The Malaysian - Thai Working Group
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GEOLOGY OF THE BELUM – HALA TRANSECT AREA ALONG THE MALAYSIA–THAILAND BORDER GEOLOGICAL PAPERS VOLUME 9 by The Malaysian - Thai Working Group A joint project carried out by Minerals and Geoscience Department, Malaysia and Department of Mineral Resources, Thailand The Malaysia-Thailand Border Joint Geological Survey Committee (MT-JGSC) 2012 GEOLOGY OF THE BELUM-HALA TRANSECT AREA ALONG THE MALAYSIA-THAILAND BORDER by The Malaysian-Thai Working Group A joint project carried out by Minerals and Geoscience Department, Malaysia and Department of Mineral Resources, Thailand The Malaysia-Thailand Border Joint Geological Survey Committee (MT-JGSC) 2012 PREFACE This report together with the accompanying geological map on the scale 1:250,000 is the result of close cooperation between the Minerals and Geoscience Department Malaysia, and the Department of Mineral Resources Thailand in resolving problems related to cross border geological correlation between Malaysia and Thailand. The Transect area covers about 2,020 square kilometres along the common Malaysia-Thailand border. Fieldwork was carried out in October 2005, January 2010 and March 2010 in the Belum area, Malaysia. A joint field check was carried out in the Belum area from 9th to 14th March 2010 by the geoscientists from both Malaysia and Thailand. There was no fieldwork carried out in the Hala area, Thailand due to security and accessibility reasons (very thick jungle). Thus, geological interpretation in the Hala area was based on the remote sensing interpretation and correlation of the photogeological units with the Belum area, Malaysia as well as previous works done in the Batu Melintang-Sungai Kolok and Pengkalan Hulu-Betong Transects areas. Problems on the discontinuity of time rock unit boundaries between the various rock units found on both sides of the common border areas have been satisfactorily resolved. Potential mineral deposits occur along the border areas but the present security situation, as well as environmental issues does not encourage the exploitation of these mineral deposits. Future increase in the price of minerals coupled with advances in mining technology may facilitate joint exploitation of these mineral deposits. Dato‟ Yunus Abdul Razak Mr. Nitat Pootanakul Director General Director General Minerals and Geoscience Department Department of Mineral Resources Malaysia Thailand March 2012 March 2012 i ACKNOWLEDGEMENTS The Malaysian - Thai Working Group would like to express their gratitude to the Director General, officers and staffs of the Minerals and Geoscience Department Malaysia (JMG) and the Director General, officers and staffs of the Department of Mineral Resources, Thailand (DMR) for their encouragement, support and funding of this project. Thanks are extended to Mr. Alexander Unya Ambun, Director of Technical Services Division, Minerals and Geoscience Department Malaysia and Dr. Tawsaporn Nuchanong, Director of Bureau of Geological Survey, Department of Mineral Resources, Thailand, for their encouragements during the study. Thanks also due to all staffs of the Minerals and Geoscience Department Malaysia and Department of Mineral Resources, Thailand for their involvement in this project either directly or indirectly. The Malaysian and Thai military, provincials and border police officials are duly thanked for their assistance in the security matters especially during the field trips in the Royal Belum State Park and Temengor Lake areas. Last but not least to all local residences for their support and assistance during the fieldworks. ii Geology of the Belum-Hala Transect along the Malaysia-Thailand Border by The Malaysian-Thai Working Group EXECUTIVE SUMMARY According to the Sixth Meeting of the Malaysia-Thailand Border Joint Geological Survey Committee held in Kuala Lumpur on 11th June 2009, both parties have agreed to carry out the study on the Geology of the Belum-Hala Transect as proposed by the Malaysian-Thai Working Group. Since then, the project has been carried out by the geoscientists from the Minerals and Geoscience Department Malaysia and the Department of Mineral Resources Thailand in 2010 and 2011. On the Malaysian side, systematic geological mapping in the Belum, Gunung Hulu Merah and Kerunai areas where the Belum-Hala Transect is located was carried out by the Geological Survey Department during the year 1991-1993. During that time, the Malaysian side of the Transect area was mapped on the scale of 1:63,360. For the purpose of this joint geological mapping, the Malaysian Working Group has undertaken geological field checks on the scale 1:50,000 at selected localities in October 2005 and January 2010. In the areas where the ground data is not available, the remote sensing interpretation has been done. Then the geological map on the scale 1:250,000 was produced and attached to this report. On the Thai side, the geology mapping of the Belum-Hala Transect area was carried out based on the remote sensing interpretation and previous works on the Batu Melintang-Sungai Kolok and Pengkalan Hulu-Betong Transect areas. A geological map based on remote sensing data has been prepared since January 2010. A joint field check had been carried out on the Malaysian side of the Transect area close to the Malaysia-Thailand border in conjuction with the Malaysia-Thailand Working Group Meeting on the Belum-Hala Transect area that was held from 9th to 14th March, 2010 at the Belum Rainforest Resort, Malaysia. Then the photo-geological map has been improved by using the data and information collected from the joint field check. In addition, raw data from the field works in the Batu Melintang-Sungai Kolok and the Pengkalan Hulu-Betong Transect areas were also included in describing the characteristics of rock units. The Transect area is covered by the Silurian-Devonian Betong Formation (SDbt), Carboniferous Tiang schist (Cts), Carboniferous Kubang Pasu/Yaha Formation (Ckp/yh), Carboniferous-Permian Mangga formation (CPmg) and Permian Gerik formation (Pgk). The Betong Formation is only exposed on the Thai side, whereas the Mangga formation and the Gerik formation are only exposed on the Malaysian side. The photogeological ST1 unit is well exposed as the long, narrow roof pendant area in the vicinity of the granite/shear zones in the upper central and northwestern parts of the area. The unit iii is represented mainly by schist and phyllite, which can be correlated to the metamorphic rocks of the Silurian-Devonian Betong Formation (SDbt1). The photogeological ST2 unit forms a long, narrow-shaped roof pendant in the vicinity of the granite/shear zone in the northwestern part of the Transect area. The characteristic of this unit is similar to the ST1 unit but has more resistance. The unit is interpreted to be schist, phyllite and minor quartzite which can be correlated to the metamorphic rocks of the Silurian-Devonian Betong Formation (SDbt2). The Tiang schist (Cts) comprises purplish grey to dark grey quartz-mica schist, quartz schist, quartz-mica-graphite schist and quartz-mica-garnet schist with minor hornfels. The schist is strongly schistosed, well foliated, consisting essentially of medium-grained elongated quartz and mica. On the Malaysian side, the Kubang Pasu/Yaha Formation (Ckp/yh) occupies the Sungai Kenerong valley in the western and central parts of the Transect area. The rocks in this area are metamorphosed to hornfels, phyllite, schist, metasandstone and metaconglomerate. On the Thai side, the Yaha Formation (Ckp/yh: S3) unit is distributed in the south-western part of the Transect area adjacent to the Malaysia-Thailand border. The unit shows a wide roof pendant on granite with prominent N-S bedding trace. The unit is characterized by well-bedded sandstone and shale which can be correlated to the arenaceous and argillaceous facies within the Carboniferous Kubang Pasu/Yaha Formation (Ckpar/yh1 and Ckpag/yh2). Only arenaceous facies of the Mangga formation (CPmg) is exposed in the southeastern part of the Transect area. The arenaceous facies consists of yellowish grey, light grey, thin- to medium-bedded, fine- to medium-grained metasandstone and metagreywacke interbedded with minor metasiltstone. The Gerik formation (Pgk) is distributed in the southwestern part of the Transect area. It comprises predominantly tuffs of rhyolitic to rhyodacitic composition. In addition, interbeds of tuffs, limestone, calcareous shale, tuffaceous sandstone and chert as well as siliceous shale also occur in places. Foliation can be seen in the groundmass of the tuffs as a result of regional metamorphism. On the Malaysian side, the igneous rock that is predominantly consists of granitic rock and distributed as N-S linear masses in the middle part of the Transect area known as the Main Range Granite. It comprises the Kabut granite (Trgrkt), Merah granite (Trgrmr) and Singor granite (Trgrsg). Based on remote sensing interpretation, four types of the granitic rocks are identified on the Thai side of the Transect area and can be described as follows: i. The G1 unit that is correlatable with the Merah granite/Bu Do granite (Trgrmr/bd) is widely distributed as batholith in the eastern-central part of the Transect area and some stocks are located in the central and western parts. It is also extented to the eastern part of the Belum area in Malaysia ii. The G2 unit that is correlatable with the Kabut Granite (Trgrkt) unit is exposed as the N-S trending batholith in the western part of the Transect area. It is also extented to the Bang iv Lang reservoir in Thailand and the upper reaches of Sungai Perak in Malaysia. Many roof pendants are taken place in this granite type. iii. The G3 unit or Chantharat Granite (Trgrch) is characterized by its medium- to coarse- grained, sparsely megacrystic to good megacrystic, unfoliated to weakly foliated biotite granite. It can be traced along the western flank of the Belum-Hala Transect area. iv. The G4 unit that is correlatable with the Singor Granite/Hala granite (Trgrsg/hl) is light grey or leucocratic, fine- to medium-grained, equigranular to inequigranular biotite- muscovite granite.