Jil. 20, No.2 (Vol. 20, No.2) Mar-Apr 1994 KANDUNGAN (Contents) Sivagnanam Sivalingam: Clay mineralogy and sandstone diagenesis of turbidite deposits from 69 the Crocker Formation, Sabah, East Malaysia J.K. Raj: Uniaxial compressive strengths of Tertiary sedimentary rocks from the Batu Arang area, 77 Selangor Darul Ehsan R.C. Tewari: Recent advances in tectono-sedimentary models and paleogeography of Gondwana 85 Basins of peninsular India R.J. Weimer: Sequence stratigraphy - Historical perspective of concepts, problems and 87 challenges in exploration K. Naha: Structural history as a clue to crustal evolution 88 Permo-Triassic of Malaysia and Associated Mineralization - Seminar & Fieldtrip Report 89 Ucapan Pengerusi, Dr. Mohd Shafeea Leman 91 Ucapan Pembukaan, YB Prof. Dr. Anuwar Ali 92 Programme & Abstract of Papers 94 Fieldtrip Report 109 Annual General Meeting & Annual Dinner 1994 - Report 113 Speech by GSM President, En. Fateh Chand 115 Speech by YB Dato' Seri Dr. Lim Keng Yaik, Menteri Perusahaan Utama 117 Minutes of the 27th Annual General Meeting 124 ...................................... ............................. .................. .....................:.;.;.:.;.:.:.:.:.:.;.;.;.:.:.:. ................. ,', ........................... :::·:::!5g! . rl;~ : ~B!i~::R!BiB,!HI,~ .:i ~N .il~: . gff:!1g : B9B~~~X~ :: .:.::·::.:::::::::;::::::::;l:":l:. :.. :: ::··:::::::(::::::(,::l:i:i.:::::::::::.-:.::::::i::((: :,,::::::;;" :::0::::::: ::: ::::: :::::::: Keahlian (Membership) 143 Pertukaran Alamat (Change of Address) 143 Pertambahan Baru Perpustakaan (New Library Additions) 144 Sponsorships to AAPG Convention 1994 145 List of theses titles Session 1991/92 UKM & UM 146 Quantified Risk Analysis & Environmental Impact Assessment - Training Courses 149 The 16th New Zealand Geothermal Workshop 152 GEOSEA '95 - 2nd Circular 153 Kalendar (Calendar) 161 Majlis (Council) 1994/95 Presiden (President) FatehChand Naib Presiden (Vice-President) Ibrahim Komoo Setiausaha (Secretary) Ahmad Tajuddin Ibrahim Penolong Setiausaha (Asst. Secretary) Nik Ramli Nik Hassan Bendahari (Treasurer) Lee Chai Peng Pengarang (Editor) TehGuanHoe Presiden Yang Dahulu (Immediate Past President) : Ahmad Said Juruodit Kehormat (Honorary Auditor) Law Jack Foo 1994-96 1994-95 Abd. Ghani Mohd Rafek Ali Mohd. Sharif Abdul Rahim Samsudin Choo Mun Keong Effendy Cheng Abdullah Idris Mohamad Tan Boon Kong Jimmy Khoo Khay Khean Jawatankuasa Kecil Pengarang (Editorial Subcommittee) Teh Guan Hoe (PengerusilChairman) Dorsihah Mohamad J ais Lili Sulastri Fan Ah Kwai Ng Tham Fatt J.J. Pereira Noor Ilmi Abu Bakar Lembaga Penasihat Pengarang (Editorial Advisory Board) AwPeckChin Denis N.K. Tan Leong Lap Sau P.H. Stauffer Azhar Hj. Hussin FooWahYang Mazlan Madon Tan Boon Kong K.R. Chakraborty C.AFoss Ian Metcalfe Tan Teong Ring Choo Mun Keong N.S. Haile John Kuna Raj H.D. Tjia Chu Leng Heng C.S. Hutchison Senathi Rajah Yeap Cheng Hock Lee Chai Peng Shu Yeoh Khoon The Society was founded in 1967 with the aim of promoting the advancement of earth sciences particularly in Malaysia and the Southeast Asian region. The Society has a membership ofabout 600 earth scientists interested in Malaysia and other Southeast Asian regions. The membership is worldwide in distribution. Published by the Geological Society of Malaysia. Department of Geology. University of Malaya. 59100 Kuala Lumpur. Tel: 603-757 7036 Fax: 603-756 3900 Printed by M PrInting Works Sdn. Bhd.. 29 Jolon Rlong. 59100 Kuo/o Lumpur. Clay mineralogy and sandstone diagenesis of turbidite deposits from the Crocker Formation, Sabah, East Malaysia SIVAGNANAM SIVALINGAM 9918 W 50th Terrace Merriam KS 66203 USA Abstract: The Crocker Fonnation in the Tenom-Pangi Area can be classified into three different turbidite facies. X-ray diffraction analysis of the shale beds from the various turbidite facies in the Crocker Fonnation show that illite, chlorite and kaolinite are the most common clay minerals. There is no relationship between clay type and facies. The sandstones in the thick bedded facies are classified as sublithe arenite and as quartz arenite in the thin bedded facies. These sandstone have undergone a high degree of diagenetic modifications such as compaction, silica overgrowth, precipitation of authigenic chlorite and kaolinite,and carbonate cementation. The diagenetic modifications have reduced the porosity of the sandstones and their potential as hydrocarbon reservoirs. INTRODUCTION GENERAL GEOLOGY AND STRATIGRAPHY Shales and sandstones from the various turbidite facies in the Crocker Formation were The Crocker Formation belongs to the selected for detailed mineralogical investigation. Rajang Group of rock which were deposited The sandstone from the various facies were from late Cretaceous to Tertiary in the North studied to determine the mineralogy and West Borneo Geosyncline (Haile, 1961). The diagenesis to evaluate the reservoir properties Rajang Group extends in an arcuate belt about of these rocks. 200 km wide eastward from central Sarawak into western Sabah. The Crocker Formation Clay minerals in various shale beds from in the study area is exposed in the Padas Valley the Crocker Formation were investigated using area. X-ray diffraction techniques. Shale samples from the thick bedded sandstone facies, the The stratigraphy ofthe Padas Valley and thin bedded sandstone facies and the mudstone Labuan area is described by Wilson (1964). facies were selected for clay analysis. The Crocker Formation is underlain by the Sapulut Formation (Paleocene), which consists Clay minerals in sedimentary rocks are of conglomerate, sandstone, siltstone and widely used as a geothermometer to measure mudstone with small lenses of limestone and the thermal history of the basins and overlain by the Meligan Formation (Oligocene­ environment of deposition. With increased Lower Miocene). The Meligan Formation activity in hydrocarbon exploration offshore of consists largely of cross bedded sandstone with Sabah, there is great interest in facies analysis, thick layers of shale and is overlain by the mineralogy and diagenesis of Crocker sediments. Belait Formation (Upper Miocene to Pliocene) Similar studies to the present investigation which consists of estuarine and shallow marine can be used as a tool to interpret offshore deposits of sandstone, shale and coal beds. The sedimentary sequences for understanding basin Liang Formation (late Pliocene and Pleistocene) history. overlies unconformably the Belait Formation ISSN 0126-5539 Warta Geologi, Vol. 20, No.2, Mar-Apr 1994, pp. 69-75 70 SIVAGNANAM SIVALINGAM and consists mainly of marine sediments and Copper K-alpha radiation with a nickel marine and albivial terraces. The stratigraphy filter was used. A divergence slit of 112 mm, of the Padas Valley area shows an upward rece~vUig slit of 0.1 mm, anti-scatter slit of 1 progression from deep water turbidite deposits mm and a time constant of 2 second with to shallow water deposits. goniometer speed at 1° per minute were selected The Crocker Formation in the Tenom-Pangi for the X-ray diffractometer settings. The area consists of Cenozoic turbidite deposits instrument was operated at a voltage of 40 forming a thick succession of sandstone shale kilovolts and 20 milli-amperes. All the slides alternations. The deposits can be divided into were scanned from 2 to 35 degrees under the thick bedded sandstone facies, thin to medium same instrument conditions. Clay minerals bedded sandstone facies and mudstone/shale were identified based on published data and facies (Sivalingam, 1984). diffractograms (JCPDs Files; Thorez, 1975). Illite/smectite mixed layers and % illite were determined based on Weaver (1955), and MATERIALS SELECTED FOR ANALYSIS Reynolds and Hower (1980). Shale samples from the mudstone/shale facies, and from shale layers interbedded with RESULTS the thick and thin sandstone facies were collected for clay analysis (Fig. 1). Ten shale samples Thick Bedded Facies were analyzed for clay mineralogy; three samples The thick bedded sandstone facies consists from the mudstone/shale facies (Sla, Slb and largely of sandstone interbedded with siltstone S9), six samples from the thin bedded sandstone and shale. Sandstone bed thickness generally facies (S2, S4, S11a, S11b, S12 and S15), and ranges from 0.3 m to 2 m with amalgamated one sample from the thick bedded sandstone beds as thick as 15 to 20 m. Shale beds are facies (S8). Five sandstone thin sections were absent where the sandstone beds are selected for point counting for rock classification amalgamated. The basal contacts of these beds purpose, two from the thick bedded sandstone are abrupt, planar, or irregular. Internally, facies and three from the thin bedded sandstone the sandstone beds are structureless and Bouma facies. sequences (1962) cannot be recognized. Sandstone Petrology METHODS OF STUDY The thick sandstone beds are coarse to Thin sections of sandstones were examined medium grained, poorly sorted, and strongly using a petrographic microscope equipped with cemented. The sandstones are composed largely a camera. The sandstones were classified using of quartz, feldspars, matrix and rock fragments. point counting methods according to McBride Detrital quartz makes up about 60%, feldspars (1963). The less than 2 micron clay fraction about 5%, rock fragments about 4 to 9%, and was separated from the shale through simple matrix about 25%. Under McBrides's scheme gravity sedimentation techniques and the of sandstone classification, these rocks are powdered sample was suspended