Cenozoic Stratigraphic Nomenclature in East Kutai Basin, Kalimantan

PROCEEDINGS INDONESIAN PETROLEUM ASSOCIATION Eleventh Annual Convention, June 1982

CENOZOIC STRATIGRAPHIC NOMENCLATURE IN EAST KUTAI BASIN, KALIMANTAN

by Edward Marks*,Sujatmiko**,Lki Samuel***,

H.'Dhanutirto*,T. Ismoyowati* and BB. Sidik*

A B S T K A C T

The Cenozoic sediments of the eastern Kutai Basin, East Kalimantan, are composed of several deposystems that can be distinguished by their lithic successions and separated by disconformities evident on seismic records.

Five deposystcms are separated into the following Groups with their subdivisions: the Pleistocene to Recent Mahakam Group, divided into the deltaic Handil Dua Formation to the west and the marine Attaka Formation to the east; the middle Miocene to Pliocene Kampong Baru Grocp, consisting of the deltaic Tanjung Batu Formation to the west and the marine Sepinggan Formation to the east; the middle Miocene Balikpapan Group, containing the upperrnost carbonate to marine clastic Klanda- san Tongue of the marine Gelingseh Formation and the paralicdeltaic beds of the Mentawir Formation; the early to middle Miocene Bebulu Group divided into a carbonate Maruat Forma- tion and a deeper water clastic and carbonate Pulau Balang Formation, and the late Oligocene to early Miocene Pamaluan Formation.

These Groups and their subdivisions are described at their type and reference localities, and their inter-relationships and boundaries are discussed with vertical and horizontal sections.

* Union Oil Co. of Indonesia -Balikpapan ** Total Indonesie - Balikpapan

*** 'Pertamiia Unit EP IV - Balkpapan

INTRODUCTION

Present multicompany intensive exploration in tk Kutai Basin, as in other parts of lndone- sia, has made it imperative that we review and refine previous lithostratigraphic terms in the light of modern concepts.

Aims

The aims of this work are to get satisfactory answers on nomenclature, which should be based upon the nature of the rock bodies in time and space. In turn, the nomenclature should have value the better to understand the distribution of potential and realized reservoirs found in the Kutai Basin.

Problems

Previously published nomenclatonal systems have not accomplished the aims of the work to everyone's satisfaction. Many workers have noted tendencies in previous work to neglect thin but very important lithic as well as time boundaries. Companies have differed as to nomenclature as well as to time relationships of the rocks.

Purpose

The purpose of this paper is to present a formal system of group and formation names for the lithostratigraphic units encountered in the 'South East Kutai Basin, Kalimantan, Indonesia.

© IPA, 2006 - 11th Annual Convention Proceedings, 1982

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We have limited our-selves to the late Oligocene to Recent sediments where, to date, we have production.

This work is condensed from the Workshop of Stratigraphic Nomenclature, held on 29 September 1981, in Balikpapan. Five papers on the Stratigraphic Nomenclature in E. Kutai Basin were presented and discussed. This work is pursued upon the recommendations made by the management and governing ooards of Pertamina, and the Stratigraphic Commission of Ikatan Ahli Geologi Indonesia.

The writers wish to thank the management of Pertamina, Total Indonesie and Union Oil Co. of Indonesia for their help and encourage- ment in producing this paper.

Location

The Kutai Basin straddles the eastern margin of Kalimantan (textfig. 1). The northern boundary is the Mangkalihat Penninsula, to the east is the Makassar Straits Trough, and to the swth the Kutai Basin is bounded by the Paternoster Shelf.

Geologic History

In the Kutai Basin (text figs. 2 and 3), sediments are known to have been deposited since early Tertiary time, filling the basin progressively from the west toward the east. The area of maximum sediment thickness, the Depocenter, shifted progressively eastward with time, and the maximum thickness of late Miocene to Recent sediments is formed in the offshore portion of the basin (Billman and Kartaadiputra 1974, p. 1). Packages of sediments were formed in a series of deposystems. A cross-section A-A’ on figure 1 can be seen in figure 2. Each deposystem developed a group of formations in a sea regressing to the east.

The earliest unit in our discussion is the Pa- maluan Formation of Oligo-Miocene age. Bathyal sediments continued to infill the basin until at the top of the unit Outer Neritic sediments are present. In the early to basal

middle Miocene Bebulu Group, the Maruat Formation accumulated in a shallow carbonate shelf, while the Pulau Balang Formation was deposited in Inner to Middle Neritic waters, consisting of more clastic sediments.

I n the middle Miocene, the Balikpapan Group Paralic to Deltaic Mentawir Formation was deposited, while the Gelingseh Formation sediments were laid down in Middle Neritic waters with occasional Outer Neritic to Bathyal incursions. At the end of the Balikpapan Group time, an Inner Carbonate Shelf, Reef Shoal sequence was deposited in shallower waters. and a Middle Neritic, low oxygen invimnment was deposited deeper at the time ofthe Nan- dasan Tongue Member. A break in sediments is noted here, then the Miocene to Pliocene Kampong Baru Group Tanjung Batu deltaic Formation prograded to the east, while the Se- pinggan Formation was deposited in Inner to Middlo Neritic waters, with some shallow carbonate accumulations. At the end d the Plio- cene, a lowering of sea level produced a hiatus, especially to the west. During the Pleistocene to Recent still&and, the present Mahakam delta H a n d Dua Formation continued its prograda- tion from the west over the more marine Atta- ka Formation in the east.

Previous Work

One of the earliest workers was L.M.R. Rut- ten (1914) who published notes on the Balik- papan Beds, the Pulau Balang and the Bebulu. 1.M. van der Vlerk and J.H.F. Umbgrove (1927) established the Tertiary Letter Stages Ta to Tf. Later, Umbgrove (1929) added Tg and Th.

W. Leupold and I.M. van der Vlerk (1931) published a table of bio-and lithostratigraphic units for the Kutai Basin. In 1943, M.F. Glaessner (pp. 63, 64) summarized the above work, tying the Indo-Pacific Area to European stages. R.M. van Bemmelen (1949, pp 134- 142) discussed the lithic and paleontologic units of the Kutai Basin.

The Stratigraphic Lexicon of Indonesia was

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issued in 1961 by P. Marks which alphabetically listed units named to that time.

C.G. Adams (1 970) revised the Tertiary Letter Stages in accordance with the works of Bolli (1966) and Blow (1969). H.G. Billman and L.W. Kartaadiputra (1 974) published a late Neogene zonation applied to the Offshore Kutai Basin. L. Samuel and S. Muchsin presented a litho-and bio-stratigraphic section of the Kutai Basin in 1975. R. Haak and J.A. Postuma (1975) correlated the Tertiary Letter Stages with the pelagic zones of Blow (1969).

Boundaries

The upper boundary of the Pan'aluan Fo:- ination is rrpresentzd by limestone beds which are pa; t of the Maruat Formation of the Bebulu G r m p 'T!iere is also an upper contact with the base of the Pulau Balang. The lower boundary is difficult to define lithologically as monoto- nous mudstoiles and shales also occur in the underlying Oligoccne '--uyu Formation.

Distribution Stratigraphy

On textfigures 3 and 4 are summarized the general stratigraphic sequence for the Cenozoic System in the Kutai Basin. The Age, Groups, Formations, Lithology, Seismic markers, and Environment are listed for the lithostratigrapliic units. As the Sea Level Curve demonstrates, the seas were regressive until the latest Pliocene, when a deepening started another cycle in the Recent.

STRATOTYPE SECTIONS

Type and Hypostratotype sections have been designated for the formations listed here. Where possible, classic type sections have been used. If on examination, many beds are covered or inaccessible, Hypostratotype sections are also designated.

PAMALUAN FORMATION*

Name Origin

The name Pamaluan was taken from the village of Pamaluan, 30 Km NNW of Balikpa- pan, East Kalimantan (Leupold and v.d. Vlerk 1931, p. Marks 1961).

'The Painaluan Formation is exposed over much of the western half of the Kutai Basin, and it also appears at the surface ill the core of some of the most easterly anticlines. The formation has been intersected in some wells drilled onshore and offshore.

Type Section

The original type section was mentioned near Pamaluan village but in that locality only the upper Pamaluan is exposed. Hence, the Peringtali Anticline arid Janibu Syncline, located 80 Km NW of Balikpapan, East Kali- mantan, are proposed as hypostratotypes of the Pamaluan Formation, see textfig. 7.

Lithologic description

in general, the Pamaluan Formation is represented by light gray to black mudstones and shales with carbonaceous plant remains.

The lower Pamaluan consists of massive siltstones and mudstones with occasional thin (1 5 cm), very fine, tight sandstones.

The Upper Pamaluan is predominantly mudstone with conchoidal fractures, or bedded shales, often with carbonaceous leaf remains. Sandstone and coal interbeds are also found, and a thin limestone occurs near the top of the

* L.Samuel. formation.

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Paleontology

Globorotalia kugleri, Glo bigeniza ciperoeilsis, Globorotalia opinuz, Globorotalia izana, Globi- gerina sellii, Globigerina ampliapertura, Globi- gerina prasaepis, Uvigerina h ispida, Ra thy sip h on sp. , Animodiscus spp., Cydammitza spp., Sphaeroiu'ina bulloides.

Zones : N 2 - N4.

PULAU BALANG FORMATION**

Enviroiiment

Generally marine, with an Outer Neritic to Bathyal environment of deposition.

Late Oligocene to early Miocene (N2 - N4).

BEBULU GROUP*

Name Origin

The name for this group is derived from Sungai Bebulu, a small creek about 45 Km southeast of Balikpapan, East Kalimantan, Indonesia (Umbgrove 1927, pp 28-41).

Leupold and v.d. Vlerk's (1931, p. 614) name of Bebulu beds in part is synonymous with the Bebulu group. The Bebulu as considered by Leupold and v.d. Vlerk above, which consists of marls and limestones, is here placed in the Maruat Formation. Onshore, this formation underlies the Pulau Balang Formation. In places offshore, a portion of the Maruat overlies the Pulau Balang. Both the Pulau Balang and the Maruat Formations are included in the Bebulu Group.

Name Origin

Tile name of this formation was originally taken from Pulau Balang (Balang Island), an island located approximately 8 Km north-east of the city of Balikpapan in the Balikpapan Bay (Rutten, L.M. 1914).

Boundaries

The Pulau Balang Formation is a deeper marine unit of the Bebulu Group which is overlying the Pamaluan Formation and underlying the Balikpapari Group, Mentawir and Gelingseh Formations. However this formation shows an inter-fingering relationship with the Maruat limestone Formation. The top of the Pulau Ralang is indicated by the Total Indone- sia Co seismic marker, which is traced into the subsurface.

Distribution

Distribution of the Pulau Balang Formation can be noted onshore (see fig. 6) and offshore in the Total Maruat No. 1 well and Tengah Field.

Type Section

Type section : Pulau Balang surface section (Textfig. 8).

Location : Pulau Balang, Balikpapan Bay, 8 Km northeast of Balikpapan, East Kaliman- tan.

: + 1855 m (6086 feet). -

Thickness


The Pulau Balang Formation consists of interbedded sandstones and siltstones with occa-

* Sujatmiko ** T. Ismoyowati

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siona; limestones and claystones. The limestones contain Foraminifera, fragments of Bivalves and Algae in a micritic matrix. The sandstones occur in thin to thick beds with cross bedding and worm burrows. The sandstones are dominantly quartzose, light gray to white, friable to hard, occasionaly calcareous, fine to coarse grained. In the lower part ofthese beds a few thin layers of coal and sand are noted.

Paleontology

Globigerinoides altiapertunts, Globigerinoi- des difninutus, LepidocJdina ( N ) sitmatrensis, Lepidocyclina (N) angulosa, Flosculinella bontangensis, Flosculinella globulosa, Ro bulus inornatus, Bulimina sp, Trochammina sp., Nonion sp., Eponides repandus, Amphistegina papillosa, Brizalina limbata, etc.

Zones : N5 - N7 or younger.

cated 42 Km S.S.E. of Balikpapan. The name Maruat is derived from Tanjung hlaruat, a pro- montory located 50 Km S.S.W. of Balikpapan.

Boundaries

The upper boundary of the Maruat Formation is placed at the top of the upper carbonate sequence, well defined by the Co seismic marker. The Ralikpapan Group Mentawir Formati- on and the Gelingseh Formation is found zbove it. The lower boundary is placed at the base of the lower carbonate sequence, usually a fair seismic marker, above the Pamaluan Formation. To the east, in a deeper environment, the more clastic Pulau Balang Formation is encountered.

Distribution

The Maruat formation can be mapped onshore, East Kalimantan (Textfig. 6). In tfie offshore area, it can be traced seismically throughout the southemmost portion of the East Kutai Basin.

Environment Type Section

The lower part of the Pulau Balang Formati- on onshore was deposited in an lnner Neritic environment with Deltaic - Paralic influence. In the upper part Middle Neritic open marine sediments were deposited.

Early Miocene Te5 possibly higher; N5 - N7 possibly higher.

MARUAT FORMATION*

Name Origin

The name Maruat was taken from Total In- donesie Pertamina Maruat No. 1 well, an offshore exploration well drilled in 1971. It is lo-

* Sujatmiko

Type well

Coordinates

R T E Water Depth Total Depth Interval

Thickness

: Total Indonesie--1npex - Pertamina Maruat No. 1 (textfig. 9).

: 11 6’ 55’ 22.0” E 1’ 38’ 20.7” S

: 9m (30’) : 42m (1 38’) : 3455m (1 1335’) : 1261m (4137’)-1690m

: 429m (1408’) (5545’)

Lithologic Description

The formation consists of two main carbonate sequences at its type locality, consisting of bioclastic calcarenite (reefal facies). These two carbonates are separated by 30m (98’) of interbedded gray shale and fine grained

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argillaceous sandstone prohabiy bzlongirig to a tongue of the Pulau Balang Poiination (textfig. 9).

hi iro.rrncnt

Shallow Carbonate Shelf.

.4gc

Te5 - Tf! (Early Miocenc Miocene)

BALIKPAPAN GROUP1/

Name Origin

this is preoccupied by Rutten (1914), Mohler aid ten Berge (1949) and Luki Samuel (1980). According to the Stratigraphic Code of Indo- nesia (Suyono 19751, the name Klandasan of Marshall and Schumann is considered a junior synonym to the Mentawir.

Boundaries

Tlic upper boundary of the Paralic Mentawir is marked by an onlap of the overlying Klanda- san Tongue Member of the Gelingseh Formati- on, represented by the Bu seismic marker of Total lndonesie in the offshore area. The lower boundary is placed at the top of the Bebulu Group Maruat Formation or Pulau Balang Formation, marked by the Cu seismic marker.

Distribution Early Middle

'Ihe Mentawir Formation can be mapped onshore, over the southern part of the East Kutai Basin (textfig. 6) , and in the offshore by using electric log;.

The name for this group is derived from the town of Balikpapan located on the east coast of East Kalimantan. W. Leupold and I . M. van der Vlerk (1931) called this group as layers, but since "Layers" is not formal stratigraphic terminology (Suyono 1975) it is recommended that this sequence be called a group.

The Balikpapan Group is here divided into two formations: the Mentawir Formation and the Gelingseh Formation.

MENTAWIR FORMATION * Name Origin

The name Mentawir is taken from the Men- tawir river located app. 23 Km NNW of Balik- papan town (texfig. 5). This formation was called in 1981 as the Klandasan Formation by Marshall & Schumann (1981, p. 285) but

* H.Dhanutirto

Type Section

The Type Section for the Mentawir Formati- on is at S . Mentawir (Rutten, 1914), 23 Km NNW of Balikpapan, East Kalimantan. Many of the sequences are covered by soil, and the Reference Locality below described is here by proposed.

Hypostratotype Section

Location : Outerops on the beach behind the Pertamina ten- nis court near the Banua Patra building and along J1. Minyak in front of Gate I11 Pertamina refinery complex. At Gn. Pancur, outcrops of Mentawir occur in a quarry cut approximately 300 metres south of Pertamina Area

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Thickness

IV Main Office, Balikpa- pan, East Kalimantan, In- donesia (textfig. 10). 540 m (1772').

(1914) from S. Gelingseh located near Sang- kulirang Bay, East Kalimantan.

Boundaries


This formation consists mainly of massive sands and sandstones, white, light gray to brown, fine to medium grained, soft to friable, occasionally interbedded with clays, siltstones and lignite beds. Intercalated with this formation, a number of marls and limestones are found, which possibly belong to the Gelingseh Formation or as discontinuous limestone streaks.

Paleontology

No guide fossils have been found in the Mentawir Formation. Some benthonic fossils occur, mainly arenaceous forms including Tro- chammina, ltaplophragrnoides and Ammoba- culites. However, the Gelingseh equivalent marls and limestones already discussed above contain Miog.vpsina, Miog),psinoides, Lepidoqv- tibia, Flosc~dinella borneensis in the upper portion and Flosculinella bontangensis in the lower portion.

Environment

Paralic to Deltaic environment.

Age range

Middle Miocene Tfl--2 (N9 - NI3) by homotaxy.

GELINGSEH FORMATION*

Name Origin

The name Gelingseh was taken by Rutten

* B.B. Sidik

The upper boundary of the formation in the Union - Perlamina Sepinggan No. V 1 well is represented by a disconformity of Middle Miocene T f - 2 age. This boundary is a good electric marker, and represents a change from the shales and limestones in the Klanda- san Tongue Member above, indicated by the Bo seismic marker of Total lndonesie, to the sands, marls and clays in tile Gelingseh. The lower boundary is placed at the top of the Ma- ruat and Pulau Balang Formation of tile Bebulu Group, and is marked by the 6~ Seismic marker.

Distribution

The distribution of the Gelingseh formation can be noted onshore in the Klandasan Tongue Member, see below. It is present in the offshore in wells in the Kenndingan and Attaka Fields in the northern Kutai Basin and extends to the Southern portion of Kutai Basin.

Type Section

Although the Gelingseh was named from S. Gelingseh, no type section was made. It is there fore recommended that the Union Oil Co. of Indonesia - Pertamina Sepinggan No. V--1 well be designated as the Hypstratotype Section for the Gelingseh Formation.

Hypostratotype Sectie ~

Hypostratotype section well

Coordinates

R T E Water Depth

: Union Oil Co. of Indonesia Sepinggan No. V - I (textfig. 11).

: Lat 1 ° 25' 45.54 S [~ng I 160 54' 19.67 E

: 31' (9m) KB : 133' (40m)

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Total Depth : 11974’ (3650m) Interval

Thickness : 3,140’ (957m)

: 7,900’ (2408m) to 1 1,040’ (3365m).


The sequences are mainly sandy clay, clay, and thin limestone beds. 79007( 2408m)

8000’(2438m)

8400’ (2560m)

8686’(2647m)

10,620’ (3237m)

11,040’ (3365m)

Top of the Gelingseh formation. Clay/claystone, light gray, soft, occasionally firm, non calcareous; with a little caal, black moderate hard, shiny, brittle. Sandstone, white-light gray, very fine to fine grained, moderate sorting, subrounded, friable, occasionally moderately hard; with thin limestone, brown, bioclastic, hard, to very hard. Clay, gray to drown, moderately hard, very slightly calcareous; Inter- bedded with thin layers of sandstone, friable, moderately hard, white gray, very fine to fine grained, grading into siltstone with carbonaceous material. Claystone, light gray to brown, buff, soft to slightly firm, slightly calcareous. Bottom of Gelingseh formation.

Paleontology

Globorotalia siakensis, Flosculinella bonra- ngensis, Globigerinoides cf. altiapertums, Miogypsina sp, Lepidocyclina spp, Miogypsi- noides sp. ’ Zones : N9 - N13.

Nannoplankton

Sphenolithus moriformis, Cyclicargolitus floridanus.

Environment

The general environment of this formation is Middle Neritic, with occasionally a trans- gressive phase bringing in Outer Neritic to Bathyal sediments.

Age range

Middle Miocene.

KLANDASAN TONGUE MEMBER*

Name Origin

The name Kiandasan was originally derived from a small creek which flows in the eastern part of Balikpapan town. Muller (1922) gave this name to the limestone and marl sequence which can be found at the surface at Gn. Mar- koni, Balikpapan, and placed it in the upper part of the then named ”Balikpapan Layers”. Leupold and v.d. Vlerk (1931, p. 619) placed it in the ”Gelingseh or Upper Balikpapan Beds”. The name Klandasan was used by Marshall and Schumann (1981, p. 285) for another unit, the Mentawir (ut supra p. 13), but this is preoccupied by Muller 1922, Rutten 1927, Mohler and ten Berge (1949) and L. Sa- muel (1980). According to the Stratigraphic Code of Indonesia (Suyono 1975) the Klanda- sari as used by Marshall and Schumann is a junior synonym of the Mentawir.

* LukiSamuel

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Boundaries Paleontology

The Klandasan Tongue is a member of the Gelingseh formation of the Balikpapan Group. At the type locality in Gn. Markoni, the Klan- dasan limestone overlies the Mentawir Formati- on and underlies the Tanjung Batu Formation of the Kampong Baru Group (textfig. 12). In the Offshore area, this member coincides with the Bo seismic marker as defined by Total Indonesie. Lithologically it changes into mark and shales, and can be distinguished electrically as- well as lithologically from the overlying Sepinggan or Tanjung Batu Formation and the underlying Gelingseh Formation.

Miogypsina spp., Miogypsinoides spp., Lepidocyclina rutteni, Flosculinella borneensis. Down dip : GIobobulimina sp. (pyritized),

Bolivina sp., Robulus inornatus. Zone : Tf2, N11 - N13.

Environment

Onshore : Inner shelf, Reef Shoal carbonates; in the offshore, a Middle Neritic, low oxygen environment.

Age : Middle Miocene Tf2.

KAMPONG BARU GROUP*

Distribution Name Origin

The Kiandasan Member is well distributed in the southern flank and eastern plunge of Klandasan Anticline, Balikpapan, East Kaliman- tan. In the northern flank of the anticline, however, only small patches of the limestone are exposed.

The KamPong Baru was referred to by LeuPold and van der Vlerk in 1931 (P. 61913 from "Kampong Baru near Samarinda, Kutai District, E.(Kalimantan). This village lies E. of Sanga-Sanga, not to be confounded with another Kampong Baru only 3 Km N. of Balikpa- pan (where the same beds are out-cropping)". (P. Marks 1961, p. 61). The Kampong Baru Group has two formations, the Tanjung Batu and the Sepinggan Formations.

Type Section

Gunung Markoni is designated as the Type Section (Muller 1922). It is a hillside about 700 m north of Jalan Markoni at KM 5, southeast of 'Balikpapan Town, East Kalimantan (textfig. TAN J ~ G BATU FORMATION** 12). Along the hill at Gn. Markoni, a 35m thick section of limestone (Sudarjanto 1981) and marls belonging to the Klandasan Member is quarried, so the limestone is well exposed, texfig. 12.

Name Origin

The proposed name of this formation was taken from Tanjung Batu, a small Peninsula located approximately 4 Km N 338' E of ITCI Jetty, Balikpapan, East Kalimantan. Lithological description

Limestone, gray hard, massive, fossiliferous, * E. Marks ** T. Ismoyowati intercalated with marls.

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Boundaries Lithologic description

The Tanjung Batu Formation is a unit of the Kampong Baru Group which overlies the Klan- dasan Tongue Member of the Balikpapan Gro- up, represented by the Bo seismic marker of Total Indonesie. It underlies the Sepinggan Formation, and in some areas where the latter is removed, the Handil Dua and the Attaka Formations of the Mahakam Group overlie it. Towards the east, the Tanjung Batu Formation makes an inter-fingering contact with the lower part of the Sepinggan Formation.

Distribution

The Tanjung Batu Formation can be noted onshore within the bounds of the Kampong Baru Group (textfig. 6). Offshore it is found in wells from Kerindingan Field in the northern part of Kutai Basin to the Total Maruat No. 1 well in the south.

Type Section

Type section

Thickness

: Tanjung Batu surface sec-

: A 15m (Section I ) and +_

tion (textfig. 13).

57m (Section 11).

Hypostratotype Section

Hypostratotype Section Well

Coordinates

RT elevation : 55’ (17m) Water Depth’ : 149’ (46m). Total Depth Interval

Thickness : 3788’ (1 155m)

: Union Oil Sepinggan S - -1

: Lat 01’ 25’ 47.418” S (textfig. 14).

Long 116’ 56’ 0.117”E

: 12500’ (381 lm) : 7520’ to 11308’ (2293m

to 3448m)

The type sections of the Tanjung Batu For- mation consist of rather different lithologies. Lithologically Section I consists of interbedded shales, clays, siltstones, sands and coals. The sandstones are white to yellowish white in co- lor, composed mainly of frne to medium quartz grains, moderate to well sorted, mostly friable and loose. The sandstones have a channel type geometry and become more shaly toward the margin of the channel. Three cycles of deltaic depositional sequences can be observed along this exposure. Each cycle is distinguished by the existence of coal seams. They are mostly black, lignitic, occasionally friable. Alternation of shales and siltstones can be observed in the small gully, showing current ripples and laminations.

In the lower part of this sequence a thin la- yer of concretions of clayironstone, dark brown, hard, occurs above the sandy clay layers.

In Section 11, the sequence which is in latera- lly the same position as Section l , lithologically consists of clays, shales and coals. The clays are carbonaceous, gray, soft and plastic. The shales occur in thin to thick beds, dark gray, soft and carbonaceous. Thin layers ofsandy clay are noted in the lower part of the sequence. In the upper part, the coal beds occur in very thick sequences. Above these thick coal beds, a hundred foot section is covered by soil, and then in the very upper part laminated sandstone beds occur with intercalated clays and shales.

Paleontology

Trochanzmina arenosa; Textularia aggluti- nans.

Zone : possibly N13 - - N15 equivalent, by homotaxy.

Environment

This formation is almost barren of fauna,

157

only few arenaceous forams being noted. The occurrence of the coal beds suggest paralicdeltaic environment, and also the fining upward of sand grain-size of the sand layers is typical of a channel deposit.

Middle Miocene to Pliocene, Tf3-Th equivalent.

SEPINGGAN FORMATION*

Type well

Coordinates

R T E Water Depth Total Depth lnterval

Thickness

Type Section

: Union Oil Co. of Indone- sia -Pertamha Sepinggan S- 1, Textfig. 15.

Long. 11 6’ 56’ 00.71 1” E : Lat 01’ 25’ 47.418” S

: 55’ (17m) : 149’ (46m) : 12500’ (381 lm) : 1010’ (308m) to 7520’

: 6510’(1984m) (2292m)

Narne Origin Lithologic description

The Sepinggan Formation name is taken from the Sepinggan Field and from the type section, Union Oil Co. of Indonesia Sepinggan S-I. The name $Sepinggan’is derived from Su- ngai Sepinggan, township of Balikpapan, East Kalimantan.

Boundaries

The upper boundary is placed at the top of shallow marine shales, sands and carbonates, just under a lowering of sea level that in some areas left a non-conformable surface above which is the Mahakam Group Handil Dua and Attaka Formations. The lower boundary is marked by a seismic reflector, the flu marker, as defined by Total Indonesie at the Klandasan Tongue Member of the Gelingseh Formation. The lower Sepinggan Formation lies to the east of the deltaic Tanjung Batu Formation, but the upper part of the Sepinggan overlies the Tan- jung Batu offshore, and onshore where not erosionally removed.

Distribution

The Sepinggan Formation runs from the south to the north of the Kutai Basin area offshore, and onshore where not erosionally removed.

* Sujatmiko and E. Marks

1010’ - 5000’ (308m -1 524m)

Clays, medium to dark gray, soft, sticky, with thin sands, loose, quartzose, very fine to fine, subangular to subrounded, clear, some thick lignite beds at 1700’. limestones, white, hard, 5000’ - 6200’

(1 524m-1890m) crystalline to chalky. 6200’-6500’ Sands, loose, quartzose, f i e (1 890m- 198 Im) grained, subrounded, clear,

occasional calcareous ce- menting, thin limestone beds as above, and clays as above.

6500’-7520’ Limestones as above, with (1981m-2292m) siltstones, medium brown,

medium gray, soft to firm, and sands at base of section, loose, fine to medium grained, subrounded, clear, occasional calcareous ce- menting.

Base of Sepinggan Formati- on.

7520’ (2292m)

Pale ontology

1010’ (308m) Late Pliocene Anzrnunia ikebei (Billman and Karta- adiputra 1974,p.305).

I58

1190’ (363m) Early Pliocene Asanoina sp (idem)

1790’ (546m) Late Miocene Pseudorofalia catifliformis (idem).

5000’ ( I 524m) Late Miocene Ammonia yabei (idem).

7520’ (2292m) Base of Sepinggan Formati- on.

Zones : N13 - N21

Environments

1010’ (308m) Inner to Middle Neritic, Reef-Reef Shoal in part.

7520’ (2292m) Base of Sepinggan Formati- on.

Age

Middle Miocene Tf3, N13 equivalent, to late Pliocene Th, N21 equivalent.

MAHAKAM GROUP*

Name Origin

The name is derived from the Mahakam River, Kutai District, Kalimantan, forming the latest deposystem and contributing its sediments to this Group. The Mahakam Group has two formations, the Handil Dua and the Attaka formations.

ATTAKA FORMATION *

Please note that this formation does not correspond to the pay zones of Handil field. Pays are in the Kampong Barn and Balikpapan Groups.

Boundaries

The upper limit is the present day sea floor or land surface where it is exposed. The lower boundary is a contact, in places unconformable, with the underlying Kainpong Baru Group Sepinggan Formation or Tanjung Batu Formation. This contact can be seen in seismic sections as a fair marker.

Distribution

The western side of the Straits of Makdssar, forming the offshore eastern Kutai Basin, is covered with the Attaka Formation.

Type Section

Type well : Union Oit Co. of Indonesia - lnpex - Pertamina Atta- ka 1A (textfig. 16).

: La1 0’ 10’ 55.053” S; L,ong. 117’ 38’ 14.665” E

Coordinates

U T E : 32’(10m) Water Depth : 175’ (53m) Total Depth Interval : 216’ (seafloor) to 1350’

Thickness : 1 134’ (346m)

: I 1660’ (3554m)

(66m - 41 I m)


2 1 6’-700’ (66m - 213m)

Clays, light greenish gray to medium gray, plastic, slightly calcareous; shell fragments, gastropods, pelecy- pods; trace glauconite. Lig- nitic interbeds.

700’-900’ Sand, white, pale yellow, (21 3m - 274m) clear, angular to subroun-

ded, medium to coarse, in part very coarse to pebbly.

Name Origin

The formation name, Attaka, is taken from the Attaka field and the Union-lnpex-Pertamina Attaka 1A well, where it is normally found. This name is derived from the Japanese Atsuta- ka, meaning Bonanza (Seventy Six, 1973).

* E.Marks

I59

900’- 1000’ Claystone, light olive gray, (274111 - 305m) slightly plastic, slightly cal-

careous. 1000’- 1 350’ Bioclastics, coralgal, mollus- (305m---41 lrn) can shells, foraminifera;thin

interbeds, Lignite. 1350’ (411m) Base of Attaka Formation

Paleontology

Sea floor to 389m (1 19m) No samples. 389’ to 1350’ (1 19m - 41 lm)

900’-1 350’ (274m-4 11 m)

Cdcarih zone (Billman and Kartaadiputra 1974 p. 305). Calcarina calcar, Calcarina spengleri, Asterorotalia pul- chella, Pseudorotalia schme- teriana, Pseudorotalia conoi- des, Operculina complrmata, Operculina ammonoides, Common Pelagics. Globoquadrma humerosa N16-bN22 found in this interval.

Nannoplankton

910’ (277m) Coccolithus domnicokfes “17 - “19 (N21-N22)

Zones : N22-N23.

Environment

Sea floor 216‘ (66m) Middle Neritic Sea floor -389’ No samples (66m - 119m) 389’ - 630’ Outer Neritic (1 19m - 192m) 630’ - 900’ (192m - 274m) 900’ - 1350’ (274m - 41 lm)

Shallow Marine - Restricted

Neritic, Open Marine

HANDIL DUA FORMATION *

Name Origin

The name Handil Dua was taken from Handil Dua village, some 80 Km NE of Balik- papan and 37km SSE of Samarinda (textfig; 17). This village, which is located in the Maha- kam Delta, has been chosen by Total Indonesie as its operational base for the Mahakam Delta.

Please note that this formation does not correspond to the pay zones of Handil field. Pays are in the Kampong Baru and Balikpapan Groups.

Boundaries

The Handil Dua Formation, which are modern marine deltaic sediments formed during the last phase of the Holocene Transgression, overlies unconfomably the Pliocene sediments of the Tanjung Batu Formation (textfig. 4).

Distribution

As a Recent sediment, the Handil Dua For-

9 mation is developing in a prograding Mahak Delta, comprising approximately 1300 km of predominantly marshy and swampy subaerial delta plain, 1000 km2 of delta front and 2700 km2 of prodelta accumulations (Allen et al, 1979), textfig. 18.

Type Sections

In the Mahakam Delta borings S5 and S7 are among a number of shallow (15 to SOm) cored borings which have been chosen as co-type sections (textfigs. 1 7 and 18). In addition, a large number of surface sediment samples were taken from many parts of the Mahakam Delta, situated between 0’ 21’ and l o lo’ South Latitude, and 1170 15’ and 117’ 40’ East Longitude .

Pleistocene to Recent N22 - N23. * Sujatmiko

160

Lithological description

The Handil Dua Formation is composed of sand, clay, and mud. These sediments are found either in delta plain, delta front or prodelta environments.

Paleontology

The following foraminiferal assemblages were examined from sea bottom samples taken by a Berthois hand dredge. The samples repre- sent approximately the upper lOcm of sediments.

Hyposaline fauna : Hapbphragmodes spp., Trochammina spp., Palmerinella spp.

Tidal Marine fauna: ’ Fseudoepon ides ” nakanoen sis, As terorota- lia trispinosa, EMhidium koeboeensis

Marginal Marine fauna : Aeudorotalia spp., Elphidium spp.

Shallow Marine fauna: Operculina spp.

Environment

Mixed Fluvial - Tidal Marine Deltaic System

Age

Post - Holocene transgression (SO00 - 7000 years b.p.) (Allen et al, 1979).

SUMMARY AND CONCLUSIONS

In summary we have recommended the adoption of the following lithostratigraphic units for use in the Kutai Basin: In the late Oligocene to Early Miocene, the ‘Pamaluan formation; The Early to Middle Miocene Be-

bulu Group divided into the Maruat Formation and the Pulau Balang Formation; The Middle Miocene Balikpapan Group divided into the Mentawir Formation, the Gelingseh Formation, and the Klandasan Tongue Member of the Ge- lingseh; the Middle Miocene to Late Pliocene Kampong Baru Group consisting of the Tanjung Batu and the Sepinggan Formation, and the Ple- istocene to Recent Mahakam Group divided into the Attaka and the Handil Dua Formati- ons.

R E F E R E N C E S

ADAMS, C.G., 1970. A reconsideration of the East Indian letter classification of the Ter- tiary. Wl. Brit. Mus. (Nat. Hist.) Geol., v.19, no. 3, p. 85-137,3 textfigs,

AGUNG, H., 1981. Stratigrafi daerah Pulau Balang, Teluk Balikpapan, Kalimantan Ti- mur. Unpub. Honors paper. Cadjah Mada Univ., Fak. Tek. Jur. Tek. Geol., Yogya- karta.

ALLEN, C.P. LAURIER, D. & THOWENIN, J., 1979. Etude se’dimentologique du delta dc la Mahakam. Notes et Memoirs, No. 15, Compagnie Francaise des Petroles, Paris, 156, p., 2 p l .

BILLMAN, H. G. & KARXAADIPUTRA, L. W., 1974. Late Tertiary biostratigraphic zonation, Kutai Basin, Offshore, East Kali- mantan, Indonesia. Proc. Ind. Petr. Assn. 3d Ann. Conv., p. 301-310.

BLOW, W.H., 1968. Late Middle Eocene to Recent planktonic foraminiferal biostrati- graphy. Eroc. 1st Internat. Conf. Plankt. Microfossils, p. 199-421.

BOLLI, H. M., 1966. Zonation of Cretaceous to Pliocene marine sediments based on planktonic foraminifera. Bol. Informativo Assoc. Venezolana Geol. Min. Petr. v. 9, no. 1,32 p.

GLAESSNER, M. F,, 1943. Problems of stratigraphic correlation in the Indo-Pacific Region. Proc. Roy. SOC. Victoria, v. 55 (N.S.) pt. 1, p. 41 -80.

161

MULLER, F. T., 1922. Berichte uber die geo- tion between the tropical planktonic logische Untersuchung der Klandasan Anti- foraminiferal zonation and the Tertiary Minale. B.P.M. Report, unpubl. Far East Letter Classification. Geol. en RUTTEN, L. M. R., 1914. Studien uber Fora- Mijnb. v. 54,no. 314, p. 195-198. miniferen aus Ost-Asien (Fortsetzung).

INDONESIAN PETR, ASSN., 1974. ~ d k - S-1. Geol. Reichs-Mus. Netherlands. Ser. 1, v. 9 (1911 - 1914), no. 4, p. 281- papan-Tandjung Field Trip Guidebook,

30-., 5 pl. 324.

LEU~OLD, w. & VAN DER v ~ m , 1. M., SAMUEL, L., 1980. Pengaruh Kegiatan Permi-

Kota Balikpapan. Jour. Ikatan Ahli Geolo- tin, Leidsche Geol. Meded., v.5, p t . 3 , ~ . gy, Indonesia, June, 1980, 6 fgs. 611-650.

& MUCHSIN, S., 1975. Stratigraphy MARKS, P., 1961A. Stratigraphic Lexicon of -----

Pusat Djawat. Geol. Bandung, Publ. Keilm. Ind- Petr. 4th An. No. 31, Ser. Geol., 233 p- 6 pls.

1961B. ~ d ~ , stratigraphic hxicon SEVENTY SIX, 1973. Attaka means bonanza. of Indonesia. Rep. Indonesia Kement. Seventy six, March, p- 14- perekon. pusat DjaWat. ~ ~ ~ 1 . Bandung. SUDARJANTO, 198 1. Stratigrafi batubara dan

pub. Honors paper, Gadjah Mada Univ., Fak. Tek. Jur, Tek. Geol., Yogyakarta.

HAAK, R. & POSTUMA, J. A, 1975. The rela-

1931. The Tertiary. In Festbundel K. Mar- nyakan Terhadap Geologi Tatalingkungan

Indonesia, Rep. Indonesia Kement. Perekon. and sedimentation in the Kutai Basin, Kdi-

Conv. p. 27-39.

h b l . K e h . no. 31 A, Ser. Geol. 135 p., 1 batugamping daerah Balkpapan Timur* un-

Pi- MARSHALL, A. J. & SCHUMANN, H. O.,

198 1. Stratigraphy and Hydroarbon poten- SUYONO MARTODJOJO, 1975- Stratigraphic t i4 of the Beds in the Kutei Ba- Code Of Indonesia. lkatafl Ahli Geologi sin, East Kalimantan, Indonesia. Proc. Ind. Petr. h s n - 10th Ann. Conv. p. 285 - 295. UMBGROVE, J.H. F., 1927- Neogene formi-

1943, Palaeontology and niferen van de Soengai Beboeloe, Pasir, Stratigraphy of the ti^^ of SJ. B ~ ~ ~ ~ ~ . Zuidoost-Borneo. Wetensch. Meded. Dienst. Unpubl. Rep't., Chishitsuchosajo. Bandung, Mijnb- Ned. Indie- v.5, Pa 28-41- 12 p, 4 PIS. ., 1929. Tertiary sea connections

MOHLER, W. A. &TEN BERCE, J.R.J., 1949. between Europe and the Indo-Pacific area. Palaeontologisch onderzoek Mentawir en Proc. 4th Pacif. Sci. Congr. Jawa (reprint standardsectie Klandasan. Unpubl. Rep't, p. 1-14). B. P. M. Report, no. 10415,20 p. VAN BEMMELEN, KW., 1949. Geology of

MUGNIOT, J. F., 1981. Seismic facies inter- pretation, a contribution to the stratigraphi- VAN DER VLERK, I.M. & UMBGROVE, J.H. cal framework of the Mahakam Delta, F., 1927. Tertiare gids foraminiferen van Workshop on Strat. Nomencl. in East Kutai Nederlandsche Oost-Indie. Wetensch. Me- Basin, Kalimantan, 8 p., 8 fgs. ded., vol. 6,35 p.

Indonesia, l9 P.

MOHLER, W. A*,

Indonesia, p. 126-142, &art p. 139.

162

MAJOR STRUCTURAL

OF KALIMANTAN i m j Pre-Tertiary Basement ELEMENTS .......... 1 0 0 0 Ft . Bathymetric

Contour

Km. Figure 1

163

DIAGRAMMATIC CROSS-SECTION A --A'

K U T A I B A S I N

FIGURE

h 1 f I

0 SANDSTONE

LIMESTONE

0 SHALE

BASEMENT

164

DIAGRAMMATIC STRATIGRAPHIC SUCCESSION SOUTH EAST KUTAl BASIN

EAST KALIMANTAN - INDONESIA FIGURE 3

AGE

PLEIST

TO

RECENT

"CIOCENE

LATE

MIOCENE

MIDDLE MIOCENE

? T f t x vouMcn

MIODLE

MIOCENE

EARLY MIOCENE

Te 5

N 4 EARLY

MIOCENE

LATE 3LIGOCENI

GROUP . . . . . - . . . . . . . . . . . . . . . . -. . . . . . .

. . . . . . .

LEGEND 0 ::,"n", B liqnite

silts @ limestone

shale -a- Seismic Marker

165

. LITHO -AND BIO - STRATIGRAPHY

SOUTH EAST KUTAI BASIN EAST KALIMANTAN - INDONESIA

L

N 23/22

N 21

N 20

N 19

N 18

N 17

N 16

N 15

N 14

N 13

N 12

N I I

-

~

I Q

Th

T g

-

T f 3

T f 2

- LATE

QUATERNAR)

W z W V

I! -I a

W 2 w 0 0

2 -

L A T E OLIGOCENE

:ARL'

-

LATE

WDDL

-

EARL'

FIGURE 4 I . BENTHONIC I L l T H O U N I T PROPOSED

Te 5

LOCALZONES I GROUP

MAHAKAM CALCARINA GROUP I

I

\MMONIA IKCEEI

ASANOINA

~

S C A T I L L I F O R M I S

AMMONIA YABEIl

FORMATIONS / M E R S

TANJUNG B A T U

F M z MARUAT PULAUBALANG

r; P A M A L U A N

F M

166

167

FIG. 6 DISTRIBUTION OF GROUPS I

MAHAKAM GROUP

KAYPUNG BARU BROUP

n BALMPAPAM O R O ~ P

168

T Y P E S E C T I O N PRlNGTALl AND JAMBU SURFACE SECTIONS

PAMALUAN FORMATION FIGURE 7

A G E HICKNESS ENVIRONMENT g

g z =

m 0 a & - 0' W L L c I -I

I- z D E S C R I P T I O N S E Y c

ANG -

OOO.

iooo

TUYU FORMATION

Mudstone with conchoidal fractures or bedded shales, often with carbonaceous

leaf remains.

Sandstone and coal beds are also found.

Thin limestone occurs near the top o f

the formation.

Groy to block shales with no visible

plant fragments.

Interbedded with medium groined sandstone up to ( 5 m thick

I

T Y P E S E C T I O N B A L A N G I S L A N D SURFACE S E C T I O N

P U L A U BALANG FORMATION

Light gray t o white, f r iable t o -

hard, occosionally calcareous,

f l ne t o coarse grained, quar tz -

ose sondstones.

The sandstones occur i n thin

t o thick beds with cross bedding

and worm burrows. Interbedded

with the sandstones ore thin to

moderately thick beds of dark gray,

occasional;y carbonaceous, calca - reous, siltstones and claystones.

In the upper part of the column

ore 1.2 - 2. 2 m., white to tan,

massive, fossiliferous limestones.

FIGURE THICKNESS . ENVIR(

- = r O W t 5 - 6 - L Z Q o m " C

D E S C R I P T I O N S v) I S L !I L i w -1 I ' L

1 70

z e

fr

0

B

T Y P E S E C T I O N

MARUAT FORMATION TOTAL INDONESIE - INPEX - PERTAMINA MARUAT No.1

ENVl RONMENT DEPTH 2

O W (METERS) "2 Ef 4 !$( AGE

MENT,

z 0 I-

z U 0 LL

- a

I-

U

z

%! a

- PULA1

FEET IN t- - D E S C R I P T I0 N S -ikI;~ 1 1 $

IIR FM

UPPER

LIMESTONE

PUL4U BALANG FY

LOWER

LIMESTONE

BALANG FM

171

D E S C R I P T I O N S 4 0 I t 3

HYPOSTRATOTY PE SECTION

MENTAW IR F 0 R M A TlON BALIKPAPAN SURFACE SECTION

I z E l ITHICKNESS

--- --_- .......... ---- . . . . . . . . . . . . . . . . . - --- --- - - - - -eoe

- -- - .........

. . . . . . .

-. . . . . . . . . . ........ ........ . . . . . . . . ........ _ _ . _ _ _ . . . . . . . . . . . . . . . . . . . . . . . . - . ~ ._ . . . . . . . . . . . . . . . . - . . -. . - . . . . . . . . . . . . . . . . . . - . . . . . . . . . .

-

(LANDASAN TONGUE MBR.

Sandrtones, quortzore, white, l i h t gray

"' to brownish, soft to friable, fine to

coarse grained.

The sandstones occur in thin to very

- B o a

. . -a06

- TH

5 - 3 0 W

!2 z I a, z

.WE%

500 -- 1650

400 --I320

ZOO -- too0

200 - - 6 6 0

100 --330

UNKNOWI

P U L A U B A L A N G FM.

FIGURE 10 I ENVIRONMENT

f...:? ...... cross bedding - ... - ... ....... - . ......... ......... ......... . . . . . . . . . -. . . . - . . - . . . . . . . . . . . . . . . . . . . . . . . . . . . . - .... . . . . . . . . . --- . . . . . . . . 1 . . . . . . . .

lnterbadded with the sandstones ore

thin to m e d i u m l ignite layers, clays

and siltstoner in t h e upper part . ' 0 0 3 ........ . . . . . . .

. . . . . . . ......... 8 0 2 . . . . . . . . . . . . . . . . ---leo, ......... . . . . . . . . . . . . . . . . . . . . . . .

172

f,

5 E U

HYPOSTRATOTYPE SECTION UNION - PERTAMINA SEPINGGAN V - 1

G EL I N G S E H FOR MATI 0 N

ENVIRONMENT DEPTH $ I N 0 2 $ % u s 0 E S C R I P T I O N S E E k g

(METERS) f g ; z m Y 4 c z A G E F E E T

FIGURE I 1

LANDASAN TONGUE MBR 1 I L

rr)

z c

I (3,

z

Clay .claystone,liqht pray ,soft .occasionally f i rm non coRareous,with l i l t le coal, black moderate

hard, bri t t le, shiny. Sandstones,while light gray,very f ine to fine grained ,mod sorting rubrounded,friable.

occortonatly mod hard with thin limestone brown, bioclostic.hord

Clay .pray to brown, moderate hard, ver y

slightly cokareouf

lnlerbedded with thm layers sandstone, whlte-

9ray.very fine to fine proined.prading to siltstone with carboniferous moteriol

Cloyrlone, light pray - brown. buf f , soft to slightly f i rm,r l ightly calcareaus.

Interbedded wtlh lh in layers sendstone,

KLA

ND

ASA

N T

ON

GU

E M

BR c

z

MID

DLE

M

IOC

EN

E

1: C

n

T

Tf -

2

- a N

:: 1

U

1-

P s

II

0

m n -

-4- 0

174

- I-! -

m w =

l N 3 l V A l I I O 3 91 - E 4 1

3 ~ 3 3 0 1 ~ m a a i w

N O l l V W M O j n1V9 S N I I P N V I '

175

HY POSTRATOTY PE SECTION

T A N J U N G B A T U F O R M A T I O N UNION - P E R T A M I N A SEPINGGAN S - 1

0 ' A G E IN 2 D E S C R I P T I O N S E F E E T 2 (METERS) 5

SEPlNGGAl

z 0

I- 4

-

= w a

O Z LL 0 0 -

= r I- 4 co

W I- 4 c3

=>

z I-

z - 1

7

a

KLANDASAN TON

176

T Y P E S E C T I O N

SEPINGGAN F O R M A T I O N UNION-PERTAMINA SEPINGGAN S - I

Cloys medium to dark p r a y , s o t l , ~ l t c h y ;

with thin sands,loose,quarliose.~~ry fine

lo fine qratnad.subonpulor lo subrouded,

clear. lOme thin l i p n i l 0 beds 0 1 1700'

Limeslones ,whi le . hord.cryrlolline lo chnlky

i 57

T Y P E S E C T I O N UNION - INPEX - PERTAMINA ATTAKA I A

A T T A K A FORMATION I

FlGUl z DEPTH 0

0 ESC RIP T I 0 N S a IN s I AGE FEET s 2 2

I-

(METERS) C cc

Colcorina

nite, lignitic interbeds. Sond,white, pole yellow, cleor angular to subroundrd, medium to coarsetin port very coarse to pebbly.

Bioclostics , corolgal ,molluscon shells,forominifera , thin interbeds lignite.

IE 16 E N VIRONMENT

WAKA FIELD

n

178

A G E

T Y P E S E C T I O N C O R E S - 5 / B 1

HANDIL DUA F O R M A T I O N

D E P T H ENVIRONMENT s -1 w 0 -

I- 0 E S C R I P T I O N S + J c * a c ’ 3 e

y : c -1 8 : ’ s +

4ND SURFACE

c z W 0 W

I W z lLl

a

SE NOT

2!!izLL BALlKPAPAW

179

T Y P E S E C T I O N CORE S-7

HANDIL DUA F O R M A T I O N FIGURE 18

L A N D SURFACE

I - * z W 0 W

I W z w u 0 -I 0 I

a

8ASE NOT R

I---+ Sands, clayey , clays. dark gray plant remains

Sands, f ine grained, gray, clayey.

~~ . . . . . . . . . .

--- . . . . . . . . . --- --

Clays, g r a y , lenlicular

Clays,gray,with lenses o f sand and silt5

Sands, very fine .c layey, w i t h lenses Of silty clays

Clays, g ray , with horizontal laminations, Plant remains, abundant bioturbations and shell fragments

\ i.

Documents

Cenozoic Stratigraphic Nomenclature in East Kutai Basin, Kalimantan