolitic domain, whereas the vesiculated samples, a rhyolitic composition (Fig.3).
On the whole, the felsic rocks from Oraşu Nou may be seen as a rhyodacitic variety of
volcanites. New radiometric data point out 11 M.a for the felsic rock of the Oraşu Nou (Kovacs et
al., 1988) a similar age with the Ilba pyroxene andesite.
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Fig. 2. Plots of some Neogene vitrophyric volcanites in the total alkali-silica diagram of Le Bas et al.
(1986). 1 – perlitised rhyodacite of Orasu Nou; 2 – tised and breccified rhyodacite of Orasu Nou;
vitrophyric hyperstenic “andesites” of Tamaseni and Turt (Oas); 4 – hyalodacite of Batarci (Oas); 5 –
“dacite” of Sindileu (Gutai Mts.); 6 – felsic rock with lapilli-pumiceous tuffs, nearly of Sf. Ana crater,
Southern edge of The Harghita Mts. (Radulescu et al. (1981).
perli 3 –
arlea (1969).
Fig. 3. Geologic sketch of the rhyodacitic volcanic structure of Orasu Nou, with occurrences of perlitised and bentonitised vitrophyric rocks. Simplified and modified from B1 - Quaternary sediments; 2 - vitrophyric dacite; 3 - pyroclastites; 4 – Sarmatian sedimentary deposits; 5 – perlitized rhyodacite; 6 – occurrences of bentonites; 7 – fault; 8 – quarry.
The perlitization, a secondary-post volcanic process involving the massive and brecciated rhyodacitic rocks to the borders of the Orasu Nou structure (Mujdeni quarry, Mediaş–Vii, Dealu Negru) seem to be produced, especially, by hot springs and (or) hydrothermally agents (Jude, 2006). On the other hand, the argillitic alteration with smectic minerals (the bentonitic rock) follows the perlitization of the rhyodacitic
rock. Far to the North, in the Oaş county, the vitrophyric Neogene volcanites occur as lapillic pumices within the Calinesti dacitic tuffs and as massive hyalodacites and hyaloandesites at Coca-Călineşti, Bătarci and Tămăşeni- Turţ. As lava flow and breccias these vitrophyric volcanites occupy the periphery of the volcanic edifices – frequently as extrusive domes. The Pannonian hyalodacite of Bătarci, with an obsidian aspect and some perlitized zones, consist of phenocrysts of plagioclase (40–45 % An; 55–60 % An) and hypersthene (scarce fragments of green-bluish amphibole) in a glassy groundmass with a fluidale texture; as to Oraşu Nou, the crystals of quartz are lacking. The silica mineral phase is virtually present into glassy groundmass;
73
apatite, Fe and Ti oxides occur as accessory minerals. In thin sections may be seen spherulitic concretions of fibrous alkaline feldspars ± cristobalite and litophyses of trydimite (Jude 1971, 1977). The refringence of the natural glass N = 1.505 mark a content of 70–72 % SiO2 (Jude, 1971). The chemical analyzes relieve 61.23 – 64.92 % SiO2; 1.15 – 3.16 Na2O and 1.19: 3.0 to 5.49 % K2O; the content of H2O (>105oC) of 2.98 to 6.83 %. The laboratory tests mark an expanding temperature of approx. 1275oC. The hypersthenic hyaloandesite of Chicera-Ursoi (eastern of Turţ) and Hămlieţi-Vârticel, adjacent to the Piatra Cerbului extrusive dome (near Tămăşeni and Bătarci localities) have a notable flow banded texture; the vitreous-compact bands alternate with vesiculated ones. The microscopic studies reveal that the phenocrysts of plagioclase (55–60 % An) and hypersthene, subordinate brown hornblende (at Ursoi-Turţ) and scarce augite (at Tămăşeni) are incorporated into a glassy groundmass, with some microlites of plagioclase and Fe+Ti oxides and apatite, as accessory minerals. The lithophyses of trydimite are present especially in the areas of volcanic center. The refringence of the natural glass for the samples of Chicera- Turţ, N = 1.509 denote a content of 68 % SiO2, whereas the refringence of the pearls of fused rock, N = 1.517 and 1.515, mark a content of 67 respectively 65 % SiO2. The refringence of the pearls of fused rock from Tamaseni, N = 1.518; 1.522 and 1.527 correspond to 65; 62 resp. 60 % SiO2. The plots of chemical data in the total alkali-silica diagram of Le Bas et al. (1986) reveal the qz-andesite to trachy-andesite character of the analyzed samples. In the Transcarpathian Ukraine the interesting vytrophyric rocks of dacitic and rhyolitic composition belong to the Badenian and Sarmatian volcanism. At Beregovo, between Uj and Latoritza river there is an important deposit of perlite. Other occurrences are mapped to NW, at Vishnitza, belonging to the Vihorlat-Gutin volcanic chain. In the extrusive cupola Hertzovsk, the volcanic glass has a marekanit aspect. The perlitized rhyolites and andesites are characterized by a content of 2.5 to 3.5 % H2O (Soloninko, 1969). On the Hungarian territory the Neogene vitrophyric volcanites have an exceptional widespread as volcanoclastic products (tuffs and ignimbrites) as well as massive obsidian, frequently in a perlitized stage. In the Tokaj Mts, there are approx. 20 perlitic deposits, Palhaza and Telkibania are known as the principal extraction areas (Gyarmati, 1984). Some discussions.
Geochemical investigations published by Danilovics (1978) point out that the Miocene acid volcanic rocks of the Ukrainian Carpathians are characterized by low values of Y and Rb trace elements and by very low contents of radioactive elements as U, Th, Pb, characteristic to the calco-alkaline-tholeiitic series of magmatites. The 87Sr/86Sr ratio of 0.705 – 0.707 for the felsic rocks of Ukrainian Transcarpathians, respectively 0.702 – 0.706 for the Tokaj volcanites (Hungary) reveal “the undercrustal, slightly differentiated sources of magmas” (Danilovich, 1979), properly to the island arc type of magmatites. Similar data of 87Sr/86Sr ratio were published by Seghedi (1995) for the Oaş Neogene volcanites.
New geochemical studies on zircon and biotite crystals and on volcanic glass samples of pumices from Badenian ignimbrites of the Bukkalya (Hungary) were performed by Lucacs and Harangi (2002). They reveal the important role of the mantelic magmas for the origin of the felsic (rhyolitic) lavas. The bimodal character of the zircon crystals morphology and the trace elements
74
composition of the pumiceous glass point out a mingling process of two distinctly rhyolitic magmas in the magmatic chambers, with a possible assimilation of crustal matter.
Our previous investigations emphasized the calc-alkaline nature of the Neogene volcanites from the NW-ern part of the Oaş region, with some tholeiitic affinities of the pyroxene andesites and amphibole andesites (Jude, 1977, p.154).
The present paper points out that the vitrophyric volcanites of Bătarci, Tămăeni and Turţ and possible the vitrophyric rhyodacite of Oraşu Nou as well as of Şindileu qz-andesite belong to the Pannonian hypersthenic andesites.
The geologic mapping often emphasize that the hyperstenic andesites succeed the common two pyroxene-andesites. This is proved for the Pannonian pyroxenic andesites from Tarna Mare, Bătarci, Tur and Cămârzana to NW part of the Oaş Mts. (Jude, 1977). Thus features may be found, also, to the Ilba, Mara and Igni pyroxene andesites of Gutâi Mts.
As concerns the hypersthenic volcanites, it is accepted that the assimilation of meta-aluminous crustal matter by the mafic melts, augment the rate (proportion) of orthorhombic pyroxene on the expense of the monoclinic (calcic) pyroxene, as well as the rise of the anorthitic component of the plagioclase. The reaction commented by Deer et al. (1969) ac. to Read (1935) has the following expression:
Ca (MgFe) Si2O6 + Al2SiO5 → (MgFe) SiO3 + CaAlSi2O8 The vitrophyric varieties of hypersthenic volcanites resulted, possible, by the segregation of a felsic fraction of magmatic melt enriched in volatile components. In this context it should be mentioned that the phenocrysts of plagioclase, as well as those of hypersthene exhibit a marked corrosions by the glassy groundmass. This may suggest some chemical disequilibrium between the primary – magmatic minerals and the “pyromagma” enriched in gases (Rittmann, 1963, p.258) prior to the volcanic phenomena. It is noteworthy to mention the chemical similarities between the Batarci hyalodacite and the dacitic (microgranodiorite porphyry) of Viezuri subvolcanic intrusion of Tarna Mare-Oaş- Gutâi, with hydrothermal mineralizations (Jude, 1986). Selected references
Bârlea V. (1969) – Ignimbritele de la Oraşu Nou (jud. Satu Mare) – St. si cerc. de geol. geofiz. geogr., Seria Geologie, t.14, nr.1, p.83-96, Ed. Academiei R.S.Romania.
Danilovics Ludmila (1978) – Geochemistry of trace elements in acid volcanic rocks of the Ukrainian Carpathians, Geologicky Sbornik – Geologika Carpathica, 29, 2, Bratislava, Nov.1978.
Francis P. (1993) – VOLCANOES, A Planetary Perspective, Charendon Press, 1993. Giuşcă D., Borcoş M., Lang B., Stan N. (1973) – Neogene Volcanism and Metallogenesis in the
Gutâi Mountains, Guide to Excursion, 1 AB, Symp. Volcanism and Metallog., Bucureşti, 1973. Gyarmaty P. (1984) – The perlites of the Tokaj Mountains, Magmatism and Associated
Metallogenesis during Molasses formation, Ed. Acad.R.S. Romania, p. 93-98. Jude R. (1971) – Asupra unor vulcanite sticloase din nord-vestul Muntilor Oaşului, St. cerc. geol.
geofiz. geogr. Geologie, t 16, nr.2, p.377-386, Ed.Academiei R.S. Romania. Jude R. (1977) – Geologia şi Petrologia vulcanitelor neogene din nord-vestul zonei eruptive a
Muntilor Oaş (Regiunea Tarna Mare –Turţ), St. tehn.econ. seria A, nr. 11, 1977, Institutul de Geologie si Geofizica, p.111-174.
75
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Jude R. (2006) – Introducere în Geologia Zacamintelor Nemetalifere, Ed. Universitatii din Bucuresti. Kovacs M., Edelstein O., Gabor (1998) – Neogene Magmatism and Metallogeny in the Oaş-Gutâi-
Tibles Mts: A new approach Based on Radiometric Dating – Rom. Journal of Mineral Deposits, Vol.78, p.35-46, Inst.Geol.Rom.
Kováč M., Lexa I., Konecny V and. Sefara J. (2002) – Geodynamic Evolution of the Carpathian – Panonian Region During the Neogene, Proceeding of the XVII Congress of Carpathian – Balkan Geol. Assoc., Bratislava.
Lukacs R and Harangi (2002) – Petrogenesis of the Miocene silicic magmas in the Panonian Basin – A case study in the Eastern Bükkaljan Valc. Field, Nothern Hungary – Proceeding of the XVII Congress of Carpathian – Balkan Geol. Assoc., Bratislava, p. 13-14.
Ponto G. (1969) – Geology of Northern Hungary. Carpathian–Balkan Geol. Assoc., IXth Congress, Budapest.
Rădulescu D. (1958) – Studiul petrografic al formaţiunlor eruptive din regiunea Şeini – Ilba-Nistru (Baia Mare) – An. Comitetului Geologic, Vol. XXXI, p. 151-294.
Rittmann A. (1963) – Les volcans et leur Activité, Masson et Cie Éditeurs. Soloninko I.S. (1969) – Vulkaniceskie Vodosoderjascie stekla severo-zapadnoi ciasti Vihorlat-
Gutinskoi vulcaniceskoi gryada Zakarpatia, In vol.Zakon, formirovania vulk.-stekla, Ed. Nauka, Moskva, p. 59-62.
THE KLIWA SANDSTONE FORMATION FROM THE AREA BETWEEN SUCEAVA AND MOLDOVA VALLEYS (EASTERN CARPATHIANS).
ECONOMIC CONSIDERATIONS
Doru-Toader JURAVLE 1, Florinel Fănică FLOREA 2, Delia Anne-Marie ANDRONE 1, Laurenţiu BOGATU 3
1Faculty of Geography and Geology, Univ.”Al. I. Cuza” Iaşi; 2S.C. “Geomold” S.A. Câmpulung Moldovenesc; 3National Agency for Mineral Resources Bucureşti.
INTRODUCTION
In a highly technologized world, with fast high-standards developing building industries, the
raw materials issue is necessarily imposed, from the trivial mortar aggregates, to the classy
composite materials. In this context, the quartz sands resources appear to be more and more
restrictive, both on world and national level. Observing the map of the sand resources occurring in
Romania [15], it may be inferred that by the time of the mapping 14 deposits were in operation
(excepting the ballast-producing areas), as follows: 6 within the formations belonging to the
Transylvanian Basin, 2 in the Pannonian Basin, 2 in the NE of the Moldavian Platform, 2 in the
Southern Carpathians, 1 in the turning area of the Eastern Carpathians and 1 in the Southern
Dobrogea Platform. Regarding the exploited volume versus the market control, the same distribution
may be considered, as the BEGA GRUP holding possesses up to 49% of the quartz market in
Romania [19]. As for the research field, it is prevailingly situated in the proximity of the exploitation
areas, as the investments regarding the new favourably prognosed areas were abandoned. In this
situation it seems only justified drawing the attention upon a quartz sand resource of great future
potential, namely the Kliwa Sandstone Formation situated between Suceava and Moldova valleys.
GEOLOGICAL SETTING
The proposed area belongs from a physico-geographical point of view to Obcina Mare of
the northernmost Eastern Carpathians and from a geological point of view to the Paleogene flysch,
corresponding to the Moldavidic Tarcău and Vrancea Nappes. The geology of the region is presented
in detail in certain monographic works [1, 3, 8, 10, 11, 12] and may be concisely chrono-
stratigraphically presented as follows.
During the Oligocene, the differentiated sedimentation within the Vrancea and Tarcău
domains determined the accumulation of euxinic deposits corresponding to the Kliwa Lithofacies (in
the east), Fusaru Lithofacies (in the west) and Moldoviţa Lithofacies – partly covering the Eocene
deposits [5, 7, 12, 13, 14]. The lithological differences lie within the much more bituminuous
character of the pelitic formations belonging to the eastern Kliwa Lithofacies, as compared to the
western Fusaru Lithofacies, as well as the westwards increase of the arenitic fraction and the demise
77
of the green schist elements. The region has a complicated tectonic history, as on the eastern rim the
Vrancea Nappe deposits are outcropping within the tectonic semi-windows Gura-Putnei and Humor
as well as within the tectonic wedges Arşiţa and Voivodeasa, whereas to the west the Tarcău Nappe
deposits are present. This latter nappe has itself a complicated structure, being affected by digitations
and faulted overturned folds, which makes difficult to follow the observed formations both in surface
and in depth. Westwards, the faulted overturned folds are replaced by large synclinal and anticlinal
folds, which are consistent with the mechanical behaviour of the predominant arenitic formations
(fig. 1).
THE KLIWA SANDSTONE FORMATION. This unit has an intermediate or an upper
place within the Oligocene lithostratigraphic succession, occupying the upper part of the normal limb
of the faulted overturned folds from the east side and the axial part of the synclinal folds in the west
side. The formation is developed within the Kliwa and the Moldoviţa Lithofacies, whilst within the
western Fusaru Lithofacies it is replaced by massive micaceous sandstones having sometimes a
calcareous cement (the Fusaru Sandstone).
Lithostratigraphycally, the Kliwa Sandstone Formation covers conformably the Lower
Dysodile Formation and is overlain by the Upper Dysodile and Menilite Formation within the
Vrancea domain and within the Moldoviţa Lithofacies of the Tarcău Lithofacies. An exception is the
eastern part of the Tarcău domain, corresponding to the Kliwa Lithofacies, where this formation
concludes the Oligocene series. The unit thickness ranges between 70-80 m in the Suceava Valley
and 400 m in Moldova Valley.
The bedding is characterized by the predominance of the Kliwa Sandstone beds, 10-20 cm
to 50-80 cm thick, occasionally passing in 4-5 m thick banks. Within the sandstones there are
dysodilic and menilitic intercalations representing 20-40% of the stratigraphic succession.
Southwards, in the Humor Basin, the Kliwa Sandstone beds are sometimes entirely replaced by green
schist elements conglomerates, forerunning the eastermost Pietricica Lithofacies [9].
Petrographically, the Kliwa Sandstone is considered a quartz-arenite having over 80%
arenitic fraction, with a massive structure in thick beds, or presenting a plane-parallel lamination in
decimetric beds.
The Kliwa Sandstone between Suceava and Moldova valleys has been studied as a raw
material for the construction and composite materials industries [1, 3, 4, 9], resulting a chemical-
mineralogical composition and both the granulometric distribution statistical parameters and the
morphometrical parameters with very close or identic values as those of the present-day exploited
sand deposits [2, 6, 15, 20]. According to the effective quality norm, the quartz sands obtained from
the Kliwa Sandstone may be used for the fabrication of crystal glass-sheets, semi-polished semi-
crystal glass-sheets, laminated glass-sheets, white and coloured glass receptacles, glass fibres,
foundry sands [4, 6, 9, 16-21].
78
CONCLUSIONS
As a consequence of mapping revisions operated in the investigated region [12], a series of
areas were selected, where we consider that the geomorphologic and geologic conditions are fulfilled
for the surface mining of the Kliwa sandstone on purpose of using it as quartz sand. In these areas
further investigation of the deposits is necessary in geological, chemical-mineralogical,
granulommetrical and morphometrical directions, in order to create a database for industrial reserve
calculations (fig.1).
79
80
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vol. XXXVIII. JURAVLE D.-T. (2007) – Geologia regiunii dintre Valea Sucevei şi Valea Putnei (Carpaţii Orientali). Casa Editorială Demiurg,
Iaşi, ISBN 978-973-7603-78-4. Juravle D-T., Florea F. F., Bogatu L.(2008) – The importance of calcareous nannoplankton in establishing lithostratigraphic
landmarks in The Eocene column of Tarcău Nappe in The Suceava River Basin (Obcina Mare). Acta Paleontologica Romaniae, Vol. VI, Iaşi, Editori: Olaru L., Ţabără D., Editura Universităţii „AL. I. Cuza” Iaşi
MICU M. (1981) - Nouvelles données sur la stratigraphie et la tectonique du flysch externe du bassin de la Sucevita. D.S. Inst Geol. Geof., vol. LXIV, Bucureşti.
MICU M., CONSTANTIN P. (1993) – Contribuţii la geologia Semiferestrei Gura Putnei. Rom. Journ. Stratigraphy, vol. 75, Inst. geol. geof., Bucureşti.
POPA M., ANASTASIU N., ROBAN R. (2005) - Raport de Cercetare: Resurse minerale asociate formaţiunilor sedimentare din România – reconsiderări sedimentologice şi petrografice şi reevaluarea potenţialului lor economic. Revista de Politica Ştiinţei şi Scientometrie, nr. special, 2005, ISSN 1582-1218, http://frf.cncsis.ro/documente/360A443.doc.
*** http://www.begaminerale.ro/aghiresu/ *** http://www.begaminerale.ro/faget/ *** http://www.begaminerale.ro/orsova/ *** http://www.chimforex.ro/ *** http://www.sticloval.ro/index.html *** http://www.mindo.ro/
SOME GEOLOGICAL DATA USED FOR RATING OF THE STAGE OF PRESERVATION OF RUPESTRAL CHURCH “CORBII DE PIATRA”
Anca LUCA 1, Sorin BARZOI 2, Relu ROBAN 3
1, 2, 3 University of Bucharest, Faculty of Geology and Geophysics, Department of Mineralogy, Balcescu, No.1, 010041 Bucharest, Romania
1 [email protected], 2 [email protected], [email protected]
The “Corbii de Piatra” church is placed in relative hard sandstone outcrop on the left
side of the Doamnei River in the territory of the Corbi village, Argeş region. The geological
body in which the church is excavated is stratiform, with a slight deep of 5 degrees on south and
a medium thickness of roughly 15 – 20 m, made mostly from sandstone. The layer of sandstone
is a structural component of a stratified sedimentary complex of Oligocene age, either Rupelian
(Jipa, 1980, 1982, Bombiţă et al., 1980), or Chattian (Ryer, 1998). Above “the Corbi sandstone
are in stratigraphic continuity a centimetre layers of pelitic rocks, mostly bituminous, in
alternation with siltic and gypsum rocks, with rare sandstone insertions, age Upper Oligocene –
Miocene (Roban and Melinte, 2005).
The interior walls of the rupestral church have been covered with fresco (about XIV –
XVI century), strongly deteriorated in our days. The sandstone supporting the painting layer of
the church has a relative homogenous mineralogical composition (table nr. 1), and homogenous
structure. The binder of the sandstone represents only 3 – 10% from the volume of the rock.
Usually, the binder is a thin criptocristaline layer around the epiclastic granules and only very
rare as cement of pores, being a mixture of iron oxides and hydroxides with philosilicates from
the group of the clay minerals. This composition was determined by optic microscopy, X-rays
diffraction and chemical analyses (tables no. 2, 3 and 4).
The sandstone from the interior of the church has a weekly anisotropy given by the
preferential orientation of the micas in the plan of stratification, with approximately east-west
direction and a slight deep to south, with 5-10°.
The characteristics of the pores system of the sandstone is presented in table no. 5.
Thus the pores have a slight trend of flattening in the stratification plan and they have an
overcapillary size, which allows the circulation of liquid water. As a result, the sandstone has an
advanced degree of permeability and, thus, a large capacity of absorbing the water. The humidity
of the sandstone from the interior of the church is presented in table no. 6.
81
Table no. 1. The mineral composition of the granoclastes from 10 sample of sandstone resulting from the inside of
the “Corbii de Piatră” Church.
Number of the sample / Proportion (%) The mineral 2d 6 7d 9 10d 11d 12 13d 19d 22d 27 Quartz 37 47 43 52 49 55 51 54 60 48 46
Plagioclase feldspar
10 15 20 15 25 20 22 15 10 10 20
Potassium feldspar
18 15 12 15 5 8 15 10 10 15 15
Muscovite 8 4 10 4 5 5 2 6 2 5 6 Biotite 2 1 1 1 2 2 2 2 1 2 1
Chlorite - 0.1 0.5 0.5 0.1 0.5 0.5 - - 0.5 0.5 Clay
minerals 5 8 7 5 7 4 4 8 6 10 5
Amphibole - - - - - - - - - - - Pyroxene - - - - - - - - - - - Epidote - - 0.1 0.5 - - - - - - - Garnet 2 - 1 - - 1 0.5 - - - 0.5
Staurolite - - 0.5 - - 1 0.5 - - - 0.5 Kyanite - - - - - - - - - - - Zircone - - - - - - - - - - 0.1
Tourmaline - - - - - 0.1 0.5 - 0.1 0.5 - Apatite 1 0.1 - - - - - - - - -
Magnetite 3 4 1 3 3 2 1 1 3 1 2 Iron
hidroxides 1 2 2 2 2 2 2 2 1 0.5 1
Rutile - 0.1 - - - - 0.1 - - - - Carbonates - - - - - 0.1 - - - - -
Table no. 2. The X-rays diffraction analyses of the thin fraction of sandstone
The mineral The chemical formula d (A) Caolinite Al2Si2O5(OH)5 7.28; 4.38; 3.68; 2.56; 5.50; 2.39; 2.20; 1.99; 1.79; 1.66; 1.54
Illite KAl3Si3O10(OH)2 10; 5.03; 4.32; 3.63; 3.35; 3.10; 2.90; 2.60; 2.47; 2.39; 2.27; 2.14; 1.99; 1.72; 1.65; 1.51.
Quartz SiO2 4.26; 3.34; 2.45; 2.28; 2.23; 2.12; 1.98; 1.81; 1.67; 1.54 Biotite (trace) K(Fe, Mg)3AlSi3O10(OH)2 10.1; 4.39; 3.37; 3.06; 2.52; 2.45; 2.28; 2.00; 1.91; 1.75; 1.67, 1.54
Table no. 3. The chemical composition of the thin fraction from 4 samples of the sandstone from the
inside of the church
Table no. 4. The normative mineral phases from 4 samples of the thin fraction of the sandstone
Sample P1 P2 P3 P4
The mineral [% [% Sample (%)
P1 P2 P3 P4
SiO2 66.48 65.52 68.90 63.42 TiO2 0.62 0.80 0.59 0.84 Al2O3 16.21 15.43 12.91 13.95 MnO 0.04 0.02 0.04 0.06 Fe2O3 4.36 4.45 4.57 6.83 MgO 1.05 1.28 2.21 6.36 CaO 0.59 0.64 1.51 1.67 Na2O 2.07 2.11 3.29 2.95 K2O 2.47 2.51 2.26 2.80 P2O5 0.34 0.30 0.19 0.32 SO3 0.00 0.38 0.00 0.00
[% [%
Albite 24.68 25.35 37.88 26.02 Anorthite 4.55 4.48 10.05 8.63 Chlorite 7.41 8.91 5.65 24.31 Illite 41.08 42.68 17.90 17.29 Caolinite 9.87 6.24 0.00 0.00 Biotite 0.00 0.00 17.12 16.54 Quartz 11.01 10.89 10.25 5.89 Iron hydroxides
1.38 1.43 1.14 1.32
82
Shape of the pores Generally irregular, but with a slight tendency of flattening in the anisotropy sandstone
Dimension of the pores The same as magnitude order with the dimension of the granules from the sandstone, 0.1 – 0.8 mm
Mutual connection of the pores 25 – 65 %
Stage of cementation / filling of the pores (a) empty pores (50–70% from the system of pores); (b) partial filling on the walls (20–40%) (c) entirely filled (2–10%)
Porosity 5 – 15 %
Table no. 5. The characteristics of the pores system in the sandstone
Table no. 6. The humidity of the sandstone samples, from the inside walls of the “Corbii de Piatră” Church
No. sample
Weight of wet rock (g)
Weight of dry rock (g)
Humidity (%)
2 6.52 6.16 5.84
6 9.32 8.95 4.13
7 7.59 7.15 6.15
10 6.94 6.71 3.43
11 5.12 4.84 5.78
12 7.81 7.34 6.40
13 4.88 4.67 4.50
19 9.70 9.32 4.08
22 4.46 4.31 3.48
27 8.10 7.56 7.14
The humidity is not uniform, and it is
related with the properties of the rock
(mineralogical composition, petrographic texture
and porosity).
The entire pile of sedimentary rocks in
which the church is excavated, is fractured and
fissured. A set of planar cracks were found in the
interior, affecting the north wall of the church
where it is a high humidity. The presence of water
hire shows that the cracks system are probably the
main path through which water is infiltrating from
the outside in the church. The dominant way of
the infiltration is nearly from N to S. The analysis of the salts from the infiltrated water through
the ceiling of the church showed that the dominant phase is the gypsum, subordinately the
magnesium sulphates and the alkaline chloride.
The mineral crusts are developing on the interior walls of the church, both on the
sandstone and on the fresco, and is made of gypsum (70 – 90%), epsomite (10 – 15%), halite and
silvinite (0 – 5%).
Generally, the water infiltration trough the local system of cracks and pores, has two
important consequences: (1) the transport of the soluble salts from the upper layers to the interior
walls of the church; (2) maintaining an advanced humidity on the walls of the church, mainly at
the rock / fresco interface. The indirect most important consequences are: (a) the deposition of
salts efflorescence on the surface of the fresco; (b) the disintegration of the sandstone, especially
at the rock / fresco interface. These last processes are the most important inorganic ways led to
the degradation of the interior walls of the church, including the painting layer.
83
84
References
JIPA, D. (1980). Sedimentological features of the basal Paleogene in the Vâlsan Valley. In
Sandulescu et al.: Cretaceous and Tertiary molasses in the Eastern Carpathians and Getic
Depression. Guidebook fieldworks group 3.3. Institute of Geology and Geophysics
Bucharest, p. 17-31.
JIPA, D. (1982). Explanatory Notes to Lithotectonic Profile of the Getic Paleogene Deposits
(Southern Carpathians, Romania), Sedimentological Coment to Annex 13. Veroff.
Zentralinst. Phys. Erde AdW DDR, p. 137-146.
ROBAN, R. D., MELINTE, M. C. (2005). Paleogene Litho- and Biostratigraphy of the NE Getic
Depression (Romania), Acta Palaeontologica Romaniae v. 5, p. 423-439
RYER, M. (1998). Sequence stratigraphy and geologic evolution of the Paleogene and Lower
Miocene strata, eastern Getic Basin, Romania. PhD Thesis, University of Bucharest, 230 pp.
SALT EXPLOITATION AND TRANSPORT FROM THE
OCNA MUREŞ SALINE
Nicolae LUDUŞAN1, Levente DIMEN1 1“1 Decembrie 1918" University, Alba Iulia
In Transylvania, exploiting salt goes back to the Dacian-Roman period, in towns with old
traditions in the field, such as the exploitations from Turda, Ocna Mureş and Ocna Sibiului.
The town of Ocna Mureş, known since the oldest times, is located on the left bank of the Mureş
river, at 265 m altitude, being surrounded by the Banţa Hill, with steep slopes near Mureş on which
several fortified settlements have been built along the centuries. The documentary attestation of the
town appears in 1202, under the name of “the Vyuuar villa” (Doc. Rom. C., a I 21), being united with
the settlement of Uioara de Sus.
NNESSV
500
0
-2000
-1500
-1000
-500
1 2 3 4 5 6 7
Cisteiu Ocna Mureş
Mureş
Lunca Mureş Copand
Arieş
Viişoara
SynclineCisteiu-Unirea
AnticlineOcna Mure -Turda
SynclineFeldioara
AnticlineCopand-C l rai
SynclineGligoreti-Poiana
AnticlineH d reni-C.Turzii
The whole area is placed on a gigantic mass of salt, respectively a diapiric structure, that lies on
an area between the Banţa Hill and the bank of the Mureş river (fig.1). The upper side of the structure
pierces the upper formations in an area situated at less than 500 m from the civic centre of the town,
where the first galleries were dug and where the Dacians discovered salt 2000 years ago.
Before the area between the Carpathians was occupied by the Roman army, in the
neighbourhood of the town of Ocna Mureş, the Dacians created the “Marisiodava” location, mainly
inhabited by the miners who were exploiting the deposits situated dozens of metres below the ground.
During the Roman administration, the town was known under the name of “Salinae”, being one
of the most important exploitations of salt in Dacia. The miners, that used to be slaves and freed Roman
6-Eocene - Oligocene, 7- crystalline foundation (according to: Stoica, Gherasie, 1981)
Fig. 1. Geological section through the salt structure Ocna Mureş - Turda
1-Sarmatian, 2-Buglovian, 3-Higher Badenian, 4-Lower Badenian (the horizon of the salt), 5-Burdigalian - Helvetian,
81
slaves, were extracting salt from underground galleries, in rooms that were 15-30 meters long, 8 meters
wide and 15 meters deep. The special importance of salt for the Romans is emphasized in the history of
the words “salariu” and “solda” from the bag in which the Roman soldiers put the salt, which
constituted good payment for their services, called “salinarium-salarium.”
Salt exploitation continued in the Middle Ages as well, in the same rhythm and, apparently,
with the same technologies. According to some historians’ hypotheses, medieval exploitations, that
were more developed than the ancient ones, were opened near the Roman ones, using a part of the old
work.
A special role in developing salt exploitation was played by the Mureş river which, for a long
period of time, constituted an important way of communication and transport. The written and
unwritten proof show the fact that ever since ancient times and up to the modern period, rafting has
been practised. The transported materials varied, but most of the kept notes refer to the transport of
salt. The first writings referring to sailing on Mureş go back to the period of the Roman times. Thus, in
an inscription from Apulum, a “Collegium nautorum” is mentioned, an association of the shipmen on
Mureş, and a “genius nautorum” is represented on a bas-relief. These artefacts show the fact that
rafting, and probably with the help of small ships as well, played an important part during the Roman
administration in Dacia. After the Romans’ withdrawal, there were no more references on this topic
for a while, which did not mean that rafting was not practised anymore.
Starting with the nineteenth century, mentions of rafting on the Mureş river can be found in
different documents. Thus, the “Annales Fuldenses” mentioned that at the end of the ninth and the
beginning of the tenth century, salt was exported from Transylvania to Moldavia; there were even tax
collectors and guardians whose mission was to collect tax for the boats that were transporting this kind
of salt on the Mureş river. “Anonymus’s Chronicle” and “St. Gerard’s Legend” also mention the
existence of guardians and tax collectors in the early eleventh century, employed by king Achtum to
collect taxes from the raft men that were coming from Transylvania on the Mureş heading for the Tisza
river, for the Hungarian kingdom. A document from 1075, issued by the king Geza I, mentions for the
first time the salt tax collecting from Turda, located on the Arieş and Mureş rivers.
In the following centuries, references to salt transportation on the Mureş multiply. References
are also made to certain privileges or rights that came from exploiting, storing (in the so called “salt
rooms”) and transporting salt. Besides the notes from the official documents, references to the given
topic can also be found in the notes of foreign chroniclers or travellers who walked these lands. Thus,
Nicolaus Olahus (1493-1568) in “Hungaria”, chapter 19, wrote: the salt which is dug and cut in
Transylvania is usually transported by raft on the two rivers, Mureş and Someş up to the Tisza and
there it is distributed and given for sale in all Hungary. David Frolich (1595-1648), in “Medulla
Geograpihae Practicae”, chapter 10, also mentions that: in Transylvania there are three rivers that can
83
be sailed on: the Criş, the Mureş and the Olt.
But the most important story related to exploiting and transporting salt is due to Hans
Dernschwam “De Hradeczin” (1494-1568), Hans Alber’s cashier, Fugger’s Factory manager in Buda.
Sent by the houses of Fugger and Turzo, the managers of the salt mines exploitation, to evaluate the
state of the salt mines, he also refers in his report to the transport of salt on the Mureş river. Speaking
about the carriers, he wrote that they “… loaded the salt and carried it on to a village called Decea,
they took it to the bank of the river and unloaded it there… In Decea, a big storage room should be
built, in which salt could be deposited so that it cannot be stolen or ruined by rain. As salt often had to
stay there for a long time, until the river was flooded by the rains in the spring and the snow melted
down; that is why this storage room is necessary. Salt is not shipped abroad in autumn as waters do
rise. In Turda, rafts for transporting salt are built; there are big and small rafts, having the same shape
as the extremely large rafts. Then they are transported on the Arieş until they get to Decea, on the
Mureş river ... Those that have rafts and earn their living with their help are called ‘celeristi’… After
Easter, when the river’s waters begin to rise, the rafts are loaded in Decea, leave Transylvania and go
to the other areas”.
In the eighteenth century, more subsidiary or transit warehouses are mentioned, among which
the one from Mirăslău as well. References to this warehouse are also present in the notes about the
1784 rebellion, when, the baron Seeberg, from the warehouses of Mirăslău, enlisted the inhabitants of
Decea and the raft men of Mirăslău in the future border regiments.
For a long time after the Roman period, especially in the Middle Ages, the town of Partoş,
today a district of the city of Alba Iulia, played an important role in the transport of salt by rafts on the
Mureş river until the place where it flows into the Tisza, transport that dates back to the pre-Hungarian
period. Partoş is mentioned in the documents written in Latin letters under the name of “Portus,” from
which the name of Partoş derived or under different names such as : “villa Salis” (the salt village),
“Salzdorf” (the salt village), “Salgafen” (the salt harbour). In the time of the Habsburg domination, the
chronicles show that Partoş was the most important subsidiary for depositing and transit of the salt,
from where it was transported by raft and by the ferry pulled by horses to the great cities downstream
the mines and even up to Budapest. The raft men dealing with salt transportation were called ‘heiuşi’,
which many inhabitants of the Alba Iulia have as family names.
The transport of salt by raft on the Mureş river stopped in 1871, when the railroad Teiuş-
Războieni was put to use, which absorbed the whole salt transport.
The intensive exploitation of salt led in time to an instability of the ground, thus affecting the
area. The ceilings of the exploitation rooms fell. The first time the stability of the underground was
affected was in 1791, when the Roman and the medieval mines, that were situated under Ocna Mureş,
were flooded by the Mureş river. In the same year, the exploitations were resumed, new hall-shaped
galleries being opened, and Ocna Mureş became the most important salt exploitation in Transylvania of
the eighteenth-nineteenth centuries.
The water that came from floods dissolved in time the salt layer and in 1913, the first landslides
occurred. During World War II, the main street, that was actually the civic centre of the town, sank as
the ceiling of the medieval mines Ferdinand, Iosef and Stefania collapsed. A similar phenomenon was
registered in 1972, when the last houses on the mentioned street collapsed into the salty water,
buildings that had once hosted a pharmacy and a bookshop.
Despite all these inconveniences, the exploitation of the deposit in the mining system continued
until the late twentieth century. In 1952, the method of salt extracting using drills was introduced for
the first time in the world, through the salt pipes method, a procedure protecting the upper side of the
deposit and, at the same time, the stability of the ground.
The studies and the measurements that were systematically taken emphasize the fact that the
ground layer is not perfectly stabile and that the land on which the buildings were constructed has the
tendency to subside by 2 mm/year, but this does not mean that there is no immediate danger for the
town to sink. In the 1970’s, there were some infiltrations in the gallery walls, and breaking a wall let
the water get in and flood a gallery completely. Despite the fact that the water from the mines is deep
enough, the waters that flood the water table make the salt layer thinner, weakening the ground
strength. The solution for saving the town would be to build some drenching canals on the Banţa Hill in
order to avoid the water circulation into the water table and the flooded mines. Despite all these, every
time it rains heavily, the salt layer gets a little thinner and the resistance of the ceiling of the halls on
which Ocna Mureş was built decreases, the danger becoming greater by the year.
In order to avoid a ground collapse, the company Salina, which exploits the salt deposits, builds
clay backfills on the banks of the salted lakes in order to stop erosion. Nevertheless, in the case of
heavy rain or an earthquake similar to the one on October 3, 1880, that started in the Gâmbuţ-Ozd area,
with a seismic intensity of almost seven degrees, a good part of the town of Ocna Mureş could become
a lacustrian town in just a few minutes.
REFERENCE
Brana, V., Avramescu, C., Cãlugãru, D.: Substanţe minerale nemetalifere, Ed. Tehnicã, Bucureşti, 1986.
Jude, R.: Iuntroducere în geologia zăcămintelor nemetalifere, Ed. Univ. din Bucureşti, 2006.
Mutihac, V., Stratulat, M.I., Fechet, R.M.: Geologia României, E.D.P., Bucureşti, 2004.
Pauliuc, S.: Zăcăminte de combustibili minerali şi sare, Univ. Bucureşti, 1975.
Stoica C., Gherasie I. (1981) Sarea şi sărurile de potasiu şi magneziu din România, Ed. Tehnică, Bucureşti
Wollman, V.: Mineritul metalifer, extragerea sării şi carierele de piatrã din Dacia Romană, Cluj-Napoca, 1996.
85
GEOCHEMICAL CHARACTERISTICS AND THE EVOLUTION OF THE MINERALIZING FLUIDS WITHIN THE EASTERN RHODOPIAN
SEDIMENTARY ROCK-HOSTED LOW-SULPIDATION EPITHERMAL GOLD SYSTEMS, BULGARIA
István MÁRTON, Robert MORITZ
University of Geneva, Department of Mineralogy, rue des Maraichers, 1205-Geneva, Switzerland, [email protected].
Tertiary, sedimentary rock-hosted gold deposits with low-sulfidation characteristics have
been recently reported in the Eastern Rhodopes, Bulgaria (Marchev et al., 2004; Marinova, 2006;
Márton et al., submitted; Fig. 1). These newly discovered deposits are economically significant
and open up new mining-industrial and scientific interest in this part of the Tethyan Metallogenic
Belt. There is presently the potential for an open pit mine at the Ada Tepe deposit (Krumovgrad
area) with high grade ore (5.22 Mt @ 5.0 g/t Au and 3.0 g/t Ag), with a total of 835,000 ounces
of gold and 440,000 ounces of silver indicated by Balkan Mineral and Mining (Dundee Precious
Metals Inc., Report on Feasibility Study, 2006). Another prospect at Rosino has been developed
up to the feasibility level with a 15.8 Mt of ore, but at estimated lower gold grade (0.85 g/t;
Cambridge Mineral Resources Plc., Press Release, 2007). Gold deposits with similar
characteristics and hosted by sedimentary rocks are well known in western North America (e.g.,
detachment-hosted gold deposits, Carlin-type deposits, distal disseminated gold deposits; Cline
et al., 2005), where they constitute one of the largest gold endowment of the Earth (Frimmel,
2008). Some of the Eastern Rhodopian sedimentary rock-hosted gold prospects (especially Ada
Tepe and Kuklitza) show also many similarities with the widely distributed low-sulfidation type
epithermal gold deposits (or adularia-sericite type; Hedenquist et al., 2000), which emphasize the
significance and diversity of these mineralizations in this part of the Aegean region.
The factors controlling the formation of these sedimentary rock-hosted gold deposits
from the Eastern Rhodopes, Bulgaria, vary from lithosphere scale (regional tectonics; Fig. 1) to
deposit scale (structural framework, host-rock lithology; Fig. 2). The ore mineralogy and
alteration assemblages from the sedimentary rock-hosted gold prospects in the Eastern Rhodopes
reflect the temperature-pressure-time evolution of mineralizing fluids (Fig. 3). The alteration
characteristics, textural relationships and the typical ore parageneses prove that the distribution
and coincidence of feeder, reactive and permeable lithologies also favored gold transport and
precipitation over extended areas. Lithologies, such as marbles, marls and granitic rocks, had a
great pH-buffering capacity and lower ability for de-sulfidising a H2S-rich fluid, therefore they
89
provided an excellent environment to acid neutralization, which maintained a sulphide-rich fluid
at near-neutral pH conditions and optimized gold transport over extended areas.
Fig.1. Schematic geological outline of the Eastern Rhodopes showing the lithotectonic units, Eocene volcanic centers, the sedimentary rock-hosted gold districts (the rectangular areas), and other epithermal ore deposits
(triangles), modified after Marchev et al. (2004) and Bonev et al. (2006). Inset: plate tectonic configuration of the area around the Aegean and recent plate vectors based on Papazachos et al. (1998). The metamorphic domes are the (1)
Rhodope Massif, (2) Olympos-Peilon Region, (3) Cyclades-Archipelago, (4) Crete, (5) Menderes Massif and (6) Kazdag Massif
Based on geochemical and mineralogical constrains it is possible that gold may have been
deposited as a consequence of two main physical-chemical processes in the various prospects. The
abundant bladed quartz pseudomorphs replacing platy calcite suggest boiling in different
prospects, including at Ada Tepe and Kuklitsa. The chemical changes the fluid undergoes during
boiling include a raise in pH caused by the partitioning of volatiles preferentially into the steam
phase and an increase in concentration of non volatile constituents that remain in the liquid phase
90
as a result of the separation of steam. These factors promote supersaturation, which results in the
sudden precipitation of silica, along with metastable potassium-rich feldspar, sulfides and ore.
However, in cases of other prospects, such as Rosino and Surnak, boiling textures are scarce to
absent, and intense fluid-rock interaction may be responsible for gold mineralization. In such case
the deposition of gold was controlled by the cooling of sulphide-rich fluid, change in oxidation and
mass transfer accompanied by sulphidation of active iron.
Fig. 2. Typical cross section through the Krumovgrad area in the Eastern Rhodopes. At Ada Tepe the main gold ore body is located above the detachment fault in the sedimentary cover. The alteration (predominantly silicification) and gold mineralization are controlled by steep normal faults. In addition, a tabular ore body (called the “Wall”) lies directly
along the detachment. Modified after Bonev et al. (2006) and Marchev et al. (2004).
Fig. 3. Simplified paragenetic sequence of ore, gangue, and alteration minerals for the sedimentary rock-hosted gold prospects form the Eastern Rhodopes. A) Ore paragenesis associated with boiling assemblages. B) Ore paragenesis
associated with water/rock interaction, sulphidation and subsequent cooling.
The geochemical characteristics of the ore assemblages and the mass transfer studies show
that that the gold might be associated with the co-transport and co-deposition of other elements
during the formation of the studied sedimentary rock-hosted gold mineralizations. The
91
92
Rhodopes.
thermodynamic conditions of this co-precipitation can be modelled for the phase relationships in the
Fe-Au-As-Sb-Hg-Ag-S-O-H-Cl system (Fig. 4). These conditions plot within the stability fields of
the pyrite (FeS2; close to the pyrrhotite fields as this mineral was also observed in one case), native
gold (Au), arsenopyrite (FeAsS), stibnite (Sb2S3), and argentite (Ag2S). Because of low
concentration of Sb and Ag in the studied deposits they probably do not form separate phases, but are
incorporated in the composition of arsenic-rich pyrite and sulphosalts. Decline in temperature (at a
constant oxygen fugacity) leads to a reduction in solubility of all elements. Changes in oxidation
state, accompanied by H2S-loss during sulphidation of host rock iron, have the greatest effect on gold
and arsenic solubility. Finally, because changes in arsenic mineral stability and solubility are so
sensitive to the oxidation state of the system, arsenic minerals are likely an important indicator of
redox conditions during the formation of sedimentary rock-hosted gold deposits in the Eastern
F
from the Ea olid phase stability fields, long dashed lines show solubility contours where
the total sulphur concentration is 0.05 m, pH is 5.0, and pyrrhotite activity is equal to 0.5. A) Gold phase relations; B) Arsenic phase relations.
, 2005: SEG 100th
he
Marinova, I., 2006: Comptes-rendus de l'Académie Bulgare des Sciences, v. 59/9, p. 945-948.
ig. 4. Phase relationships in the Fe-Au-As-Sb-Ag-S-O-H-Cl system based on calculations by Bessinger and Apps(2005). The star show the conditions inferred for the main ore stages at the sedimentary rock-hosted gold deposits
stern Rhodopes, based on fluid inclusion and mineral paragenesis data. Solid lines show s show aqueous stability fields, and short dashed lines
References: Bessinger, B., Apps, J.A, 2005: Lawrence Berkeley National Laboratory. Paper LBNL-57395. Bonev, N., Burg, J.P., Ivanov, Z., 2006: International Journal of Earth Sciences. 95/2, 318-340. Cline, J.S., Hofstra, A.H., Muntean, J.L., Tosdal, R.M., Hickey, K.A.
Anniversary Volume, p. 451-484. Frimmel, H.E., 2008: Earth and Planetary Science Letters, v. 267, p. 45-55. Hedenquist, J.W., and Henley, R.W., 1985: Economic Geology, v. 80, p. 1640-1668. Marchev, P., Singer, B., Jelev, D., Hasson, H., Moritz, R., Bonev, N., 2004: Schweizerisc
Mineralogische und Petrographische Mitteilungen, 84/1-2, 59-78.
EVALUATION AND ZONING OF GROUND INSTABILITY RISK IN SALT MINING AREAS (OCNA DEJ CASE STUDY)
Cristian MARUNTEANU 1, Victor NICULESCU 1, Mihai MAFTEIU 1 1University of Bucarest, 6, Traian Vuia St., [email protected]
Introduction
The instability phenomena generated by salt mining provide in time strong economical and
social impact in the mining areas, sometimes having hazard potential: water infiltration in active or
abandoned mining works, landslides, geomechanical interaction between old and contemporary
works, underground or/and surface subsidence, sometimes with spectacular subsidence effects due to
sudden falling of the roofs. Large sinkholes formed at the surface determine afterwards their natural
or artificial backfilling or generate salt lakes. These phenomena affected both salt mining and the
environment and also human activities in the influence zones.
The Ocna-Dej salt deposit has a tabular shape with some variation in thickness. The salt
formation (middle Badenian) with a breccia at its upper limit lies between the Dej Tuff (lower
Badenian) and an upper Badenian sedimentary complex consisting of marls, clays, and thin
intercalations of tuffs. The first mining works for salt in the Ocna-Dej region date from the Dacian-
Roman period (100-200 a. C.), but the industrial scale mining of salt started in the 17th century, when
new mining methods were adopted, with large, bell-shape exploitation rooms, reaching 100 m height
and 45-50 m in diameter. Due to the geometry of such rooms and in accordance with the
geomechanical parameters of the salt and the geomechanical conditions in the location area, most of
the voids determined by the mining works were preserved until present time. Some of these rooms
were flooded by the intrusion of the water from an aquifer located at the salt floor and/or were filled
by anthropic and natural filling. Beginning with the 19th century the mining was performed by
square rooms and pillars method and the new mining works often intersected those operated in
earlier times. To evaluate and classify the ground instability risk, diagnosis and then prognosis of the
instability phenomena are proposed as main tools.
1. Diagnosis of the instability phenomena
1.1. Geomorphologic elements
- Subsidence depressions and sinkholes: Stefan mine sinkhole (Fig. 1), past lake, now
backfilled with sterile, Mina Mare sinkhole lake Fig. 2), Iosif mine depression, past
swimming pool, now backfilled, Ferdinand (23 August)-Ciciri sinkhole (Fig. 3), still in
evolution from 1998.
93
Fig.1. Stefan mine sinkhole Fig. 2. Mina Mare sinkhole lake
Fig. 3. Ciciri sinkhole Fig. 4. Landslides between Ferdinand mine and Mina Mare
- Landslides: were evidenced by geomorphological features, like minor scarps, transverse
ridges, radial cracks, crumpled topography, isolated swamps or ponds and by electrometric
measurements. These phenomena are located generally between Ferdinand and Mina Mare mines,
being determined by the ground morphology and the mining subsidence in the area (Fig. 4).
1.2. Tectonic elements
An intense fracture zone has been revealed in the gallery 1 Mai, between meters 520-640,
vertical and N-S oriented. This major element has been confirmed by electrometric measurements.
Other fracture lines have been cited in the documentations of the mines Stefan and Iosif.
1.3. Instability elements deduced by geoelectric and seismic measurements
- Linear ruptural elements. These elements represent planar ruptural elements, determined
by the interpretation of planar anomalies (anomal gradients) from maps and sections of aparent
resistivity, correlated with the seismic data. They are oriented mainly NW-SE and are both tectonic
elements, or subsidence plans.
94
- Circular ruptural elements. They
represent electrometric and seismic
anomalies, interpreted as local
structural modification of the salt
massif due to denivelations on the
salt back or due to collapse of the
roof of the old bell-shaped mines,
not always reflected by the ground
morphology (Georgescu et al., 2000,
Marunteanu et al., 2002).
The localized underground openings
have been confirmed by geoelectric
measurements and besides, at
least two
unknown old mines have been
localized by the geoelectric
mapping: Old mine 4 and Old mine
6 (confirmed by the drilling L7-
IGG) (Fig. 5).
Fig. 5. Map of the ground instability due to
mining subsidence.
2. Prognosis of the instability phenomena and effects on the environment
and human activities
2.1. Instability in evolution, high risk zone (A). The zone of mines Ferdinand and Ciciri,
with the sinkhole Ciciri (Fig. 6) and developing subsidence, water infiltration and landslides.
2.2. Partially stabilized zone, but with potential risk of subsidence and collapse (C, D).
- The area of the old mines Mina Mare, Stefan, Vechi 1, 2 and 3 (zone C) is characterized
by the backfilling of the mine Stefan and the developing of the lake Mina Mare. The risk of
subsidence, hidden sometimes by the surface slidings, including the potential collapse of the old
mines, even colmatated, the risk of landsliding and the risk of water infiltration, increased by the
presence of the lake, are the main risks of the area. Any construction or elements on risk must be
prohibited.
95
96
Fig. 6. Evolution of the sinkh . Sections NW-SE and N-S ole Ciciri
- The area of the administrative buildings and old mines Iosif and Vechi 4, 5 and 6 (zone D)
is characterized by the flooding and partial filling of the mine Iosif (one bell-shaped and large rooms
openings). This situation and the oldness of the mine (the XVIII-XIX century) make any
construction not allowed in this zone. The other old mines (with circular contour) represent a certain
risk for developing constructions due to their approximately location or even their unkown existence
(see the mine Miron, affecting partially by differential settlement the main building of the salt mine
Ocna Dej). The extension of the buildings is allowed after a deep exploration (by geophysical
methods and drillings) of the ground.
2.3. Stable zone but with long term instability potential (B). The zone of the mine 1
Mai and gallery Transilvania is defined by a thicker salt roof and sterile cover comparing with the
other zones. However, some instability phenomena (fractures and deformations, water infiltration)
have been revealed in the mine and at the surface by mining, geoelectric and displacements
measurements. The area is habitated and the displacement monitoring must continue.
References
1. Georgescu, P., Marunteanu, C., Ioane, D., Niculescu, V., Mafteiu, M., Rădulescu, M., 2000, Salt mining subsidence in Ocna Dej (Romania) as revealed by geoelectric and gravity techniques. Analele Universităţii Bucureşti, 2000, p 29-38. 2. Marunteanu, C., Medves, E., Niculescu, V., Mogos, S., Reisz, P., Lukacs, F., 2002, Mining subsidence as effect of the interaction between the contemporary mining works and those from the 17th-18th century at Ocna Dej Saline. Proceedings of the 5th Conference on the Mechanical Behavior of Salt MECASALT 5, August 9-11, 1999, Bucharest, Romania, 43-48, Swets & Zeitlinger Publishers, The Netherlands, 2002.
GAS – CHROMATOGRAPHY – A MODERN PHYSICO – CHEMICAL
METHOD OF INVESTIGATION FOR POLLUTED SITES WITH PETROLEUM PRODUCTS
Consuela MILU 1 , Irina CATIANIS 1
1Bucharest university, Faculty of Geology and Geophysics, 6 Traian Vuia Street, Bucharest, 70139, [email protected], [email protected]
Introduction. Chromatography represents a unique technique of investigation, and could be
applied in many different domains of science. In the last 40 years it has known a great development.
Chromatography is a separation technique, mostly used in chemical analysis. This technique is based
on different migration of components from studied mixture between two phases, a stationary phase
and a mobile phase; it can separate a mixture into its individual components and concurrently give a
quantitative estimate of each constituent. Then, solutes are eluted from the system as local
concentrations in the mobile phase (gaseous or liquid) in order of their increasing distribution
coefficients (different rates) in accordance with stationary phase.
The equilibrium between phases represents the fundament of components separation from
distillation (gaseous – liquid), sublimation (liquid – solid). Because of this fact chromatographically
separation is determined by two factors: the distribution of substances between two phases and the
mass transfer from diffusion process (especially in mobile phase).
Chromatography classification:
the mobile phase (gas or liquid) offers two basic types of chromatography;
- Gas chromatography (GC) where the moving phase is a gas;
- Liquid chromatography (LC) where the moving phase is a liquid.
the stationary phase (liquid or solid) leads to four sub-groups of chromatography:
- Gas-liquid chromatography (GLC),
- Gas-solid chromatography (GSC),
- Liquid-liquid chromatography (LLC)
- Liquid-solid chromatography (LSC).
- Super critical fluid chromatography (SCFC) - some special situations when the mobile phase (gas
or liquid) occur under super critical conditions.
Liquid chromatography represent a method of separation which supposes a liquid mobile
phase and either a solid (LSC) or a liquid (LLC) immobilized on a solid.
Gas chromatography is a method of separation which employs a gas mobile phase and either
a solid (GSC) or a liquid (GLC) adsorbed on a solid as a stationary phase.
97
Chromatography has numerous applications in many domains. It is utilized in biochemical
studies for the separation and identification of chemical compounds of biological origin. In the
petroleum industry this method analyzes complex mixtures of hydrocarbons. Also it is used in
pharmaceutical industry, environmental protection, forensic investigations, etc. Chromatography as a
fundamental procedure in analytic chemistry is used for the separation of gases, liquids, or dissolved
substances. After separation, the individual constituents can be identified or purified through
standard techniques.
Investigated substances are introduced with a special device in separation column at an
adequate temperature. It is important to mention that the vaporization temperature could be
sometimes more than temperature of analyzed decomposed substances. Further on, we emphasize the
main steps of chromatographically analyses: prepare column, apply sample, wash, elute, collect and
analyze fractions, primary chromatography data processing. It is important to mention that every
stage has its particularities and requires some individual treatment optimization.
CASE STUDIES
Soil pollution includes the pollution of soils with materials, especially chemicals that are
presents at concentrations higher than normal. This could have noxious effects on humans or
organisms. The most remarkable chemical groups of organic contaminants are fuel hydrocarbons,
polynuclear aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), chlorinated aromatic
compounds, detergents, and pesticides. Inorganic species comprise nitrates, phosphates, and heavy
metals, inorganic acids, radio nuclides, etc.
In many areas industrial development induced the contamination of large perimeters,
disturbing the equilibrium in ecological systems and causing the contamination of soil and water
sources.
In our study was utilized a preliminary quantitative determination of petroleum products in
contaminated soils by using gas-chromatography method (SR ISO/TR 11046-97). The involved
perimeters were situated in two different places of Romania, meaning in Pitesti county area and also
in Botosani area.
The main objective of the study in Pitesti area was represented by investigation of
contaminated soil with petroleum products situated nearby a commercial society.
Gas-chromatography method (SR ISO/TR 11046-98 - B) was used in order to determine the
presence of petroleum products and polynuclear aromatic hydrocarbons – PAHs (SR ISO/13877-99).
It was sampled a number of twelve drillings and between them were selected just four drillings in
98
order to distinguish the relationship from among infestations concentration and alert limits. The
achieved results are represented into the table 1.
Table 1. Determined values by gas-chromatography (Pitesti area).
Obtained
values
Susceptible alert limits (56/1997Order)
Drilling’s number
Analysed parameter
0.30 cm 0.60 cm Alert limit F1
– control area Petroleum products, polynuclear aromatic hydrocarbons (PAHs)
<25 0.42
<25 0.37
<100 7.5
F9 Petroleum products, polynuclear aromatic hydrocarbons (PAHs)
72.6 0.89
55.3 0.59
<100 7.5
F10 Petroleum products, polynuclear aromatic hydrocarbons (PAHs)
190.9 8.96
161.8 7.90
<100 7.5
F11 Petroleum products, polynuclear aromatic hydrocarbons (PAHs)
1457.8 9.62
175.9 8.38
<100 7.5
The chromatographically obtained data from Pitesti perimeter emphasized the fact that in the
area were registered some anomalous values of petroleum products. These results were very useful in
order to create an abnormal distribution map, indicating also the possible supply sources with
analyzed contamination.
The next point of investigation performed in the vicinity of Botosani Plant was represented by
investigation of contaminated soil. Gas chromatography method (SR ISO/TR 11046-97), was
utilized in order to sketch out the soil contamination with petroleum products.
Table 2. Determined values by gas-chromatography (Botosani area).
Sample symbol/determined values Sample’s number
Performed
analyse
U.M. 1F-
pr.1 2F-pr.1
2F-pr.2
3F- pr.1
3F-pr.2
4F-pr.1
4F- pr.2
5F- pr.1
1 Petroleum products (GC) C10-C14 C14-C20 C20-C26 C26-C34 C34-C40
mg/kg s.u. % % % % %
98,2 <5 75 25 <5 <5
79,20
<5 75 25 <5 <5
44,58
<5 75 25 <5 <5
91,25 <5 75 25 <5 <5
81,67
<5 75 25 <5 <5
96,25
<5 75 25 <5 <5
42,08
<5 75 25 <5 <5
96,25 <5 75 25 <5 <5
1 Petroleum products (GC) C10-C14 C14-C20 C20-C26 C26-C34 C34-C40
mg/kg s.u. % % % % %
70,80
<5 75 25 <5 <5
125,43 <5 75 25 <5 <5
85,42
<5 75 25 <5 <5
65,73 <5 75 25 <5 <5
129,58 <5 75 25 <5 <5
50,77
<5 75 25 <5 <5
98,02
<5 75 25 <5 <5
87,50 <5 75 25 <5 <5
99
Soil samples were chemically treated with some chosen solvent (chloroform, petroleum ether,
dimethyl ethyl cetona) and further on were evaporated, to a small volume particularly of the sample.
After samples preparation these were injected into the column of the Gas-Chromatograph instrument
to a specific temperature in order to determine the petroleum products. Gas-chromatographically
analyse determine the retention time which further on carry out to identification of every unknown
substances. Also it was establish percentage amount of every component existent in the samples
(Table 2).
It was sampling a number of fifteen drillings and between them was chosen just five, in order
to fix the relationship between infestations concentration and alert limits. Gas - chromatographically
analyse indicates that the western part and the south-eastern part of the investigated perimeter are the
most polluted with petroleum products. Registered values are situated bellow normal limits
according to SR ISO/11046-97 (Table 3).
In conclusion, the present investigation revealed that the n-alcans concentration fraction
distribution is constant for every samples; the chromatogram, represent a characteristic for some
petroleum products as Diesel oil. The global content of petroleum products represented in mg/kg
(table no. 3) shows an obviously soil pollution according to 756 Order from 03.11.1997 (< 2000
mg/kg alert limits).
Table 3. Soil petroleum products concentration evidenced by gas-chromatography.
Sample’s number
Petroleum products
rate (mg/kg)
Type of contaminant
1F –pr.1 98.2 Diesel oil 2 F – pr.1 79.20 Diesel oil 3 F – pr.1 91.25 Diesel oil 4 F – pr.1 96.25 Diesel oil 5 F – pr.1 96.25 Diesel oil 6 F – pr.1 125.43 Diesel oil 7F – pr.1 65.73 Diesel oil 8F – pr.1 129.58 Diesel oil
9F – pr.2 50.77 Diesel oil 10 F – pr.1 98.02 Diesel oil 11 F – pr.1 87.50 Diesel oil
The results led to the conclusion that for the both case studies (Pitesti and Botosani) it was
possible to outline the contaminated area using the gas-chromatography method. The petroleum
products represent the main pollution sources from industrialized perimeters.
References Florea N., 1964, Cercetarea solului pe teren, , Editura Stiintifica, Bucuresti. ***Impact of industrial activities on groundwater, Proceeding of the International Hydrogeological
Symposium, 23-28 may 1994, Constanta, Romania.
100
Rb/Ba RATIO IN K – MINERALS OF THE GRANITIC PEGMATITES AS A METALLOGENIC INDICATOR
MURARIU TITUS1, RĂILEANU MARICEL1, CALCAN CRISTINA1
1 “Al. I. Cuza” University of Iaşi, Department of Mineralogy and Geochemistry, 20A, Carol I Blv., RO-700505, Iaşi. e-mail: [email protected]; [email protected]
Granitic pegmatites are a classic example of diversified mineral sources of optical quartz and
fluorite, ceramic and dental feldspar, micas, ceramic amblygonite and spodumene, gems
(aquamarine, chrysoberyl, heliodore, morganite, topaz, tourmaline), rare elements: Li, Rb, Cs
(spodumene, petalite, amblygonite, lepidolite, zinnwaldite, pollucite etc.), Be (beryl, bertrandite,
fenacite, helvine etc.), REE+Y (allanite, monazite, gadolinite, xenotime etc.), Sc (thortveitite), Zr+Hf
(zircon, cyrtolite, malacon), Nb+Ta (columbite, tantalite, fergusonite, tapiolite, microlite, betafite
etc.); radioactive elements: U, Th (uraninite, bröggerite, cleveite, thorianite, thorite, thucholite,
monazite, allanite, euxenite etc.) and other elements such as: Ti, Sn, B, F, P etc.(rutile, cassiterite,
tourmaline, apatite etc.).
The metallogenic potential for rare metals Li, Rb, Cs, Be, Y, REE, Zr, Hf, Nb, Ta (Smirnov
et al., 1986) in the granitic pegmatites can be assessed using geochemical criteria and representative
diagrams for the pegmatites and for the pegmatitic minerals (Shmakin, 1973, 1979; Černý, 1992;
Murariu, 2001; Stumbea, 2001; Murariu and Gandrabura,1995; Murariu and Rădăşănu, 2000;
Androne, 2005; Černý and Ercit, 2005; Murariu and Răileanu, 2006; Murariu et al., 1999, 2007).
This paper presents the importance of Rb/Ba ratio of the potassium minerals from granitic
pegmatites as metallogenic indicator.
The rare alkali element rubidium does not form its proper minerals, but occurs in significant
amounts in potassium minerals. Potassium feldspar and micas are the most important bearers of
rubidium in granitic pegmatites. The highest contents are typical of K – feldspar and micas from rare
element pegmatites: NYF (Nb >Ta, Ti, Y, Sc, REE, Zr, U, Th, F) and LCT (Li, Rb, Cs, Be, Sn, Ga,
TA > NB, B, P, F) types (Černý, 1992). In coexisting potassium feldspar + micas pairs, rubidium is
usually higher enriched in micas and particularly in ferromagnesian and Li, Al – micas.
During the pegmatitic processes the rubidium and the barium (LILE: large – ion lithophyle
elements) presents geochemical affinity for potassium. The Rb for K substitution is also
accompanied by the Rb-Ba substitution.
101
The Rb/K and Rb/Ba values make possible the differentiation of the mineralized pegmatites
(rare metal-muscovite pegmatites and rare metal pegmatites) and barren pegmatites (feldspar
pegmatites; mica bearing pegmatites).
Table 1: Rb/Ba in K – minerals of the granitic pegmatites as metallogen indicator*
Mineral Location Pegmatite type Rb/BaCarpathian Pegmatitic Province (PPC)
Feldspar 3.20 K - feldspars Muscovite 1.98Feldspar 4.82
Muscovite 0.17Muscovite
Muscovite 0.10Feldspar 0.42Biotite
Preluca Pegmatitic
Subprovince
Muscovite 0.22Microcline Albite-spodumene 107.80
Feldspar (+muscovite) 0.0819.4892.35
Muscovite Albite-spodumene
105.77Feldspar 0.18
0.09
Biotite
Conţu field,
Getică Pegmatitic Subprovince
Feldspar (+muscovite) 0.13
U.S. pegmatitic fields337.031.250.0
Kings Mountains, North Carolina
Rare metal
56.70.20Muscovite 0.3510.95
Spruce Pine, North Carolina Rare metal muscovite
9.73Rare metal 80.55Black Hills, Soputh Dakota
Rare earths (+U) 3.287.94South Platte, Colorado Rare earths 2.90
Middletown, Connecticut Rare metal muscovite 52.77
K-feldspar
Medicine Bow, Wyoming Rare earths (+U) 3.28Bihar Pegmatitic field - India
Muscovite 0.27Primary units 1.34Poorly mineralized muscovite 23.20
K-feldspar Quartz core Rare metal 173.00Muscovite 0.32
Poorly mineralized muscovite 1.84Quartz+muscovite
complex Rare metal 141.00
Rare metal enriched muscovite 74.00
Muscovite Quartz core Rare metal 1928.00Muscovite 0.99Contact zone
2.37Intermediate zone 9.70
Biotie
Muscovitization zone
Rare metal enriched muscovite
62.00Aplite-pegmatite 7.67
Two feldspars 10.53Albite 43.26
K-feldspar
Siberia pegmatitic field
Albite-spodumene 59.03Rozna 20.66Muscovite
19.66Biotite
Dobrá Voda Czech Republic
Lepidolite subtype
26.00*Shmakin (1973, 1975); Zagorski and Kuznetzova (1980); Černý et al. (1995); Rădăşanu (2002); Androne (2005)
102
The data presented in Table 1 show that the Rb/Ba ratio is higher in the potassium minerals
from the rare metal pegmatites ( K- feldspar from Kings Mountains field: 31.2 – 337.0, Black Hills:
80.5; Bihar Pegmatitic field: 23.2; Siberia pegmatitic field: 59.0; muscovite from quartz + muscovite
complex: 141.0 and muscovite from quartz core: 1928.0 of the Bihar pegmatitic field; biotite from
muscovitic zone of the Bihar pegmatitic field: 62.0 and biotite from the Dobrá Voda pegmatites etc.)
and rare metal muscovite pegmatites (K-feldspar from the Middletown field: 52.7; muscovite of
quartz core: 74.0 from the Bihar pegmatitic field; biotite of muscovitization zone: 62.0 from the
Bihar pegmatitic field) as compared to the values obtained for the potassium minerals from the
barren pegmatites (K – feldspar from Spruce Pine pegmatitic field: 0.20; muscovite from quartz +
muscovite complex of the Bihar Pegmatitic field: 0.32; biotite from the contact zone of the Bihar
Pegmatitic field: 0.99).
On the basis of their mineralogical and geochemical features the pegmatites from the
Carpathian Province are assigned to the following classes: (1) feldspat pegmatites; (2) mica – bearing
pegmatites and (3) rare element pegmatites (Murariu, 2001).
In the potassium minerals from the albite spodumene pegmatites of the Conţu field, Getică
Pegmatitic Subprovince, the Rb/Ba ratio is higher (microcline : 107.80; muscovite: 19.48 – 105.77)
as compared to the values obtained for the potassium minerals from the barren pegmatites
(microcline: 0.08; biotite: 0.09 – 0.13).
In the Rb/Ba:Rb/K diagram for the K- minerals the investigated samples are plotted in two
distinctive fields: mineralized pegmatites and barren pegmatites. Similar results have been obtained
by the K:Rb/K diagram and Rb:Rb/K diagram (Murariu, 2001; Murariu et al., 2007).
Conclusions
Potassium minerals of the granitic pegmatites are remarkable for their regularity regarding
the Rb and Ba contents.
Rb and Ba present geochemical affinity for K.
Rb for K substitution is also accompanied by the Rb-Ba substitution.
During the pegmatitic processes the Rb content increase and the Ba content decrease.
The value Rb/Ba makes possible the differentiation between the mineralized granitic
pegmatites (rare metal pegmatites) and the barren granitic pegmatites (feldspar pegmatites; mica
bearing pegmatites). The value Rb/Ba is higher than in K-minerals of the rare metal pegmatites and
lower than in barren pegmatites.
103
104
The obtained results emphasize the low metallogen potential for rare elements of the
Carpathian Pegmatite Province, except for the Conţu field pegmatites (albite - spodumene type).
References
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Černý, P., Ercit,T.S., 2005, The classification of granitic pegmatites revised. Canad. Mineral, 43, 6: 2005-2086.
Hann, H.P. 1987, Pegmatitele din Carpaţii Meridionali. Ed. Acad. Română: 141p. Liahovich,V.V., 1972, Redkie elementî v porodoobrazuiuşcih mineralah granitoidov. Nedra,
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et la province pegmatitique carpathique. An. Inst. Geol. Geophys., LVIII, Bucureşti: 423-431. Murariu, T., 2001, Geochimia pegmatitelor din România. Ed. Acad. Română: 356p. Murariu, T., Gandrabura. E., 1995, Le lithium et le rubidium dans les pegmatites de Roumanie
comme indicateurs métallogénétiques. Studia Univ. Babeş-Bolyai, Geologia, XL, 1, Cluj-Napoca: 137-146.
Murariu, T., Rădăşanu, S., Androne, D., 1999, Garnet in pegmatites from Romania as a metallogenetic indicator. Geologica Carpathica, 50, special Issue, Bratislava: 125-126.
Murariu, T., Rădăşanu, S., Kasper, U.H., Schoenbeck, Th., 2003, Geochemical features of beryl from Voislova pegmatites (South Carpathians-Romania). Studia Univ. Babeş-Bolyai, Cluj-Napoca, Geologia, Special Issue: 68-72.
Murariu, T., Răileanu, M., 2006, Rare alkali metal lithium from granitic pegmatites as metallogenetic indicator for the rare elements. Journ. of Mineralogy, 82, Bucureşti: 212-216.
Rădăşanu, S., 2002, The geochemistry and geothermometry of the pegmatites from Preluca Mts. – Romania (in Romanian) Ph. D. Thesis, Al.I.Cuza University, Iaşi: 172p. Salie, M.E. Glebovitzky, V. A., 1976, Metallogeniceskaia specializatiia pegmatitov. Izd. Nauka,
Sankt Petersburg: 187p. Solodov, N.A., Balaşov,L.C., Kremenetzky, A.A., 1980, Geohimia litia, rubidia i cesia. Isd. Nedra,
Moskva: 233p. Shmakin, B.M., 1973, Soderjanie şcelocinîh i nekotorîh elementov v mineralah dokembriskih
pegmatitov Indii v sviazi s nih geohimiceskoi speţializaţii. Geohimiia, 8, Moskva: 1179-1187. Shmakin, B.M., 1979, Composition and structural state of K-feldspar from some U.S. pegmatites.
Amer. Mineral., 64: 49-56. Smirnov, V.I., Ginzburg, A.I., Grigoriev, V.M., Iakovlev, G.F., 1986, Kurs rudnîh mestorojdenie Izd
Nedra, Moskva: 360p. Stumbea, D., 2001, Geochimia pegmatitelor din cristalinul Gilăului (Munţii Apuseni). Ed. Univ.
Al.I.Cuza - Iaşi: 266p. Zagorski, V.E., Kuznetzova, L.G.,1990, Geohimia spodumenovîh pegmatitov i şcelocino
redkometalinîh metasomatitov. Izd. Nauka, Novosibirsk: 187p.
CONTEXTE TECTONIQUE ET LITHOSTRATIGRAPHIQUE DES MINÉRALISATIONS LOGÉES DANS LA PARTIE MÉRIDIONALE DU
COMPARTIMENT TISA-CIUC DE LA ZONE CRITALLINO-MÉSOZOÏQUE DES CARPATES ORIENTALES
MIRCEA MUREŞAN
Institutul Geologic al României – str. Caransebeş 1, Sector 1, 012271 Bucureşti 32, e-mail: [email protected]
Contexte géologique. Dans la Zone cristallino-mésozoïque (ZCM), Săndulescu (1967,
1969, 1973, 1975, 1976, 1984) a séparé deux systèmes de nappes mésocrétacées (autrichiennes): Le
système des Nappes central-est carpatiques – Dacides médianes, qui englobe: I. Nappe
bucovinienne à Série mésozoïque bucovinienne (principalement, Trias; Jurassique et le wildflysch
barrémien-albien); II. Nappe subbucovinienne – NSBu (y compris la Serie mésozoïque
subbucovinienne); III. Nappes infrabucoviniennes – NIBu, (à termes de la Série mésozoïque
infrabucovinienne); Nappes transylvaines (unités de couverture).
Les nappes bucovinienne (NBu) et subbucovinienne (NIBu), dans notre conception,
représentent des unités tectoniques plus complexes que le modèle des ceux-ci presenté par
Săndulescu (tableau ci-jointe). Les minéralisations examinées sont logées dans la région limitée par
le Rivière Bistricioara (au nord) et l’extremité méridionale du CTC (près de Miercurea Ciuc) et
constituée à jour par la NBu et la NSBu, la première ayant la plus grande extension.
Minéralisations (MIN). Dans la région présentée, la majeure partie des MIN sont logées
dans la NBu et sont associées aux métamorphites des quelques nappes de charriage et, comme
d’habitude, sont du type syngénétiques (voir le tableau). (1) Les plus anciennes MIN sont logées
dans le Groupe Rebra (de la Nappe de Rodna), étant représentées par les petites et faibles
concentrations stratiformes (formées par des disséminations finement grenues et couches minces) de
galène et de sphalérite, logées dans les roches carbonatés de la Rb2 (Valea Lunca – au NO de localité
Tomeşti), auparavant prospectées par GEOLEX S.A. – Miercurea Ciuc. Leur association avec les
roches carbonatées de la Rb2, qui représent une ancienne et épaisse plate- forme carbonatée (formée
pendant le Protérozoïque moyen, l’âge du Groupe Rebra) et l’association galène-sphalérite est très
semblables avec les gisements plombo-zincifères Guşet et Valea Blaznei, du type Mississippi Valley
(étudiés par Udubaşa, 1970,1976, 1978), aussi logées dans les roches carbonatées de la Rb2 du
Groupe Rebra, des Monts Rodna. (2) Dans la Nappe de Capu Corbului, la Tg2 abrite une MIN
manganésifère (principalement, rodhonite et rodhochrosite), du type hydrothermal-sédimentaire,
associée aux quartzites noirs du ce terme. Cette MIN est connue dans le forage 1 Hagota (au sud de
105
Tulgheş) et, à jour, dans le secteur Capu Corbului (Mureşan, 1966, 2002 a, 2002 b). (3) Dans la
Nappe de Sadocut, la Tg3 loge un niveau à MIN de sulfures (principalement, pyrite et calcopyrite),
du type Kuroko (Kräutner, Bindea, 1995; Mureşan, rapports 1991-1997 et 2002 a, 2002 b), associée
aux métavolcanites rhyolitques du ce terme. Cette MIN a été mise en évidence et poursuivie par
Airinei (1988 1997) dans les forages (executés par GEOLEX S.A. – Miercurea Ciuc), creusés dans la
Demi-fenêtre Tulgheş. Selon Mureşan (2002 a, 2002 b), cette MIN correspond du point de vue
lithostratigraphique avec l’Horizon à sulfures Leşul Ursului (les Zones I et II Leşul Ursului), séparé
dans la Tg3 des Monts Bistriţa (Kräutner et al., 1992). (4) Dans la Nappe de Bălan, le terme Tg3 de
la Succession du type Bălan (Kräutner, Bindea (1995) loge l’important Gisement Bălan-Fagul Cetăţii
(principalement, pyrite et calcopyrite), du type Kuroko, étudié, parmi les autres, par Popescu, (1967,
1974, 1975, 1977), Kräutner (1965, 1984, 1989), Kräutner, Popa (1973), Kräutner et al. (1992),
Petrulian et al. (1974). Vers NO, à Hărlăgia, affleure la même nappe (cf. Kräutner & Bindea, 2003),
dans laquelle, la Tg3 abrite une MIN du type Kuroko, etudiée par Mureşan & G. Mureşan (1977). (5)
Dans la Nappe de Belcina, la Tg4 présent des corps letilliformes syngénétiques férrifères ±
manganésifères (quarzites à hématite et magnétite ± spéssartine) – par exemple, à Dealul Gherman
(au nord de village Bicaz Chei) et à l’est de Piatra Roşie (au Nord de localité Tulgheş), toutes du type
Lahn-Dill (Mureşan, 2002 b). (6) Dans la même Nappe de Belcina, la Tg4 loge des concentrations
stratiformes manganésifères rodhonito-rodhochrositiques ± spéssartine (d’origine hydrothermal-
sédimentaire) à Pârâul lui Iacob (à quelques km vers l’ouest de Borsec), ou sont associées avec des
schistes verts (Jakab, 1990). (7) La Nappe de Belcina englobe dans la même pile de la Tg4, les
corps des Porphyroïdes de Mândra (métarhyolites intrusifs), qui abritent des MIN plombo-zincifères
(galène et spalérite ± pyrite) filoniennes, métamorphisées régionalement, du type Paltin (Mureşan,
G. Mureşan, 1977), les plus importantes étant connues au nord de Rivière Bistricioara (Paltin ,
Pârâul cu Linia, Sângeroasa) et à Gherpotoc (quelques km à l’est de ville Gheorgheni). (8) Dans la
Nappe de Rarău, les mésométamorphites du Groupe Bretila de la Nappe de Rarău, abritent des MIN
épigénétiques uranifères, explorées dans le secteur Primătar-Toşorog (Ene et al., 1989), similaires
avec le Gisement Crucea (présentée par Petrescu et al., 1995), logées dans les Monts Bistriţa. Pour
le dernier, les âges U–Pb (déterminés par Vîjdea & Anastase, 1971, Arch. I.G.R) indiquent, selon
nous, l’âge permien du minerai primaire (255-290 m.a.), fait vraisemblable parce que dans le Banat,
à Ciudanoviţa, il y a un gisement uranifer, associé aux dépôts permiens. (9) Dans les dépôts
mésozoïques de la Nappe de Lacul-Roşu-Licaş, englobée dans les NBu, NSBu et NIBu, il ya des
petites apparitions férrugineuses liassiques continentales et marines. (a) Selon nous, le premier type
génétique représent un vestige d’une crôute d’altération continentale, développée sur le paléorelief
carstique des roches carbonatées anisiennes. La plus importante concentration férrugineuse
106
continentale est logée dans la NSBu (dans la Fenêtre tectonique Tomeşti, à Vârful Ascuţit – au NO
de localité Tomeşti), Là, cette MIN a été explorée par GEOLEX S.A. – Miercurea Ciuc. Cf. Zakarias
(1979), cette MIN.est constituée principalement par limonite, goethite, jarosite, alumite, diaspore,
logés dans une matrice quartzeuse; les analyses chimiques relèvent le caractère férro-alumineux du
ce minerai. (b) Le Lias marin contient des roches férrugineuses – calcaires oolithiques rouges
hématitiques, d’âge sinémurien-carixien (Săndulescu, 1975; Grasu, Turculeţ, 1978; Grasu et al.,
1995): dans la NBu (la région de Hăghimaş; dans la NSBu (dans le lambeau de rabotage Dămuc,
logé à limite ZCM / ZF (Săndulescu, 1973, 1975, 1976); dans la Nappe infrabucovinienne de
Iacobeni (parmi les autres: Săndulescu, 1976; Grasu et al., 1995). Selon nous, la présence des dépôts
continentaux férrugineux liassiques relève une exondation générale post-triassique des domaines
bucovinien-subbucovinien-infrabucovinien pendant le commencement des mouvements cimmériens
anciens. (10) Dans la NBe, nous avons mise en évidence (1989), dans les forages 532 (près de
Sommet Pângăraţi) et 163 (secteur Gherpotoc), dans les épimétamorphites de la Tg4, des
concentrations épigénétiques (filons et imprégnations) de barytine ± withérite, du même type comme
le gisement d’Ostra, d’âge mésozoïque. (11). Les MIN, liées génétiquement de MAD, sont
représentées pricipalement (cf. Jakab, 1998) par des MIN de Mo (Jolotca et Aurora), de terres rares
et de sulfures.
BIBLIOGRAPHIE SÉLECTIVE
Airinei I. (1988-1997) Rapports sur les forages executés dans la région Tulghes. Arch. GEOLEX S.A., M. Ciuc.
Balintoni I. (1981). Acad. R.S.R., Rév. Roum. Géol., Géophys., Géogr., Série Géol., 25, p. 89-94, Bucureşti.
Bercia I., Kräutner H.G., Mureşan M. (1976). An. Inst. Geol. Geofiz., L, p. 37-70, Bucureşti.
Jakab G. (1998). Geologia Masivului Alcalin Ditrău. Edit. Pallas-Akadémia, 298 p., Miercurea Ciuc.
Kräutner H.G., Kräutner Fl., Tănăsescu A., Neacşu V. (1976). An. Inst. Geol. Geofiz., L, p. 167-229, Bucureşti.
Kräutner H.G., Bindea G. (2002). 27-th Congr. Carp.-Balc. Ass., p. 1-5, Bratislava.
Kräutner H.G., Bindea G. (2003). Carte géologique de la ZCM – 1: 200.000. Arch. Inst. Geol. Rom., Bucureşti.
Mînzatu S., Lemne M., Vîjdea E., Tănăsescu A., Ioncică M., Tiepac I. (1975). D.S. Inst. Geol.Geofiz. LXI, 5, p. 85-111, Buc. .
Mureşan M. (2002 b). Rom. Journ. Min. Deposits, 80, p. 94-97, Bucureşti.
Mureşan M. (2006). An. Inst. Geol. Rom., 74, Special Issue, p. 153-159, Bucureşti.
Popescu C. Gh. (1974). Thèse de doctorat concernant le Gisement Bălan. O.D.P.T. – M.M.P.G., 114 p., Bucureşti.
Săndulescu M. (1975). Thèse de doctorat concernant la géologie et la tectonique de la région des Monts Hăghimaş.
An. Inst. Geol. Geofiz., XLV, 200 p., Bucureşti.
Săndulescu M. (1984). Geotectonica României, Edit. Tehnică, 334 p., Bucureşti.
Udubaşa, (1978). D.S. Inst. Geol. Geofiz., LXV, 2, p. 113-130, Bucureşti.
Vodă Al. (1999). .Acad. Rom., Stud.Cerc. Geol., 43-44., p. 147-153, Bucureşti.
Vodă Al. (2000) Synthèse de la Zone cristallino-mésozoique. Rapport. Arch. Prospecţiuni S.A., Bucureşti.
Zakarias L. (1979). Rapport concernant la minéralisation férrugineuse de Vârful Ascuţit. Arch. GEOLEX S.A., M. Ciuc.
107
Fig. 1. Coupe synthétique tectonique et métallogénique dans le secteur Fenêtre Tomeşti-Bălan-Hăghimaş-Vallée Dămuc
1, Volcanites neogènes; 2-15, Nappe bucovinienne: 2, Conglomérats de Bârnadu; 3, 4, Nappe de Wyldflysch de Perşani- Hăghimaş (3, Nappe de Hăghimaş; 4, Wyldflysch de Perşani-Hăghimaş); 5, Nappe de Liunca; 6, Nappe de Lacul Roşu-Licaş; 7, Nappe des
Granitoïdes de Hăghimaş; 8, Nappe de Rarău; 9, Nappe de Bălan (a. Formation Tg4; b. Formation Tg3); 10, Nappe de Belcina (Formation Tg4)); 11, Nappe de Sadocut (Formation Tg3); 12, Nappe de Şumuleu (Formation Tg4); 13, Nappe de Porphyroïdes de
Pietrosul; 14, Nappe de Negrişoara; 15, Nappe de Rodna; 16-18, Nappe subucovinienne: 16, Nappe de Lacul Roşu-Licaş; 17, Nappe de Rarău; 18, Nappes plus anciennes que le Massif alcalin Ditrău; 19, Zone du flysch (Nappe de Ceahlău); 20, Charriage autrichien de
la Nappe bucovinienne; 21, Charriage autrichien dans l’interieur des Nappes bucovinienne et suibbucovinienne; 22, Charriage ante-autrichien; 23, Charriage post-cénomanien (intra-bourdigalien ?) de la ZCM sur la Zone du flysch; 24, Secteur à forages.
Abréviations: Pt2, Protérozoïque moyen; O1, Ordovicien inférieur;
108
COMPARATIVE PHYSICO-MINERALOGICAL STUDY OF ROMANITE AND BALTIC AMBER; PRELIMINARY FT-IR AND XRD DATA
Antonela NEACŞU1, Delia Georgeta DUMITRAŞ2
1 University of Bucharest, Faculty of Geology and Geophysics, 1, N. Bălcescu Ave., 010041 Bucharest, Romania
2 Geological Institute of Romania, 1 Caransebeş St., Bucharest, Romania [email protected], [email protected]
Amber is fossilized resin that once exuded out of the bark or was produced in the heartwood of
different types of Conifers and certain flowering trees, particulary in hot weather. Many scientists
thought that time was important in the fossilization of resin to produce amber, this process beeeing
estimated as taking from 2-10 milion years. But it appears that the types of sediment in which the
resin is deposited is much more important than time for amber formation, although it is not so clear
the effect of water and sediment chemistry on the resin (Ross, 1998).
This work presents some preliminary data of a larger project aiming to establish the local or
Baltic origin of the materials found in archaeological sites on the Romanian territory. The
complexity of the theme, making the object of a strong debate in the specialty literature, reveals the
necessity of using diverse analytical techniques, i.e. optical microscopy, infrared spectrometry (IR,
FT-IR), X- rays diffraction (XRD), nuclear magnetic resonance (NMR).
In Romania, a beautifull amber was exploited from the 19th century near Colţi (Buzău
County), on the Sibiciu Valley. The resin-bearing strata belong to the Oligocene in the Eastern
Carpathian flysch. They are intercalated within the lower and medium part of the lower Kliwa
sandstone, having a thickness that is not constant (0.20-1.40 m). They consist of siliceous clay
always containing thin intercalations of bituminous shales (2-5 cm) and of preanthracite coal (1-2
cm). The paleobotanical and palynological researches on the amber-bearing formations give the age
as Upper Rupelian-Early Chattian (Ghiurca & Vavra, 1990). Having become a symbol of our
country, the crud, brown–reddish amber named romanite or rumanite was exposed at the Universal
Exposition in Paris, 1867. The systematical exploitation began in 1920, and between 1923 and 1925
more than 300 kg were extracted. By 1935 the exploration ceased. Between 1981 and 1986 the
Ministry of Mines and Oil organized a systematical exploitation, but the extracted material was lost
or became part of private collections (Ciobanu, Dicu 2005). Today amber of the Colţi area is not for
sale commercially. It is found in small amounts, retained more for scientific value. People continue
to look for amber along rivers after rain and regularly in the spring, but with less enthusiasm than
109
their ancestors. In order to expose the crude and processed amber objects, a special museum was
opened in 1980 at Colţi. Today it is a sad situation in Colti: the unique Amber Museum is in an
advanced degradation stage and very few people practice amber processing.
Baltic amber or succinite is by far the earliest and wellknown of all fossil resins. Resin secreted
by coniferous trees at least 40 million years ago was carried southwards by river from the
Scandinavia and the present-day Baltic Sea and laid down in the Tertiary marine sediments known as
blue earth. On the Sambian Peninsula (Russia) Baltic amber has been extracted from this deposit,
from depth of 50 m, almost continually since the 17 th century (Kosmowska-Ceranowicz, 2003).
Poland has become one of the leading producers of amber jewlery in the past 30 years, processing
some 200 tons annually (www.pan.pl).
The role of optical microscopy in the study of fossil resins is of prime importance. Apart from
efficiency and commodity, it offers a precision grade comparable only with the chemical analyses
and at the same time it allows detailed mineralogical investigations of the resins and of the host-rock.
The observations have been marked up at the Faculty of Geology and Geophysics, Economic
Geology & Metallogeny Laboratory, using a PANPHOT microscope transmitted light, to which a
Nikon Eclipse E-400, 40 W has been attached, being thus possible to obtain microscopically images.
The thin sections have been manufactured at the Sections Laboratory from the Mineralogy
Department, using samples of romanite from Colţi region and Baltic amber from Poland, Rusia and
Germany.
Diagenetic processes played a significant role in the creation of romanite (Kosmowska-
Ceranowicz, 1999, Neacşu, 2006). One of the most important consequences is the appearance of an
internal organization tendency, proved by its weak anisotropy; although in literature is mentioned the
fact that amber does not present crystallization tendencies (Kucharska & Kwiatkowski 1977, Stout et
al., 1995), the microscopic study on thin sections of romanite allowed the emphasizing of a light
anisotropy with grey-yellowish to light-blue colors. The second consequence is represented by
remineralizations in romanite, consisting in the substitution of organic matter by anhydrite and albite
(fig. 1, 2). Having a novelty character, is the obvious presence on sections of two different romanite
types: an older one, with distinct fissures, impregnated with organic material, and a recent one, light
yellow, which borders the previous one and penetrates its fissures.
Baltic amber studied with this occasion revealed no anisotropy. A certain circular zonality of
the inclusions’ disposal may be observed. If the fluid inclusions are very characteristic in many
Baltic amber samples (fig. 6), in the case of romanite fluid inclusions had time to be emitted, due to a
110
longer exposure to sunlight, or/and to the influence of the temperature during the diagenesis. As a
result of water and volatiles drastic elimination, microfissures can be also seen (fig.3).
Fig.1 Neoformation albite surrounded by idiomorphic Fig. 2 Organic spherules (pollen?) replaced by
crystals in romanite NII 10x/0.25 Albite albite crystals in romanite NII 20x/0.33
The microscopic study of romanite emphasized the presence of pollen of Sequoiapollenites
type? from the European Tertiary, (fig. 4), of spores (of Osmundaceae?) and of wood vessels
remains, free, cortex, all of them comprised by the resin. Ligneous tissue may be also observed in the
sections from Baltic amber (fig.5). The microscopic study of amber revealed the identification of
certain paleofossils of the Insects Class (fig.6) in Baltic amber.
Fig. 3 Polygonal cracks filled with organic Fig. 4 Sequoiapollenites ? in romanite, material in romanite NII, 20x/0.33 NII, 6x/0.18
Both X-ray diffraction and infrared spectroscopy studies have been made with equipments of
Geological Institute of Romania. X-ray powder diffraction analyses was performed on a Bruker D8
Advance automated diffractometer equipped with a graphite-diffracted beam monochromator (Cu
K radiation, = 1.54056 Å), at an operating voltage of 40 kV and a beam current of 40 mA. The
patterns were collected using fixed 1º divergence and anti-scatter slits and a 0.6 mm receiving slit.
111
Fig. 5 Ligneous tissue in Baltic amber, Fig. 6 Insects Ord. Coleoptera? and fluid
NII, 20x/0.33 inclusions in Baltic amber, NII, 20x/0.33
The records were made using an external Si standard (NBS 640b). They seem to indicate for
romanite some internal organizing tendency confirmed by microscopically studies (Neacsu, 2006 and
this paper). Some crystalline components may give rise to diffraction patterns and could have a
genetic significance. Our data indicate oleandrine (one of several alkaloids found in the leaves of
Nerium oleander) as a possible crystalline compound in romanite.
Fig. 7 X-ray diffraction patterns of romanite
Fig. 8 X-ray diffraction patterns of succinite
112
The infrared transmittance spectra were recorded with a Bruker Tensor 27 FT-IR spectrometer,
using ATR accessory. The main technical specifications are: DTGS detector, KBr beamsplitter,
spectral range 7,500 to 370 cm-1, resolution ± 1 cm-1, ± 2 cm-1 respectively, software OPUS. Baltic
amber is further distinguished by a small transmittance near 890 cm-1 that indicates out-of-plane
vibrational frequencies of an exocyclic methylene group (Beck et al., 1965). We do not find
exocyclic groups (and aromatic compounds either) at the romanite samples. This fact prouves a
higher intensity of the alteration and fossilization processes which affected the resin from which
romanite was formed; these processes might have acted on the organic substance, transforming it in
simpler compounds. The 3700-3100 cm-1 region is different at romanite, indicating the lessening of
free water proportion in comparison with succinite. Between 3000-2750 cm-1 peaks are
aproximatelly disposed in the same way: romanite presents two peaks with a maximum intensity at
about 2924, 2866 cm-1, in comparison with those of succinite about 2924, 2867, 2848 cm-1, all for
carboxyl groups. The transmittance range is evidently higher in the case of romanite, meaning that it
has more carboxylic groups than succinite, probably because of a stronger oxidized process. The
differences appeared in 1574 cm-1 band of Baltic amber with respect to 1591 cm-1 band of romanite
are determined by the shift of asymmetry vibration frequencies for the carboxylic type groups, as
function of the length of hydrocarbonated chains which come in resonance with (Teodor et al., in
press).
Fig. 9. Transmittance spectrum of romanite
Another discussion could appear in relation with intensity of the band at 1640 cm-1assigned to
the simple aliphatic unsaturation of the olefin group C=C; it could be compare with the intensity of
the band at 1450 cm-1, assigned to the deformation of CH2 bonds to quantify the process of
breakdown of C=C bonds (Moreno, 2000 in Shashoua, 2002). In the literature is mentioned that the
breakdown of C=C bonds was related to the extent of maturation of amber from the liquid resin
stage; the intensity of the two relevant bands were rationed and found to be lower for Baltic amber
(0.35), but for romanite there is no information about it, although other studies have already
advanced a higher maturation of romanite in comparison with succinite (Kosmowska-Ceranowicz,
1999, Neacşu, 2003 unpublished).
113
Fig. 10. Transmittance spectrum of Baltic amber
Conclusions
Light Microscopy analysis demonstrate that diagenetic processes played a significant role in the creation of romanite: it’s characteristic small surface cracks as a consequence of the lessening of free water proportion attest to this fact, in comparison with Baltic amber where a lot of fluid inclusions could be observed. It could see also remineralizations in Romanite, i.e. substitution of organic matter by anhydrite and feldspar. In other situation, the organic tissue was replaced by resin. The microscopic study seems to prove the crystallization tendency of romanite, raising thus the possibility of using X-ray diffraction as a diagnostic method for romanite. Regardless of the FT-IR technique applied, there are no notable differences between romanite spectra and Baltic amber spectra in the 3700-3100 cm-1 region. They appear in ‘Baltic shoulder’ region 1250-1150 cm-1 (Beck, 1965) but other differences could be found in order to clarify the geological origin of amber.
References
Beck, C.,W., Wilbur, Elizabeth & Meret, Silja (1965): Infra-red spectra and the origin of amber. Nature, 201, p. 256-257 Ghiurcă, V. & Vavra, N. (1990): Occurrence and chemical characterization of fossil resins from Colţi (District of Buzău, România). N. Jb. Geol. Paläont. Mh., H.5, 283-294. Stuttgart. Ciobanu, Doina & Dicu, Ana (2005): Chihlimbarul, bijuterie şi elixir, Muzeul Judeţean Buzău Kosmowska-Ceranowicz, Barbara (1999): Succinite and some other fossil resins in Poland and Europe, Estudios del Museo de Ciencias Naturales de Alava. 14, p. 73-117 Kosmowska-Ceranowicz, Barbara (2003): Amber from liquid resin to jewellery Ed. J. Popiolek, Bucureşti Kucharska, Małgorzata & Kwiatkowski, A. (1977): Research methods of chemical composition of fossil resins and origin problems of amber. Prace Muzeum Ziemi, Z.29. Warsaw Neacşu, Antonela (2006): Remarks on the geological origine of rumanite. Acta Universitatis Szegediensis Acta Miner.- Petrogr., 5, 83, Szeged Ross, A. (1998): Amber the natural time capsule, The Natural History Museum, London Stout, C., Beck, C.,W. & Kosmowska-Ceranowicz, Barbara (1995): Gedanite and gedano-succinite, ACS Symposium Series, 617, Washington, DC. Shashoua, Yvonne (2002): Degradation and inhibitive conservation of Baltic amber in museum collections. Department of Conservation. The National Museum of Denmark. Teodor, Eugenia, Liţescu, Simona, Carmen, Neacşu, Antonela, Truică, Georgiana & Albu, Camelia (2008): Analytical methods to differentiate Romanian amber and Baltic amber for archaeological applications, Central European Journal of Chemistry (in press)
www.pan.pl
Acknowledgements: This study has been supported by the Romanian Ministry of Education and Research under Research Contract 91-019/2007, National Center for Programs Management. Special thanks to dr. L. Petrescu, Faculty of Geology and Geophysics, University of Bucharest and to dr. Călin Ricman, Geological Institute of Romania
114
LIQUID INCLUSIONS MICROTHERMOMETRY IN THE BADENIAN HALITE AND ACTUAL EVAPORITE SALT CRUST FROM ROMANIA
IOAN PINTEA
Geological Institute of Romania, P.O.Box 181, 3400 Cluj-Napoca, 1, Romania, [email protected]
Introduction
The fluid inclusions assemblages (FIAs) from Badenian halite were documented in the salt
samples collected from Ocna Dej, Saratel, Sarata, Nires, Unguras, Dumitra, Orsova, Turda, Ocna
Sibiului, Sovata and Praid (project MEC (MIR)-3/2003 on “Salt deposits from Transilvania and
Maramures basins coordinated by dr. M. Ticleanu at the Geological Institute of Romania).
Additionally halite samples from Cacica, Tg. Ocna and Slanic Prahova salt deposits from outer
Carpathians were used (collected, 1988). Actual saline crust precipitated July-September, 2003
around and above old mining prospects from Cojocna and Ocna Dej was analyzed for a comparative
data set. Air temperature recorded July – September, 2003 around Cluj district emitted by INMH
Cluj-Napoca and the temperature measured by Maxim (1933) in the perennial lakes from Turda were
used for verification. An earlier version of this report was presented as an oral communication at
ECROFI XVIII Conference, held in Siena (Pintea, 2005).
Brief review on liquid inclusions microthermometry in halite and data reliability
Many published data on monophase liquid inclusions thermometry in halite were
systematically overestimated mainly because of the natural stretching induced by many post
depositional factors e.g. plastic deformation during folding events etc. So, the fluid inclusions in
ancient evaporite salt deposits were found and described as sedimentary microtextural remnants (e.g.
Petrichenko, 1977; Roedder, 1984a). Moreover it is know that halite also stretching during
heating/freezing cycles in laboratory runs (Petrichenko, 1974; Roedder, 1984a; Loucks, 2000). Since
Sorby’s time (1858) the Th estimation as precipitation temperature of halite has been a debatable
subject among scientists, e.g. Ingerson, 1947, Dreyer et al., 1949; Petrichenko, 1974, 1977; Roedder
& Belkin, 1988; Pomarleanu & Marza, 2003 etc. Nowadays systematic studies on liquid inclusions
from halite worldwide used an artificially method to generate vapor bubble in each individual
primary liquid inclusion and then homogenizing them by the common microthermometric technique.
This method includes a simple procedure by moderate cooling of the sample in a common freezer or
directly in the stage under the microscope (Roberts & Spencer, 1995; Lowenstein et al., 1998;
Benison & Goldstein, 1999; Pintea, 2005 - fig 2, table 1). An ultimate high-tech method using
femtosecond laser pulse is now proposed to generate vapor and other phases in metastable liquid
inclusions from quartz, calcite and halite too (Kruger et al., 2007; Kruger, 2008 pers. comm.).
Primary liquid inclusions from Badenian halite
115
Pristine cubic shaped monophase liquid inclusions decorating growth zones in “hopper’ and
“chevron” salt had trapped the samples of the mother seawater in sedimentary bedded salt. But
usually these salt deposits were recrystalized or even diagenized and primary liquid inclusion were
only documented in microtexturaly sedimentary relics as isolated or clouds of different FIAs (fig.1).
These are the best choice for measure initial precipitation temperature and calculate chemical
composition of the included seawater of the primary bedded halite (e.g. Petrichenko, 1988 pers.
comm; Kovalevich et al., 1998; Zimmerman, 2001).
V
L
L
V
L
L
L L
VL
Fig.1. Fluid inclusions assemblages (FIAs) in Badenian halite from Ocna Dej and Slanic Prahova salt deposits. V-vapor, L-liquid.
After recovering the vapor bubble in each liquid inclusion from several selected salt
samples from Ocna Dej, Slanic Prahova, Ocna Sibiului and Saratel the homogenization temperature
was measured in a USGS stage with +/- 0.1oC precision. The precipitation temperature was estimated
between +2oC and +32oC for the Badenian salt from Transylvania basin. The eutectic ice melting
temperature ranged between –18oC and –36oC and hydrohalite melted around +/-0.1oC. The
precipitation temperature of the chevron salt from Slanic Prahova (Baia Baciului) was estimated
between +1oC and +26oC. The eutectic ice melted between –24oC and –34oC and hydrohalite melted
around +/-0.1oC. The seawater chemistry could be then reconstructed in the Na-K-Mg-Ca-Cl/SO4
system based upon freezing behavior of the primary liquid inclusions (e.g. Zimmerman, 2000).
B L
V
A L C L
Fig. 2. A,B,C. The reliability of the “bubble recovering” method verified for a single primary liquid inclusion from Badenian halite (Ocna Dej, P173 sample). Serial microphotographs showing the homogenization procedure: A. by cooling in the
USGS stage at +/-0.1oC precision, a bubble (V) is recovered at –13oC into the liquid inclusion (L) showed in B, on heating the bubble homogenized at Th = +10.0oC, and inclusion become again liquid monophase (L) in C (e.g.last cycle).
Scale bar: 50 µ
116
Table 1.Bubble recovering/homogenization data set (No = 40 cycles) of the same liquid inclusion pictured in Fig.2 shown slight homogenization temperature variations between +10.0oC to +13.0oC, but “bubble recovered temperature” fluctuated widely between –35.4oC and +2.6oC. The variation of measured values suggesting metastability of the trapped solution as predicted by theoretical approach of salt - water system at low vapor pressure, i.e. less than 760mmHg (e.g. Filipescu &
Pincovschi,1980).Tn = recovered bubble temperature, Th = homogenization temperature
No 1 2 3 4 5 6 7 8 9 10 Tn -30 -29 -16.4 -35.4 -23.4 -15.0 -20.0 -9.6 -18.8 -8.8
Th +10.9 +12.6 +11.6 +10.3 +10.3 +10.2 +11.3 +11.8 +11.6 +11.4 continued
11 12 13 14 15 16 17 18 19 20 -8.0 -11.6 -12.0 -12.9 -9.3 -18.3 -11.3 - 0.0 -2.5 -5.2 +11.1 +11.7 +10.9 +11.4 +10.8 +10.4 +11.4 +12.4 +12.6 +12.3
continued 21 22 23 24 25 26 27 28 29 30 -7.7 -9.3 -13.0 -16.7 -24.2 -13.6 -11.9 + 0.4 -0.9 -21.2+12.4 +12.5 +12.1 +12.0 +11.4 +11.8 +11.9 +12.6 +12.7 +11.5
continued 31 32 33 34 35 36 37 38 39 40 -9.2 -33.4 -17.3 -15.8 +2.6 -3.6 -10.3 -35 -34.4 -13.0 +11.5 +10.9 +10.2 +13.0 +13.0 +12.8 +12.8 +11.3 +11.6 +10.0
Primary liquid inclusion in the actual salt crust.
The verification of halite precipitation temperature is done by using liquid inclusions from
the modern salt formed in perennial lakes above and around ancient or actual mining prospects from
sedimentary basins (e.g. Lowenstein, et al., 1998), or even in laboratory-grown halite (e.g. Davis et
al., 1990). The salt samples collected for this study were precipitated July – September, 2003 around
Ocna Dej and Cojocna district. White and pink crystallized halite crust of 1-2 mm thickness were
used directly without any preparation to avoid mechanical stretching of the primary monophase
liquid inclusions (Fig.3). The formation temperature of the halite crust from Ocna-Dej and Cojocna
measured in the same way as the Badenian samples ranged between +4oC and +38oC. Eutectic ice
melting temperature ranged between –19oC and –25oC (suggesting chemical deviation from
Badenian seawater!) and hydrohalite melted around +/-0.1oC. It was noted a very good correlation
of our data with perennial lakes temperature ranged between +14oC and +50oC, measured by Maxim
(e.g. 1933 at Turda). The air temperature recorded July – September, 2003 around Cluj district and
emitted by INMH Cluj – Napoca (www.weather.com, Monitorul de Cluj) ranged between +6oC and
+38oC, which is in good agreement with our measured microthermometric values too. Fig.3. Cloud of primary fluid inclusions in modern halite crust collected September 30, 2003 from Cojocna ancient mining prospect. L – liquid, V – vapor. Scale bar 50µm. Surface recorded temperature: below salt crust = +11oC; water/air interface = +17oC /+20oC respectively.
.
Discussion and conclusions
L
V
L
117
118
Because the vapor pressure of saturated brine is very low and the trapped liquid from fluid
inclusions in salt usually appearing without bubble at room temperature (i.e. metastability under
negative pressure, e.g. Roedder, 1984b; Filipescu & Pincovschi, 1980), the “recovering bubble
method” seem to be a precisely method to estimate formation temperature of mineral precipitated
from seawater in the sedimentary basins worldwide. These have a crucial importance in
paleotemperature estimation, paleogeographical reconstruction and understanding of ancient and
modern climate change issues.
Acknowledgements. I thank Oleg I. Petrichenko and Volodymyr M. Kovalevich from
“Institute of Geology and Geochemistry of Combustible Minerals” for introducing me to fluid
inclusions study in the evaporite minerals during a week in October 1988 at Lviv (Ukraine). I wish to
tank A. Hadnagy, Rodica Stan, M. Ticleanu and F. Wanek who provided some of the salt samples
used in this study.
References
Benison K.C., Goldstein R.H. (1999) Chem.Geol.154,113-132. Davis D.W., Lowemstein T.K., Spencer R.J. (1990) Geochim.Cosmochim.Acta, 54,591-601. Dreyer M.R., Garrels R.M., Howland A.I. (1949) Amer.Min. 34,26-34. Filipescu L., Pincovschi E.(1980) Echilibrul solid-lichid.Aplicatii in tehnologia sarurilor
minerale.Ed.Tehn.300p. Ingerson E. (1947) Amer.Min.32,7,8,375-387. Kovalevich V.M., Peryt T.M., Petrichenko O.I. (1998) Jour.Geol.,106,6, 695-722. Kruger Y., Stoller P., Ricka J., Frenz M. (2007) Eur.J.Mineral. 19,693-706. Loucks R.R.. (2000) Amer. Jour. Sci. 300,23-59. Lowenstein T.K., Li J., Brown C.B. (1998) Chem.Geol.150,223-245. Maxim I. (1936) Rev.Muz.Geol.Min.VI,209-320. Petrichenko O.I. (1973) Metody doslidshennya vkluchen’v mineralakh galogennykh porid. Kiev,
Naukova Dumka, 91p. Petrichenko O.I. (1977) Atlas microvkluchnly v mineralakh galogenykh porod. Kiev, Naukova
Dumka,182p. Pintea I. (2005) ECROFI XVIII, Abstract CD-ROM, Pomarleanu V., Marza I. (2003) Studia UBB, spec.iss. 86-89. Roberts S.M., Spencer R.J. (1995) Geochim.Cosmochim.Acta, 59,3929-3942. Roedder E. (1984a) Amer.Min. 69, 413-439. Roedder E. (1984b) Fluid inclusions, Rev in Min, 12, 644p. Roedder E., Belkin H.E. (1988) C.R,.Acad. Sci. Paris, 306, Ser.II,283-287. Sorby H.C. (1858) Quarl. Jour. Geol. Soc. London, 14,453-500. Zimmermann H. (2000) Amer.Jour. Sci., 300, 723-767.
MINERALOGY OF VIVIANITE FROM ROSIA POIENI; METALLOGENETIC SIGNIFICANCE
Gheorghe C. POPESCU 1, Gheorghe ILINCA 1, Antonela NEACSU 1
1University of Bucharest, Faculty of Geology and Geophysics, Department of Mineralogy, N. Balcescu, Ave., 010041 Bucharest [email protected], [email protected], [email protected]
The Rosia Poieni ore deposit represents the largest Cu-Au porphyry structure in the Metaliferi
Mts., matching in celebrity the gold-silver deposit at Rosia Montana, located at approximately 4
km to the East. Positive correlation has been observed between Cu/Te and Cu/Au ratios for
pyrite-hosted fluid inclusions in Rosia Poieni ore deposit (Kouzmanov et al, 2004). A similar
trend was established by Wallier (2004) & Rey (2004) – in their master thesis, for low-salinity
epithermal fluids in the neighboring intermediate-sulfidation epithermal Au-Ag deposit of Rosia
Montana, thus suggesting a possible genetic link between the two deposits. Copper, gold and
tellurium show similar element ratios trends for fluids of porphyry-copper and epithermal
deposits. These data strongly support the hypothesis for a common origin of mineralizing fluids
forming the two styles of hydrothermal ore deposit in the area.
These elements plus the regional-general observations regarding structural and metallogenetic
features, suggested the existence of caldera-type structures in Metaliferi Mts. yielding favorable
conditions for the coexistence of Au-Ag and porphyry copper deposits (Popescu & Neacsu,
2007).
Within this body a copper stockwork has formed, spanning over 1200 m in height. The lower-
central zone is occupied by potassic alteration in close association with metallic minerals
(magnetite, pyrite, enargite, hematite, chalcopyrite, bornite, digenite, molybdenite, tetrahedrite,
sphalerite and galena). Towards the upper-external areas, sericite, argillic and propylitic areas
develop, together with disseminated pyrite.
The existence of paleo-calderas in the Metaliferi Mts. has recently been recognized in the
Rosia Montana- Bucium district (O’Connor et al., 2004, Popescu& Neacsu, 2007) and in other
perimeters. It is very probable that such calderas like is drawing in figure 1 have functioned as
complex, circular-shaped structures which hosted hydrothermal activity.
The evolution of a trapdoor caldera in the Rosia Montana-Rosia Poieni area have following
stages: a) the upper part of the magma chamber froths, expands and flows up the vent only in the
south-west part; magma from the deeper parts of the chamber begins to flow out and the rocks
overlying the magma begin to collapse along the fractures into the now emptied chamber; a gold
119
silver metallogenesis is succeeded; b) the magma chamber is then depleted in gases - a minor
volcanic and subvolcanic activity are initialized in relation with a porphyry copper
metallogenesis is manifested; c) the magma continues to be more basic; volcanic bodies are
manifested only in the north-eastern part of the caldera.
c
b
a
Au
Cu
13.6-13.2My
9.42-9.16 My
~7.5 My
Meteoric water recharge Magmatic fluid flow
Fig 1. The evolution of Rosia Montana – Rosia Poieni volcanism and associated hydrothermal activity
Vivianite Fe2+
3(PO4)2.8H2O, is one of the significant hydrothermal components, especially in
the lower south-west part of the open pit (Fig. 2), where vivianite occurs as dark-blue prismatic crystals of up to 6 cm in length, against a background of mainly argillic (subordinately potassic and silicic) hydrothermal and supergene alteration affecting host microdiorites. The newly described vivianite occurrence might be similar with the one described in Musca gallery which intersected the lower part of Rosia Poieni complex (Giusca and Pavelescu, 1954)
120
Fig 2. The Rosia Poieni open pit Arrow indicates the main area of vivianite occurrence.
Larger crystals of vivianite occur in veinlets or vugs, associated with quartz, pyrite,
chalcopyrite, enargite and a yellowish argillic matter (Figures 3, 4 and 5). Thin films of vivianite may also occur along fine fissures in silicified, dark-gray microdiorites and on cleavage planes of hydrothermalized Cretaceous sedimentary rocks.
Based on the physiographic relationship with the other minerals, vivianite appears to be the last hydrothermal mineral. Semi-quantitative EDS chemical analyses revealed iron, phosphorous and oxygen (hydrogen inferred) as the main chemical constituents: FeO ~ 43 %, P2O5 ~ 28 % and H2O ~ 29 %. Due to the determination limits of the method used, the presence of minor substituents of Fe2+ (i.e., Mn2+, Mg, Fe3+) could not however be completely precluded. Powder X-ray diffraction revealed the main typical maxima of vivianite at (d/n in Å and relative intensities): 8.08 (15) 6.73 (100), 4.96 (12), 4.89 (20), 4.07 (54), 3.85 (12), 3.21 (58), 2.97 (16), 2.77 (16), 2.70 (61), 2.59 (34), 2.53 (32), 2.51 (23), 2.32 (49), 2.23 (19), 2.19 (28), 2.07 (19), 2.01 (16), etc. A ten-cycle unit-cell refinement based on 32 measured reflections resulted in the following parameters: a = 10.0591, b = 13.4415, c = 4.7000 Å, = 104.37o, largely comparable with other vivianites quoted by various sources.
Fig 3. Typical aspect of large prismatic crystals of vivianite from Rosia Poieni
121
Fig 4. Thin films of vivianite on altered microdiorites
Fig 5. Vivianite associated with pyrite and enargite in late veinlets within altered microdiorite breccias.
122
123
References Giusca D., Pavelescu L. (1954) Contributii la studiul cristalografic al mineralelor din zacamantul de la Musca. Com. Acad., 4, 11-12. Kuzmanov, K., Wallier, S., Rey, R., Pettke, T., Ivascanu, P., Heinrich, C. (2004) Fluid processes at the porphyry to epithermal transition: Rosia Poieni copper-gold deposit, Romania, In: J. Muhling et al. (Eds.), Predictive Mineral Discovery under Cover. Proceedings, SEG 2004 Conference , Perth,
Western Australia, 383-386. O’ Connor, G., Nash, C., R., Szentesy, Cecilia. (2004) The structural setting of the Rosia Montana gold deposit, Romania, Rom J. Mineral Dep. 81, 51-57. Popescu,G,.C,. Neacsu, Antonela (2007) Relationship between gold and copper metallogenesis in the Metaliferi Mountains, Anal. St. Univ. “Al. I. Cuza” Iasi, (in press). Udubasa, G., Rosu, E., Seghedi, I., Ivascanu, P., M. (2001) The “Golden Quadrangle” of the Metaliferi Mts., Romania: What does this really mean? Rom. Jour. Min. Dep. 79, suppl. 2, Special Issue, the
Second ABCD- GEODE Workshop, Vata 2001, 23-32, Bucharest.
LIVE CYCLE ASSESSMENT FOR A SALT MINING PROJECT
Toma PRIDA1, Gabriela SUCIU2, Nicolae Emanuel GIURGIU3
S.C. MINESA ICPM S.A. Cluj – Napoca [email protected]
In order to determine the interaction between a product or a process and the environment it
is necessary to understand the environmental aspects of them throughout the product or the process
life cycle. The methods for environmentally oriented life cycle assessment (LCA) of products,
processes or services where developed to provide this understanding. This work tries to put the
problem of LCA for mining projects.
Definition of Life Cycle Assessment– LCA
Human activities of production, services and consume, in order to inscribe in the concept of
sustainable development must obey a set of principles and procedures, instruments and politics that
integrate all aspects related to the environment, in all their stages of life cycle on the purpose to
improve environment performances.
Life cycle assessment is already the object of European standards since 1997 when came into
being ISO 14040 – Life cycle assessment – Principles and frame for work – Standard improved in
2006, when came into being also ISO 14044 – LCA – Requirements and Guide lines.
Life cycle of a product or system of services is formed in all consecutive stages and
interconnected from the extraction of natural resources to the storing of final/ultimate waste that can
be no more recycled or reused.
Life cycle assessment may be defined as a system of inventories and analysis of the effects
on the environment caused by a product or a process, starting with the extraction of raw materials,
production, use, etc to dismantling and waste processing. For each stage the inventory of relevant
entrances and exits of materials and energy is done, as well as that of emissions. With this inventory
may be established the environmental profile of the respective product or process, by evaluating
impacts. The inventory and impacts may lead through analysis and interpretation to finding out weak
points in the life cycle of the studied system. On these weak points must focus scientific research and
technological development in order to minimize the impact to the environment. That determines that
designers of products and processes face some problems the more complex and the more difficult.
123
Life cycle assessment for projects of salt mining
Mining projects for the exploitation of salt are among the most complex projects and maybe
they have the longest life cycle – sometimes centuries or even millenniums. Salt mines dating from
Middle Ages still have a significant environment impact.
Inappropriate approach of projects of salt mining lead and will lead to major risks.
Now, after, risk assessments were performed to some salt mines, we can certainly affirm that
in the stage of geological research were not taken into account and not researched and determined
some aspects important for the subsequent phases of design and operation and that lead latter to
affections of natural and entropic environment (Ocna Mureş, Ocna Şugatag, Ocnele Mari).
Although the phases of geological research and work methods are similar for all solid mineral
substances, due to the specificity of salt, its geological research means a series of particularities of
essential approach in taking a solution for design, operation and closure that minimizes risks for the
whole life cycle of the project.
In figure 1 is represented a schedule of life cycle for a mining project that has the object of
salt minig.
Act of Mines no.85/2003, by instituting the obligation to elaborate the plan for ceasing the
activity (chapter VII art.51-53) and Order of Ministry of Industry and Resources no.273/2001, for the
approval of the Manual of closing mines, by instituting the miner operator’s obligation to elaborate
since the initiation phase for the license to exploit, the initial plan for closing the mine, and since
2002, also the obligation that General Exploit Plan is accompanied by the Technical Project of
Closing the Mine created the legal frame that cans make easier the work of assessment of life cycle
for a mining project. Although there are these regulations we do not know in Romania cases of
assessment of a mining project.
Methodologies used in the assessment of life cycle
Developed countries had the problem of the assessment of products from the environmental
point of view through the whole life cycle (”Life cycle” or “cradle-to-grave”) since the years ’70, but
only in early ’90, at UNO Assembly in 1992, it was stated that methodologies of life cycle
assessment are the most promising new instruments for the management of environment. During last
ten years several methodologies were elaborated for LCA, among which we remind the followings:
124
Ecoindicator 99 is a methodology elaborated under the coordination of National Institute for
Public Health and Environment, Netherlands and Environment Agency in Switzerland through which
it was established a method to quantify the impact on the environment, bases on all effects in the life
cycle, on the form of a number called ecoindicator. Standard values of the ecoindicator are reported
to units of product (kg, tkm, kw, etc.)
CML – methodology elaborated by the Institute for Environmental Science Leiden in
Netherlands in 2002.
EDIP 2003 methodology created by Technical University and Institute for Technological
Services from Denmark.
Bibliography
(ISO 14040) ISO 14040 Standard, Life Cycle Assessment - Principles and Framework; 2006
(ISO 14044) ISO 14044 Standard, Life Cycle Assessment - Requirements and Guideline;
The Eco-indicator 99 A damage oriented method for Life Cycle Assessment Methodology Report -
The third edition 2001, internet: www.pre.nl/EI99
Eco-indicator 99 Manual for Designers; internet: www.pre.nl
CML 2002; internet: www.leidenuniv.nl/cml/ssp/index.html
EDIP 2003; internet: www.lca-center-dk
Alan Astrup Jensen, Life Cycle Assessment – A guide to approaches experiences and information
Sources, European Environment Agency, Environmental Issues Series /no./6/1997
Management of works of opening, operate and closure of wells for salt in solution, on the purpose of
reducing pollution risk: MINESA-ICPM Cluj-Napoca; University of Bucharest – June 2007.
125
126
Fig. 1. Life cycle of a mining project for salt
Entrances Stages of life cycle Exits
Prospecting, exploration and geological research: Necessary works and activities: - access ways: roads; - drillings; - electric powering; - underground mining works; - dumps for mining waste; - pilot installations for processing.
Technological Development
↓ M
ater
ials
+ E
ner
gy +
Wat
er +
Min
eral
res
ourc
es
↓
Activities for making the works necessary to extract and put in value the salt: access roads: roads, railways; facilities to assure utilities: electricity, methane gas, thermal
energy, compressed air, water, sewage, water treatment, mechanical workshop, auto workshop, auto basis, laboratories, technical-social group, canteen, warehouses for explosives etc.;
mining works for opening and preparation (underground / surface); dumps; facilities to process the extracted mineral; facilities to manage finite products (warehouses for concentrated,
sorts,), of sub-products and a of waste
↓ M
inin
g p
rod
uct
s +
Min
ing
Ste
rile
+ O
ther
deb
ris
+
Em
issi
ons
↓
Extraction
↓
Mat
eria
ls +
En
ergy
+ W
ater
+ M
iner
al r
esou
rces
↓
The activity of extraction itself (underground or on surface) and the transport to facilities for processing.
Processing raw salt extracted Activities of processing salt by grinding, separation, purification, drying, storing, packaging, shipping to consumers. Activities of managing sub-products and waste(dumps, ponds). Activities of technologic and quality control. Maintenance activities. Activities of environmental monitoring. Closure of mining activity Activities to prepare for closing underground or surface mining works. Activities of closure itself: dismantling, ecological reconstruction of mining sites, dumps, ponds, used fields, waste managing works (recovery, reuse, recycling and storing). Monitoring activities of mining constructions (underground mining works, dumps, and ponds) during the closure period.
Post closure maintenance and monitoring Activities of monitoring underground mining works, dumps, ponds and facilities of treatment for mine waters, ex-filtration waters as well as activities of their maintenance.
↓
Min
ing
pro
du
cts
+ M
iner
Ste
rile
+ O
ther
deb
ris
+
Em
issi
ons
CONTRIBUTIONS AT THE STUDY OF COMPLEX UTILIZATION OF THE
NEPHELINE SYENITES ON HYDROTHERMAL WAY
Victor ŞABLIOVSCHI1, Ioan BALINTONI2, Maricel RĂILEANU1, Murariu TITUS1
1 „Al. I. Cuza” University, Iaşi , Geography – Geology Faculty, Geology Department, B –dul Carol I, no. 20A, 700505 Iaşi.
2 „Babeş Bolyai” University, Cluj - Napoca, Biology – Geology, Faculty, de Mineralogy – Metalogeny Department, Street Mihai Kogălniceanu no.1. Cluj – Napoca. RO - 400844
Abstract
The study of treatament on hydrothermal way of the nepheline syenites led to the following
conclusions: 1. Depending on the conditions of hydrothermal treatment, from nephelinn syenites can be
removed potassium in proportions [] which vary in limits by 50.24 and 82.90 per cent. 2. High yiels are obtained in the following conditions: the ratio rock / lime = 1 : 1.5,
pressure by 20 at. And the treatment time by 6 hours. 3. The obtained solid residue after hydrothermal treatment of the nephelin syenites together
with different substances, at the organic binders manufacture can be utilized. LSF-0.96, SR-1.44, AR-83.66 and R:CaO – 1.5. Calculation Bogue [%], sample 9: C3S – 71,30 – alite; C2S – 13,40 – belite; C3A -15,10 – celite and C4AF – 0,20 – ferrite = Portland Cement.
4. Minor elements and TR present high content (ppm): Ba* 1011; Rb 122; Sr 1364; Zr 783, Hf 23; Nb 224; Ta 16; Sc 1,40; Zn 52; Pb 9. Between TR: mean % La 24,33ppm -24,55%; Ce 37,7 - 39,17%; Nd 22,7 - 28,79%; Sm 5,02 – 3,16%; Eu 1,11 – 0,78%; Gd 1,35ppm; Tb 0,68ppm – 0,30%; Dy 2,29ppm; Yb 2,45-1,11%; Lu 0,38-0,08%;TR total 97,44 ppm in nepheline syenite Y 62; Th 10,1 şi U 8,2.* (Jakab,1998).
1. Clinker: Compositional parameters of residues Parameters based on the oxide composition are very useful in describing clinker
characteristics. The following parameters are widely used (chemical formulae represent weight percentages): LSF – lime saturation factor; SR – silica ratio; AR – alumina ratio and R : CaO ratio of experiments (Table I).
Table I. Variation in compositional parameters of resulting residues (LSF,SR, AR and R : CaO), to similar clinkers after
potassium extraction from nepheline syenites of Ditrău (Şabliovschi et al.,2008)
Clinker paramete
r
1 2 3 4 5 6 7 8 9 Alite
10
LSF lime saturation factor 0.92 – 0.98 LSF 0,34 0,368 0,49 0,44 0,49 0,78 0,71 0,70 0,96 1,22
SR silica ratio 2.0 – 3.0 SR 1,803 2,077 1,877 2,085 1,873 1,792 1,791 2,016 1,443 1,774
AR alumina ratio 1 – 4 Ordinar Portland Cement AR 37 34,48 41,86 42 44,75 55,77 71,73 86,66 83,66 367,5
Rock : CaO ratio R : CaO 1 1 1 1 1 1,5 1,5 1,5 1,5 2
127
Relaţiile dintre AR alumino ratio, SR silica ratio şi LSF factorul de saturare a clinkerului obţinut după extragerea potasiului din sienitul nefelinic de Ditrău
0
50
100
150
200
250
300
350
400
1 2 3 4 5 6 7 8 9 10
AR
0
2
4
6
8
10
12
LSF
, SR
AR
SR
LSF
Proba
Relatia LSF - AR
0
50
100
150
200
250
300
350
400
0 0,5 1 1,5
LSF - Lime saturation factor
AR
- a
lum
ina ratio
AR
Proba
Fig.1a, 1b Correlations between AR –alumina ratio, SR – silica ratio and LSF – lime saturation factor in obtained
clinker after potassium extraction on nephelin syenite from Ditrău
Lime Saturation Factor The LSF is a ratio of CaO to the other three main oxides. Applied
to clinker, it is calculated as: LSF=CaO/(2.8SiO2 + 1.2Al2O3 + 0.65Fe2O3). Often, this is referred to as a percentage and therefore multiplied by 100. The LSF controls the ratio of alite to belite in the clinker. A clinker with a higher LSF will have a higher proportion of alite to belite than will a clinker with a low LSF. Typical LSF values in modern clinkers are 0.92-0.98. (sample 9 – 0.96). Values above 1.0 indicate that free lime is likely to be present in the clinker (sample 10 – 1.22). the surplus free lime has nothing with which to combine and will remain as free lime (sample 10). This is because, in principle, at LSF = 1.0 all the free lime should have combined with belite to form alite.
Corelatiile dintre SR, LSF in functie de raportul roca : CaO
0
2
4
6
8
10
12
0 100 200 300 400
SR
LSF
Proba
R:CaO
Corelatia SR - LSF
0
0,2
0,4
0,6
0,8
1
1,2
1,4
0 0,5 1 1,5 2 2,5
LSF
Fig.2a, 2b Correlations between SR – LSF – rock : CaO in obtained clinker after potassium extraction on nepheline syenite from Ditrău (Şabliovschi,2008)
In practice, the mixing of raw materials is never perfect and there are always regions within the clinker where the LSF is locally a little above, or a little below, the target for the clinker as a whole. This means that there is almost always some residual free lime, even where the LSF is considerably below 1.0. It also means that to convert virtually all the belite to alite, an LSF slightly above 1.0 is needed.
Silica Ratio (SR) The silica ratio is defined as: SR = SiO2/(Al2O3 + Fe2O3)
A high silica ratio means that more calcium silicates are present in the clinker and less aluminate and ferrite. SR is typically between 2.0 and 3.0. samples (R:CaO;P,at, Duration, h):
128
2 – 2.077 (1/1;10; 6 h); 4 – 2.085 (1/1;40;6 h); 8 – 2.016 (1-1,5;20;6 h) and 9 - 1.443 (1-1.5;20, 8 h). The silica ratio is sometimes called the "silica modulus."
Alumina Ratio (AR) The alumina ratio is defined as: AR = (Al2O3/(Fe2O3)
3
This determines the potential relative proportions of aluminate and ferrite phase in the clinker. An increase in clinker AR (also sometimes written as A/F) means there will be proportionally more aluminate and less ferrite in the clinker. In Ordinary Portland Cement clinker, the AR is usually between 1 and 4. The above three parameters are those most commonly used. A fourth, the 'Lime Combination Factor' (LCF) is the same as the LSF parameter, but with the clinker free lime content subtracted from the total CaO content. With an LCF=1.0, therefore, the maximum amount of silica is present as C3S.
2. Clinker: the Bogue calculation
The standard Bogue calculation refers to cement clinker, rather than cement, although it can be adjusted for use with cement. This is a very commonly-used calculation in the cement industry. The calculation assumes that the four main clinker minerals are pure minerals with compositions: alite: C3S, or tricalcium silicate; belite: C2S, or dicalcium silicate; aluminate phase: C3A, or tricalcium aluminate and ferrite phase: C4AF, or tetracalcium aluminoferrite. These assumed compositions are only approximations to the actual compositions of the minerals. Clinker is made by combining lime and silica and also lime with alumina and iron. If some of the lime remains uncombined, (which it almost certainly will) we need to subtract this from the total lime content before we do the calculation. For this reason, a clinker analysis normally gives a figure for uncombined free lime.
C3S = 4.0710CaO-7.6024SiO2-1.4297Fe2O3-6.7187Al2O3 ; C2S = 8.6024SiO2 + 1.0785Fe2O3+5.0683Al2O3-3.0710CaO; C3A = 2.6504Al2O3-1.6920Fe2O3; C4AF = 3.0432Fe2O
The calculation is simple in principle: Firstly, according to the assumed mineral compositions, ferrite phase is the only mineral to contain iron. The iron content of the clinker therefore fixes the ferrite content. Secondly, the aluminate content is fixed by the total alumina content of the clinker, minus the alumina in the ferrite phase. This can now be calculated, since the amount of ferrite phase has been calculated. Thirdly, it is assumed that all the silica is present as belite and the next calculation determines how much lime is needed to form belite from the total silica content of the clinker. There will be a surplus of lime. Fourthly, the lime surplus is allocated to the belite, converting some of it to alite. In practice, the above process of allocating the oxides can be reduced to the following equations, in which the oxides represent the weight percentages of the oxides in the clinker.
Table 2. Bogue calculation for residues after hydrothermal tratment of the nepheline syenites (Şabliovschi,2008)
No C3S Alit-
C2S Belit
C3A Celit
C4AF Ferrit
P at
Time H
1 190,4 228,13 41.43 1,31 5 6
2 -168,26 209,36 34,99 1,18 10 6
3 -107,11 150,02 32,77 0,91 20 6
129
130
4 -124,68 168,61 31,79 0,88 40 6
5 -110,79 154,12 32,74 0,85 60 6
6 147,46 59,11 26,31 0,54 20 2
7 -173,75 77,4 28,26 0,45 20 4
8 -31,76 84,5 27,24 0,57 20 6
9 124,69
%71,30
23,43
%13,40
26,41
%15,10
0,36
%0,20
20 8
10 72.6 -17,28 19,46 0,06 20 6
References
Ababi V., Şabliovschi V., Murariu T., Dumitrescu M., (1973) Contribuţii la studiul valorificării complexe a sienitelor nefelinice pe cale hidrotermală. An.şt. Univ ”Al.I.Cuza” Iaşi (s.n). Secţiunea 1, c. Chimie, tom XVIII,fasc.2, p.211 – 221.
Anastasiu, N., Constantinescu, E., (1975) On the mineralogy of syenites from the alkaline massif of Ditrău. Comunicări Geol., Buc., p. 77-85.
Burke, E.A.J, (2001) Raman microspectroscopy of fluid inclusions. Lithos 55, p.139-158. Codarcea Al., Codarcea Dessila Marcella, Ianovici V.,(1957) – Structura geologică a masivului de
roci alcaline de la Ditrău. Bull. St. Acad. RSR, II/ 3 – 4, p. 385, Bucureşti Constantinescu, E., Anastasiu, N., (1979) - Nepheline from the alkaline massif of Ditrău. Analele
Univ. Buc., Geol., XVIII, p.15-27. Fall A., (2005) Fluid evolution in the nepheline syenites of the Ditrău Alkaline Massif, Transylvania,
Romania. Master in Geoştiinţe. Blacksburg, Virginia. Ianovici, V., (1938) Considération sur la consolidation du massif syénitique de Ditrău, en relation
avec la tectonique de la région. C. R. Acad. Sci. Roum. 2,p. 689-694. Jakab Gy., (1998) –Geologia masivului alcalin de la Ditrău. Ed. Alutus S.A. Miercurea Ciuc. 298 p. Jones A. P., Larsen L.M., (1985) Geochemistry and REE minerals of nepheline syenites from zhe
Motzfeldst Centre, South Greenland. American Mineralogist, v,70, p. 1087 – 1100. Kräutner, H.G., Bindea, G., (1998) Timing of the Ditrău alkaline intrusive complex (Eastern
Carpathians, Romania). Slovak Geol. Mag. 4, p. 213-221.
AMBLYGONITE - MONTEBRASITES FROM DIVINO DAS LARANJEIRAS - MENDES PIMENTEL PEGMATITIC SWARM, MINAS GERAIS,
BRAZIL I. GEOLOGIC SETTING
Ricardo SCHOLZ1, Joachim KARFUNKEL2, Vladimir BERMANEC3, Geraldo Magela da COSTA4, Adolf Heirich HORN5, Luiz Antônio Cruz SOUZA6 & Essaid BILAL7
1 Departamento de Geologia, Instituto de Geociências, Programa de Pós-Graduação em Geologia,
Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil – [email protected] 2 Departamento de Geologia, Instituto de Geociências, Universidade Federal de Minas Gerais, Belo
Horizonte, MG, Brasil – [email protected] 3 Mineralogy and Petrology Institute, Faculty of Sciences and Mathematics, University of Zagreb,
Zagreb, Croatia - [email protected] 4 Departamento de Química, Instituto de Ciências Exatas e Biológicas, Universidade Federal de
Ouro Preto, Ouro Preto, MG, Brasil - [email protected] 5 Departamento de Geologia, Instituto de Geociências, Centro de Pesquisa Professor Manoel
Teixeira da Costa, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil – [email protected]
6 Escola de Belas Artes, Centro de Conservação e Restauração, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil – [email protected]
7 Ecole Nationale Supérieure des Mines de Saint Etienne, SPIN, Instituto Héliopolis, [email protected]
INTRODUCTION AND PROBLEM
Phosphates of the isomorphous series amblygonite-montebrasite – (Li,Na)Al(PO4)(F,OH)
belong to the amblygonite group together with natromontebrasite - (Na,Li)Al(PO4)(OH,F) and
tavorite - LiFe3+(PO4)(OH,F).
The chemical composition of amblygonite-montebrasites can differ: besides the main
elements P, O, Al, Li, F and H, the elements Mg, Fe, and Ca can occur in minor proportion and Na
can substitute partially or completely the Li. Černá et al. (1972) indicate a considerable influence of
substitutions like F/OH and Li/Na on the physical properties.
These minerals form as primary crystallization products of a pegmatitic magma,
penecontemporaneous with other predominant minerals (Černá et al. 1972). They can be of
secondary origin too, as alteration products of the primary phase by late fluids, filling partially
substitution bodies. These authors describe, that amblygonite-montebrasites of secondary origin are
poorer in the fluorine content than those of primary crystallization.
London & Burt (1982) mentioned montebrasites from the pegmatite district of White
Picacho, AZ, with a low fluorine content, associated with crandallite, hydroxylapatite, brazilianite,
augelite, scorzalite, kulanite, willeite and carbonate-fluorapatite. They are of metasomatic origin
formed as alteration products of primary montebrasites rich in fluorine.
131
Boruckij (1966, in Černá et al. 1972) observed a decrease in the fluorine content in zoned
amblygonite-montebrasite crystals from Siberia. He suggested a link between crystallization
temperatures and F/OH rates; minerals richer in fluorine crystallize at higher temperatures. In most
cases the only minerals to compete with amblygonite-montebrasites for the fluorine, are the micas.
The lower fluorine content of secondary amblygonite-montebrasites can be explained by
alteration processes of these minerals, which involve the substitution of fluorine ions by hydroxyl
ions through diffusion. Thus, according to Fransolet & Tarte (1977) this substitution during the
sequence of pegmatite differentiation can represent an important instrument for the study of
petrogenetic evolution of pegmatites.
Correia-Neves et al. (1987) describe minerals of the crandallite group (plumbogumite,
goyazite, and gorcexite) and kaolinite, as supergenic alteration products of primary amblygonite-
montebrasites in pegmatites from north Minas Gerais, however not discussing the F/OH content in
relation to secondary alteration process.
The Divino das Laranjeiras – Mendes Pimentel pegmatitic swarm field is situated 65 km ENE
of Governador Valadares and approximately 380 km from Belo Horizonte, capital of the Minas
Gerais State (Fig. 1). It can be inserted geologically and in the context of the Araçuaí Fold Belt, in
the central-northen part of the Mantiqueira Province Almeida (1981). The rocks, of neoproterozoic
age, in the region belong to the Tumiritinga Formation and São Tomé Formation (Rio Doce Group),
or are composed of São Vítor and Galiléia Tonalites.
More than 60 pegmatites are known to date from this area, distributed in a quadrangle of 400
km2. Phosphate minerals are commom (e.g.: Cassedane & Batista 1999, Karfunkel et al. 1999) and
several new minerals have been discovered in these pegmatites (e.g.: Pough & Henderson 1945,
Pecora & Fahey 1949).
The majority of phosphate minerals occur in pegmatites or in intrusive cupolae of
granitic/sienitic derivation. According to Howthorne (1998) pegmatitic phosphates are related to
coarse granitic pegmatites with well developed zones, in which the primary phosphates crystallize at
or near the core. The phosphates in the studied area occur in all the pegmatitic zones, nevertheless
generally they are more abundant in the intermediate zone or in the substitution bodies. Primary
amblygonite-montebrasite is known only from 5 pegmatite bodies, sometimes together with
triphylite-lithiophilite, another primary phosphate.
The secondary mineral assemblages are composed of a large variety of phosphates with a
wide diversity of parageneses. Outstanding are montebrasite, roscherite, zanazziite, brazilianite,
132
childrenite-eosphorite, crandallite, moraesite, souzalite-lazulite, beryllonite, hydroxylherderite,
scorzalite and autunite.
However, the complex genetic, structural and compositional features of pegmatitic rocks turn
them susceptible to an extreme variety of chemical reactions, which include, according to Moore
(1973), primary crystallization stages (800-600), metasomatic (600-350), hydrothermal (350-
50), and still supergenic alterations. Fisher (1958) pointed out that a large number of phosphates are
relatively limited in their range of stability. Many of them can be considered as delicate indicators of
the particular conditions present at the time of their formation.
Fig. 1. Location and geological map of the Divino das Laranjeiras Mendes Pimentel Pegmatitic swarm. CF – Córrego Frio,
JF – João Firmino, TE – Telírio, PO – Pomarolli, AF- Afrânio and JL – Jove Louriano.
133
134
The present papers aim not only to describe primary and secondary phosphates, mainly
amblygonite-montebrasites and their alteration products, but pretend to demonstrate the utility of
analytical data in detecting the primary, secondary and/or supergene character of these minerals
GEOLOGIC SETTING
The Brazilian Oriental Pegmatite Province ("Província Pegmatítica Oriental Brasileira"), defined by Paiva (1946), occupies a vast region in NE of Minas Gerais, NW of Espirito Santo, and SE of Bahia, covering an area of almost 80.000 km2. Due to its huge extension several Precambrian sequences of different ages (Archean to Neoproterozoic) crop out.
The Araçuaí Fold Belt (Almeida et al. 1977) is a mobile belt that extends to the east of the São Francisco Craton. Correlations between this fold belt and the West-Congo Fold Belt have been mentioned in the geologic literature (e.g. Brito Neves & Cordani 1991, Pedrosa-Soares et al. 2001). In the studied area rocks of the Tumiritinga and São Tomé formations (Rio Doce Group), as well as of the Galiléia Tonalite and the São Vitor Tonalite, are exposed (Fig. 1). Therse sequences are of Neoproterozoic age. The Tumiritinga and São Tomé formations have been first described by Barbosa et al. (1966). Contacts between both (mainly quartzites, schists and amphibolites) are gradational, but discordant with the tonalite suites. The Galiléia Tonalite is composed of biotite-sillimanite-(graphite)-garnet gneisses, sillimanite-biotite gneisses, and cordierite-sillimanite gneisses. The rocks are slightly peraluminous of calc-alcaline affinity, with granitoides of the Type I, represented by tonalites, granodiorites, granites and microgranites (Nalini 1997).
The São Vitor Tonalite (Netto et al. 1998) is composed by quartz, feldspars, amfibole and biotite, with enclaves of calc-silicate rocks and biotite schists.
The project called "Projeto Leste" and carried out by DNPM/CPRM (Netto et al. 1998), proposed a metallogenetic division of this province in Minas Gerais in 7 pegmatitic districts, each one still subdivided in fields, according to their geological and geographical features. Thus, the pegmatitic district of Conselheiro Pena has been subdivided in 5 fields: Itatiaia - Barra do Cuité, Alvarenga - Itanhomi, Resplendor, Goiabeira, and Galiléia - Mendes Pimentel. The studied pegmatites of the area of Divino das Laranjeiras - Mendes Pimentel swarm is located at the northern part of the latter pegmatitic field (Fig. 1).
The pegmatite swarm in the area intruded mainly biotite-quartz-schists of the São Tomé Formation, occasionally rocks of the São Vitor Tonalite, too (Fig. 1). The pegmatite bodies are inclosed concordantly in the foliation of the schists and cut the tonalites parallel to regional fracture systems (Karfunkel et al. 1999). Most pegmatites have a characteristic mineralogy of differentiated bodies (Ribeiro 1996), with Li-, Ta-, Sn-, Nb-, and Be-minerals.
Pegmatite bodies are tabular or lenticular, 2 to 30 m in thickness with extensions up to 80 m. They usually do not show pronounced textural zones (Cameron et al. 1949), however at a larger scale, they have zones which differ in texture and composition.
Predominant pegmatitic minerals of the area are: quartz, feldspars (microcline and albite), muscovite and, in several bodies, amblygonite-montebrasite, triphylite-lithiophilite and fluorapatite. Schorlite is common, and in some bodies, even principal (Addad et al. 2000, 2001). Lepidolite and spodumene are relatively scarce. A large number of accessory minerals are phosphates of late crystallization forming complex parageneses, besides others like spessartite, siderite, coockeite and cassiterite. References are given at the end of part III.
135
AMBLYGONITE - MONTEBRASITES FROM DIVINO DAS LARANJEIRAS - MENDES PIMENTEL PEGMATITIC SWARM,
MINAS GERAIS, BRAZIL. II. MINERALOGY
Ricardo SCHOLZ1, Joachim KARFUNKEL2, Vladimir BERMANEC3, Geraldo Magela da COSTA4, Adolf Heirich HORN5, Luiz Antônio Cruz SOUZA6 & Essaid BILAL7 1 Departamento de Geologia, Instituto de Geociências, Programa de Pós-Graduação em
Geologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil – [email protected]
2 Departamento de Geologia, Instituto de Geociências, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil – [email protected]
3 Mineralogy and Petrology Institute, Faculty of Sciences and Mathematics, University of Zagreb, Zagreb, Croatia - [email protected]
4 Departamento de Química, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brasil - [email protected]
5 Departamento de Geologia, Instituto de Geociências, Centro de Pesquisa Professor Manoel Teixeira da Costa, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil – [email protected]
6 Escola de Belas Artes, Centro de Conservação e Restauração, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil – [email protected]
7 Ecole Nationale Supérieure des Mines de Saint Etienne, SPIN, Instituto Héliopolis, [email protected]
EXPERIMENTAL METHODS
A total of 72 samples, including primary and secondary phosphates, have been analyzed.
The X-ray diffraction were carried out at the Instituto de Ciências Exatas e Biológicas,
Universidade Federal de Ouro Preto, utilizing a Shimadzu model XRd 6000, with a Co tube and
an iron filter and scanning velocities of 0.5/min. Lattice parameters have been calculated with
the more intense reflections after the subtraction of the background and the K2.
Several samples were studied with the SEM at the Microanalysis Laboratory of the
Universidade Federal de Minas Gerais, with a JEOL-JSM840A under varying current and
tension conditions.
The infrared spectroscopical analysis (FTIR) have been carried out at the infrared
laboratory of the Centro de Conservação e Restauração, Escola de Belas Artes, Universidade
Federal de Minas Gerais with powder samples at a BOMEM/HARTMANN & BRAUN
spectrometer, model MB100C23, with a diamond cell for micro beam, SPG46G model.
136
Collected spectrums covered the range of 4000cm-1 – 400 cm-1 with a 4 cm-1 resolution, and have
been interpreted by using the Win-Bomen Easy, 3.01c version.
Chemical analysis with the EPMA were made at the Microanalysis Laboratory of the
Universidade Federal de Minas Gerais with an JEOL-JXA8900R in the EDS and WDS modes,
under the following conditions: acceleration tension 15 kV, current on the sample 2.00x10-8
Amps.
RESULTS
Today there are approximately 20 explored pegmatite bodies in the studied area;
amblygonite-montebrasites have been detected in 5 of them as primary phosphates (Fig. 1): CF –
Córrego Frio, JF – João Firmino, TE – Telírio, PO – Pomarolli, AF- Afrânio and JL – Jove
Louriano. These primary minerals occur together with quartz, muscovite and microcline,
sometimes with triphylite too. Crystals of amblygonite-montebrasites show a well developed
habitus and are of greenish color, sometimes creme or colorless. Once in a while small
completely transparent pieces in gem quality are seen in local markets.
Secondary amblygonite-montebrasites fill partially and/or totally substitution bodies.
However, they can occur at body walls too, usually as massive blocks.
Taken in account mineralogical assemblages and their mode of occurrence in the
pegmatite body (Scholz et al. 2001), the amblygonite-montebrasites of Divino das Laranjeiras -
Mendes Pimentel could be divided in 3 types:
- Type I: amblygonite-montebrasites of primary origin, associated with other primary minerals,
found usually at the intermediate zone;
- Type II: Secondary amblygonite-montebrasites, occuring in substitution/alteration bodies. The
habitus is hard to identify due to Dissolutions parallel to cleavage planes and etched
and corroded surfaces (Fig. 1). They are accompanied by other minerals of secondary
origin, like fluorapatite, muscovite and albite, and are related to a metasomatic stage
of crystallization (Moore 1973);
- Type III: Are also of secondary origin similar to Type II, however their habitus is prismatic
and elongated according to the crystallographic c-axis. The mineralogical assamblage
is complex, and Moore (1973) related minerals of this type to a hydrothermal
crystallization phase.
CK
Fig.1. Montebrasite (Mo) with dissolution marks parallel to cleavage planes, associated to coockeite (Ck).
Infrared Spectroscopy
Measured infrared spectras where obtained for 5 samples. In the interval 1150-1050 cm-1
the transmission band of the (PO4)3- anion can be observed, with weak to medium absorption
intensities, caused by assymetric vibration of the PO4 tetrahedra. The stretching effect occur at
the interval of 1200-1150 cm-1. The Li-O bond contributes to a transmission below the 500 cm-1
region. Bending effect of the PO4, as well as the vibration of AlO6 stretching, yield transmitance
bands in the 650-500 cm-1 interval.
Using the correlation curve established by Fransolet & Tarte (1977) between OH
frequencies (OH in the region between 3400-3350 cm-1 and OH in the 840-800 cm-1 region) and
the fluorine percentage in amblygonite-montebrasites , calculation of fluorine content in the
analyzed specimen were done.
Correlation curves are given by the equations:
OH = (-4.06x + 3396.5) cm-1 (1)
OH = (2.74x + 804.6) cm-1 (2) x = percentage of fluorine.
137
138
We used the OH band and equation 2, due to minor average errors. The percentage
calculations of the fluorine show contents between 1.78% and 4.03%. Values of OH frequency
and fluorine percentage are shown in Tab.1, together with the type characterization (I, II or III).
Table 1- Type of montebrasites, infrared values of OH bands and the calculated fluorine percentage (Scholz et al. 2001).
Sample JF-28 JF-13 JF-15 JF-25 CF-01
Type III II II II I
Frequence
OH /cm-1
809.5
810.2
810.6
810.8
816.4
Calculated
F (%)
1.78 2.04 2.19 2.26 4.03
Chemical analytical data for montebrasites have shown values of fluorine between 0.07
and 4.91. The data are presented in Tab. 2. The Fig. 2 shows the relation between the fluorine
content and the origin of the montebrasite – primary, metasomatic or hydrothermal.
Table 2 - Chemical composition and the Type of montebrasites.
Type III III III III III III III II II I I I
Sam - ple
TE -23
TE -26
TE -22
JF -33
JF-12
AF-01
JF - 28
JF-15
JF-25
JL-01 CF-01
PO-01
F 0.07 0.22 0.23 0.33 0.81 1.11 1.98 2.25 2.45 3.32 3.86 4.91
FeO 0.04 0.07 0.07 0.04 0.03 0.2 0.08 0.03 0.0 0.02 0.02 0.04
K2O 0.00 0.01 0.00 0.00 0.00 0.1 0.00 0.00 0.0 0.00 0.00 0.01
Na2
O 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.03 0.00 0.13 0.04
CaO 0.00 0.00 0.01 0.00 0.01 0.01 0.01 0.01 0.0 0.01 0.01 0.20
P2O5 50.44 50.40 50.00 49.98 50.69 50.59 50.39 50.49 50.18 49.93 49.62 49.81
MnO 0.01 0.00 0.01 0.00 0.01 0.01 0.01 0.01 0.02 0.01 0.02 0.01
Al2O 34.11 34.23 34.12 34.06 34.52 34.09 34.08 34.33 34.20 34.18 34.28 34.183
Total 84.65 84.84 84.34 84.30 85.73 85.38 84.60 85.00 86.88 86.07 86.31 87.12
Fig. 2. Relation between the fluorine content and the origin of the montebrasite.
References are given at the end of part III.
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140
AMBLYGONITE - MONTEBRASITES FROM DIVINO DAS LARANJEIRAS - MENDES PIMENTEL PEGMATITIC SWARM, MINAS
GERAIS, BRAZIL III. SECONDARY PHOSPHATES
Ricardo SCHOLZ1, Joachim KARFUNKEL2, Vladimir BERMANEC3, Geraldo Magela da COSTA4, Adolf Heirich HORN5, Luiz Antônio Cruz SOUZA6 & Essaid BILAL7
1 Departamento de Geologia, Instituto de Geociências, Programa de Pós-Graduação em
Geologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil – [email protected]
2 Departamento de Geologia, Instituto de Geociências, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil – [email protected]
3 Mineralogy and Petrology Institute, Faculty of Sciences and Mathematics, University of Zagreb, Zagreb, Croatia - [email protected]
4 Departamento de Química, Instituto de Ciências Exatas e Biológicas, Universidade Federal de Ouro Preto, Ouro Preto, MG, Brasil - [email protected]
5 Departamento de Geologia, Instituto de Geociências, Centro de Pesquisa Professor Manoel Teixeira da Costa, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil – [email protected]
6 Escola de Belas Artes, Centro de Conservação e Restauração, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil – [email protected]
7 Ecole Nationale Supérieure des Mines de Saint Etienne, SPIN, Instituto Héliopolis, [email protected]
SECONDARY PHOSPHATES
The Divino das Laranjeiras – Mendes Pimentel pegmatitic swarm is internationally know
since the 1940 decade, when 3 new minerals have been discovered in the Córrego Frio
pegmatite: brazilianite (Pough & Henderson 1945) and scorzalite and souzalite (Pecora & Fahey
1949). Later, many other secoundary phosphates related to amblygonite-montebrasites have been
described (Cassedann & Baptista, 1999; Lindberg, 1958; Leavens et al. 1990; Ribeiro, 1996;
Karfunkel et al. 1999).
Eosphorite, childrenite and ernstite
Eosphorite - (Mn2+, Fe2+)Al(PO4)(OH)2H2O) and childrenite (Fe2+, Mn2+)
Al(PO4)(OH)2H2O) form as alteration products of primary pegmatitic phosphates such as
amblygonite-montebrasite (Moore 1973) and triphylite (London & Burt 1982). Although they
are usually associated with pegmatites, they can occur in other environments like in Pb-Zn
deposits of Stari Trg, Trepča, Kosovo (Bermanec et al 1995).
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Ernstite – (Mn1-x2+, Fex
3+)Al(PO4)(OH)2-xOx – was described by Seelinger & Mücke
(1970) as an alteration (oxydation) product of childrenite. Controversy concerning the genesis of
the mineral was shown by Alves et al. (1980), who indicated that childrenite reists the oxydation;
however, Braithwaite & Cooper (1982) describe an excess of Fe3+ in relation to Fe2+ due to
supergenic alteration. Ginsburg & Voronkova (1950) report a complete oxydation of Fe2+ to Fe3+
of specimens from Kasakstan.
Eosphorite, childrenite and ernstite are common minerals in pegmatites of Divino das
Laranjeiras – Mendes Pimentel. The first two are associated with amblygonite-montebrasites,
mainly as dissolution cavity fillings or grown on their faces. Other allied minerals are zanazziite,
roscherite, fluorapatite, hydroxylherderite and brazilianite. Ernstite has been identified in 1
pegmatite of the region: João Firmino. It occurs in late alteration/substitution bodies together
with hydroxylherderite, muscovite and montebrasite.
Roscherite and Zanazziite
Roscherite - Ca(Mn2+,Fe2+)2Be3(PO4)3.2H2O - was first described by F. Slavik as a
hydrated phosphate of calcium, iron, manganese and aluminium (Lindberg, 1958). It crystalize
as granulate masses of green to brownish color and is usually associated with other secondary
phosphates (e.g. eosphorite, gormanite, montebrasite, fluorapatite, and frondelite).
The studied samples from the João Firmino mine are monoclinic, space group C2/c, in
agreement with datas presented by Lindberg (1958). However, Fanfani et al. (1975), studying
samples from Foote Mine (North Caroline), indicate a triclinic symmetry.
Zanazziite – Ca2(Mg,Fe2+)(Mg,Fe2+,Al)4Be4(PO4)6(OH)4.6H2O – has been described by
Leavens et al. (1990) from the Ilha mine, Taquaral county, in north of Minas Gerais. These
samples are usually associated with montebrasite and eosphorite. X-ray diffraction of samples
from the Gentil pegmatite in the studied area indicate a monoclinic symmetry and a C2/c spacel
group.
Herderite - Hydroxylherderite
Herderite and Hydroxylherderite represent end members of the isomorphous series
Herderite - Hydroxylherderite. They were discovered by Haidinger in 1828 and by S. Penfield in
1894, respectively (Leavens et al. 1978). Palache et al. (1951) divided this serie into 2 members.
These minerals form during late crystallization stages as hydrothermal alteration products of
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beryl and beryllonite (Leavens et al. 1978). Moore (1973) describe temperatures between 350C-
200C as characteristic for late hydrothermal fluids.
Hydroxylherderite occur in all pegmatites of Divino das Laranjeiras - Mendes Pimentel
area, that are rich in montebrasite. Crystalls have a flat prismatic habitus, usually twinned after
100, sometimes 100 conjoint with 001. In fresh samples its color is light yellow, however
it has sometimes a white alteration rim. In the Piano pegmatite pseudomorphs of
hydroxylherderite substituting eosphorite are common.
Samples with an alteration rim have been studied by x-ray diffraction and by EPMA).
These studies point towards a mixture of muscovite and hydroxylherderite in the altered zone.
Chemical analyses in the EDS mode show absence of fluorine, reforcing the definition as
hydroxylherderite. Infrared spectroscopical studies reafirm the results, due to the presence of two
well defined bands in the interval 3567cm-1 and 3605 cm-1, indicating the presence of OH- in the
structure of this mineral.
Brazilianite
Pough & Henderson (1945) were the first to describe and denominate a hydrated, sodium
phosphate from the studies area, as brazilianite - NaAl3(PO4)2(OH)4. The mineral is quite rare
and most specimens on the mineral market come from this area. Besides the Córrego Frio
pegmatite, brazilianite is known from at least a dozen localities in the region, with the Telúrio
pegmatite outstanding at present time. Brazilianite occur as green to yellow-greenish monoclinic
crystalls, often in gem quality (cuttable), up to 3 cm long. Together with fluorapatite,
montebrasite, hydroxylherderite, beryllonite, eosphorite, Mn rich siderite, albite, muscovite,
casiterite and quartz.
Beryllonite
Beryllonite – NaBePO4 – crystallize in the monoclinic system with a
pseudoorthorhombic habitus, usually as hydrothermal alteration product of beryl and
amblygonite-montebrasites (Moore 1973).
In the Divino das Laranjeiras - Mendes Pimentel area beryllonite has been described only
from two pegmatites (Telírio and Roberto). The mineral occurs together with secondary
phosphates like brazilianite, hydroxylherderite, montebrasite poor in fluorine, childrenite-
eosphorite and fluorapatite, besides other non phosphatic minerals (e.g. muscovite, quartz and
143
albite). The colorless transparent crystalls, up to 3 cm in diameter have an extreme short
prismatic habitus. Twinning is common and many specimens are of gem quality.
Infrared spectroscopy show a non-hydratic structure with absence of transmittance band
at the interval 3600 cm-1 to 3400 cm-1 . In the 1150 cm-1 to 1150 cm-1 interval occur most
transmittance bands due to the PO4 tetrahedra. The cation Na and Be2+ are responsible for
transmittance bands in the interval 775 cm-1 to 480 cm-1.
Fluorapatite, hydroxylapatite and carbonate-hydroxylapatite
Of the apatite group, fluorapatite (Ca5(PO4)3F) and hydroxylapatite (Ca5(PO4)3(OH)) are
the most common minerals. In pegmatites fluorapatite occurs as a primary phosphate, as well as
during the whole pegmatitic-hydrothermal evolution from 780C to 125C (Moore 1973).
Hydroxylapatite, as well as carbonate-hydroxylapatite (Ca5(PO4, CO3)3(OH)) are common in
late crystallization stages and form as hydrothermal alteration products of primary phosphates
(Campbell & Roberts 1986).
In Divino das Laranjeiras - Mendes Pimentel these minerals occur together with
brazilianite, eosphorite-childrenite, beryllonite, amblygonite-montebrasite, roscherite, zanazziite,
frondelite, herderite, hydroxylherderite and siderite. Crystalls are hexagonal, blue, green, pink,
white, or colorless, with a long or short prismatic habitus. They have been found mainly in late
substitution bodies or as alteration products pseudomorph after eosphorite.
THE PHOSPHATIC PARAGENESES IN THE STUDIES AREA
Primary phosphatic phases can be substituted partially or completely by late stage
processes and thus masquerade the chemical evolution of a pegmatite. Therefore, although a first
attempt, the following parageneses described below can help to establish a chemical evolution
scheme for the crystallization of phosphatic pegmatite minerals in the studies area.
The following phosphatic mineral assemblages in pegmatites with primary montebrasite
have been determined:
a – montebrasite Type I + fluorapatite
b – montebrasite Type II + fluorapatite
c – montebrasite Type II + montebrasite Type III + eosphorite
d – brazilianite + montebrasite Type III + fluorapatite + beryllonite
e – brazilianite + eosphorite
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f – montebrasite Type III + eosphorite
g – montebrasite Type III + fluorapatite + hydroxylherderite
h – eosphorite + siderite + fluorapatite + hydroxylherderite
i – eosphorite + fluorapatite + hydroxylherderite + coockeite
j – eosphorite + roscherite
k – siderite + fluorapatite + hidroxylherderite
l – hydroxylherderite + carbonate-hydroxylapatite + crandalite
m – ernstite + roscherite
n – eosphorite + zanazziite + leucophosphite
o – hydroxylherderite + crandallite + moraesite.
The evolution scheme is shown in Fig. 1, and has been divided, according to the
phosphatic mineralogy, in 4 stages: (i) Primary with montebrasite rich in fluorine; (ii) a second,
metasomatic stage, at which fluorapatite and montebrasite Type II form through alteration of the
primary montebrasite; (iii) The evolution of the crystallization took place simultaneously with
the presence of hydrothermal fluids, which alterate the primary mineralogy, accompanied by
metasomatic processes. It corresponds to the more diversified phosphatic mineralogy and is
found in late substitution or alteration bodies; (iv) at the end of the hydrtothermal stage, under
influence of external agents (e.g. meteoric water) the last crystalization/alteration took place with
phosphatic minerals of supergenic origin.
DISCUSSION AND CONCLUSION
The results of our analyses supported by datas from the mineralogical literature showed
that amblygonite-montebrasites occur in about one third of all pegmatites from Divino das
Laranjeiras - Mendes Pimentel. Moreover, these minerals differ in their fluorine content and
allow to distinguish three types. Type I is of primary nature and occur together with the main
mineral constituents. Fluorine content is around 4-5%. The second type (Type II) could be
detected in late crystallization and substitution bodies, usually with dissolutions on cleavage
plans and without a well defined habitus. The fluorine content is in average 2.3-2.5%. Minerals
of the Type III amblygonite-montebrasites have a well defined crystallographical habitus and
occur as late crystallization products and in substitution bodies. They are associated with other
phosphates of late crystallization, like brazilianite, eosphorite-childrenite, and have an average
fluorine content lower than 1.1%.
Fig. 1. Evolution scheme of crystallization/alteration of phosphatic mineralogy in pegmatites rich in primary montebrasite from Divino das Laranjeiras – Mendes Pimentel.
Although late cristallization and alteration can change the primary mineralogy and thus
have masqueraded partially the evolution of crystallization processes in a pegmatite, the authors
suggest to use these specific phosphatic parageneses as a possible clue for establishing chemical
evolution schemes in phosphatic pegmatites. As known from the specific literature and
confirmed by own analyses, the fluorine content decrease in amblygonite-montebrasites during
differentiation processes due to a substitution of F- by OH-. This led us to suggest the threefold
division of these minerals, related to three crystalization/alteration stages during the evolution of
a phosphatic pegmatite. Since there is a slight overlapping in the fluorine content of the different
types, the evolution scheme represent just an attempt to relate effects (fluorine content) to causes
(differenciation/alteration) in a complicated multy-system.
ACKNOWLEDGEMENTS The authors wish to thank the following institutions for partial support: FAPEMIG – Fundação de Amparo à Pesquisa do Estado de Minas Gerais; CNPq – Conselho Nacional de Desenvolvimento Científico e Tecnológico; CAPES – Coordenação de aperfeiçoamento de Pessoal de Nível Superior. Ministry of Science and Technology of Croatia ( Project # 0119420).
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RIBEIRO, S. H. 1996. Caracterização mineralógica da região de Divino das Laranjeiras – Mendes Pimentel (MG) com ênfase a seus depósitos gemíferos e minerais de coleção. Dissertação de Mestrado. UFMG/IGC. 115pp.
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HOW TO DETECT SUBMICROSCOPIC MINERALS AND THEIR BEARING ON THE EXTENSION OF THE MINERAL PARAGENESES
Sorin Silviu UDUBASA1, Gheorghe UDUBASA1, Paulina HIRTOPANU1, Serban CONSTANTINESCU2, Nicoleta POPESCU-POGRION2, Ion V.POPESCU3, Claudia
STIHI3, Lucian PETRESCU1, 1University of Bucharest, Faculty of Geology and Geophysics, 1 N. Balcescu Blvd.,
[email protected]; 2National Institute of Material Physics, Bucharest-Magurele, 105bis Atomistilor Str.;
3VALAHIA University of Targoviste, 2 Regele Carol I Blvd.
Annually some 50-60 new mineral species are discovered, a fact exceeding the number of
discredited (mostly old) mineral species. As a result, about 4000 to 4200 valid mineral species are
officially registered by IMA by its very active CNMNC (Commission on New Minerals,
Nomenclature and Classification). About 75-80 % of the newly described mineral species are
submicroscopic compounds (almost exclusively meteorite minerals), which can be detected only by
using structural techniques such as EPMA, NGR, TEM/SAED, HRTEM, AEM, XRD, etc.
Transmitted and reflected light optical microscopy is still used mainly to detect unknown phases, to
eventually ascertain their homogeneity or inhomogeneity and to finally integrate the new mineral
species into a geologically related interpretation of the evolution (metamorphic, magmatic,
hydrothermal and alteration) of the investigated geological bodies.
The future of mineralogy is thus almost strictly related to the application of physical-
structural methods, the only way in investigating the world of submicroscopic systems.
The aim of this paper is to show how a combination of mineralogical and structural methods
was able to bring new mineralogical data for several ore occurrences in Romania.
Investigated occurrences
(1) The Mn-Fe Razoare deposit
It is a high-grade metamorphosed deposit, composed of about 70 mineral species, of which
the most important are: manganoan fayalite (the former knebelite), pyroxmangite, mangangrünerite
(the former dannemorite), rhodochrosite, jacobsite, manganite, Mn-humites, tephroite, spessartite,
etc. The ores form lenses hosted by micaschists and gneisses and are rimmed by black quartzites.
The ore sequence displays a striking vertical zoning with a rhodochrosite-dominant association at the
bottom and a mangangrünerite at the top (Fig. 1).
148
The manganoan fayalite has been proved to be a refractory mineral, surviving the pervasive
transformation into the mangangrunerite and “keeping alive” some minerals of the probably prograde
stage of metamorphism, i.e. wüstite and pyroxferroite. They occur only as nanoinclusions in
manganoan fayalite, showing reducing conditions (wüstite) and probably high TP conditions
(pyroxferroite, a mostly Lunar-confined mineral) of the prograde phase (Fig. 2).
(a) TEM on mangangrunerite (with parallel cleavage) and wustite precipitations/ inclusions. (b) BFTEM, DFTEM and SAED on Mn fayalite crystals with nanoprecipitations of wustite and pyroxferroite.
(c) NGR spectra showing superposed signals of 57Fe in different local vicinities, characterized by electric field gradient (EFG) and/or internal magnetic field (B). The central part of spectra corresponds to the olivine contribution.
Fig. 2. Wustite and pyroxferroite as nanoinclusions in mangangrunerite, as revealed by different structural methods
(a)
(b)
149
(2) Gold ores in the metamorphics of the South Carpathians – Valea lui Stan/Brezoi,
Costesti/Horezu, Jidostita/Tr. Severin
The main mineral species are given in the Table 1 the ore bodies form either veins or lenses
concordant with the secondary schistosity (shear related) with quartz as dominant mineral phase (Fig.
3).
1- pyrite 2- arsenopyrite 3- quartz 4- microblastic gneisses [Costesti mine]
1- gneisses & amphibolites 2- quartz 3- feldspars 4- chlorites/biotite 5- carbonates + chlorites 6- arsenopyrite 7- carbonates [Costesti mine]
Fig. 3. Different types of ore bodies of the gold ores in the metamorphics of the South Carpathians
Gold inclusions are mainly confined to the arsenopyrite, ranging in size from microscopic to
nanometric.
Uytenbogaardtite and auricupride (first occurrences in Romania) as well as moganite,
löllingite, cobaltite have been added to the parageneses by using high resolution structural techniques
(TEM/SAED, NGR, XRD). The most amazing feature of gold distribution in sulfides is the presence
of isolated gold spheres or coral-like aggregates disposed on the sulfide interfaces (Fig. 4). This is an
additional form of gold distribution (nanogold) which is an alternative to the “invisible gold” showed
by Cathelineau et al. (1989) to substitute either Fe or As in the arsenopyrite structure.
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Monocristal of pyrite, with Au inclusions and coral-like aggregates ~60nm in 08_pyVS-h sample.
Monocrystals of pyrrhotite with gold and Ag3AuS inclusions as well as “coral-like” aggregates of gold in 10_pyrCN_g01 sample
Fig. 4. Coral-like aggregates of gold disposed on the sulfide interfaces.
Summary
Generally, the crystal/grain size of minerals can vary between 102 m and 10-9 m. An early
proposed size-related classification includes the following categories (and methods of
observation/investigation):
• A – macrominerals: 105 – 10-3 m (naked-eye mineralogical observations)
• B – microminerals: 10-4 – 10-6 m (optical mineralogy)
• C – inframinerals: 10-7 – 10-8 m (EPMA, NGR, XRD)
• D – nanominerals: less than 10-8 m (TEM/SAED)
About 4000 mineral species are known to date; some 500 belong to the categories C and D.
151
152
Investigated samples of gold ores from Southern Carpathians Category Mineral species Methods used
A - macrominerals Pyrite, arsenopyrite, galena, chaecopyrite,sphalerite, GOLD
Observed by naked eyes and OM1
B - microminerals Pyrrhotite, GOLD, Bi OM Greenockite, GOLD,schreibersite-like, Bi-sulphosalts
EMPA
Uytenbogaardtite XRD
C - inframinerals
Cobaltite,löllingite NGR D- nanominerals GOLD (coral – like aggregates) TEM/SAED
Investigated samples from Mn-Fe Razoare deposit Category Mineral species Methods used
Mn-fayalite Grains up to 20 cm long OM Mangangunerite, magnetite Manganese humites OM, XRD
A - macrominerals
Pyroxmangite B - microminerals Jacobsite, Magnetite inclusion in
fayalite OM
Magnetite OM ? C - inframinerals Ferrosilite (Mn) XRD Magnetite, Mn-Fe oxides inclusions in fayalite
NGR
Wüstite TEM/SAED
D- nanominerals
Pyroxferroite
Acknowledgements
The financial support of the Ministry of Education and Research of Romania through the
research grant C31-081/2007 in the frame of PNCDI II is gratefully acknowledged.
References
Cathelineau M., Boiron M., Hollinger P., Marion P., Denis M. (1989) Gold in arsenopyrites: crystal
chemistry, location and state, physical and chemical conditions of deposition. Econ. Geol.
Monograph 6, pg. 328-341.
1 Optical microscopy
DESIGNING DACITE QUARRY DEVELOPING OPTIONS
URECHE I. 1, ONESCU D. 2, PAPP D. C. 3
1. Lafarge Romania – Concrete and Aggregate Division, Bucharest, Romania 2. Belevion Ltd., Bucharest, Romania
3. Geological Institute of Romania – Cluj-Napoca Branch, Romania .
ABSTRACT
We report a coupled petrographic, geochemical, fluid inclusion and geophysical study of the Magura Sturzii Neogene dacite quarry, Bargau Mountains, East Carphatians. New geophysical investigations facilitated a first evaluation of a porphyry copper structure within the quarry, the establishment of a chronology for the emplacement of the magmatic body, and the delineation of the optimal sectors for mining. The geophysical surveying consists in: magnetic (total field intensity ∆T), electric (IP and rezistivity ρa), and radiometric (global gamma ray lγ) investigations. Two relatively high magnetic anomalies sources, located in the middle north and south side of the quarry, are the main feature of the local magnetic field distribution. They correspond to fresh dacite and porphyry type mineralized dacite. High IP (95 mV/V,) relatively low ρa (<250 Ωm), and low gamma ray intensities (16 imp./min) also pointed out the occurrence of a porphyry type system. The porphyry body core is surrounded by a polymictic breccia, and intruded by an andesite body, placed in central-south part of the surveying area, having good exploitation perspectives.
1. INTRODUCTION
The aim of this study was to acquire, in addition to previous geological, geochemical, and fluid
inclusions investigations, new geophysical data in order to design developing options for the Magura
Sturzii Neogene dacite quarry, Bargau Mountains, Romania. At present, the dacite rocks extracted from
the quarry are used for road and railways construction. Our complex investigations facilitated the
evaluation of a porphyry copper structure within the quarry which was not mentioned before, the
establishment of a chronology for the emplacement of the magmatic body, and the delineation of the
optimal sectors for exploitation, preventing future mining operations in those directions with high risks
(un-conform rocks, thick overburden, interbeded rocks and structural features). The results of the study
have critical importance both for scientific community, allowing a better understanding of the evolution
of the Neogene magmatic activity in the area, and for the decision makers in forecasting low operating
costs quarry development, and for minimizing the environmental impact. The case study presented here
is presently extended to other quarries concessions within the LAFARGE portfolio.
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2. GENERAL GEOLOGY AND STUDY AREA
The Bargau Mountains, which host the Magura Sturzii dacite quarry, belong to the Neogene
subvolcanic zone of the Inner Carpathain arc. Neogene magmatism was associated with the consumption
of a small piece of ocean crust, attached to the Eastern European plate, beneath the ALCAPA (Alpine –
Carpathian – Pannonian) and Tisia – Getia continental blocks (Seghedi et al., 1998). The subduction
zone is located on the Tisia – Getia block close to the boundary with both the ALCAPA block and the
East European plate, between the two volcanic segments: Oas – Gutai in the north-west and Calimani –
Gurghiu – Harghita in the south-east (Fig. 1).
Fig. 1. Location sketch map of the Magura Sturzii dacite quarry
In the Bargau area special geological and structural conditions resulted from the tectonic contact
of the Rodna metamorphic massif with the Transcarpathian Flysch zone, delineated by the Somes Fault
system. The host rocks of the magmatites are sedimentary deposits of the Transcarpathian Flysch. The
main intrusive units consist of dacites, quartz garnet andesites, andesites, microdiorites, and basaltic
andesites. The intrusions vary in volume and have a surface exposure from 1 km2 to 20 km2. The surface
exposure of the Sturzii dacite intrusive unit is about 4.5 km2, and its maximum elevation is 942 m.
3. PREVIOUS PETROGRAPHIC, GEOCHEMICAL AND FLUID INCLUSION STUDIES
Prior to the present work, we have performed detailed petrographic, geochemical, and fluid
inclusions studies on the Neogene magmatic rocks of the subvolcanic zone (e. g. Papp et al., 2003,
2005). Main results are summarized bellow.
The magmas that generated the magmatic rocks in the Bargau Mountains had a calck-alkaline
character and show a complete differentiation trend from basaltic andesites to rhyolites. Transitional
textures occur between subvolcanic and plutonic facies, and between hypabisal and volcanic-like facies.
There is a relative high degree of crystallization and most of the rocks are porphyritic.
Based on mineral compositional data, major and trace elements, as well as Sr and O isotope data
two different series of rocks have been separated within the Bargau Mountains: one medium-K and
another high-K (Papp et al., 2005). The Magura Sturzii dacites belong to the medium-K series, which is
the oldest, being emplaced at about 10.6 Ma.
The magmas of the medium-K series had a rapid ascent toward the surface, as proven by the
presence of primary garnet bearing rocks (quartz garnet andesites, dacites), or by the sporadic
occurrence of mafic cognate enclaves. The δ18O values of amphiboles vary from 4.2 to 5.4 ‰ (SMOW).
The δ18O value measured on amphiboles from Magura Sturzii dacite is 4.3. The range of 87Sr/86Sr ratios
is from 0.70588 to 0.70887. The decrease of the δ18O values as 87Sr/86Sr ratios and SiO2 increase shows
a progressive contamination of a mantle derived magma with a contaminant depleted in δ18O and
enriched in 87Sr/86Sr (i. e. hydrothermally altered lower crustal rocks).
The intrusive unit Sturzii consists of dacites, andesites, as well as contact and eruptive breccias.
In the inner part of the unit hydrothermal alteration processes (silicification, argillization and
propilitization) occur. The associated mineralization consists of pyrite and chalcopyrite either as small
veins or they are disseminated within the rock.
Amphyboles are the main mafic minerals within the Sturzii dacite. They are Ca-rich and (ferro-
tschermakite). Zoning is present within most of the amphibole crystals (Mg-richer rim and Fe-richer
core). Biotite is present in association with amphiboles. Plagioclase feldspars are the main component of
the rock. They form both phenocrysts and microlites in the matrix. Anorthite content varies between 45
– 50 % (andesine). Plagioclase feldspar frequently show normal and oscillatory zoning, indicating
modification of crystallization conditions (i. e. rapid cooling during the emplacement of the intrusive
body). The presence of primary garnets is a special feature of these rocks. They represent 1 -2 % of the
rock volume. They form phenocrysts with subhedral or euhedral morphologies, 0.5 – 2.5 mm in size,
and have Almandine-rich composition (over 55 %).
Pressure estimations for amphibole crystallization record significant differences between the
pressure values corresponding to the core of the crystals (~780 MPa) and the pressure values
155
corresponding to the rim (~ 490 MPa). This finding clearly shows that decompression occurred during
crystallization of amphiboles. The pressure estimates suggest mid-crustal depth of approximately 15 –
25 km for amphibole crystallization.
Fluid inclusion study (Papp et al., 2003) revealed the exclusively presence of aqueous fluids
(H2O – NaCl system). Homogenization, both to liquid and vapour, occurs between 120 and 540 oC. The
general evolution of aqueous fluids is to decreasing salinity with decreasing temperature. Low salinities
(from 6 to 1.4 wt.% NaCl eq.) indicate the presence of meteoric water. The occurrence of exploded fluid
inclusions indicates decompression regime during magma uplift. Pressure decreasing, inferred from the
chemical composition of amphiboles in Magura Sturrzii dacite, also suggest a decompression regime.
High temperature, high salinity fluids are early, most probably magmatic, followed by a boiling event of
the hydrothermal system, possibly related to a change of fluid pressure from litho- to hydrostatic and
dilution by the meteoric fluids, at about 400 oC. The characteristics of the fluid inclusions suggested the
tendency of the intrusions to evolve towards a porphyry copper system. This was the first indication of
the presence of a porphyry copper structure within the Magura Sturzii dacite quarry.
In order to evaluate the porphyry copper structure and to design dacite quarry developing
options, additional geophysical investigations were performed.
4. GEOPHYSICAL INVESTIGATION
4.1. Methods
The geophysical data were acquired and processed by Belevion Ltd. The geophysical surveying
consists in: magnetic (total field intensity ∆T), electric (IP and rezistivity ρa), and radiometric (global
gamma ray lγ) investigations. The operated equipments were: EDA proton magnetometer, Scintrex
electric equipment (receiver and transmitter), Garmin GPS, Leica topographic station, HR Geiger type
radiometer, and Leica Disto laser distances equipment.
Surface surveyed morphology was framed in the “highest difficulty” class (slopes angles
between 27 and 49o, young thickset forest, cliffs, detritus and fallen trees).
The east quarry extension (0.075 km2) was covered with 4.8 km of magnetic and gamma ray
measurements and 2.0 km of electric measurements distributed on 3 investigation profiles (100 m
depth). In addition, 6 drill holes/400 m (F1 to F7) were drilled for verifying the geophysical anomalies.
4.2 Results
The assumed interpretation keys based on “in situ” measurements are summarized in Table 1.
Processed magnetic, radiometric and electric data are plotted as maps and cross-sections (1:2000
scale).
Fig.2. Magnetic profile, resistivity and chargeability, cross-sections in the Magura Sturzii dacite quarry – Profile no.2.
D – dacite, Dpy – mineralized dacite, Bc – breccias, A – andesite.
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Magnetic images bring out the anomalies sources, as high, intermediate and low types. Two
relatively high magnetic anomalies sources, located in central-north and south side are the main feature
of the local magnetic field distribution. They correspond to propylitized and mineralized dacite in the
central-north side and to intrusive andesite in the south side. The intrusive andesite was also intercepted
in the F3, F4 and F5 drill holes.
The high magnetic anomalies are cut by low horizontal gradient weak magnetic field, indicated a
homogenous source with intermediate to low magnetic properties. Altered dacite (weak argilic
alteration, partly silicified ± disseminated pyrite and polymictic explosion breccia, intercepted in F6 and
F5 drill holes) is a magnetic low to intermediate source type.
In the north side a well defined dipolar magnetic anomaly is produced by a high magnetized
source: i. e. a porphyry copper structure with pyrite + chalcopyrite + pyrrhotite + magnetite.
In the south side of the surveyed area, a low magnetic anomaly is characterized by intermediate
magnetic horizontal gradients. The anomaly is ascribed to a sharp vertical contact (fault type), which put
in contact an andesite type source with a low magnetic source type (i.e. polymictic breccia, altered
dacite and mineralized dacite). The dacite was also intercepted in F2 drill hole.
The electric survey (IP and resistivity measurements) was performed along three north-south
parallel lines, on the east side of the quarry. The electric survey covers a 100 m depth as resolution.
The second and third profiles (IP and ρa line presented as cross-sections), showed the highest IP
in the north (95mV/V) (Fig. 2). This is double by a relatively low ρa (<250 Ωm). The source draws a
classic mineralized body, belonging to a porphyry type system, as the magnetic data pointed as well.
In the south side, high ρa sources are disclosed, and there are extended in the depth. They overlap
the high magnetic sources and show the occurrence of intrusive andesite.
In the upper part of the cross-sections, high ρa values are accompanied by low IP, showing a
heterogeneous developing source.
Global gamma ray data indicate the fresh and altered dacite subsurface extension, by
intermediate intensities (20 imp./min.). The highest gamma ray intensity is located in the south side of
the area and is possible to reflect a clay stone enclave in the dacite rock (30 imp./min). In the north side,
the gamma ray intensities show the lowest intensities (16 imp/min.) The allocated source is mineralized
dacite.
Table1 – Summary of the geophysical survey in Sturzii dacite quarry
Rock type IP ρa χ Iγ Note
Dacite
(partly propylitized) LL H H I - H
Andesite LL HH HH L
Dacite (argillized,
partly silicified ± py) I - L LL I - L I - H mds
Dacite – mineralized
(porphyry type) HH I - L H I - L mds
Clay stone –
thermally affected I H L HH
Structural features I - L L L -
IP – chargeability; ρa – electric resistivity; χ - magnetic susceptibility; Iγ: - gamma ray intensity
HH: highest, H: high; I: intermediate; L: low; LL: lowest
mds – magnetite destruction sources
5. CONCLUSIONS
Magura Sturzii dacite quarry opened, in the east side, a classic immature porphyry copper
structure, host by a dacite intrusion, with a inner stock-work (silicified in the depth and argilized in the
upper part), with low magnetic properties, high IP signal and low to intermediate resistivities.
The porphyry body core is surrounded by a polymictic breccia, intruded by an andesite body,
placed in central-south part of the surveying area with good mining perspectives.
The outer ring of the porphyry intrusive structure is represented by fresh and propylitic dacite
(mined in the central, west and north side of the quarry). In the surveying area fresh and propylitic dacite
are developing in the north part. In extreme south, breccia is outcropping. In the east extension of the
quarry, un-conform rocks are developed as: altered and mineralized dacite and polymictic explosion
breccia, which are in contact with andesite.
Based on the previous geological, geochemical and fluid inclusion studies, as well as on the
geophysical investigations, a possible model for the emplacement of the Magura Sturzii intrusive unit
could be established. The interpretative model is presented in Fig. 3.
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Fig. 3. Geological model of the Magura Sturzii dacite quarry
The emplacement of the dacite, related to a decompression regime, was the first intrusive event.
The dacite intrusion locally and laterally is interstratified with schists and Flysch sedimentary deposits
(clays). The emplacement of the andesite body represents the second intrusive event. Critical mechanical
and chemical interactions with the pre-existing dacite occurred. In the north side and sporadically in the
south side of the intrusive unit contact breccia (schist and dacite fragments) developed. The
emplacement of the andesite body also fractured the pre-existing rocks and induced circulation of
sulphur-rich hydrothermal fluids. The end result was the mineralization of the dacite and the
development of a porphyry copper structure.
REFERENCES
Papp D.C., Tecce F., Frezzotti M. L and Ureche I., 2003, Microthermometric study of fluid inclusions in Neogene shallow intrusions from Inner Carpathian arc (Romania), J. Geochem. Expl., 78-79, 105-109.
Papp D.C., Ureche I., Seghedi I., Downes H., Dallai L., 2005, Petrogenesis of convergent-margin calc-alkaline rocks and the significance of the low oxygen isotope ratios: the Rodna-Bargau Neogene subvolcanic area (East Carpathians), Geologica Carpathica, 56, 1, 77-90.
Seghedi I., Balintoni I., Szakacs A., 1998, Interplay of tectonics and Neogene post-collisonal magmatism in the Intra-Carpatathian region. Lythos, 45, 483 – 497.
Toate Drepturile rezervate Editurii Institutului Geologic al României All rights reserved to the Geological Institute of Romania
Volum editat cu sprijinul Universităţii “1 Decembrie 1918" din Alba Iulia Edited with the support of the “1 Decembrie 1918" University of Alba Iulia
Editorial Staff: Sorin Silviu Udubaşa
Nicolae Luduşan
