GEOLOGY OF THE BATU

MELINTANG-SUNGAI KOLOK

TRANSECT AREA ALONG THE

MALAYSIA – THAILAND BORDER

By

The Malaysian and Thai Working Groups

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) 2006

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PREFACE

This report together with its 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. Fieldwork was carried out separately

(July – August 2001) in the Batu Melintang and Sungai Kolok areas and then jointly checked

(5-11 April 2002) by geoscientists from both Malaysia and Thailand, covering a total area of

about 1,350 square kilometres along the common border.

Problems on the discontinuity of time rock unit boundaries between the various rocks

found in 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.

Dr. Chu Ling Heng

Director General

Minerals and Geoscience Department

Malaysia.

December 2003

Mr. Somsak Potisat

Director General

Department of Mineral Resources,

Thailand.

December 2003

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Geology of the Batu Melintang-Sungai Kolok Transect area

along the Malaysia-Thailand border by

The Malaysian and Thai Working Groups

Executive Summary Detailed systematic geological mapping in the Batu Melintang-Sungai Kolok Transect area on scales of 1:100,000 and 1:250,000 (originally mapped on the scale of 1:50,000), was carried out independently by the working groups of Malaysia and Thailand covering individual territories within the Transect area i.e. during July-August 2001 and re-checked during November 2001. This was followed by detailed works on the Quaternary Geology in October 2001 and January 2002 (Malaysian side) followed by re-checking works during February 2002 (Thai side). A joint field check at selected localities along the Transect area by geoscientists from both Minerals and Geoscience Department Malaysia, and Department of Mineral Resources, Thailand was conducted in Thailand (5-7 April 2002) and in Malaysia (9-11 April 2002). Problems on the discontinuity of time rock unit boundaries between the Paleozoic rocks to Quaternary deposits, and the extension of granitic rocks (including the mineral association), have been satisfactorily resolved. The oldest rocks, the Silurian-Devonian succession of the Tiang schist/Ban Sa formation (SDts/bs), consist mainly of medium- to thick-banded para-gneiss, augen gneiss with subordinate amphibolite schist, schist and hornfels. The main succession is exposed in the vicinity of Sungai Cherok (Malaysia) and at Khlong Ai Ku Sa (Thailand), in the western part of the Transect area. A smaller rock body is exposed near Sungai Golok (Malaysia), extending to the eastern side of the Ba Tu Ta Mong-Jeli granitic belt (Thailand). High-grade regional metamorphism (amphibolite facies) is obviously recognised by the presence of amphibole mineral group. No fossil assemblages were found and the thickness of the succession is indeterminable.

The Carboniferous-Permian clastic rocks occur in the western and southeastern parts of the Transect area. The rock units in the western part are enclosed by two granitic belts, between the Kemahang Granite/Sukhirin granite (Trgrkg/su) and the Merah granite/Bu Do granite (Trgrmr/bd). The succession is subdivided into three formations, in ascending order: the Mangga formation (CPmg)/Ai Ka Po (CPak)/ Ka Lu Bi (CPkl) formations. The three formations are found to be stratigraphically equivalent and are known as the Mangga/Ai Ka Po/ Ka Lu Bi (CPmg/ak/kl) formations. The Mangga formation (CPmg) is well exposed in the upper reaches of Sungai Machang extending southwards to Kampung Gunung in the Batu Melintang area (Malaysia). It is represented by a low grade metamorphic sequence that can be subdivided into 4 facies: argillaceous facies (CPmgag), arenaceous facies (CPmgar), pyroclastic facies (CPmgpy) and calcareous facies (CPmgcl). The Ai Ka Po formation (CPak) or the arenaceous facies is exposed as a narrow N-S trending sharp ridge hill in Thailand. It is composed mainly of thin- to thick-bedded, tuffaceous sandstone, quartzite and metaconglomerates. The Ka Lu Bi formation (CPkl) or the argillaceous facies is gradational, fining upwards from the former formation. The succession, well exposed at low relief terrain (in Thailand), consists of cycles of thin- to medium-bedded, shales, sandstones and conglomerates with quartz vein and dyke in the lower part, and sharp, even, very thin bedded or rhythmic sequence of shales and siltstones intercalated with very fine-grained sandstones in the upper part.

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The Carboniferous-Permian clastic rocks in the southern part of the Transect area is known as Taku schist/ Buke Ta formation (CPtk/bt ). The Taku schist (CPtk) is well distributed in Malaysia, whereas the Buke Ta formation (CPbt) is locally distributed at Ban Buke Ta and Mae Nam Kolok (Thailand). These formations comprise predominantly schists which are wholly crystalline and generally completely schistosed. Mica schist is the main rock type, which consists of quartz-mica schist, mica-garnet schist and quartz-mica-garnet schist. Local deformation and low-grade metamorphism took place in the shear and contact zones and metamorphosed the original rocks to slate, phyllite, phyllitic shale and spotted slate. No fossil was found in these formations and the thickness of the succession is still indeterminable. However, evidences shown by the intrusion of the well-dated Triassic granite and the stratigraphic position of the rocks enabled the Working Groups to assume that the age of the rocks is Carboniferous-Permian. The Permian-Triassic succession of the Ai Ba Lo formation (PTrab) is confined to the northwestern part of the Transect area (in Thailand). It consists mainly of sharp, even, thin-bedded cherts with recrystalline radiolarian intercalated with stringering shale beds and rare volcaniclastic sediments. The succession obviously exhibits instability of the basin during the time of deposition because of igneous activities. Stratigraphically, the age of these chert strata is considered as belonging to the Permian-Triassic Period. The Permian-Triassic succession of the Telong formation (PTrtl) is confined to the central-south and central part of the Transect area (Malaysia), in Kampung Legeh and extends eastwards to the Tanah Merah area. The Telong formation consists mainly of argillite, low-grade metasedimentary and metavolcanic rocks, and can be divided into four facies: argillaceous (PTrtlag), arenaceous (PTrtlar), calcareous (PTrtlcl) and volcanic facies (PTrtlpy). No fossil so far was found in the Transect area. However, based on bivalves and foraminifera reportedly found in the similar lithology unit to the south of the Transect area, the age of this formation may be assumed as Permian-Triassic. The Triassic submarine fanglomerate, the Bu Yong formation (Trby), is unconformably underlain by the Carboniferous-Permian and Permian-Triassic rocks. It crops out in the central-northwestern part of the area, and consists of massive to thick-bedded, conglomerates, conglomeratic sandstones, with both matrix- and clast-supported types. Clasts are mainly of sandstones, quartz, cherts, and volcanic rocks.

The Panau beds (Kpn) are locally exposed only at Bukit Panau and Bukit Jambul, about 10 km north of the Tanah Merah town, in the eastern part of the Transect area. Nonconformity between the Triassic granite and the overlying sandstone of the Panau beds can be observed at an abandoned rock quarry at the foothill of Bukit Panau. This rock unit is evidently younger than Triassic and is believed to be Cretaceous age based on plant fragments found in the fine-grained sandstone beds at the foothill of Bukit Panau.

The unconsolidated sediments were deposited in both marine and non-marine environments and can be subdivided into 3 formations in ascending order: the Simpang Formation/Waeng formation (Qhsp/wg), Beruas Formation/Sungai Kolok formation (Qhbr/sk) and Gula Formation/Tak Bai formation (Qhgl/tb). The non-marine Pleistocene deposits consisting of Colluvium/Terrace and Former floodplain members of the Simpang Formation/Waeng formation (Qpspr/wg) are dominantly characterised by gravel, sand, silt, and laterite with abundant iron concretions. The marine Holocene sediments of the Gula Formation/Tak Bai formation are subdivided into 5 members (bottom to top): Bagan Datoh Member/Shallow marine member (Qhbdsmgl/tb), Teluk Intan Member/Tidal flat (Qhtitfgl/tb), Peat swamp member (Qhpstb), Matang Gelugor Member/ Old beach member (Qhmtobgl/tb) and Recent beach member (Qhrbgl/tb). However, the Peat swamp member is only exposed extensively in Thailand. The oldest beach ridge of Old beach member exposed 12 km from

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the present shoreline at Ban Pa Wai, in the northern part of Sungai Padi District, Thailand. It is characterised by sand, gravelly sand, and silt. The non-marine Holocene sediments of the Beruas Formation/Sungai Kolok formation (Qhbr/sk) are subdivided into four members: Natural levee member, Abandoned channel member, Floodplain member and Flood basin member. However, the Flood basin member is only observed in Malaysia. It is mainly characterised by silty clay, sand, and gravel with abundant mottles and iron concretions. The Permo-Triassic volcanic rocks are subdivided into two sub-units. The intermediate volcanic association of the Muno Volcanics (PTrvtn/mn) is only represented by the small hill at Ban Mu No, near the Mae Nam Kolok at the east of the Transect area. It comprises strongly sheared and altered andesite, andesitic tuff and agglomerate. Serpentinite and relicts of ultramafic and mafic rocks with podiform chromite deposit of the Ku Mung volcanic complex (PTrvkm) are located as a narrow NE-SW trending body, occurring in the central part of the Transect area. Pillow lava basalt, basaltic andesite and gabbro are well exposed along the Mae Nam Sai Buri located in the central part of the Transect area. The unit is closely related with the Ai Ba Lo formation (PTrab). Generally, the Paleozoic rock sequences were intruded by two granitic rocks. The N-S trending granitic rocks in the central part of the Transect area, consist of equigranular to porphyritic biotite-hornblende granite with muscovite occurring as a secondary mineral resulting from the alteration of K-feldspar and/or biotite. Many phases of granitic rock types are also found in the eastern flank of the Ba Tu Ta Mong-Jeli granitic belt. The other belt which trends N-S is located in the western part of the Transect area and consists of porphyritic biotite-muscovite granite including aplite and pegmatite with associated Sn-deposit. North-South trending quartz dykes and some igneous stocks usually intrude the country rocks, especially in the Ai Ka Po (CPak) and Ka Lu Bi (CPkl) formations in the central part of the area. Contact metamorphism and associated late stage mineralisations can be observed in the country rocks. Structurally, the Paleozoic succession is characterised by strongly close fold especially in the Silurian-Devonian succession. Triassic rock sequence generally exhibits open fold. The strike-slip, normal, reverse and thrust faults are conspicuous and generally strike N-S, NW-SE and NE-SW. Historically, marine sedimentation took place continuously throughout the Paleozoic and Early Mesozoic Eras, nevertheless, large breaks can be observed due to instability of the depositional basins during the Devonian-Carboniferous and Early Triassic periods.

Various mineral resources have been discovered and exploited since the last century and a large number of them is related to granite intrusions and subsequent hydrothermal activities. Gold is the most well known mineral resource that had been produced from the To Mo (Thailand) and Kalai (Malaysia) areas for many years. Other minerals are chromite, manganese, base metals, aggregates, kaolin, ball clay, barite, limestone and dimension stone (granite). Most of these minerals have been produced for years, but production was stopped recently owing to the economic situation. However, recent study indicates that there are many interesting areas for mineral resources development in the future. New potential areas will be outlined and appropriate exploitation proposed.

North-South trending quartz dykes and some igneous stocks intruded the country rocks, especially in the Kalai area (close to the Malaysian-Thai border). Contact metamorphism derived from igneous intrusion and its association with late stage mineralisations can be observed in the country rocks.

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CONTENTS Page

PREFACE...................................................................................................................................ii Executive Summary...................................................................................................................iii 1. Introduction ...........................................................................................................................1 2. Previous works and geologic setting .....................................................................................3

2.1 Previous works ................................................................................................................3 2.1.1 In Malaysia ...............................................................................................................3 2.1.2 In Thailand................................................................................................................4

2.2 Geologic setting...............................................................................................................5 2.2.1 Geologic setting of the Transect area in Malaysia ...................................................5 2.2.2 Geologic setting of the Transect area in Thailand....................................................6

3. Lithostratigraphy ...................................................................................................................9 3.1 Sedimentary and metamorphic rocks ..............................................................................9

3.1.1 Tiang schist/ Ban Sa formation (SDts/bs)...................................................................9 3.1.2 Mangga formation/Ai Ka Po formation/Ka Lu Bi formation (CPmg/ak/kl)...............10 3.1.3 Taku schist/Buke Ta formation (CPtk/bt).................................................................15 3.1.4 Telong formation (PTrtl) .........................................................................................15 3.1.5 Ai Ba Lo formation (PTrab) ....................................................................................17 3.1.6 Bu Yong formation (Trby).......................................................................................18 3.1.7 Panau beds (Kpn).....................................................................................................18

3.2 Quaternary geology .......................................................................................................20 3.2.1 Simpang Formation/Waeng formation (Qpsp/wg) ....................................................23 3.2.2 Beruas Formation/Sungai Kolok formation (Qhbr/sk) .............................................27 3.2.3 Gula Formation/Tak Bai formation (Qhgl/tb)...........................................................30

3.3 Igneous rocks.................................................................................................................33 3.3.1 Volcanic rocks ........................................................................................................33 3.3.2 Granitic rocks .........................................................................................................36

4. Structural geology and tectonics .........................................................................................43 5. Economic Geology/Mineral Resources...............................................................................43

5.1 Metallic minerals ...........................................................................................................44 5.1.1 Gold ........................................................................................................................44 5.1.2 Chromite .................................................................................................................47 5.1.3 Manganese..............................................................................................................47 5.1.4 Iron Deposits ..........................................................................................................48 5.1.5 Alteration zones......................................................................................................53

5.2 Non-metallic minerals and others..................................................................................54 5.2.1 Granite ....................................................................................................................54 5.2.2 River sand...............................................................................................................54 5.2.3 Clay.........................................................................................................................55 5.2.4 Crystalline limestone ..............................................................................................57 5.2.5 Barite ......................................................................................................................57

6. Discussion and conclusion ..................................................................................................58 7. Acknowledgements .............................................................................................................61 8. References ...........................................................................................................................62 9. Appendices ....................................................................................................66

Appendix 1: List of samples in the Batu Melintang-Sungai Kolok Transect on the Malaysian side. ..............................................................................................67

Appendix 2: List Of The Malaysian Working Group ........................................................70

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Appendix 3: List of The Thai Working Group...................................................................71

LIST OF FIGURES

Page Figure 1: Map showing the Batu Melintang-Sungai Kolok Transect area. ..........................1 Figure 2: Schematic stratigraphic column of the Batu Melintang-Sungai Kolok Transect

area in Malaysia. ...................................................................................................8 Figure 3: Schematic stratigraphic column of the Batu Melintang-Sungai Kolok Transect

area in Thailand.....................................................................................................8 Figure 4: Photograph of augen-biotite gneiss in the Tiang schist/Ban Sa formation along

the Ban Ba La roadcut (left) and Mae Nam Kolok (right), Thailand..................10 Figure 5: Exposures of the lower part of the Mangga formation /Ai Ka Po /Ka Lu Bi

formation (CPmg/ak/kl) in Malaysia (left) and Thailand (right). ............................13 Figure 6: Deformed and folded, reddish brown to yellowish brown, medium to thick, wavy

beds of paraconglomerates and sandstone, in the upper part of the Mangga formation/Ai Ka Po formation/Ka Lu Bi formation (CPmg/ak/kl) in Thailand. .....13

Figure 7: Rhythmic sequence (left) and spotted slate (right) of sharp, even, very thin to thin and well-bedded, laminated shales and siltstones to mudstones, at the upper portion of the Mangga/Ai Ka Po/Ka Lu Bi formation (CPmg/ak/kl) in Thailand. . .......................................................................................................................14

Figure 8: The Taku schist/Buke Ta formation in Malaysia (left) and in Thailand (right) showing well-developed S1 cleavages................................................................16

Figure 9: Exposures of the arenaceous facies (left) and the pyroclastic facies (right) of the Telong formation in Malaysia. ............................................................................16

Figure 10: Exposures of strongly folded, thin-bedded chert of the Ai Ba Lo formation (PTrab) at Ban Ai Ba Lo, Thailand. .....................................................................19

Figure 11: Close-up photographs of both matrix- (right) and clast-supported (left), conglomerate of the Bu Yong formation (Trby). .................................................19

Figure 12: Photograph of sandstone strata with cross -bedding of the Panau beds at Bukit Panau, Malaysia. .................................................................................................20

Figure 13: Locations of boreholes in Malaysia. ...................................................................21 Figure 14: Locations of boreholes in Thailand.....................................................................22 Figure 15: Quaternary sediments of the Colluvium/Terrace member in Thailand...............24 Figure 16: Idealised cross section along line A-A′...............................................................26 Figure 17: Idealised cross section along B-B′. .....................................................................26 Figure 18: Sediments of the Floodplain member..................................................................29 Figure 19: Sediments of the Natural levee member. ............................................................29 Figure 20: Pleistocene crab fossils Macrophthalmus at Muno canal. ..................................33 Figure 21: Photograph of serpentinite float (left) and pillow (lava) basalt outcrop (right) of

the Ku Mung igneous complex (PTrvkm) in Thailand..........................................36 Figure 22: Photograph of the highly altered andesite and andesitic tuff (left) and

agglomerate (right) of the Tanah Merah/Muno volcanic (PTrvtn/mn)...................36 Figure 23: Photograph of the massive outcrop of ignimbrite near Temangan town. ...........36 Figure 24: The Boundary Range Granite at Bukit Buloh Quarry, near Kota Bharu,

Malaysia. ................................................................................................................. .......................................................................................................................39

Figure 25: Photographs of the Kemahang Granite/Sukhirin granite (Ttgrkg/su) in Malaysia (left) and in Thailand (right). ..............................................................................42

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Figure 26: Photographs of the Lawar granite/To Mo granite (Kgrlw/tm) in Malaysia (left) and in Thailand (right). ..............................................................................................42

Figure 27: Photographs of the Kenerong Granite/ Ba La granite (Kgrkn/bl) in Malaysia (left) and in Thailand (right) ........................................................................................42

Figure 28: Gold nuggets discovered by panning (a) and gravel bed with gold deposits (b).47 Figure 29: Chromite mine at Ban Bu Yong (a) and associated ultrabasic rocks at Ban Chang

Phuak (b) and Ban Ai Bue Nae (c)......................................................................49 Figure 30: The manganese mine at Ban Chang Phuak (left) and close-up outcrop of

psilomelane at this mine......................................................................................49 Figure 31: Photographs of the original country rocks of the Permo-Triassic Volcanic rock

in the Ban Muno area (a) and the alteration feature of the country rocks in the Ban Muno area (b)...............................................................................................54

LIST OF TABLES Page

Table 1: Summary of manganese deposits in the study area (Malaysian side). ..................50 Table 2: The composition of iron ore discovered in the Temangan area. ...........................52 Table 3: The annual production of iron ore in the Temangan area......................................53 Table 4: Summary of clay reserves in the study area. .........................................................55

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#S#S

#S

#S

#S#S

#S #S

Jeli

WaengSukhirin

Pasir Mas

Tanah Merah

Su-ngai KolokRantau Panjang

THAILAND

MALAYSIABatu Melintang

N 5°45' N 5°45'

N 6°00' N 6°00'

N 6°15' N 6°15'

E 101°45'

E 101°45'

E 102°00'

E 102°00'

ContourStream

Lake

RoadInternational Boundary

#S Town

Transect Area

Symbols

5 0 5 10 15 Kilometers

N

1. Introduction The Batu Melintang-Sungai Kolok Transect area which was proposed by the Malaysian and Thai Working Groups of the Malaysia-Thailand Border Joint Geological Survey Committee (MT-JGSC) covers approximately 3,400 square kilometres along the border (Figure 1). The area in Malaysia (1,890 square kilometres) is partially covered by eight topographic map sheets (scale 1:50,000) of Kampung Ipoh (3766), Kampung Batu Melintang (3767), Kampung Lubuk Bungor (3866), Kampung Nibong (3867), Rantau Panjang (3868), Kuala Krai (3966), Tanah Merah (3967) and Kota Bharu (3968). The area in Thailand (1,500 square kilometres), is geographically covered by five topographic map sheets (scale 1:50,000) of Ban Ko Sathon (5421 III), Amphoe Sungai Kolok (5321 II), Amphoe Waeng (5320 I), Ban To Mo (5320 IV), and Amphoe Sisakorn (5321 III) Quadrangles.

Figure 1: Map showing the Batu Melintang-Sungai Kolok Transect area. Geomorphologically, the western side of the Transect area is of mountainous terrain (50-60%) with thick forest especially in Thailand. Another 40-50% of the eastern and central

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parts are covered by relatively undulating terrain with rubber and oil palm plantation. The low-lying area in the eastern part is covered by Quarternary deposits. In Malaysia, the highest elevation is Gunung Ulu Kebeng (1,403 m above MSL) and in Thailand is Khao Ta We (1,182 m above MSL). The climate is Tropical Rainforest type (Koppen`s: ‘Af’ climate). The mean annual rainfall for 30 years (1951-1980) was 2,618.8 mm. The hottest month is May (28.4°C in average) and the coldest month is December (25.9°C). Detailed systematic geological mapping of the Batu Melintang-Sungai Kolok Transect area in Malaysia was carried out during July-August 2001 and was re-checked during November 2001 by geoscientists from the Minerals and Geoscience Department Malaysia. This was followed by detailed work on Quaternary Geology in January 2002. In Thailand, fieldwork was carried out during September-October 2001 and was re-checked from January to February 2002 by geoscientists from the Geological Survey Division and Economic Geology Division of the Department of Mineral Resources, Thailand. It was later followed by a joint field check along the Transect area in Thailand (5-7 April 2002) and in Malaysia (9-11 April 2002) by geoscientists from both countries.

Discussions, exchange of ideas and informations on geology and mineral resources were conducted. Agreement on mapping units were resolved based on lithological similarities that enabled the Working Groups to delineate the geological boundaries. Unfortunately, palaeontological evidence is currently not available because index fossils have not yet been found within the Transect area. A geological report and geological map (scale 1:250,000) covering the Transect area were jointly prepared by both parties. Attempts have been made to resolve problems related to geological boundaries within the Malaysia-Thailand border with consideration on economic potential.

Prior to this study, three major rock units known as the Tiang schist (Silurian-Devonian), Mangga formation (inferred Permian) and Triassic granite were identified in Malaysia. However, in Thailand only one rock unit considered as Silurian-Devonian in age and granites were recorded in the southernmost part of the Thailand-Malaysia border area.

The main objective of this study is to better understand the local geology and solve problems concerning the geological boundaries of the Paleozoic rocks to Quaternary unconsolidated sediments, and the extension of granitic rocks (including the mineral association) using stratigraphic succession, lithologic similarities, and fossils observed to delineate these boundaries.

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2. Previous works and geologic setting

2.1 Previous works

2.1.1 In Malaysia

The eastern part of the Transect area was first mapped by H.E.F. Savage in 1922 to 1925 (Savage, 1925). Later MacDonald (1967) carried out a more detailed study on the geology and mineral resources of Kelantan and north Terengganu on the scale 1:250,000. He introduced the term Taku schist to describe a sequence of metamorphic rocks cropping out in central Kelantan particularly along the Taku River.

In the early eighties Ab. Halim Hamzah and Mustafar Hamzah (in manuscript) remapped the Tanah Merah area (covered by topographic map sheet no. 22 of 1: 63.360 scale) that was previously covered by MacDonald. They introduced the stratigraphic term Sokor formation for the succession of argillaceous, arenaceous, calcareous and volcanic facies exposed in that area.

Mohd Nazan Awang (1985) drilled wells for groundwater investigation at Kampung Bukit Bunga, near Ban Buke Ta of Thailand. Based on the cross section produced by him, the thickness of the unconsolidated sediments in the Kampung Bukit Bunga area is estimated at only 6 m and is composed of a sequence of clay at the top, followed by fine-grained sand and pebbly coarse sand overlying the metasedimentary rocks.

Bosch (1986) studied the unconsolidated sediments within the Kelantan Delta based on aerial photograph interpretation. Bosch (1988) later divided the Quaternary deposits into three formations: the Gula Formation, Beruas Formation and Simpang Formation.

In 1989, the Regional Mineral Exploration Section of the Geological Survey Department Malaysia (now known as the Minerals and Geoscience Deparment), carried out a gold exploration project in the Bukit Kuang area, near Rantau Panjang as a follow-up to the discovery of alluvial gold deposits during random sampling by the Kelantan Geological Survey staff. From 1991 to 1995, the Industrial Minerals Project Section of the Minerals Exploration Division, Geological Survey Department Malaysia carried out exploration for ball clay deposits between central and north Kelantan.

Aw (1990) mapped the Sungai Aring area further south of the Transect area and he introduced the term Telong formation which is correlatable with the Sokor formation.

Mohd Suhaili Ismail et al. (1993) carried out a reconnaissance survey for ball clay in Kelantan State covering part of the Transect area. The survey covered mainly the coastal plain and major river basins where ball clay was considered likely to occur. Zainol Abidin Sulaiman et al. (1994, 1995a, 1995b and 1995c) carried out detailed studies on ball clay deposits in several potential areas. Mohamad Hussein Jamaluddin et al. (in manuscript) mapped the geology of the Batu Melintang area covering topographic map sheets numbers 21 (Batu Melintang) and 12 (Belum) on the scale 1: 63,360 during 1994 to 1996.

Airborne geophysical study covering eastern part of the Malaysian side’s Transect area was carried out by CGG (Compagnie General de Geophysique) during the Central Belt Project in 1980. Results of the study were later re-interpreted by Corpel & Pebeglia from BRGM in 1987, which showed that the area was under low to intermediate magnetic anomaly with few magnetic unconformities. The magnetic unconformity section was interpreted as a fracture zone with gold mineralisation.

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2.1.2 In Thailand

The Transect area was first mapped by the Geological Survey Division, Department of Mineral Resources (Muenlek et al., 1979) on scale 1:250,000 of sheet NB 47-8,5 (Changwat Narathiwas and Takbai District; reprinted in 1985) and sheet NB 47-12 (Betong District; reprinted in 1985). Muenlek et al. (1979) had introduced the Silurian-Devonian rocks as the Ban To and Betong Formations. The former consists of recrystallised limestones to marble, quartzite, phyllite, phyllitic schist and mica-schist, and the latter comprises shales with Tentaculites elegan, cherts, siliceous shales, meta-tuff, carbonaceous shales, argillite, mudstones, sandstones and bedded recrystallised limestones. Hutchison et al. (1978) proposed three geographical granite belts in the Malay peninsula based on lithology and petrochemistry of the granite. The Eastern belt granitoids are composed mostly of I-type, magnetite-series granitoids, which intruded the Paleozoic host rocks during Permo-Triassic period. The Main Range granitoids (in the central belt area) are composed mainly of S-type, ilmenite-series granitoids with minor intrusions of I-type, magnetite-series granitoids. They also intruded the Paleozoic country rocks in the Permo-Triassic age. The western belt granitoids consist of both I-type, magnetite-series granitoids and S-type, ilmenite-series granitoids of Cretaceous age. Muenlek et al. (1982) published a regional geological map, Narathiwat sheet scale 1:250,000. The individual granite pluton was preliminarily studied petrographically and subsequently three granite phases were classified as gneissic granite, coarse-grained porphyritic biotite granite and tourmaline-muscovite granite.

Hastings (1983) investigated peat swamps in Narathiwat by means of palynology. Temporal and spatial changes of the vegetation were documented by analyzing the pollen and spores obtained from sediments in the swamps. It is postulated that peat development began under a herbaceous transitional to freshwater marsh, characterised by a relatively diverse arboreal component and notable amount of Gramineae and Lycopodium. This peat swamp has possibly mixed vegetation throughout its history. Based on the evidence, there would be a possible change in sea level during the development of the swamp. Cobbing et al. (1986) completed a Southeast Asian granite project including the geological map of individual granite plutons, petrography, geochemistry and Rb/Sr age determination studies. They suggested that the granites in the east coast of Thai-Malay peninsula are mainly of Triassic age.

Vijarnsorn and Liengsakul (1986) studied peat swamps in Narathiwat and mentioned that they occurred during the period 3,000 to 7,000 years BP. The old sand bar or mangrove clay is mainly underlain by stiff clay of the Pleistocene surface.

Dheeradilok et al. (1991) mentioned that the Holocene shallow marine clay and tidal flat deposits consisting of marine clay and peat were investigated along the Pattani coastal plain. The transgression began about 8,500 years BP, and rose up to about 5 m above the present mean sea level about 5,000 years BP. The last regressive phase began 2,500 years BP, and reached the present mean sea level about 1,500 years BP.

Sawata (1991) reported that fossil crabs and cuttlefish bones were found in marine sandy clays at Sungai Kolok, southern-most Thailand. The British Museum determined the cuttlefish as Sepiabandensis adam (identified by Dr. M.K. Howarth) and the crabs are Macrophthalmus (Vetinus) latreillei (Desmarest) (identified by Dr. S.F. Morris). Based on these fossils, the sediments range in age from Pleistocene to Recent and were deposited in estuaries or mangrove swamps.

GMT (1995) investigated the soil types and engineering properties of Phru To Daeng swamp in the vicinity of Sungai Kolok District (TD7, TD8, TD9), and the areas of Tak Bai

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District, Ban Khok It, Ban Khok Ni and Khlong Bang Toei, (TD1, TD2, TD3, TD4, TD5 and TD6). According to drill-hole results, the succession of Phru To Daeng near Sungai Kolok District consists of 4 units: Residual deposits, Old alluvium Deposits (Terrace?), Nearshore Deposits and Mangrove Deposits, respectively in asccending order. The sequence of Quaternary geology at Tak Bai District can be divided into 6 units as follows: Old Alluvium Deposits (Terrace?), River Lag Deposits, Back Swamp Deposits, Nearshore Deposits, mangrove Deposits, and Overwash Deposits. The chemical analyses of clay minerals of Tak Bai District revealed that they consist of kaolinite, illite, quartz, smectite and siderite. The clay minerals at Sungai Kolok are composed of mainly kaolinite, illite, quartz, gibbsite, feldspars, pyrite and goethite.

Chaimanee (1999) reported that there are two types of peat in the coastal area of Thailand, i.e. topogeneous and ombrogeneous. These types of peat are usually associated with an undulating beach barrier and lagoonal deposits.

2.2 Geologic setting

2.2.1 Geologic setting of the Transect area in Malaysia

The geology was compiled based on completed geology and geochemical maps (scale 1:63,360) that were systematically mapped by earlier workers. This area was later studied by the Malaysian Working Group on the scale of 1:50,000.

The Silurian-Devonian Tiang schist (SDts) is considered as the oldest rock unit. It is highly folded and faulted, forming north-south trending moutainous belt distributed in the western part of the Transect area. The rock predominantly comprises quartz-mica schist and quartz garnet schist. This rock unit is unconformably overlain by the Mangga formation (CPmg), which consists of low-grade metamorphic sequence of arenaceous, argillaceous, pyroclastic, hornfelsic and calcareous rocks of probably Carboniferous-Permian age. The formation is found at the southwestern part of the Transect area.

The Taku schist (CPtk) consisting of low to high grade metamorphic rocks of probably Carboniferous age is found in the central to southeastern part of the Transect area. It is unconformably overlain by the Telong formation (PTrtl), which is probably of Permo-Triassic age. These rock units are found in the Tanah Merah area and the southern part of the Transect area. It consists of argillite, low-grade metamorphosed rocks of mainly slate and phyllite, with minor hornfels.

The Panau beds (Kpn) are locally exposed at Bukit Panau and Bukit Jambul, about 10 km north of Tanah Merah town, located in the eastern part of the Transect area. The age of this rock unit is believed to be Cretaceous; based on plant fragments found in the fine-grained sandstone beds at the foothill of Bukit Panau.

Four granitic bodies were identified namely Merah (Trgrmr), Kemahang (Trgrkg), Lawar (Kgrlw) and Kenerong (Kgrkn) Granites. The Triassic Merah granite (Trgrmr) is part of the Main Range Granite exposed as a north-south trending mountainous belt, west of the Transect area. It is moderate to strongly foliated in nature. The Triassic Kemahang Granite (Trgrkg) forms a N-S trending mountainous area near the Jeli town which is located in the central part of the Transect area. It is granodiorite, showing a strongly foliated with some gneissic textures ocurred together with porphyritic granite. The minor intrusion of I-type, Jurassic to Cretaceous Lawar granite (Kgrlw) is distributed in the northern part of the Transect area near the border. It is sheared granite to granodiorite. The Cretaceous Kenerong granite (Kgrkn) is exposed in the southeastern part in between the Kemahang and Noring Granite masses. It is light grey to grey, leucocratic, and equigranular texture.

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The regional structures are aligned in the north-south direction with local variations to the northwest-southeast and northeast-southwest. Apart from some local anticlines and synclines indicated on the geological map, minor structures such as small scale tight folding and parallel folding are common. Strata of the Tiang schist have moderate to steep dips. The Mangga formation is fairly folded and moderate to steeply dipping. The folding and faulting might have taken place probably during Triassic to Cretaceous, due to granite intrusions. Faulting is widespread and present in all the rock units. Most of the faults are normal, near vertical fractures in which only minor displacements have occurred. All major faults are trending northwest to northeast i.e. the Kalai fault trends north-south direction along the upper part of Sungai Tadoh. This fault is related to the Kalai-Tomo gold mineralisation zone. Long fault is the longest fault observed trending northeast-southwest along Sungai Long and part of Mae Nam Kolok. The Pergau fault trending northeast-southwest along part of Sungai Pergau that flows from the boundary between the Noring Granite and Mangga formation. The occurrence of olistostrome, exposed at the east-west highway (Tjia, 1989) and serpentinite boulder at Sungai Tiang close to the Thailand border, indicates that the north-south trending Bentong-Raub Suture zone is probably located in the western part of this area. Schematic stratigraphic columns of the Transect area in Malaysia is shown in Figure 2.

2.2.2 Geologic setting of the Transect area in Thailand

The geology was compiled from completed systematic geological and geophysical maps on the scale of 1:250,000 and re-checked with geological maps on the scale 1:50,000 produced by the Thai Working Group. The oldest rocks are the Silurian-Devonian Ban Sa formation (SDts/bs) which are consist mainly of medium- to thick-banded para-gneiss, augen gneiss with subordinate amphibolite schist, schist and hornfels. The succession is only exposed near the Mae Nam Kolok at the eastern side of the Ba Tu Ta Mong-Jeli granitic belt. The high-grade regional metamorphism (amphibolite facies) is obviously recognised by the prograde of amphibole mineral group in terms of petrography. No fossil assemblages found and the thickness of the succession is indeterminable.

The Carboniferous-Permian clastic rocks mainly occur in the western part of the Transect area, enclosed by two granite belts (the Sukhirin granite (Trgrsu) and Bu Do granite (Trgrbd)) with local occurrence in the central part of the Transect area. The succession is subdivided into three formations, in ascending order: the Ai Ka Po (CPak), Ka Lu Bi (CPkl) and Buke Ta (CPbt) formations. The Ai Ka Po formation (CPak) or the arenaceous facies, exposed as a narrow N-S trend along the sharp ridge hill, is composed mainly of thin- to thick-bedded, tuffaceous sandstones, quartzite, and metaconglomerates. The Ka Lu Bi formation (CPkl) or the argillaceous facies is the gradational fining upward sequence from the former formation. The succession consists of cycles of thin- to medium-bedded shales, sandstones and conglomerates, with quartz veins and dykes at the lower part. At the upper part it consists of sharp, even, very thin-bedded or rhythmic sequence of shales and siltstones intercalated with very fine-grained sandstones. Local deformation and low-grade metamorphism took place in the shear and contact zones resulting in the metamorphism of the original rocks to slate, phyllite, phyllitic shale and spotted slate. The Buke Ta formation (CPbt) is locally distributed at Ban Buke Ta and Mae Nam Kolok. This formation comprises predominantly schists, which are wholly crystalline and generally schistosed. Narrow bands of amphibolite schist and quartz schist occur in mica schists. Fossil has not yet been found so far in these formations and the thickness of the succession is still indeterminable. However, from evidences of intrusion by Triassic granite and the stratigraphical position of the rocks, it can be assumed that the rocks are Carboniferous-Permian age.

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The Permian-Triassic succession of the Ai Ba Lo formation (PTrab) is confined to the northwestern part of the Transect area. It consists mainly of sharp, even, thin-bedded cherts with recrystalline radiolarian intercalated with thin shale beds and rare volcaniclastic sediments. The succession obviously exhibits instability of the basin during the time of deposition because of igneous activities. Stratigraphically, the age of these chert strata can be considered as Permian-Triassic. The Triassic submarine fanglomerate, Bu Yong formation (Trby), is unconformably underlain by the Carboniferous-Permian and Permian-Triassic rocks. It crops out in the northwestern part of the Transect area, consisting of massive to thick-bedded conglomerates and conglomeratic sandstones, with both matrix- and clast-supported types. Clasts are made up of sandstones, quartz, cherts, and volcanic rocks. The Waeng formation (Pleistocene sediments), Sungai Kolok formation (Holocene fluvial deposits), and Tak Bai formation (Holocene marine deposits including peat swamp, old and recent beach sand deposits), cover most of the eastern part of the Transect area. The Permo-Triassic volcanic rocks are subdivided into 2 sub-units: the Muno Volcanics (PTrvmn) and the Ku Mung volcanic complex (PTrvkm) The intermediate volcanic association of the Muno Volcanics (PTrvmn) is only represented by a small hill (not mappable) at Ban Mu No, near Mae Nam Kolok in the eastern part of the Transect area. This unit comprises strongly sheared and altered andesite, andesitic tuff and agglomerate. Serpentinite and relicts of ultramafic and mafic rocks, with podiform chromite deposit of the Ku Mung volcanic complex (PTrvkm) occur as a narrow, NE-SW trending body in the northwestern part of the Transect area. Pillow lava basalt, basaltic andesite and gabbro are well exposed along Mae Nam Sai Buri. The unit is closely related with the Ai Ba Lo formation (PTrab). Generally, the Paleozoic sequences were intruded by two granitic rocks. The N-S trending granitic rocks in the central part of the Transect area consist of equigranular to porphyritic biotite-hornblende granite, with muscovite as secondary minerals resulting from the alteration of K-feldspar and/or biotite. Many phases of granitic rock types are also found in the eastern flank of the Ba Tu Ta Mong-Jeli granitic belt. The other belt, trending N-S, is located in the western part of the Transect area. It consists of porphyritic biotite-muscovite granite including aplite and pegmatite with associated Sn-deposit. North-South trending quartz dykes and some other igneous stocks usually intruded the country rocks, especially in the Ai Ka Po (CPak) and Ka Lu Bi (CPkl) formations in the western part of the Transect area. Contact metamorphism and associated late stage mineralisations can be observed in the country rocks. Structurally, the Paleozoic succession is characterised by tightly folded isoclinal folds, especially in the Silurian-Devonian succession. The Triassic sequence generally exhibits open fold. The strike-slip, normal, reverse and thrust faults are conspicuous with three main N-S, NW-SE and NE-SW directions. Historically, marine sedimentation took place continuously throughout the Paleozoic and Early Mesozoic Eras, but the large breaks can be due to instability of the depositional basins during the Devonian-Carboniferous and Early Triassic.

Schematic stratigraphic columns of the Transect area in Thailand is shown in Figure 3.

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ERA PERIOD FORMATION/ UNIT

_ _ _ _ _ __._._._._._._._.._._._._._._._._.__._._._._._._._._.. . . . . . . . . . . . . ._ _ _ _ _ __._._._._._._._.._._._._._._._._.__._._._._._._._._.. . . . . . . . . . . . . .

_._. _._._._._._._. . . . . . . . . . . . . . ._._._._._._._._._.. . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . .. . . . . . . . . . . . . .

. . . . . . . . . . . . .

. . . . . . . . .

. . . . . . . . . .

Telong Formation

Conglomerate and interbedded of sandstone and argillite beds, exhibits cross lamination and graded bedding. The sandstone varies from very coarse-grained at the bottom and fine to medium-grained at the top

Fine-grained metasandstone

Quartz-mica schist and quartz-mica-garnet schist

Metasandstone and metagraywacke with lenses of metatuff

Shale, slate, phyllite, schist and hornfelsLenses of white marble within calc-silicate hornfelsLenses of volcanic rock within argillites

QU

ATE

RN

ARY

Quartz-mica schist and quartz mica-garnet schistInterbedded of metasandstone and metasiltstone with lenses of metatuffInterbedded of siliceous shale and chert

Mangga formationCARBONIFEROUS

Tiang schistDEVONIAN

. . . . . . . . . .

. . . . . . . . . .

SILURIAN

MES

OZO

ICPA

LEO

ZOIC

TRIASSIC

Taku schistPERMIAN

Panau beds

Quartz-mica schist and quartz-mica-chiastolite schist

STRATIGRAPHIC COLUMN

CEN

OZO

IC

LITHOLOGY

CRETACEOUS

JURASSIC

Pleistocene

Holocene

Marine deposits : old beach deposits, tidal flat deposits and shallow marine deposits: clay, clayey sand and sandGula Formation

Beruas Formation

Simpang Formation. . . . . . . . . . . .

Terrestrial deposits : natural levee deposits, abandoned channel deposits and flood plain deposits : clay, sandy clay, silty sand, sand, granules and pebbles, minor lateritic pebbles present

Terrestrial deposits : former flood plain/colluvium deposits : clay, sand and some granules and pebbles, iron concretions present

Figure 2: Schematic stratigraphic column of the Batu Melintang-Sungai Kolok Transect area in Malaysia.

Figure 3: Schematic stratigraphic column of the Batu Melintang-Sungai Kolok Transect area in Thailand.

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3. Lithostratigraphy

3.1 Sedimentary and metamorphic rocks

3.1.1 Tiang schist/ Ban Sa formation (SDts/bs)

Tiang schist/Ban Sa formation is the oldest lithostratigraphic unit in the Transect area. The term Tiang schist was introduced by Mohamad Hussein Jamaluddin et al. (in manuscript) to describe a sequence of metamorphic rocks cropping out in the east of the Main Range Granite in the Belum area. It is named after Sungai Tiang where good outcrops can be observed. The term Ban Sa formation is proposed during this project to describe the high-grade metamorphic rocks in Thailand. It is named after the Ban Sa village, near Mae Nam Kolok where good outcrops are exposed.

Distribution

There are two localities of the Tiang schist/Ban Sa formation within the Transect area. The western part of the unit forms a north-south belt from Ai Ku Sa stream (Thailand) to Bukit Luat Lantai down to Kuala Sungai Machang in the south (Malaysia). It is in contact with the Merah granite/Ba La granite (part of the Main Range Granite) to the west. Another locality of this unit is restricted to stream-cut outcrops near Ban Sa and the road-cut outcrops at Ban Ba La, the southern part of Waeng District, Narathiwat Province, Thailand.

Lithology

The Tiang schist/Ban Sa formation in Malaysia consists of quartz schist and quartz-mica schist. The quartz-mica schist is strongly schistosed, well foliated, consisting essentially of quartz and mica (commonly muscovite) with chlorite, calcite and pyrite as accessory mineral. Although muscovite is predominant, biotite is fairly common. Lenses of amphibolite schist comprising quartz-actinolite-tremolite schist and quartz-hornblende schist occur at several localities along Sungai Tiang. Rohayu (1994) reported that sillimanite gneiss has been found at higher terrain along the East-West Highway in the Belum area, 10 km southwest of the Transect area. The presence of quartz-mica-chiastolite schist indicates that it might be the result of both contact and regional metamorphisms. Although granite is not exposed in the surrounding area of quartz-mica-chiastolite schist, it is believed that granite is sub-cropping below the metamorphic rocks. The foliation has various trends and dip steeply both eastwards and westwards resulting from intensive folding and faulting. The rock unit is highly folded and faulted throughout the area and it is difficult to estimate its thickness (Mohamad Hussein Jamaluddin et al., in manuscript).

In Thailand, the Tiang schist/Ban Sa formation, along the Mae Nam Kolok at Ban Sa and road-cut succession at Ban Ba La, consists mainly of thin- to thick-bedded, light grey, biotite-augen gneiss (40-90%) intercalated with grey banded schistose biotite gneiss (10-60%). Augen biotite gneiss has well-developed gneissocity, 1 cm per band (Figure 2). It has 40-50% phenocrysts by volume. The phenocrysts are composed mainly of K-feldspar, porphyroblastic texture and are 0.5-1 x 2-4 cm in size. Groundmass is medium- to coarse-grained and shows well-developed gneissic texture. Mineral composition consists of sheared quartz (30%), feldspar (40%) and platy biotite (30%). The schistose biotite-gneiss outcrop at Ban Sa has a similar lithology to the augen gneiss but with fewer phenocrysts than the former and is richer in mica. Quartz-amphibolite schist at Ban Ba La has similar texture with the Ban Sa outcrop

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but more siliceous and calcareous compositions. Thin banded, dark brown biotite, hornblende and actinolite are usually common.

Figure 4: Photograph of augen-biotite gneiss in the Tiang schist/Ban Sa formation along the Ban Ba La roadcut

(left) and Mae Nam Kolok (right), Thailand.

The rock displays well developed N-S and NE-SW trending S1-cleavages, which dip steeply eastward (Ban Sa). Kink bands and S2-cleavages are generally recognised.

Age and correlation

No fossil assemblage is recorded and the thickness of the succession is indeterminable. However, owing to the fact that the Tiang schist and a well-documented Silurian-Devonian Kroh formation (about 20 km to the west of the Tiang schist in Malaysia) are only separated by the Main Range Granite, it is believed that both of them might be of the same age. Moreover, the high-grade regional metamorphism (amphibolite facies) in Thailand is indicated by strongly metamorphosed, pelitic and quartzo-feldsparthic sources during the Middle Paleozoic. Hence, the succession of the Tiang schist/ Ban Sa formation (SDts/bs) can be dated as probably Silurian-Devonian age.

3.1.2 Mangga formation/Ai Ka Po formation/Ka Lu Bi formation (CPmg/ak/kl)

The term Mangga formation was introduced in Malaysia by Mohamad Hussein Jamaluddin et al. (in manuscript) to describe the low-grade metamorphic sequences of arenaceous, argillaceous, pyroclastic, hornfels and marble as well as schistose rocks in the eastern part of the Belum area. It is named after the Sungai Mangga where this rock unit was first mapped and good outcrops of this unit had been recorded. In Thailand, the terms Ai Ka Po formation (CPak) and the Ka Lu Bi formation (CPkl) are introduced by the Thai Working Group. They represent the sedimentary and locally low-grade metamorphic sequence of clastic rocks that occur in the central to western parts of the Transect area. It is named after Ai Ka Po and Ka Lu Bi villages where good outcrops are developed along roads and streams.

Distribution

The Mangga formation/Ai Ka Po formation/Ka Lu Bi formation (CPmg/ak/kl) in Malaysia is well exposed in the upper reaches of Sungai Machang extending southeastwards to Kampung Gunung. To the north, the Mangga formation is believed to have extended into the Thailand frontier. This rock unit is well exposed in the western part of the Transect area and also extends southwards to the Temengor and Sungai Jenera areas.

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In Thailand, the Mangga formation /Ai Ka Po formation /Ka Lu Bi formation (CPmg/ak/kl ) is well exposed in the central and western parts of the Transect area. It is enclosed by two N-S trending granitic belts (the Sukhirin granite (Trgrsu) to the east, and Bu Do granite (Trgrbd) to the west). The Ai Ka Po formation (CPak) is well exposed along road-cuts and streams as a narrow N-S trending strip along the sharp ridge landform. For example, it is located on a sharp ridge hill near the Ka Lu Bi–Laem Thong village, west of the Le Pae-Jeli granitic belt, and also the N-S trending sharp ridge from the north of Licho mountain range to Ai Ka Bu village. The other belt is well exposed as a long sharp ridge west of Khao Soon Patthana village, and a small narrow sharp ridge to the west of Chang Perk village. The Ka Lu Bi formation (CPkl) is well exposed continuously along road-cuts and stream in low relief terrains of the Sukhirin, Ka Lu Bi, To Mo-Phu Khao Thong, Ku Mung-Ka To, Ka To-Nam Hom, Khao Soon Patthana, Ai Ba Lo-Chang Perk, and Ban So Wo areas.

Lithology

In Malaysia, the Mangga formation/Ai Ka Po formation/Ka Lu Bi formation (CPmg/ak/kl) is represented by a low-grade metamorphic sequence that can be subdivided into 4 facies: argillaceous (CPmgag), arenaceous (CPmgar), pyroclastic (CPmgpy), and calcareous (CPmgcl). The argillaceous facies consists mainly of metamorphosed siliceous shale, slate, phyllite, metasiltstone and hornfels. There are two argilliceous facies strata representing the lower and upper parts of this formation. The upper part consists of hornfelsic rocks such as calc-silicate hornfels. The best outcrop of hornfels is located near the junction to Felda Tumbi Rapat, near Gunung Reng, Batu Melintang. The rocks are light grey in colour, very fine-grained, slightly foliated and recrystallised with both quartz and calcite veinlets. Petrographically, the main minerals are quartz with minor muscovite, biotite, diopsite and iron oxide. The chert is light grey to grey with some impure thin-bedded cherts. The best outcrop is at Kilometre 173.2 of the East-West Highway. So far, no radiolaria fossils were found. The slate and phyllite are grey to dark grey and usually interbeded with metasiltstone.

The arenaceous unit consists of metasandstone and metagraywacke interbedded with minor metasiltstone and schist (Figure 5). The schist comprises quartz-mica schist, quartz-mica-garnet schist and quartz-mica-graphite schist. The pyroclastic rock unit is composed mainly of rhyolitic tuff and occurs as lenses within the arenaceous and argillaceous strata.

The calcareous facies consists of impure marble and pure white marble that occurs as lenses within other facies. Gunung Reng is a limestone lens within hornfelsic rocks that forms karst topography at Kampung Gunung. The Mangga formation/Ai Ka Po formation/Ka Lu Bi formation (CPmg/ak/kl), which is strongly deformed and metamorphosed, trends N-S and dips moderately to steeply either to the west or east. In Thailand, the rocks are less metamorphosed but thicker than those in Malaysia. This is because of the low effect from intrusion by granitic rocks and the deeper depositional environment, which can be observed in the lithologic succession.

The lower part, Ai Ka Po formation (CPak), is generally exposed as a narrow N-S trending sharp ridge and is mainly composed of greenish grey, light grey, thin- to thick-bedded, medium-grained, tuffaceous and quartzitic sandstones (Figure 5), and fine-grained clasts and matrix-supported conglomerates. The rocks are locally metamorphosed especially at the contact and shear zones to quartzite and metaconglomerates. Nevertheless, at least 3 large quartz dykes (3-5 km long and 0.5-1 km wide) are recognised in the formation.

The strongly deformed and metamorphosed rocks of the Ai Ka Po formation (CPak) at Ka Lu Bi–Laem Thong village, west of the Le Pae-Jeli granitic belt, are observed in stream outcrops. The N-S trending formation, dipping moderately to steeply eastwards, consists of

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thin- to medium-bedded, medium-grained, greenish grey quartzite with quartz veinlet and base metal sulfide deposit fillings. The large N-S trending quartz dyke intrusion is obviously recognised.

The N-S trending sharp ridge from the north of the Licho mountain range to Ai Ka Bu village, east of the To Mo town, is represented by deformed sedimentary rocks of the Ai Ka Po formation (CPak). This N-S trending formation which dips steeply eastwards, consists of greenish grey to light grey, thin- to thick-bedded, medium-grained, tuffaceous sandstones including fine-grained, matrix-supported conglomerates. The rocks are locally metamorphosed at the contact and shear zones to quartzite and metaconglomerates. The large N-S trending quartz dyke is found in the northern part.

The Ai Ka Po formation (CPak) at Khao Soon Patthana village and a small narrow sharp ridge to the west of Chang Perk village, are located in the central part of To Mo Quadrangle. The succession is strongly deformed and metamorphosed because it is intruded by acid to intermediate igneous rocks. The N-S trending rocks, which dip in various directions, consist of thin- to medium-bedded, fine- to medium-grained, greenish grey quartzite and silicified shales. It is recognised that the base metal sulphide deposit is clearly observed in fine-grained rocks.

The Ka Lu Bi formation (CPkl) is the argillaceous facies conformably overlying the former formation. The succession comprises cycles of thin- to medium-bedded, shales, sandstones and conglomerates with quartz veins and dykes at the lower portion, and sharp, even, very thin-bedded or rhythmic sequence of shales and siltstones intercalated with very fine-grained sandstones in the upper portion. Local deformation and low-grade metamorphism took place within the shear and contact zones resulting in metamorphism of the original rocks to slate, phyllite, phyllitic shale and spotted slate. Repeated sequence of rocks is usually observed.

The lower portion of the Ka Lu Bi formation (CPkl) is well exposed at Sukhirin-So Wo road and Sukhirin-Ai Ba Jo village road, Nam Tok village and north of Ku Mung village. It is noted that this sequence is exposed close to the Ai Ka Po formation (CPak). The rocks which trend NNW-SSE to NNE-SSW and generally dip westwards, consist of deformed and folded, fining upward sequence of shales, sandstones and conglomerates (Figure 6). Paraconglomerates (60%), reddish brown to yellowish brown when weathered, have medium to thick (0.5-1.5 m thick) and wavy beds. Their texture comprises 20-30 % clasts of angular to subangular, low sphericity and poorly sorted, various sizes from pebble to cobble (1-2 to>5 cm in diameter) of smoky to white quartz veins (95%), and pale brown sandstones (5%). Orientation of clasts commonly follows the S1-cleavage direction. Matrix of rocks is fine- to medium-grained, brownish orange (weathered), dirty sandstones exhibiting well-developed cleavages in various directions. Sandstone (10%), reddish brown when weathered, is thin- to medium-bedded, fine-grained sandstones. Siltstones and shales (30%) are 0.5-1.2 m thick in each cycle. The rocks, grey to dark grey, very thin to thin, even and well-bedded, are deformed as indicated by the presence of small kink bands and folds in several outcrops.

Local deformation and low-grade metamorphism took place in shear and contact zones, for example, at 3 km west of Sukhirin District. The sequence is cross-cut in various directions by quartz veinlets, gash veins, and tight folds in strata which are well-developed. Argillaceous rocks are metamorphosed to phyllite and phyllitic shales. Furthermore, these rocks in the area between Phu Khao Thong-Ka Lu Bi-Ai Ti Mung villages show felsic igneous intrusion in the country rocks and the original pelitic rocks are metamorphosed to hornfels and spotted slate.

In low relief terrain, the upper portion of the Ka Lu Bi formation (CPkl) is widely exposed as slightly deformed rocks in the Sukhirin-To Mo area. Strongly deformed or sheared rocks are situated at the Kata–Nam Hom and Khao Soon Patthana villages, to the north and

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northwest of the Transect area. The lithological unit is only investigated from the road-cut and stream outcrops because deep weathering has taken place in the succession.

The successions at the To Mo area are N-S to NNE-SSW trending with various dipping angles and directions. They consist of a rhythmic sequence of dark grey to greenish-grey (fresh) and brownish red (weathered), sharp, even, very thin to thin and well-bedded, laminated shales (60%) interbedded with grey to greenish grey, thin-bedded siltstones to mudstones (40%). At the uppermost sequence, the rocks are intercalated with dark grey to black, even, thin-bedded, carbonaceous shales with high calcite veinlets and red, purplish red shales. Generally, tight, asymmetrical folding, deformation and low-grade contact metamorphism are observed in the rocks, especially in the fault zone area. This resulted in the conversion of the original rocks to slate, phyllite, phyllitic shales and spotted slate (Figure 7).

Figure 5: Exposures of the lower part of the Mangga formation /Ai Ka Po /Ka Lu Bi formation (CPmg/ak/kl) in

Malaysia (left) and Thailand (right).

Figure 6: Deformed and folded, reddish brown to yellowish brown, medium to thick, wavy beds of

paraconglomerates and sandstone, in the upper part of the Mangga formation/Ai Ka Po formation/Ka Lu Bi formation (CPmg/ak/kl) in Thailand.

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Figure 7: Rhythmic sequence (left) and spotted slate (right) of sharp, even, very thin to thin and well-bedded, laminated shales and siltstones to mudstones, at the upper portion of the Mangga/Ai Ka Po/Ka Lu Bi formation (CPmg/ak/kl) in Thailand.

The successions in the Sukhirin-So Wo area trend N-S to NNE-SSW and generally dip

steeply in various directions. They are composed of weathered rhythmic sequence. The carbonaceous material content in this succession is more than that of the To Mo succession in the south. Generally, strong deformation and metamorphism such as tight, asymmetrical folding are observed in this area because the succession is located near the major N-S fault zone. Furthermore, exposures of the N-S volcanic-dykes, which intruded the country rock, resulted in low-grade metamorphism of the original pelitic rocks to be spotted slate zone in several locations.

The rock succession at the Ai Ka Bu-Khao Soon Patthana village and the Ai Ba Lo-Chang Perk area trends N-S to NNE-SSW with foliations dipping in various directions as a result of intensive folding and faulting. These are mainly low-grade metamorphic rocks such as thin-banded, dark grey, grey, brownish grey and bluish grey, phyllite, phyllitic shale, phyllitic schist and schist with well-developed S1, S2 cleavages. The original rocks should be the rhythmic sequence. Tight, asymmetrical and recumbent folds are well observed, especially in the fault zone area. The rock sequence in contact with the granite pluton usually shows relict, altered texture, and spotted slate.

The succession in the Ka To area is well studied at Du Sung Yo–Ka To, Ka To-Nam Hom and Ka To-Ai Sue Rae road-cuts. Generally, the rock structures are controlled by the NE-SW fault. Locally, the rock unit has well-developed S1 and S2 cleavages. Low-grade metamorphic rocks such as thin banded, dark grey, grey, brownish grey and bluish grey, phyllite, phyllitic shale, phyllitic schist and schist with quartz veinlets and gash veins are common. Tight, asymmetrical and recumbent folds are well observed. In the fault zone, there are several rock types, such as mixed rocks, sheared rocks of conglomerate, quartzite, spotted slate, minor intrusive of volcanic rocks and aplite.

Age and correlation

No fossil assemblage is present and the thickness of the succession is indeterminable. The pooly preserved fossils such as Paleaojera sp., brachiopod of Costiferina sp. and gastropod found by MacDonald (1955) in the Mangga formation at Kampung Belimbing, in the Batu Melintang area (Malaysia), may locally indicate a Permian age. However, the age of the succession was assigned as Carboniferous-Permian by the Malaysian and Thai Working Groups, based on lithologic and stratigraphic correlations.

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3.1.3 Taku schist/Buke Ta formation (CPtk/bt)

The Taku schist/Buke Ta formation (CPtk/bt) is the metamorphic rock equivalent to the Mangga formation/Ai Ka Po formation/Ka Lu Bi formation (CPmg/ak/kl). The term Taku schist was introduced by MacDonald (1967) to describe a sequence of metamorphic rocks cropping out in central Kelantan (Malaysia). It was named after Sungai Taku (30 km south of Tanah Merah town) where good outcrops were observed. The term Buke Ta formation is proposed during this project to describe the low-grade regionally metamorphosed argillaceous rocks in Thailand. It is named after Ban Buke Ta, near Mae Nam Kolok where good outcrops were observed.

Distribution

In Malaysia, the Taku schist outcrops occupy a broad belt in central north Kelantan State; from the railway line south of Sungai Galas to Tanah Merah in the south eastern part of the Transect area. The western margin trends northward from Sungai Galas, along Sungai Kenik, passing Ulu Sungai Taku and then Sungai Sokor at Kuala Bertam to the Kemahang granite mass. The eastern margin roughly follows the downstream direction of Sungai Lebir and part of Sungai Kelantan. In Thailand, only one stream outcrop was observed at Ban Buke Ta, in the central part of the Transect area near the Malaysia-Thailand border.

Lithology

In Malaysia, the Taku schist/Buke Ta formation (CPtk/bt) comprises predominantly schists which are wholly crystalline and completely schistosed (Figure 8). Mica schist which is the main rock type consists of quartz-mica schist, mica-garnet schist and quartz-mica-garnet schist. Narrow bands of amphibolite schist and even narrower bands of quartz schist occur in the mica schists. The occurrence of carbonate schist is rare. Hornfels are found in contact with the granitic body.

In Thailand, the Taku schist/Buke Ta formation (CPtk/bt) consists of thin banded, dark grey to black, amphibolite schist interbedded with pale grey quartz-amphibolite schist (Figure 8). The horizon commonly exhibits well-developed S1 cleavage in the NW-SE direction with steeply dipping westwardly but the S2 cleavage is indeterminable. Petrographic study indicates that the essential minerals are the amphibole group such as hornblende, tremolite, and actinolite (Salyapongse, personal communication).

Age and correlation

The age of the Taku schist/Buke Ta formation (CPtk/bt) is still uncertain because its origin remains a controversy (Khoo, 1983). However, MacDonald (1967) considered the age of the Taku schist to be pre-Carboniferous as he believed that the Taku schist is overlain unconformably by the Permain to Triassic Telong formation. The Malaysian and Thai Working Groups considered an age of Carboniceous-Permian being equivalent to the Mangga formation/Ai Ka Po formation/Ka Lu Bi formation (CPmg/ak/kl).

3.1.4 Telong formation (PTrtl)

The term Telong formation was introduced by Aw (1990) after the rock sequence cropping out along part of the Sungai Telong in the Sungai Aring area, Kelantan (Malaysia).

- 16 -

Distribution

In Malaysia, the formation is exposed at Kampung Legeh and extends eastwards to the Tanah Merah area, on the eastern part of the Transect area. However, it is not exposed in Thailand because most of the outcrops are covered by thick Quaternary sediments.

Lithology

The Telong formation consists mainly of argillite, low-grade metasedimentary and metavolcanic rocks. In early eighties, Ab. Halim Hamzah and Mustafar Hamzah (in manuscript) mapped Sungai Sokor area, in the southern part of the Transect area. They distinguished four facies in the Sokor formation (now known as the Telong formation (PTrtl)) namely argillaceous, arenaceous, calcareous and volcanic facies. The argillaceous facies consists of greenish to reddish grey to black slate, phyllite, schist and hornfels. Pyrite is abundant in the carbonaceous rocks. The arenaceous facies consists of fine-grained sandstone and metasandstone (Figure 9). The calcareous facies is composed of grey marble that crops out at Gua Setir, located at the southwest of the Transect area.

Figure 8: The Taku schist/Buke Ta formation in Malaysia (left) and in Thailand (right) showing well-

developed S1 cleavages.

Figure 9: Exposures of the arenaceous facies (left) and the pyroclastic facies (right) of the Telong formation in

Malaysia.

Age and correlation

There is no palaeontological evidence in the Transect area. However, based on lithological correlation with similar rock units exposed further to the south of this area (Sungai Aring and Kuala Betis areas in Kelantan), the age of the formation is believed to

- 17 -

range from Late Permian to Triassic (Ab. Halim Hamzah and Mustafar Hamzah, in manuscript).

Chronostratigraphically, the Permo-Triassic Telong formation can be correlated with the Permo-Triassic Ai Ba Lo formation (PTrab) in Thailand.

3.1.5 Ai Ba Lo formation (PTrab)

The term Ai Ba Lo formation (PTrab) is introduced by the Thai Working Group to describe a sequence of deeper marine sedimentary rocks cropping out in Cha Nae District, Narathiwat Province (Thailand). It is named after the Ai Ba Lo road which cuts across the rock formation in the Ku Mung-Ai Ba Lo area, Cha Nae District, on the western side of Narathiwat Province. In Malaysia, the Ai Ba Lo formation is not currently observed.

Distribution

The formation is continuously exposed (5 km long and 1-2 km wide) in the Ku Mung area extending southward to the upper part of the Khao Soon Patthana area, northwest of the Transect area. The rocks are generally NNE-SSW trending with steeply dipping to east and west, resulting from the plastic characteristics of the rocks, and intensive folding and faulting.

Lithology

Two road-cut outcrops along Mae Nam Sai Buri (Ai Sue Re-Bu Yong) show good exposures of the repeated sequence of highly folded succession in 2-3 km long. The rocks consist mainly of white to smoky white, sharp, even, thin-bedded cherts with recrystalline radiolarians intercalated with stringering shale beds and rare volcaniclastic sediments. This horizon commonly exhibits well-developed, N-S trending cleavages (S1) that are steeply dipping but the S2 cleavage is indeterminable. Tight, recumbent and overturned folds are usually observed, hence thickness of the rock cannot be estimated (Figure 10). It is noted that the rock exposures are close to the red colour of weathered mafic volcanic rocks.

The Ai Ba Lo formation (PTrab) exposed at the Ai Ba Lo village (new road-cut) consists of white to smoky white, sharp, even, very thin banded (1-2 cm) cherts with recrystallised radiolarians intercalated with stringering of thin-bedded carbonaceous shales with rare volcaniclastic sediments. Tight, recumbent and overturned folds are usually observed. It is noted that the rocks are exposed close to the ultramafic, mafic igneous rocks and serpentinite.

Age and correlation

There is no palaeontological evidence in the Transect area. However, the age of the chert strata is presumably Permian-Triassic Period based on stratigraphical grounds.

This formation can be correlated with the Telong formation in Malaysia in terms of chronostratigraphy because both successions obviously exhibit instability of the basin during the time of deposition due to igneous activities. The Working Groups have the opinion that the Permo-Triassic basin in Thailand (the western side of the Transect area) should be deeper than in Malaysia (the eastern side of the Transect area).

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3.1.6 Bu Yong formation (Trby)

The submarine fan Triassic rocks are only exposed in Thailand. The term Bu Yong formation (Trby) is introduced by the Thai Working Group after rock exposures along the Bu Yong road-cut and outcrops along the stream across the rock formation in the Ku Mung–Bu Yong area, Cha Nae District in the western side of Narathiwat Province. In Malaysia, the Bu Yong formation is not currently exposed.

Distribution

The formation is confined to the very sharp ridge mountain at the Bu Yong-Em Se area located in the lower portion of the northwestern part of the Transect area. Good exposures of the succession are found along a stream at Bu Yong and along the road-cut at the Em Se village.

Lithology

The formation is unconformably overlain the Ai Ba Lo formation (PTrab) and the Mangga/Ai Ka Po/Ka Lu Bi formation (CPmg/ak/kl), and trending NE-SW,. It consists of massive to thick-bedded conglomerate, conglomeratic sandstone, with both matrix- and clast-supported (Figure 11) with various types of clasts ranging in size from 1-30 cm in diameter. Clasts are made up of subangular to rounded, pale brown sandstones (5-30%), white to smoky quartz (30-40%), white to grey cherts (10-70%), brownish grey to bluish grey phyllite (0-20%) and volcanic rocks (5-10%). The difference in composition of clasts in the rocks is reflected by the original source rocks. Matrix of the rock is reddish brown, fine- to medium-grained, dirty sandstone.

Age and correlation

Based on the relationship with the unconformably underlying Permo-Triassic and Carboniferous-Permian successions, this unit is younger than Permo-Triassic age. Historically and sedimentologically, the formation is assigned, therefore, to be deposited in the proximal submarine fan environment during the Triassic period.

3.1.7 Panau beds (Kpn)

The term Panau beds is a name given to a sequence of continental, channel lag deposit, sedimentary rocks cropping out at Tanah Merah town. The term is introduced by the Malaysian Working Group after a sedimentary sequence cropping out at an abandoned quarry at the foothill and peak of Bukit Panau, about 30 km north of Tanah Merah town, Kelantan, southeast of the Transect area. The unit is not currently observed in Thailand.

Distribution

The Panau beds crop out only at the Bukit Panau area. Nonconformity between the granite and the overlying Panau beds can be observed at an abandoned rock quarry at the foothill of Bukit Panau.

Lithology

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The Panau beds consist of interbedded thin argillite beds, laminated fine-grained sandstone, poorly sorted pebbly sandstone and paraconglomerate. The argillite rocks are maroon in colour. Some of the argillite rocks are channel lenses within the sandstone beds. This indicates that the rocks were deposited in a channel lag, in oxygenated and continental environments.

The argillite rock consists of maroon, sandy shale and some pebbly sandstone and light greyish to light brownish siliceous shale. The thickness of the beds varies from 1 cm to 1.5 m. Most of the sandy shale shows coarsening upward sequence, in which sand-sized quartz grains can be observed towards the top part of the bed. Some of the argillite beds contain plant fragments.

The arenaceous rock consists of light grey poorly sorted sandstone, mostly pebbly and laminated fine-grained sandstone. The laminated fine-grained sandstone exhibits cross bedding which can be observed at the foothill and peak of Bukit Panau (Figure 12). The pebbles within the pebbly sandstone are up to 3 cm in diameter. Some sandstone beds show graded bedding. The clasts are angular to subrounded.

Figure 10: Exposures of strongly folded, thin-bedded chert of the Ai Ba Lo formation (PTrab) at Ban Ai Ba Lo, Thailand.

Figure 11: Close-up photographs of both matrix- (right) and clast-supported (left), conglomerate of the Bu Yong formation (Trby).

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Figure 12: Photograph of sandstone strata with cross -

bedding of the Panau beds at Bukit Panau, Malaysia.

Mineralogically, the sandstones are arkosic due to high content of feldspar which is

mostly altered to kaolinite. This indicates that the nearby Boundary Range Granite may be a provenance of this rock unit.

Age and correlation

The nonconformity structure between the granite and the overlying unit can be observed at an abandoned Bukit Panau quarry, indicating that the Bukit Panau bed is younger than the granite. The presence of plant fossils, most probably fragments of Frenelopsis sp., Otozamites sp., Calamites sp., and Pecopteris sp. probably indicates Cretaceous age. 3.2 Quaternary geology Fieldwork for the Quaternary geology study in Malaysia was carried out in the period 15-28 January 2002. In Thailand, fieldwork was carried out from 17 September to 2 October 2001 and later from 8 January to 2 February 2002. A total of 103 shallow holes were drilled in both sides of the Transect area.

Quaternary deposits of the Batu Melintang-Sungai Kolok Transect area were formed in both marine and non-marine environments. These deposits can be subdivided into three formations, in ascending order: the Simpang Formation/Waeng formation (Qpsp/wg), Beruas Formation/Sungai Kolok formation (Qhbr/sk) and Gula Formation/Tak Bai formation (Qhgl/tb). The Colluvium/Terrace member (Qpctsp/wg) and Former floodplain member (Qpffpsp/wg) of the Simpang Formation/Waeng formation are dominantly characterised by gravel, sand, silt and laterite, with abundant iron concretions.

The young fluviatile sediments of the Beruas Formation/Sungai Kolok formation (Qhbr/sk) are subdivided into four members: Pengkalan member (Qhpkbr), Floodplain member (Qhfpbr/sk), Natural levee (Qhnlbr/sk) and Abandoned channel (Qhchbr/sk). It is mainly characterised by silty clay, sand, and gravel with abundant mottles and iron concretions.

The marine Holocene sediments of the Gula Formation/Tak Bai formation were subdivided into five members, from bottom to top: Bagan Datoh Member/Shallow marine member (Qhbdsmgl/tb), Teluk Intan Member/Tidal flat (Qhtitfgl/tb), Peat swamp member (Qhpstb), Matang Gelugor Member/Old beach member (Qhmtobgl/tb) and Recent beach member (Qhrbgl/tb). The oldest beach ridge of the Old beach member occurs at 12 and 6 km from the present shoreline in the Thai and Malaysian sides, respectively. It is characterised by sand, gravelly sand, and silt.

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The locations of boreholes in Malaysia and Thailand are shown in Figures 13 and 14, respectively.

Km 5 0 5 Km

102° 05' 102° 10'102° 00' 102° 15'

102° 00'

102° 05' East of Greenwich 102° 10' 102° 15'

5°45'

5°50'

5°55'

5°45'

5°50'

5°55'

6° 00'

6° 05'

6° 10'

6°00'

6°05'

6°10'

Main road

Secondary road

Railway

LEGEND

The Malaysia - Thailand Border Joint Geological Survey Committee

- Quaternary Geology Study

a b

c

Shallow holes location a - borehole number b - water table c - depth of borehole

121.3

4.4

18

5.1

17

2.8 5

4.316

11

6

1.7

31.2

2.2

71.4

1.51.2

1

11

4

192.7

10.8

14

4.51

69

1.56.5

7.213

0.35

23

220.6

6.8

70.5

4.9

241.5

4.9

7.2

25

28

5.51.5

1.5

26

5.22.3

291.5

5.5

5.3

39 1.4

8 40

6.2 38

0.5 5

PasirMas

Tumpat

Scale

634

0.75.8

32

6 2 33

2 9

36

3.5 1 37

35

1.5 4.4

3.5 3.2 6.4

3.527

River

District

Temangan

Kota Bharu

Rantau Panjang

Pengkalan Kubur

150.4

1

1

2.5

31

202

61.9

4.4

10

THAILAND

S. K e l a n t a n

S .e la n ta n

Machang

7.5

21

1.530

80.5

5.3

1.51

1.31.2

1

11

Kg.Kok

Lanas

Tanah Merah

Figure 13: Locations of boreholes in Malaysia.

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Figure 14: Locations of boreholes in Thailand.

Methodology

Shallow holes have been drilled using the Edelmen auger (Dutch auger) and the Guts auger (Gouge auger) depending on the soil or sediment types occurring in the selected localities. The localities were selected based on aerial photograph interpretation. A total of 103 boreholes had been drilled throughout the Transect area (40 holes in Malaysia and 63 holes in Thailand). The average depth is 3.5 m and the maximum depth is 7.0 m. The auger hole spacing is between 5 and 10 km, to represent the units as demarcated by the aerial photograph interpretation.

Besides the present survey, this report has also incorporated the data available from previous works on Quaternary geology, hydrogeology, mineral resources, and aerial photo interpretation.

Morphology

The area overlain by Quaternary sediments is generally flat and low-lying, is utilised for paddy (Oryza sativa), rubber and palm tree cultivations. Several isolated sand ridges, trending almost parallel to coastline, are located close to the coastal area. At the river mouths where the sediments are dumped into the sea, the coastline builds seaward especially in the Kelantan delta (Bosch, 1988). The old fluvial channel scars can be observed from aerial photographs of the flat and low-lying areas close to the present river systems. Small rivers can be seen surrounded by levees.

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In Malaysia, exposures at Kampung Bukit Lata, near Bukit Perdah area are generally hilly and are made up of highly to completely weathered volcanic rocks of the Tanah Merah volcanics. The equivalent rock unit is also exposed at Ban Mu No, Thailand.

In Thailand, the pre-Quaternary areas can be geomorphologically distinguished as high mountain and terrace in the western part, undulating and rolling landforms at the central and flat areas in the eastern part. The topography of the Sungai Kolok area has basically shown remarkable higher level of high mountain range in the western part gradually decreasing to the coastal plain in the east. The highest elevation at Khao Ta We is 1,182 m above MSL, and 1-2 m in the flat areas of Ban Khok Yang, Ban Pa Da Do, and Tak Bai town.

3.2.1 Simpang Formation/Waeng formation (Qpsp/wg)

In Malaysia, the term Simpang Formation was introduced by Suntharalingam and Teoh (1985) for clay, silt, sand, gravel and peat deposited in a terrestrial environment before the most recent major low sea level. Suntharalingam (1987) mentioned that it can be divided into an upper clay member and a lower sand member that may now be interpreted as Former floodplain member and Colluvium/Terrace member, respectively. The formation is overlain, to a large extent, by the younger Beruas and Gula Formations.

In Thailand, the term Waeng formation is introduced by the Thai Working Group during this project.

Distribution

In Malaysia, this unit is exposed in the undulating terrain south of the Rantau Panjang and Pasir Mas areas and extends to the Tanah Merah and Machang areas where it is underlain by Pre-Quaternary rock units.

In Thailand, the Simpang Formation/Waeng formation is exposed at Ban Ai Su Re, Ban Ai Ku Sa, Ban Ka Lu Bi, Ban Cha Nae, Ban Dusong Yo, Ban So Wo, Ban Buke Ta, Waeng District, Sungai Kolok District, Sungai Padi District, Ban Mu No, Ban Ai Su Re, of Waeng District, Sungai Padi District, and the western part of Sungai Kolok District.

Lithology

The Simpang Formation/Waeng formation is made up of light-grey to yellowish-brown clay, sandy with medium to coarse sand, granules and pebbles. The clay is moderate to hard in strength, and at depth is commonly stiff and difficult to penetrate using auger or hand drill. The unit also contains moderately to abundant yellow to reddish-brown mottles with some iron concretions.

The Simpang Formation/Waeng formation is subdivided into Colluvium/Terrace, and Former floodplain members as follows:

Colluvium/Terrace member (Qpctsp/wg)

The Colluvium/Terrace member refers to the sequence of gravel beds, lateritic layers, and residual sediments. In Malaysia, this unit is exposed to the south of the Rantau Panjang area, southern part of Pasir Mas District, Tanah Merah District and Machang District. In Thailand, this unit is exposed at Ban Ai Su Re, Ban Ai Ku Sa, Ban Ka Lu Bi, Ban Cha Nae, Ban Dusong Yo, Ban So Wo, Ban Buke Ta, Waeng District, Sungai Kolok District, Sungai Padi District, and Ban Mu No. These sediments are composed mainly of sand, gravelly sand,

- 24 -

clayey sand, gravel, gravel beds, and laterite, friable to very firm, abundant mottle, red to reddish brown, poorly sorted, and moderate amounts of iron concretions.

In Thailand, the Colluvium/Terrace member is further subdivided into three units, in ascending order: the Gravel beds, Lateritic layers, and Residual sand units.

a) Gravel beds unit

The Gravel beds unit is locally exposed at Ban Ai Su Re. Gravel beds with sand lenses, semi-consolidated, commonly characterise this unit. Clasts of gravel beds vary from gravel to boulder (Figure 13). They are made up of sandstone, quartz, chert, granite, and schist. The sand layers are characteristically reddish brown to red, medium- to coarse-grained, poor to moderately sorted, moderately cemented and, subangular to subrounded. This unit is 15-20 m thick and dips to the south (185°/05°-10°, dip direction/dip angle).

b) Lateritic layers unit

This unit is exposed mainly at undulating landforms of Waeng District, Sungai Padi District, and the western part of Sungai Kolok District (Figure 15).

The sediments obtained from shallow boreholes SK-40, SK-43, SK-45, SK-46, SK-48, and SK-51 of Waeng District are mainly characterised by sand, silty sand, gravelly sand, and gravel, yellow colour. Abundant mottles, strong brown to red and iron concretions are also common. The thickness of this unit varies from 2-6 m. Moreover, this unit at borehole SK-36 located in the northern part of Sungai Padi District is indicated by clayey sand, brownish yellow, sand sizes 300-420 μ of upper residual sand unit with gradual contact at the depth of 2.3 m. The thickness is more than 5 m.

c) Residual sand unit

This Residual sand unit overlies the Lateritic layers unit with gradational contact. The unit comprises mainly clayey sand, friable to firm, light olive brown to brownish yellow, very well sorted, sand sizes 300-420 μ. Most of the sand is fine- to medium-grained, subrounded with sparse iron concretions.

Figure 15: Quaternary sediments of the Colluvium/Terrace member in Thailand.

This very thick sequence (>15 m) is underlain by Triassic Kemahang Granite/Sukhirin granite (Trgrkg/su) at the northern part of Sukhirin District. The sequence consists of weathered porphyritic biotite-hornblende granite and is characterised by sand, gravelly sand, loose to friable, moderately sorted. The thickness ranges from 5 to approximately 25 m.

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Former floodplain member (Qpffpsp/wg)

Dheeradilok et al. (1991) defined the Former floodplain member as the Pleistocene Fluvial deposits member. They considered that a former plain surface was developed during the Pleistocene time and was overlain by Holocene sediments. The Former floodplain is characterised by silty clay and sandy clay, very firm, light grey to yellowish brown, moderately to abundant brown to mottled red. A small amount of iron concretion is generally present in this member. Figure 16 displays the contour (depth in metres) of Former floodplain member in Thailand, with the elevation decreasing eastwards.

The Former floodplain member consists mainly of silty clay and sandy clay, very firm, light grey to yellowish brown, moderate to abundant mottles, yellowish brown to red and small to moderate amount of iron concretions. The thickness varies from 5 to approximately 10 m. The Former floodplain member is underlain by the Colluvium member and the Holocene sediments. Sediments of this member obtained from borehole SK-16 are peat and peaty clay of the Peat swamp member (Qhpstb), with sharp contact. The Former floodplain member has a sharp contact with the overlying shallow marine sediments at borehole SK-20 (Figure 16). From borehole SK-2, this unit also has a very clear contact with underlying shallow marine sediments at the depth of 3.7 m (Figure 17). The maximum depth (>7 m) is considered to be the surface of the Former floodplain surface at Ban Khok Rama, Wat Khosit of Tak Bai District, and the depth decreases westwards to 2 m at Ban To Wo, Ban Kwa Lo Ma Tae, Ban Khok Po, and Ban Ta Se in Thailand.

Provenance and environment of deposition

The Simpang Formation appears to consist mainly of a composite of alluvial fan and stream deposits (Suntharalingam and Teoh, 1985). The yellow, brown, orange and light grey colour of the sediments and the presence of stiff, mottled clays suggest that the formation was subjected to frequent exposure and subsequent desiccation and weathering (Loh, 1992). The sediments are believed to have been derived from granitic and metasedimentary rocks occurring to the south and west of the Transect area.

Age and correlation

No fossil is found to indicate the exact age of the Simpang Formation in Malaysia. However, it is believed that the formation is Pleistocene age based on its physical characteristics, position of the deposits, and its correlation with similar sediments occurring at the east and west coasts of Peninsular Malaysia.

In Thailand, a Pleistocene age is given for this formation. Dheeradilok et al. (1991) studied Quaternary geology in the Pattani coastal plain, and designated the age of the Gravel beds member and the Former floodplain member as Lower Pleistocene and Late Pleistocene, respectively.

- 26 -

Figure 16: Idealised cross section along line A-A′.

Figure 17: Idealised cross section along B-B′.

- 27 -

3.2.2 Beruas Formation/Sungai Kolok formation (Qhbr/sk)

The term Beruas Formation was introduced by Suntharalingam (1987) for clay, silt, sand, gravel and peat deposited in a terrestrial environment after the most recent major low sea level stand. This unit overlying the Simpang Formation also includes currently deposited sediments by streams.

The Beruas Formation/Sungai Kolok formation is subdivided into Pengkalan member (Qhpkbr), Floodplain member (Qhfpbr/sk), Natural levee member (Qhnlbr/sk) and Abandoned channel member (Qhchbr/sk). In Malaysia, Flood basin/swamp member also occurs in several isolated areas.

Distribution

In Malaysia, the Beruas Formation covers most of the Kota Bharu map sheet (no. 3968) and the Rantau Panjang map sheet (no. 3868) on the scale 1:50,000. It covers the Sungai Golok/Mae Nam Kolok valley and most of the Sungai Kelantan valley, and extends from Rantau Panjang, Tumpat, Kota Bharu to Pasir Mas. At present, most of the land underlain by this sediment is utilised for wet paddy cultivation.

In Thailand, the Floodplain member is locally exposed between undulating landforms in the western part of Sungai Kolok and Sungai Padi Districts. The unit is also distributed throughout flat areas of Ban To Wo, Ban Khok Klang, Ban Pu Po, Ban Khok Ya Mu and northern part of Ban Mu No.

Lithology

Generally, the formation is made up predominantly of sandy clay, clay and sand with minor gravels. Most sandy clay and clay occur along the Sungai Golok/Mae Nam Kolok and within most of the other river valleys in the area. The sand is made up predominantly of quartz. Suntharalingam and Teoh (1985) mentioned that the lithology, heavy mineral contents, grain size characteristics and colour, of the Beruas Formation indicate that this formation is mainly fluvial deposits related to the existing river system.

Clays have been derived from sediments brought down by rivers such as Sungai Golok/Mae Nam Kolok and Sungai Kelantan as well as by their tributaries. The formation represents long continued accumulations of fine-grained suspended sediments resulting from flooding. After deposition ceased, soil was formed on the top of these sediments.

Fine mica flakes are present in most of the boreholes. The mica, predominantly muscovite, is derived from the mica schist (of the underlying Taku schist and part of the Telong Formation) as well as the granite at the upper reaches of the Sungai Golok/Mae Nam Kolok and Sungai Kelantan valleys.

In Malaysia, Mohd Suhaili Ismail et al. (1993) reported that potential ball clay deposits occur at Kampung Kajang Sebidang, Kampung Kubang Sawa, Kampung Palas Merah, near Pengkalan Kubur as well as at Kampung Bukit Pak Junos, Kampung Batu Karang and Kampung Gual Tok Cha, in the Pasir Mas area. The ball clay is believed to have been derived from the leaching out of feldspar minerals in the volcanics of the underlying Telong formation as well as the Kemahang granite exposed in the south of the Transect area.

Pengkalan member(Qhpkbr)

The term Pengkalan member was introduced by Suntharalingam (1987) for inland swamp deposits. The Pengkalan member in the Transect area is composed of clay, silt, humic clays

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(with in situ plant remains) and carbonaceous materials. It occurs only at several isolated areas in Malaysia; especially in the Gual Periok area, which covers an area of about 10 square kilometres.

Humic clays and some in situ compact decomposed plant remains were observed in some boreholes such as in borehole number 8 at Kampung Kubang Batang and borehole number 19 at Kampung Kubang Pak Hitam. In borehole number 8, humid clay with decomposed wood occurs at a depth between 2.5 and 4.4 m. In borehole number 19, it occurs at a depth from 3.1 to 9 m.

Floodplain member (Qhfpbr/sk)

The Floodplain member is characterised by silty clay and sandy clay, firm, light grey to yellowish brown, moderately to abundant mottle, brownish yellow to red. Small amount of iron concretions generally occur in this member (Figure 18a). It was deposited during the Holocene and is underlain by the stiff clay of the Former floodplain member of the Simpang Formation/Waeng formation.

Generally, kaolin sequences observed in the Floodplain member are characterised by clayey sand, gravelly sand, moderately sorted, subangular to subrounded, white, very loose to friable. The environment of deposition is floodplain origin, showing fining upward sequence (boreholes SK-29, SK-31, and SK-37) (Figure 18b, 18c and 18d). The average thickness varies from 1 to approximately 3 m, whereas the maximum thickness varies from 2 to approximately 5 m.

The Floodplain member is gradually in contact with the underlying Colluvium, Peat swamp, Shallow marine, and Abandoned channel members (Figure 16 and 17).

Natural levee member (Qh nlbr/sk)

The Natural levee member is defined as “the young Holocene sediments that overlie the floodplain deposits”. It is exposed locally along the Sungai Golok/Mae Nam Kolok (both in the Malaysian and Thai sides), Ban Li Yae and Ban Pa Dang Yo (in Thailand). It was deposited during the Holocene and overlies the Pengkalan member.

This member is characterised by sand, silt, and clayey silt, loose to friable, yellow, small amount of mottle, brownish yellow to red, moderately to very well sorted, and the sand size is approximately 150 μ (Figure 19). The thickness varies from 2 to approximately 4 m.

Abandoned channel member (Qhchbr/sk)

This member is characterised mainly by sand, gravelly sand, and clay sand, loose to friable, white, subangular to subrounded, very poor sorted, and the sand size varies from 600-2,000 μ. The sand is composed mainly of quartz, rock fragments, and dark minerals. The sequence, 2 to 3 m thick, generally shows fining upward succession. The Abandoned channel member generally interfingers with the underlying Floodplain member.

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Figure 18: Sediments of the Floodplain member.

Figure 19: Sediments of the Natural levee member.

In Malaysia, borehole number 1, sunk at Kampung Geting exhibits fluvial channel deposits characterised by poorly sorted, medium to coarse sand and abundant granules and

18a 18b

18c 18d

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pebbles even though it is located very close to the coast. These sediments are most likely deposited in the former channel of the Sungai Geting, which trends parallel to the coastline.

In Thailand, the abandoned channel member is defined as sediments that are deposited in recent alluvial deposits. The unit is generally distributed in meanders of Mae Nam Kolok at Ban Pa Da Do, Ban Khok Ya Mu, Ban Khok Klang, and Ban Ba Ngo Yi No.

Provenance and environment of deposition

Based on its present position as well as the characteristics mentioned above, it is believed that the sediments of the Beruas Formation/Sungai Kolok formation (Qhbr/sk) have been deposited during Holocene in fluviatile environment.

Age

The age of the Beruas Formation/Sungai Kolok formation ranges from Holocene to the present day. It is contemporaneous in age with marine deposits of the Gula Formation (Suntharalingam and Teoh, 1985).

Bosch (1986) has carried out radiocarbon dating on some of the peat of the Holocene sediments in the Kelantan Delta. The results indicate that the age ranges from 7,100 + 120 yrs. BP to 4,350 + 100 yrs. BP.

3.2.3 Gula Formation/Tak Bai formation (Qhgl/tb)

The Gula Formation/Tak Bai formation is subdivided (bottom to top) into the Bagan Datoh Member/Shallow marine member (Qhbdsmgl/tb), Teluk Intan/Tidal flat member (Qhtitfgl/tb), Peat swamp member (Qhpstb), Matang Gelugor/Old beach member (Qhmtobgl/tb) and Recent beach member (Qhrbgl/tb).

Distribution

In Malaysia, this formation is exposed in the present coastal area, stretching from Pengkalan Kubor area (near the estuary of the Sungai Golok) to the Tumpat and Kota Bharu coastal areas.

In Thailand, this formation occurs mainly in the northeastern part of the Transect area at Ban Khok Thurian, Ban Khok Yang, Ban Khok Nibong, Ban Khok Mu Ba, Ban Pu Yu, and Ban To Daeng. It can be traced up to about 6 and 12 km inland from the present coastline in the Malaysia and Thailand respectively.

Lithology

The formation is made up mainly of clay, silty clay, peaty clay and sand. The recent beach sand and sand ridges trending parallel to the present coastline in Pengkalan Kubor and Tumpat areas are also considered as part of this unit.

Bagan Datoh Member/Shallow marine member (Qhbdsmgl/tb)

The Bagan Datoh Member/Shallow marine member in Malaysia is represented by clay, silt and sand deposited in shallow marine, offshore environment. It consists mainly of light grey, light greenish grey and light bluish grey clayey sand and medium- to coarse-grained sand with shell fragments.

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This member is widespread and wedge out gradually southwestwardly with increasing thickness on the shoreline of the Transect area. The member also extends into the upland area as far as 12 km from the present shoreline.

This member is characterised mainly by clay, silty clay, and sand, very soft to soft, greenish grey to grey, sand sizes 80-300 μ, moderately to very well sorted, small amount of shell fragments, interbedded with thin sand lenses. Thickness of the sequence varies from 2 m to approximately >25 m (at present shoreline; GMT, 1995). The Bagan Datoh Member/Shallow marine member is in sharp contact with the underlying Former floodplain member of the Beruas Formation/Sungai Kolok formation and the overlying Tidal flat member of Gula Formation/Tak Bai formation (Figures 16 and 17).

Teluk Intan Member/Tidal flat member (Qhtitfgl/tb)

This unit is represented by sand, clay, and silt deposited in an inshore environment. It consists of light grey to olive greenish-grey clay, slightly sandy to sandy with yellowish-brown mottles as well as some roots and plant remains. The sand is composed mainly of quartz with some feldspar and mica flakes. The presence of transported humic materials suggests the tidal influence. The presence of mottled clays indicates frequent exposure. Therefore, it is interpreted that this unit had been deposited in a tidal flat environment. In Thailand, the presence of jarosite is also noticed. The shell fragment occasionally occurs in sand lenses. The thickness of this member varies from 1 to 3 m.

In Malaysia, it occurs in the Pengkalan Kubur and Tumpat areas. In Thailand, this member occurs mainly in the northeastern part of the Transect area, at Ban Khok Thurian, Ban Khok Yang, Ban Khok Nibong, Ban Khok Mu Ba, and Ban Pu Yu. It was deposited gradually overlying the Shallow marine member.

Peat swamp member (Qhpstb)

This investigation defined the Peat swamp member as the younger sediments that were deposited in the area behind the Old beach ridge. The member is exposed locally in Thailand at the low land of Ban To Daeng, at the northeastern part of Sungai Kolok District and the eastern part of Sungai Padi District.

The Peat swamp member is represented by peat, peaty clay, and silty clay, friable, dark to dark grey, moderately decomposed, with small amount of shell fragments. The thickness varies from 1 to 4 m (GMT, 1995).

Matang Gelugor Member /Old beach member (Qhmtobgl/tb)

The member is characterised by beach zones in the inland areas. The member is clearly seen and defined by aerial photos and remote sensing imagery.

The name Matang Gelugor Member has been introduced by Suntharalingam and Teoh (1985) to define the succession of clayey sand to sand that forms sand ridges exposed in the present coastal areas. In Malaysia, these sediments are composed mainly of light grey to bright yellowish brown, poorly sorted, angular to subrounded, medium to coarse sand with subordinate pebbles. It consists mainly of quartz, some feldspar and minor mica flakes. It occurs as prominent sand ridges aligned parallel to subparallel with the present coastline and can be traced up to about 6 km inland. These sand ridges form narrow zones about 3 km wide at its maximum and trend up to 8 km long in northwest-southeast direction, in the Pengkalan Kubor and Tumpat Districts.

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In Thailand, the oldest beach ridge occurs 12 km from present shoreline at Ban Pa Wai (borehole SK-26) located in the northern part of Sungai Padi District (Figure 14). The member is characterised by sand, gravelly sand, loose to friable, very dark grey to light yellowish brown, subangular to subrounded, moderately sorted.

The middle beach ridge is formed at Ban Khok Chum Bok (borehole BKS-3), Ban Plak Chang, and Ban Khok Ka Po, which is approximately 0.5 to 2 km wide. It is characterised by sand and sandy gravel, loose, light grey to brownish yellow, sand sizes 200-2,000 μ, and gravel 2-5 mm, moderately sorted.

The Old beach member is mainly formed adjacent to the present shoreline. The member is composed mainly of sand, gravelly sand, loose to friable, white, sand sizes 420-1,400 μ, subangular to subround, moderately sorted. The thickness varies from 1 to approximately 5 m.

Recent beach member(Qhrbgl/tb)

The Recent beach member (Qhrbgl/tb) is defined as the recent beach and is exposed locally at Tak Bai District, Narathiwat Province (in the northeastern corner of the Transect srea).

The member is characterised by sand and sandy gravel, loose, light to brownish yellow, sand sizes 200-1,000 μ, gravel 2-4 mm, moderately sorted. The thickness varies from 2 to approximately 5 m. The member is gradually in contact with the underlying Shallow marine member.

Provenance and environment of deposition

Based on its present position as well as the above mentioned characteristics, it is believed that the sediments of this formation have been deposited in a marine environment, namely, old beach, recent beach, tidal flat, peat swamp and shallow marine environments. The sediments have been transported by major river systems such as Sungai Kelantan and Mae Nam Kolok and were later deposited in those environments.

Age

No index fossil was found in Malaysia. However, Tjia et al. (1977) presented a series of radiocarbon dating from northern Pahang and Terengganu. The oysters and molluscs indicate an age ranging from 5580+130 yrs. BP to 185 yrs. BP. Therefore, based on correlation with similar sediments exposed in the coastal area of Peninsular Malaysia, it is believed that the age of this unit is Holocene.

Sawata (1991) studied crab fossils at Muno Canal (Ban Ko Sathon map sheet), in Thailand (Figure 20). Dr. S.F. Morris of the British Museum has determined the crabs as Charybdis (Charrybdis) aff. sinhaleya. The genus Charybdis belongs to the family Portunidae, which is a group of predatory, swimming crabs, living in very shallow inshore water. Morris (1978) mentioned that crab fossils such as Macrophthalmus (an inshore form) lived on relatively soft sandy muds ranging from littoral to 20 m deep. The age of the fauna is almost certainly Pleistocene, but crabs do not enable us to subdivide this period.

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Figure 20: Pleistocene crab fossils Macrophthalmus at Muno canal.

Vijarnsorn and Liengsakul (1986) studied peat swamps in Narathiwat and concluded

that the thickness varies from 0.4 to 3 m. The member was deposited during the period 7,000 to 3,000 yrs. BP.

3.3 Igneous rocks

Exposures of igneous rocks are widely distributed in the Batu Melintang-Sungai Kolok Transect area. The volcanic rocks occur as flow and pyroclastics in the sedimentary succession, whereas the plutonic rocks occur as batholiths and small stocks.

3.3.1 Volcanic rocks

In Malaysia, the volcanic rocks consist of several phases distributed in the Tanah Merah, Machang and Rantau Panjang areas. Pyroclastic deposits are considerably more abundant than lava flows. Most of the tuff deposits are ranging from rhyolitic to andesitic composition which can be divided into crystal and lithic tuff. Pyroclastic rocks of a predominantly rhyolitic character are far more abundant than those of an andesitic character. Most of the rhyolitic rocks are classified in between pyroclastic and volcanic flows, and may be better regarded as ignimbrite. In Thailand, the majority of volcanic rocks are basic to intermediate in composition. Most of them are trending NNW-SSE to NW-SE, and exposed within the Mangga/Ai Ka Po/Ka Lu Bi formations (CPmg/ak/kl) and Ai Ba Lo formation (PTrab). Minor volcanic extrusions are locally located in the alluvial plains adjacent to Mae Nam Kolok. According to previous works, these volcanics are correlatable with the Permo-Triassic volcanics, which are present elsewhere in the country.

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Ku Mung igneous complex (PTrvkm)

Outcrops of the Ku Mung igneous complex (PTrvkm) are restricted in a narrow NE-SW trending zone in the lower part of Sukhirin Quadrangle and in the upper portion of To Mo Quadrangle, in the northwestern part of the Transect area. The igneous complex is composed of pillow (lava) basalt, serpentinite, relicts of ultramafic and mafic rocks with podiform chromite deposits. The Ku Mung igneous complex (PTrvkm) consists of serpentinite, exposed along the road-cut from Ai Su Re-Bu Yong and in the Ai Ba Lo areas. The serpentinite is characteristically green, light green and greenish white, sheared and patched layers (Figure 21). The unit is closely associated with other sheared or mixed rocks. However, in the fresh outcrop, it is noted that relicts of the ultramafic rocks e.g. dark grey to black, dense pyroxenite, dark greenish grey peridotite and greenish grey dunite and mafic rocks with podiform chromite deposits are altered to serpentinite.

Pillow (lava) basalt, diabase, basaltic andesite and gabbro are well exposed along Mae Nam Sai Buri, located in the lower part of Sukhirin Quadrangle i.e. the central part of the Transect area. Pillow lava is represented by the thick layer of dark greenish grey to black, dense, massive, basalt and diabase. On the surface, the rocks are pillow shaped ranging in size from 20 to 30 cm in diameter. Mineral composition is mainly of pyroxene, and altered low An-content plagioclase which is interpreted to have been affected by sea water. This unit is also exposed in a stream at the Ai Ba Lo area and associated with the Ku Mung igneous complex (PTrvkm) and Ai Ba Lo formation (PTrab).

Gabbro is exposed as a massive body which is characterised by dark grey to black with white layer of feldspar. Mineral composition is pyroxene and plagioclase. Red to purplish-red rocks are observed on the weathered layer.

Generally, these rocks are strongly deformed, indicated by closely-spaced cleavages which can be clearly observed. The cleavage and the main fracture are aligned along the NE-SW direction.

Historically and tectonically, the age of the rocks are determined to be Permo-Triassic. In Malaysia, no outcrop of this rock unit has been observed.

Tanah Merah/Muno volcanics (PTrvtn/mn)

In the Malaysia side, the Tanah Merah/Muno volcanic (PTrvtn/mn) is composed of andesite flow, andesitic tuff and agglomerate but predominantly pyroclastics. It is mostly extrusive in nature, probably contemporaneous with the deposition of the associated sediments and pyroclastics. Locally, the andesite occurs as dykes or irregular bodies in sedimentary rocks. The most impressive andesite in the Transect area is located in the Tanah Merah area, to the east of the Temangan Ignimbrite. Good exposures can be observed along the Tanah Merah-Machang expressway near the bridge crossing Sungai Kelantan. The andesite is typically porphyritic, grey-green and black varieties, generally fine-grained containing abundant pyroxene phenocrysts and occasionally feldspar phenocrysts or both. They are set in a holocrystalline groundmass comprising feldspar, pyroxene and opaque minerals. The minerals are randomly oriented, hence no flow structure is visible. Andesine is the most common feldspar and it occurs both as phenocrysts and in the groundmass. Orthoclase has rarely been recorded. The clinopyroxene phenocrysts are mainly represented by augite. Magnetite is probably the most abundant opaque minerals, and is usually confined to the groundmass. A little interstitial glass has been observed, whereas quartz is rare. Secondary minerals consist of hornblende, calcite, chlorite, epidote, magnetite and sericite.

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In Thailand, the Tanah Merah/Muno volcanic (PTrvtn/mn) is strongly deformed as indicated by the presence of well-developed NE-SW S1-cleavage, which can be observed at the earth quarry in the Mu No-Pa Se Mas area. These volcanic rocks have undergone argillic alteration in which iron concretions and clay minerals are present.

The volcanic rocks comprise strongly sheared, highly altered andesite, andesitic tuff and agglomerate (Figure 22). Exposures of these volcanic rocks are limited to the small hill at Ban Muno, adjacent to Mae Nam Kolok (Sungai Kolok Quadrangle) in the eastern part of the Transect area.

Andesite and andesitic tuff are characterised by the presence of thin to medium layers of light grey and pale greenish grey rocks. The colour changes to white, light brown to reddish brown on weathered or altered surfaces. The rocks are composed mainly of mica and hornblende. Clay or other altered minerals such as talc or dickite are commonly found in the alteration zone.

Agglomerate is characterised by the abundance of rhyolitic clasts within thin to medium layers (30-40 cm). The colours of these rocks are generally pale brown, pale purple grey to light greenish grey with white spots (1-5 cm in diameter). Volcanic clasts are white or yellowish grey in colour.

MacDonald (1967) assigned this rock unit as Carboniferous to Triassic in age. Aw (1990), and Ab. Halim Hamzah and Mustafar Hamzah (in manuscript) reported that the main volcanic activities occurred during Permo-Triassic period. Accordingly, the Malaysian and Thai Working Groups have assigned the age of the volcanic rocks as Permo-Triassic.

Temangan Ignimbrite (Trvtg)

The Temangan ignimbrite presents a prominent ridge about 10 km long and 800 m wide, trending approximately N-S. The nature of contact can be observed in the Temangan area which shows the N-S trending ridge cutting the shale and sandstone (Figure 23). This evidence suggests an intrusive nature for the ignimbrite which intruded along the Lebir Fault zone (Aw, 1967). However, the rock unit is currently not exposed in Thailand.

The ignimbrite forms a hard massive outcrop with minor flow structure. The texture on the whole is quite homogenous and there is no visible change either laterally or vertically. The colour varies from pink to dark brown, while in slightly altered rock it is greenish grey. The porphyritic nature is conspicuous, with phenocrysts of quartz and feldspar set in a feldsitic matrix. In some specimens, fragments of shale and some black lenses of pumiceous material are included. More than three-quarters of the phenocrysts are of quartz. Shape of the phenocrysts varies from euhedral crystals with hexagonal outline to highly angular fragments. The feldspar phenocrysts include potash feldspar and plagioclase. The feldspar phenocrysts, and a little green biotite are set in a matrix of glass shards and cryptocrystalline material.

The age of these rocks is interpreted by the Working Groups to be Triassic.

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Figure 21: Photograph of serpentinite float (left) and pillow (lava) basalt outcrop (right) of the Ku Mung

igneous complex (PTrvkm) in Thailand.

Figure 22: Photograph of the highly altered andesite and andesitic tuff (left) and agglomerate (right) of the

Tanah Merah/Muno volcanic (PTrvtn/mn).

Figure 23: Photograph of the massive outcrop of

ignimbrite near Temangan town.

3.3.2 Granitic rocks

The Malayan orogeny is presumed by the subduction of a continental crustal plate (the western part) and an oceanic crustal plate (the eastern part) which is accompanied by the granite emplacements. Geologically, the granites are distributed as linear masses parallel to the Bentong-Raub Suture.

In Malaysia, Hutchison (1977) divided the granites into three belts based on lithology and petrochemistry of the granite: Main Range Belt, Central Belt and Eastern Belt. The Main

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Range granite is composed of S-type, ilmenite series granitoids which intruded into Paleozoic host rocks during the Permo-Triassic period. The Central Belt granite is composed mainly of S-type, ilmenite series granitoids of Triassic age with minor intrusion of Cretaceous I-type, magnetite series granitoids. The Eastern Belt granite consists mainly of I-type, magnetite series granitoids and intruded into Paleozoic host rocks during the Permo-Triassic period.

Later, Cobbing et al. (1986) divided the granite into two provinces: Main Range granite and Eastern granite, with assumption that the Central and Eastern Belts are similar. The Main Range granite has been regarded to be constituted exclusively of S-type granites of mainly Triassic age (Bignell and Snelling, 1977; Hutchison, 1977; Cobbing et al., 1986; Hutchison, 1996). In contrast, the Eastern province granite is dominated by I-type with subordinate compositional overlap S-type granites of Permo-Triassic age. Small I-type plutons of Cretaceous age are present in the central part of the Peninsular Malaysia (Bignell and Snelling, 1977; Hutchison, 1977).

The study of granite geology in the Transect area in Thailand was very limited due to security problems caused by guerrilla activities in last three decades. However, there was an effort from local DMR workers who were assigned to carry out a geological mapping programme in the southern part of the country. Muenlek et al. (1982) recorded three granite phases which were classified as gneissic granite, coarse-grained porphyritic biotite granite and tourmaline-muscovite granite. Finally, Cobbing et al. (1992) completed the Southeast Asian granite project including geological map of individual granite plutons, petrography, geochemistry classification and Rb/Sr age determination, and classified the granite in Southeast Asia into three granite provinces. The eastern granite province is composed mainly of Triassic I-type, magnetite series granitoids with minor compositional overlapping with S-type granitoids. The minor intrusion of isolated Cretaceous I-type, magnetite series is also present in this province. The western granite province consists of a mixture of S-type and I-type granites of Cretaceous age. The Main Range granite province and Northern Thai migmatite province are composed mainly of Triassic S-type, ilmenite series granitoids. However, minor intrusions of isolated Cretaceous I-type, magnetite series granite plutons can be found in the northern Thai magmatite granite province. Granitic rocks exposed in the Transect area can be divided into two major granite provinces such as Main Range Granite and Eastern Granite with small isolated plutons.

Main Range Granites

a) Merah granite/Bu Do granite (Trgrmr/bd)

In Malaysia, the Merah granite/Bu Do granite (Trgrmr/bd) is widely distributed in Sungai Perak, western part of the Transect area. The granite is characterised by grey, fine- to medium-grained showing a distinct preferred orientation of biotite and K-feldspar phenocryst.

The rock is holocrystalline, hypidiomorphic granular texture. Mineral composition is quartz (30-35%), K-feldspar (20-30%), plagioclase (20-30%), biotite (5-10%) and some amount of sphene, apatite, zircon, and epidote. Flakes of biotite are mostly kinked, deformed and interspaced between other minerals. In Thailand, the Merah granite/Bu Do granite (Trgrmr/bd) in the Bu Do batholith formed an elongated north-south trending mountain range, starting from Pattani Province in the east coast, extending southward to Yala and Narathiwat Provinces north of the Malaysia-Thailand border. It is composed of mainly ilmenite series with S-type affinity granitoids and is typically related to cassiterite mineralisation. The major rock forming minerals are quartz, K-feldspar, plagioclase (An10-30), and biotite, whereas subordinate muscovite and tourmaline are

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locally present as accessory minerals. Late stage leucocratic granites are abundant including aplite, pegmatite dykes, and quartz-feldspar veins. It is noteworthy that the major granitic rocks in the Bu Do granite batholith are generally non-foliated to slightly foliated. However, these rocks have been locally foliated along the margin and are called the marginal facies. Distribution of the Merah granite/Bu Do granite (Trgrmr/bd) is limited to the western end of the Transect area adjacent to Ai So Falls, southwest of the Ku Mung village in Cha Nae District. It is noticeable that the majority of the Bu Do granites is exposed outside of the Transect area. Granite outcrops are widely exposed along Ai So stream and the adjacent area and are widespread along the N-S trending zone from the Malaysia-Thailand border to Sisakorn District (Bu Do mountain range), in the central part of Sisakorn Quadangle, northeast of the Transect area. Petrographically, the rocks consist of mainly quartz, K-feldspar, plagioclase and biotite, which are more or less, compositionally equivalent to those of the western belt granitoids. However, the majority of these granites commonly show deep weathering features. Therefore, detailed petrography and geochemistry studies of these granites cannot be carried out for the time being.

Bignell (1972) has conducted a geochronological study for the Malaysian granites using both K/Ar and Rb/Sr methods. He concluded that the Main Range Granite is 200-230 Ma in age and granite emplacement took place during Triassic. Later on, Cobbing et al. (1992) reported the Rb/Sr isochron age of 207 Ma for Songkhla granitoid and 221 Ma for Satun granitoid. According to field observation mentioned earlier by Cobbing et al. (1992), the Bu Do granite batholith is geographically located within the Main Range granite province, which is represented by the Songkhla pluton. Therefore, the age of the intrusion of the Bu Do granite is also Triassic.

The Merah granite/Bu Do granite (Trgrmr/bd) is, therefore, assigned by the Malaysian and Thai Working Groups to be of Triassic S-type granite.

Eastern granite province

Eastern granite province occupies the area to the east of the Bentong-Raub Suture extending to the eastern side of the Ku Mung igneous complex (PTrvkm). In the Transect area, there are four granite plutons exposed, namely, Boundary Range Granite (Trgrbr/ty), Kemahang Granite/Sukhirin granite (Trgrkg/su), Lawar granite/To Mo granite (Kgrlw/tm) and Kenerong Granite/Ba La granite (Kgrkn/bl).

a) Boundary Range Granite (Trgrbr)

In Malaysia, the Boundary Range Granite (Trgrbr) is widely distributed to the eastern part of the Transect area. This granite, exposed at Bukit Panau, ranges from granite to granodiorite in composition. It is fine- to medium-grained megacrystic biotite granite with pink K-feldspar phenocrysts (Figure 24).

These granites consist of quartz (30-35%), K-feldspar (20-30%), plagioclase (20-35%), biotite (5-10%) and/or muscovite with occasionally hornblende. Allanite and sphene are fairly common in parts as accessory minerals. Inclusions of zircon and apatite are often abundant in the biotite. Chlorite, sericite, and magnetite are common as secondary alteration products.

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Figure 24: The Boundary Range Granite at Bukit Buloh

Quarry, near Kota Bharu, Malaysia.

In Thailand, the similar unit (Tan Yong granite) is widespread at Sungai Padi District, outside the Transect area. They are composed of medium- to coarse-grained, leucocratic, porphyritic biotite granite. However, the proportion of biotite in the groundmass is much less than those of the Kemahang/Sukhirin granite (Trgrkg/su). It is noticed that muscovite, which has been derived from biotite is commonly abundant.

For the purpose of correlation, a sample of granite from Kuala Krai situated about 70 km from Kota Bharu, Malaysia was dated at 227 + 6 Ma (Bignel and Snelling, 1977). In Thailand, Ishihara et al. (1980) proposed Rb/Sr model age of 252 Ma for the Tan Yong pluton granitoids. Later on, Cobbing et al. (1992) proposed Rb/Sr isochron age determination of 228 ± 5 Ma for Tan Yong granitoids.

The Boundary Range Granite (Trgrbr) is, therefore, assigned by the Malaysian and Thai Working Groups to be a mixture of Triassic I- and S-type granites.

b) Kemahang Granite/Sukhirin granite (Ttgrkg/su)

This irregular granite mass which forms the mountainous range east and west of Jeli town, Kelantan that extents to Sukhirin range in Thailand. In Malaysia, it covers Bukit Jeli, Bukit Kemahang, Bukit Kusial and several smaller hills. In Thailand, the granite of the Sukhirin batholith is largely distributed in Sukhirin and Waeng Districts adjacent to the Thailand-Malaysia border, extending northward to Jo I Rong and Sungai Padi Districts. The granite body typically forms N-S trending mountain range starting from Narathiwat Province in the eastern coast of the Thai peninsula and extending southward to Sukhirin District. It then continues to the Jeli town in the Malaysia side. Several isolated granite plutons were also found along the east coast of the Thai peninsula.

In Malaysia, the Kemahang Granite/Sukhirin granite (Trgrkg/su) consists of predominantly grey, medium- to coarse-grained megacrystic biotite-hornblende granite to granodiorite in composition (Figure 25). The feldspar phenocrysts have an average length of 2 cm but some of them may reach 10 cm and show definite orientation. It also contains abundant biotite with marked lineation of feldspar phenocrysts at a number of localities. Many varieties seem to be gneissic and show typical cataclastic textures such as deformed feldspar crystals, strained polarization and elongated quartz. Late phase microgranodiorite, microgranite and leucogranite or Cretaceous Kenerong Granite/Ba La granite (Kgrkn/bl) occur in patches and as dykes. Quartz veins and lenticles are very common at some localities.

- 40 -

The Kemahang Granite/Sukhirin granite (Trgrkg/su) in Thailand occurs as a major proportion of the rock unit and it covers most of the central part of the Transect area. Granite outcrops are well exposed along the road cut from Ban Ba La (Waeng District) to Ban Phu Khao Thong (Sukhirin District) via the Hara–Ba La wild life sanctuary. Large granite boulders are abundantly present along the road cut from the Waeng town to Sukhirin town. It is also noticed that most of the granite outcrops in the Sukhirin batholith are poorly exposed due to deep weathering surface and dense vegetation.

The Kemahang Granite/Sukhirin granite (Trgrkg/su) in Thailand consists mainly of porphyritic biotite granite with good primary granite texture, where sphene can be locally found as an accessory mineral in this rock. It is characterised by weakly developed, N-S trending foliation. The proportion of biotite mafic mineral in this rock is relatively higher than those of the Bu Do granite unit. However, the proportion of biotite in this rock occasionally drops in conjunction with the presence of muscovite. Various sizes of biotite-rich cognate xenoliths, quartz blebs and quartz strings are locally distributed in the Sukhirin granite batholith.

Petrographically, the granites are of light grey, medium- to coarse-grained, megacrystic, biotite-hornblende granite. K-feldspar megacrysts are up to 40% by volume and are lath shape to tablet with some equant crystals. The megacrysts range in size from 1x2 cm to 3x12 cm. Groundmass is composed of medium- to coarse-grained, single to cluster, quartz (20-35%, 2x2 to 5x8 mm in size), light grey to pale grey, euhedral to subhedral crystals, stubby, K-feldspar (30-40%, 2x10 to 3x15 mm in size), and chalky white, subhedral to euhedral, stubby, plagioclase (15-20%, 2x10 mm in size), whereas dark grey to black, single, flake to book, euhedral, biotite (15%, 2-5 mm in size) is the only mafic mineral found in this rock. Sphene, allanite, clinozoisite, monazite and apatite are the accessory minerals.

Various sizes of biotite-rich cognate (xenolith), quartz strings and quartz blebs are recognised in this granitic rock, especially along the margin of the granite pluton. It is noticeable that the population and size of K-feldspar megacrysts increase from east to west.

MacDonald (1967) suggested that the age of Kemahang Granite is Triassic based on age determination. According to field observation as mentioned earlier by Cobbing et al. (1992), the Sukhirin granite can be correlated with the Tan Yong granite pluton. Therefore, the intrusion of the Sukhirin granite would have occurred in the Triassic period.

The Kemahang Granite/Sukhirin granite (Ttgrkg/su) is, therefore, assigned by the Malaysian and Thai Working Groups to be Triassic I-type granite.

c) Lawar granite/To Mo granite (Kgrlw/tm)

The Lawar granite/To Mo granite (Kgrlw/tm) is exposed at Kampung Lawar (Malaysia) and extends northward to the To Mo area (Thailand). In Thailand, it is composed of granite to granodiorite, which is cut by dolerite and aplite dykes. The granite probably forms an offshoot of the Kenerong Granite/Ba La granite (Kgrkn/bl). Outcrops are exposed in the southern part of Licho-Balu mountain range near To Mo gold mine, extending southward across the border to Malaysia. They are composed of granodiorite, granite, dolerite, pegmatite and aplite, which are exposed as dykes, veins and veinlets. The granitic rocks are well exposed along the stream at the electric power plant in Ai Ka Po village and also at an abandoned quarry of To Mo gold mine.

The Lawar granite/To Mo granite (Kgrlw/tm) is characterised by light grey, fine-grained, equigranular biotite-hornblende granite which is partly sheared and modified. It is also noticeable that the intrusions of aplite, pegmatite and leucocratic granite as dykes and sills has initiated contact metamorphism of the country rocks and subsequently gold mineralisation has been introduced within the contact aureole (Figure 26).

- 41 -

Microscopically, it is granite to granodiorite in composition. The major minerals are quartz (30-35%), K-feldspar (20-30%), plagioclase (20-30%) and biotite (<10%) with occasionally hornblende. Secondary minerals are epidote, chlorite and sericite. Quartz and feldspars are normally sheared and crushed, whilst biotite has altered to chlorite. This rock is strongly sheared and crushed to such an extent that it can be classified as cataclasite.

Intrusion of the Lawar granite/To Mo granite (Kgrlw/tm) in Thailand has initiated various types of hypabyssal rocks, which formed long tabular shaped N-S trending bodies and are widespread in the north of the To Mo granite pluton. The above mentioned hypabyssal rocks are composed of dacite and andesite dykes. These dykes are locally formed as 1-2 km long N-S trending ridges and are exposed in the Khao Soon Patthana area and in the Ai Ka Po area. It is noted that these shallow intrusive rocks also contain a large proportion of silica rich materials, which represent restrictively in vugs. Moreover, the andesitic tuff that trends NE-SW can be locally found in the Ka To area.

The To Mo granite is correlatable with Cretaceous Lawar granite (Cobbing et al. 1992). Therefore, the intrusion of the granite would have happened in the Cretaceous age. Mohamad Hussein Jamaluddin et al. (in manuscript) mentioned that this I-type granite is believed to be an offshoot body of the Cretaceous Noring Granite which crops out to the south of the Transect area.

The Lawar granite/To Mo granite (Kgrlw/tm) is, therefore, assigned by the Malaysian and Thai Working Groups to be Cretaceous I-type granite.

d) Kenerong Granite/Ba La granite (Kgrkn/bl)

The Kenerong Granite/Ba La granite (Kgrkn/bl) is part of the Cretaceous plutons of the Eastern Belt (Cobbing et al., 1986). In the Transect area, Kenerong Granite/Ba La granite (Kgrkn/bl) lies between the Kemahang and Noring Granite masses.

In Malaysia, the granite is light grey to grey in colour, leucocratic, fine- to medium-grained, equigranular granite with foliated and unfoliated variations. It is holocrystalline hypidiomorphic to allotriomorphic granular texture, granite to granodiorite in composition (Figure 27). The main mineral constituents are quartz (30-35%), K-feldspar (20-30%), plagioclase (25-35%) and biotite (<10%). Accessory minerals comprise apatite, opaque minerals and subordinate muscovite. Altered minerals are sericite and chlorite. Alkali feldspar comprises predominantly orthoclase and some microcline. Intergrowth of quartz and feldspar forms myrmekitic texture.

In Thailand, the Kenerong Granite/Ba La granite (Kgrkn/bl) typically shows various types of granite, which forms a granite complex body. They intrude as subordinate late stage granite intrusions, which occur as dykes and veins including leucocratic granite and pegmatite into the Kemahang Granite/Sukhirin granite (Trgrkg/su). The Ba La granite unit can be lithologically subdivided into four phases:

1. The first granite phase is represented by the NNW-SSE foliated, dark grey, medium-grained (1-3 mm), equigranular to porphyritic biotite granite. K-feldspar phenocrysts are up to 3-5% by volume and are mainly of 1-3 cm in diameter equant crystals. The mineral composition of groundmass including 30% quartz, 50-60% K-feldspar and plagioclase and 15-20% flakes and elongated cluster biotite.

2. The second granite phase is characterised by N-S trending foliation, pale grey to light grey, equigranular, fine-grained, leucocratic granite including feldspar-rich pegmatite. The mineral composition consists of 30-40% quartz, 50-65% feldspar and 3-5% biotite, whereas red garnet is the only accessory mineral found in this rock.

- 42 -

Figure 25: Photographs of the Kemahang Granite/Sukhirin granite (Ttgrkg/su) in Malaysia (left) and in Thailand (right).

Figure 26: Photographs of the Lawar granite/To Mo granite (Kgrlw/tm) in Malaysia (left) and in Thailand (right).

Figure 27: Photographs of the Kenerong Granite/ Ba La granite (Kgrkn/bl) in Malaysia (left) and in Thailand (right)

3. The third granite phase is composed mainly of dark greenish grey fine-grained

equigranular granodiorite, slightly-moderately foliated in N-S direction. The mineral composition consists of quartz, feldspar and biotite. This phase generally occurs as dykes and veins trending WSW-ENE to NW-SE. The xenoliths of two-phase variants granites are locally included in this granite phase.

- 43 -

4. The fourth granite phase consists mainly of minor intrusions of pegmatite and aplite veinlets, trending N-S, NE-SW and E-W. Cross-cutting relationship can be observed clearly along the road cut at the top of the mountain and also at the Sirinthorn waterfall. Bignell (1972) reported that the western part of the Eastern Belt Granite in Malaysia that lies immediately east of the Bentong-Raub Suture gave the age of 64-69 Ma, which indicates granite intrusion during the Cretaceous. According to field observation as mentioned earlier by Cobbing et al. (1992), it can be concluded that the age of intrusion of Ba La granite is Cretaceous.

The Kenerong Granite/Ba La granite (Kgrkn/bl) is, therefore, assigned by the Malaysian and Thai Working Groups to be Cretaceous I-type granite.

4. Structural geology and tectonics Peninsular Malaysia was formed as a result of collision between Sinoburmalaya to the

west and Eastmal-Indosinia blocks to the east. The collision zone is represented by the Bentong-Raub Suture which can be traced northward into Thailand and southward into the Banka and Billiton Islands. This collision accompanied by the major tectonic event during Late Triassic has resulted in rock deformation in the Malay-Thai Peninsula. Pre-orogeny sedimentary successions in the Transect area are generally folded into a series of synclines and anticlines. Folding is characterised by tight, asymmetric and open folds, which cause the repeated and overturn sequence in the older sedimentary rock. The NW-SE and N-S trending fold axes are sub-parallel to the long axis of the Malay Peninsula and most of the bedding planes dip towards the east with various dip angles.

Faulting is widespread throughout the Transect area. Owing to the thick soil cover and deep tropical weathering, fault zones are seldom exposed at more than a few places along their traces. Faults are generally varies in width characterised by fractured, sheared or mylonitised rocks. There are several faults, which are mainly of strike-slip and normal faults, trending N-S, NW-SE and NE-SW. Of these, the NE-SW trending fault is the main fault of the Transect area. The major faults are Long-Kolok fault (NE-SW), Pergau fault (NE-SW), Kalai-To Mo fault (N-S) and Ka To-Bu Yong fault.

The formation of the Thai peninsula resulted from the collision between Shan Thai block to the west and Indochina block to the east, which happened during Middle to Upper Triassic. The continent-continent collision has caused uplifting and faulting along a N-S direction. On one hand, uplifting resulted in the formation of the Bu Do mountain range and Licho–Ba Lu mountain ranges, which trend in a N-S direction. On the other hand, the formation of N-S trending fault zones has caused a widespread deposition of post collisional sediments in an approximately N-S longitudinal basin. Pre-collisional rocks are fractured along a N-S direction which can be observed in the Ka Lu Bi (CPkl), Ai Ka Po (CPak) and Ai Ba Lo (PTrab) formations. However, major structures in this area may have been destroyed by the younger Cretaceous Ba La granite intrusion and multi direction fractures. Finally, younger NE-SW fractures, which can be prominently observed in both igneous and sedimentary host rocks, may have resulted from the movement of Long-Kolok fault along the Malaysia-Thailand border.

5. Economic Geology/Mineral Resources The mineral resources along the Malaysia and Thailand border are well-developed for the last century. Various types of metallic and non-metallic minerals have been discovered and

- 44 -

exploited in both countries to generate and accelerate the economy. The exploration activities are actively conducted to discover more mineral deposits.

In Malaysia, the Kelantan State is well endowed with mineral resources of metallic and non-metallic minerals. These include deposits of gold, manganese, iron, ball clay and barite as well as granitic rock as construction material. These have been mined for several years. In the near future the potential to develop ball clay, granite, and limestone for industrial raw materials can be significantly increased. Gold exploration within the area is still being carried out by the Minerals and Geoscience Department Malaysia. Apart from these, hot springs found in this area and the vicinity is potential tourist attractions.

In Thailand, the occurrences of various minerals have been recorded in Narathiwat Province. Galena discovered at Ban Khok Ko, Sungai Padi District, kaolin deposits exploited in Sungai Padi District, and silica sand from the weathered granite are good examples. Within the Transect area, the most important mineral resources i.e. gold, chromite, manganese, and their related geology have been revealed. Although the minerals were mined for several years in the past, some potential areas still remained. For example, at the Ban Muno area of Sungai Kolok District, the volcanic alteration is so strongly characterised that it could be a metallic minerals potential area.

In the Transect area, abandoned mining areas, quarries and some potential areas are investigated and economically assessed. Unfortunately, in some areas, exploration and exploitation of mineral resources are prohibited due to security reasons. 5.1 Metallic minerals

5.1.1 Gold

In Malaysia, gold is the most important metallic mineral that has been mined for years. The Minerals and Geoscience Department Malaysia identified at least 30 gold anomalies covering a total area of about 2,161 square kilometres in Kelantan State. However, Bukit Kuang and Kalai gold areas are located in the Transect area.

In Kelantan, gold mining activity has started since the 1920’s. In 1997, there were six alluvial gold mining areas in Kelantan that produced 111 kilograms of gold with revenue of RM 3.42 million. The first gold mine was situated at the Pulai area in Gua Musang. Starting from here, mining activities were widely distributed throughout the state from Sungai Galas and Sungai Pergau areas up to the Kalai area along the border of Kelantan State (Malaysia) and Narathiwat Province (Thailand). Rookeowell (1923) reported that the headwater of Sungai Pergau such as Tekok, Chinong and Chupan (situated in Kalai) were the most important gold areas.

Bukit Kuang gold area

In early 1989, the former Geological Survey of Malaysia discovered alluvial gold flakes during reconnaissance geochemical survey at the Bukit Kuang area. Subsequently, Ab. Halim Hamzah et al. (1991) conducted systematic gold exploration at the Bukit Kuang area. This gold exploration included the sampling of stream sediments (covering 30 square kilometres) and followed by grid soil sampling (0.6 square kilometres) over Bukit Kecil which could be the source of the gold mineralisation in the area. A total of 123 stream sediments, 124 heavy mineral concentrates (stream), 23 rocks, 784 soils and 608 concentrates from soil samples were collected. The stream sediments and rock samples were analysed for gold and 16 others elements (Ag, As, Co, Cu, Hg, Fe, Mn, Mo, Ni, Sn, Pb, U, Sb, Bi, Zn, and W). The heavy mineral concentrates (stream) were analysed for Au and 13 other elements (Pb, Ni, Co, Ag,

- 45 -

Mo, Cu, Zn, As, Sn, W, U, Sb, and Bi) and the soil samples were analysed for Au, As, Pb, Co, Hg, Cu, Zn, Fe, Mn, and Ba. Hence, the concentrate samples from soil were analysed for Au. Geologically, this area is underlain by Permian volcano-sedimentary rocks such as quartzite, shale and tuff.

The results indicated that the southern half of the area is significant for gold. The weak Au-Pb-Zn-Mn-Fe-Ni-Co anomalous stream sediment values are correlatable with the higher Au anomalous heavy mineral concentrate (stream) results. Based on this result, five anomalous zones were defined, two of which coincide with N750 and N2900 trending aerial photo lineaments. These two zones are classified as Priority 1 and the remaining three are Priority 2 targets.

Stream sediment gold results showed that 20% of the samples are above 50 ppb, and 7% above 100 ppb. The maximum value is 1.55 ppm. Heavy mineral concentrate (stream) gold results showed that 15% of the samples are above 50 mg/m3 and 5% samples are above 100 mg/m3. The maximum value is 805 mg/m3.

The grid soil sampling results from the Bukit Kecil area coincided with the results shown by the stream sediment and heavy mineral concentrates. Gold flakes were commonly observed in soil concentrate samples. At the southern half of Bukit Kecil, the idealised correlation between the higher Au tenor results and the more anomalous soil Au value (> 50 ppb Au) is identified. The best Au zones coincide with intersection of lineaments. A few intersections of lineaments show that the Au value in soil is above 200 ppb and the highest gold tenor value in soil concentrate is 359 mg/m3.

Kalai gold area

This area is underlain by metasedimentary rocks, which are close to the granite intrusion. The metasediments consist of interbedded metargillites and metarenites of the Mangga formation, Tiang schist and hornfelsic rocks of the Telong formation. Minor intrusion especially quartz veins/stringers and microdiorite veins can be observed in the study area.

Prior to 1923, prospecting and mining in the Kalai area were carried out mainly for gold. After 1923, there was no record of exploration work until 1980’s when the former Geological Survey Department of Malaysia and Malaysia Mining Corporation (MMC) separately carried out exploration in the Transect area. From the year 1987 to 1995, 14 Prospecting Permits (PP) and 4 mining certificates (MC) were issued. At present, local people are still working for gold in Kampung Lawar by panning.

Rookewell (1923) reported that the Ulu Pergau area comprised of 2.8 square kilometres of mineral potential land i.e. 1.6 square kilometres (at Berching and Rezorback, 0.4 square kilometres (Tekok) and 0.8 square kilometres (at Chupan and Chinong). Large amounts of Gold in these areas had been mined from the ore bodies and alluvial deposits by Chinese miners from the Chinong and Chupan areas. The ore occured in hard, grey to yellow ferruginous quartz veins and in many cases the gold could be clearly visible by the naked eye. These veins strike nearly N-S, with dips varying from 70 to 85 degrees towards the East. Their thickness varies from eight to 38 cm at Berching and Razorback, around 2 m at Tekuk, which is about 244 m below the Berching outcrops, and 60 – 90 cm at Chinong and Chupan. Rookewell also found 18 old tunnels, which were driven above the water table into the hillside (because they were no pumps to handle the water at that time) where miners had mined on the surface.

Chu et al. (1982) carried out reconnaissance geochemical sampling in the Upper Pergau area, covering Kampung Kalai Baru in the north, up to Batu Melintang and Kampung Bendang Lawar in the southern part, with an areal coverage of about 63 square kilometres. Subsequently, Safeen Baharuddin (1987) carried out follow-up geochemical sampling in that

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area. Stream sediment results showed that the area has mineral potential for gold and lead. The highest tenor of the gold value in heavy mineral concentrate was 1,574.68 mg/m3, located at a tributary of Sungai Tadoh. Other elements also showed potentially high values i.e. tin (Sn) and lead (Pb) in the north, nickel (Ni) in the central part and lead (Pb) and uranium (U) in the southern part. The background values of gold from various types of rock samples analysed (Mr. Amran of Malayan Mining Corporation and Mr. Safeen Baharuddin; personal communication) show that: slate - 0.006 ppm to 0.007 ppm, phyllite - 0.005 ppm to 0.035 ppm, schist - 0.011 ppm, tuff: 0.007 ppm to 0.029 ppm and granodiorite 0.009 ppm.

The stream sediment results obtained from reconnaissance survey for gold carried out by Mohd Azmer Ashaari et al. (1995) in the Kampung Kalai and Bukit Berching areas, within the contacts of the sediment and granite bodies showed that maximum gold (Au) value was 132 ppb and the highest grade and tenor in heavy mineral concentrate were 214 ppm and 383 mg/m3, respectively.

Mohamad Hussein Jamaluddin et al. (in manuscript) also carried out reconnaissance geochemical sampling for 18 elements (including Au) on stream sediments and heavy mineral concentrates collected in the area close to the granite intrusion underlain by interbedded metargillite and metarenites of the Mangga and the Telong formations. Based on these geochemical data, the Kalai area was interpreted as a geochemical anomalous area and rated as Priority 1, which covers about 14 square kilometres i.e from Kampung Kalai Baru in the southern part to the north close to the Malaysia-Thailand border. An immediate follow-up study was proposed. The geochemical sampling results showed that the area is potential for gold (Au) and Barium (Ba). The highest tenor for gold in heavy mineral concentrate was 391.874 mg/m3, located at a tributary of Sungai Tadoh and the lower tenor ranges from 013 ppm to 0.948 ppm. Gold (Au) recovered from the stream sediments ranges from 0.013 ppm to 0.948 ppm. Gold is the most well known mineral in the To Mo area, located in the Sukhirin District, Narathiwat Province, which covers Ban To Mo sheet (5320 IV) in a series of topographic map (scale 1:50,000). It is a primary deposit and has been exploited since the late 1890s. The first production came out during the year 1936-1940 when a French company called Societe de Mines d’ Or de Litcho exploited gold deposits by underground mining. As much as 6,000 ounces (170 kg) of gold were recovered during that period. In 1984, the deposit was back into the limelight with renewal of the mining right by Cholasin Co. Ltd. During 1990–1996, the production was recorded at 230 kilograms (Nuchanong, 1999).

Before the mining operation was stopped, gold was mined along quartz veins 30-50 cm in width; production reduced when the gold reserve was no more economic. Subsequently, in 1994, the Cholasin Company employed the Mineral Resources Office, Region 1 (Songkhla) to explore gold deposits around the To Mo area, especially, along Khlong Ti Moong and its branches covering an area of about 20 square kilometres to the northwestern part of the To Mo mine. The results revealed the presence of some gold in stream sediments with the average grade ranging from 0.057 to 0.106 g/ton. It is interesting to recognise that gold is disseminated in quartz veins, which occurred in the area, the grade is up to 0.42 g/ton (Fuangthong et al., 1994).

The gold potential area in Thailand is confined to Cretaceous granodiorite, granite, andesite and quartz veins/dykes, which intruded the Carboniferous-Permain rocks. Gold mineralisation occurs in N-S trending quartz veins. These veins are 0.1 to 2.2 m thick, and the common associated minerals are pyrite and arsenopyrite, which are usually below 3 %. Mineable reserve calculated by Cholasin at the beginning of the operation was 100,000 tons at 7 g/ton of gold metal.

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(a) (b)

Figure 28: Gold nuggets discovered by panning (a) and gravel bed with gold deposits (b).

During the reconnaissance exploration, stream sediment samples were collected along Khlong Ai Ti Moong and its tributaries extending northward from the To Mo area. Generally, gold was recovered by panning in gravel bed, varies from dust up to 3 mm in size (Figure 28). The gold potential area covers about 80 square kilometres.

5.1.2 Chromite

In Thailand, chromite has been mined at Bu Yong hill, Ban Ai Sue Rae of Cha Nae District, topographic map Amphoe Si Sakhon sheet (5321 III). The deposit was discovered as podiform in the Permian-Triassic ultrabasic rocks. Ultrabasic rocks intruded the Permo-Carboniferous shale, slaty shale, phyllitic shale and phyllite, along a well defined zone trending NE-SW. Chromite samples collected from the mine are massive, euhedral crystals with brown to dark brown colours and average chemical analysis revealed Cr2O3 = 42.5 %, Fe2O3 = 18.2 % and Cr/Fe ratio 2.37/1 (Suwannasing, 1962).

During the joint field checks, ultrabasic rocks were found extending southward at Ban Ai Ba Lo, Ban Chang Phuak and Ban Ai Bue Nae of Cha Nae District (Figure 29). However, no chromite deposit has been reported in Malaysia.

5.1.3 Manganese

In Malaysia, manganese ores are located at Gual Periok and Rantau Panjang areas. There are four manganese deposits discovered at Bukit Lubuk Itek, Bukit Gharu, Bukit Tandok and Bukit Pak Junus at the Gual Periok area, whereas, Bukit Kuang at Rantau Panjang area (Table 1). MacDonald (1967) reported that the Japanese Company had mined manganese in the year 1953 at the Bukit Tandok area, Bukit Gharu in 1937 and Bukit Lubuk Itek in 1942. Up to 1954, a number of companies investigated the areas and concluded that these mines were no longer economical. In 1959, the Eastern Minerals and Trading continued to mine these deposits.

In Thailand, three manganese mines are located along the mountainous areas, Ban Ai Ba Lo in the Ban To Mo map sheet (5320 IV). Mineral samples were collected from Ban Chang Phuak mine and were identified to be psilomelane and rhodonite (Figure 30). Generally, they occur in quartz veins that cut into phyllitic shale of Permo-Carboniferous age.

According to field investigation, the occurrences of manganese are still present in these areas, covering an area of about 6 square kilometres. However, these areas are now being reserved for forestry conservation under the name of “Suan Pa Sirikit”.

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5.1.4 Iron Deposits

In Malaysia, there are two iron ore deposits are found at Temangan (N5o 40′, E102o 8′) and Bukit Kuang (N5o 55′, E101o 57′), Kelantan. Other occurrences in Kelantan State (outside the Transect area) are at Chaning Estate, Kuala Krai (N5o 27′, E102o 12′), Ulu Anak Sungai Telong (N5o 39′, E102o 04′), Gua Musang (N4o 53′, E101o 58′), Sungai Tasin (N5o 14′, E102o 01′) and Kuala Bala (N5o 26′, E10o 55′).

Temangan

The Temangan deposit is situated within a broad westward curve of Sungai Kelantan. The terrain is below 1,200 m high and expressed as hilly to undulating. The mine is situated along the north-south trending 220 m high ridge. The deposit was probably discovered in 1921. Ishihara Sangyo Koshi initiated prospecting activities, but this company did not consider the deposit to be of economic interest. In 1934, the Southern Mining Company re-prospected the area, and estimated the reserves to be 6 million tonnes. This company commenced production during 1935 but did not export any ore until 1937. All production ceased in 1941 and the mine remained idle throughout the period of Japanese occupation. Ore which had previously been stockpiled, was smelted locally at Temangan Bharu during and after the Japanese occupation, until the supply was exhausted.

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(a)

(b)

(c)

Figure 29: Chromite mine at Ban Bu Yong (a) and associated ultrabasic rocks at Ban Chang Phuak (b) and Ban Ai Bue Nae (c).

Figure 30: The manganese mine at Ban Chang Phuak (left) and close-up outcrop of psilomelane at this mine

- 50 - Table 1: Summary of manganese deposits in the study area (Malaysian side).

Locality Year vestigation Method of

investigation Area study Reserve Grade Remarks

Gual Periok area: (N5o 56′ E102o 2′) Bt. Lubuk Itek

Bukit Gharu

Bukit Tandok

1955

1955

Has been

Solid ore; limonite and manganese boulders.

Residual deposit from shale- Psilomelane with some pyrolusite in the red earth as concretionary masses, solid boulders, limonite-magnetite and maganiferous shale.

Residual deposit from

Pitting (20 holes)

Trenching and Pitting (48 holes).

Trenching

60,702.8 m2 (only 4,046.9 m2 of potential area)

64,749.7 m2

Not

4,200

4,500

Not

Mn 46.5 %

Mn 33 %

Up to 65

Shale striking to the north and dipping towards the east. A few manganese ore with sizes up to 2.4m in diameters are noted.

Country rock consists of shale. Mined by Japanese company – (Production: 100,000 tonnes Mn ore). The opencast mine: 240 m length, 50 m width and 2.5 m depth. Country rock of shale;

Table 1: Summary of manganese deposits in the study area (cont.)

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Bukit Pak Jurus

mined since 1935

shale (psilomelane with a little pyrolusite occur as reniform, botryoidal and mammillary concretions in the red earth and clay).

Secondary deposit of limonite pebbles and psilomelane and small sizes of solid manganese.

Pitting (47 holes)

mentioned

Not mentioned

mentioned

42,000

% Mn

Average: 8.13% Mn (No economic value)

reddish in colour with quartz and calcite veins and a little quartzite. Mined by Japanese company (production: 69,124 tonne)

Country rock of shale.

Rantau Panjang area N5o 55 ‘ E101o 57‘

1960

Secondary deposit with iron boulders: haematite & limonite

Pitting (42 holes)

121,875 m2

1,226,145

2.02% Mn 58 % Fe

Country rocks of sandstone and Quartzite.

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There was little interest shown on the iron ore deposit immediately after the war, but in 1955 the deposit was re-prospected by a Malaysian-Japanese group and the result showed the iron ore deposit was still economical for mining. The Oriental Mining Company commenced production in 1958 and exhausted the deposit by the end of 1965. The ore body lies along the north-south line of the rock contact between the Taku schist to the west and shales to the east. Just east of this contact there is a large quartz-porphyry dyke, which follows the regional strike but transgresses the bedding. East of the dyke, interbedded shale, volcanic and pyroclastic rocks are present.

Diamond drill core has shown that beneath the main ore bodies, siderite veins and veinlets cut the shale. The shale in most places is grey or greyish-white in colour and contains some arenaceous and tuffaceous bands. An interesting mineralogical occurrence observed on a schist-tuff contact consists of a sheared and highly altered rock in white and apple green bands, and contains the chrome mica, fuchsite, and a chromium-bearing pyroxene.

The ores are essentially limonite with subordinate hematite and often contain a significant percentage of manganese. Two varieties of limonite were noted, hard brownish black and bluish-banded ore. The banded ore contains large cavities up to 3 m in diameter, and these are lined with hard, black, botryoidal ore. Some of the large cavities contain well-developed stalactites and stalagmites of limonite, and the smaller ones had pseudomorph of psilomelane after manganite. The more massive iron ore contains large cavities, but they are usually much smaller than those in the banded ore.

The main ore bodies were formed as secondary deposits as the result of solution and re-deposition by circulating waters of pre-existing iron-bearing materials, and information as to an adequate source of the iron was found in some of the deeper diamond-drill holes. After the consolidation of the shale a period of crustal disturbance produced shearing and faulting along the shale-schist contact. These showed that shale had been subjected to hydrothermal activity in the form of silicification, pyritisation, and impregnation by veins of siderite and it is thought the siderite was the parent from which the limonite and hematite were derived. Prolonged weathering produced a secondary limonitic ore from the siderite and country rocks by the process of solution and redeposition. The manganese originally associated with the primary carbonate mineralisation was redeposited in the same manner. Minor crustal movements caused east-west faulting with some displacement of the ore bodies. The hydrothermal solutions produced the quartz-porphyry dyke located east of the Temangan deposit. It appears significant that iron ore occurs at intervals along the length of the dyke and the Temangan deposit is located where the dyke reaches it maximum width.

The ore composition is medium grade and most of it contains a considerable percentage of manganese. Representative analyses are shown in Table 2. Its production is presented in Table 3.

Table 2: The composition of iron ore discovered in the Temangan area.

Constituent Percentages Sample Fe SiO2 Al2O3 Mn P S H2O Average 1937 49.86 7.71 4.44 3.00 0.071 0.02 10.42 Average 1941 54.69 4.28 2.71 2.13 0.076 0.04 10.65 Average 1937-41 56.30 4.10 1.55 2.26 0.076 0.04 10.56 Average of 21 samples 56.57 2.47 1.47 3.78 0.037 0.05 4.26 Average of 8 samples from adits

53.07 4.96 - 2.07 - - -

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Table 3: The annual production of iron ore in the Temangan area.

Year Production (Long Tonnes) 1935 1936 1937 1938 1939 1940 1941

1942-57 1958 1959 1960 1961 1962 1963 1964 1965

150,000 127,000 130,000 150,000 180,000 200,000 200,000

Nil 293,717 402,751 593,219 617,739 497,823 464,503 476,237 373,225

Total 4,856,214

Bukit Kuang

An iron ore deposit in this area appears as boulders of limonite and hematite and their primary body is believed to be at depth. The ore reserve is estimated to be 1.5 million tonnes with a grade of 55% Fe. There is no record of production and detailed description of iron ore from this area.

5.1.5 Alteration zones

Iron deposit has not yet been found in Thailand. However, there is a burrow pit at Ban Muno, 6 km from Sungai Kolok, on the topographic map Ban Ko Sathon sheet (5421 III). The country rocks consist of weathered andesitic tuff, agglomerate of Permo-Triassic age (Figure 31). The geology is related to a strong and very complicated alteration. Generally, clay minerals and pyrite are widespread, and the large number of thin quartz veins cut the country rocks.

Accordingly, it is interesting to note that this area is also potential for base metals and gold deposits. During field checks, 53 soil samples were collected for chemical analysis. Subsequently, the results reveal that Cu = 13-310 ppm, Pb = 4-190 ppm, Zn = 3-94 ppm, Au = 4-59 ppb (detection limit = 3 ppb). The results mentioned above revealed significant mineralisation.

The exposure at Kampung Bukit Lata near the Bukit Perdah area extends eastward in Malaysia. They are classified as a part of the Tanah Merah volcanics which are composed of tuffaceous argillite and andesitic tuff. The rocks consist of iron enrichment. Clay minerals altered from feldspar phenocrysts, quartz and also pyrite are widespread in the volcanic rocks. Currently, mineral resources in this area are not considered to be economical

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(b)

(a) Figure 31: Photographs of the original country rocks of the Permo-Triassic Volcanic rock in the Ban Muno area

(a) and the alteration feature of the country rocks in the Ban Muno area (b).

5.2 Non-metallic minerals and others

In Malaysia, non-metallic minerals such as granite, limestone, sand, clay, soil and barite, were developed and exploited in the Kelantan State. In 1997, a value of RM 36.2 million was attributed to non-metallic minerals mined in Kelantan. This income came largely from mining clay/soil (RM1.6 million), sand (RM4.4 million), limestone aggregate (RM3.8 million), barite (RM0.2 million) and granite aggregate (RM26.1 million).

5.2.1 Granite

Granite resources suitable for construction material is abundant in Malaysia. However, there is only one quarry site, Sebarang Bina Quarry situated near Kemahang currently producing road aggregates and construction materials.

Pink porphyritic Noring granite and fine-grained foliated/non-foliated Kenerong granite has potential sources for dimension stone. Perhaps the Kemahang granite is suitable for feldspar extraction indicated by the high feldspar content. A detailed study should be done for its economic potential.

5.2.2 River sand

In Malaysia, sand deposited in the river valley particularly that of Sungai Pergau can be used for construction material.

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5.2.3 Clay

In Malaysia, there are five clay deposits with an estimated reserve of 20.3 millions tonnes of ball clay and 51.5 million tonnes of mottled clay found in the Pengkalan Kubur area (Mohd Suhaili Ismail et al., 1993), Bukit Pak Junos (Zainol Abidin et al., 1994) and Kampung Bakong Kechik, Kampung Gertak 3 and Padang Lichin, Gual Lensa and Kampung Cherang Hangus (Zainol Abidin et al.,1995a). Summary of their reserves is shown in Table 4.

Gual Lemsa and Kampung Cherang Hangus ball clay

Follow-up ball clay investigation in these areas leads to discovery of a deposit covering 823 hectares in the Gual Lemsa and Kampung Cherang Hangus areas, Pasir Mas. Two types of ball clay, namely, mottled ball clay and unmottled ball clay were identified. The ball clays occur as lenses (Zainol Abidin et al., 1995a).

Table 4: Summary of clay reserves in the study area.

No. Potential area Type of clay Measured reserved

(million metric tonne)

1. Kampung Geretak Tiga and Kampung Padang Lichin.

Ball clay Mottled clay

1.8 3.9

2. Gual Lemsa and Cherang Hangus

Ball clay Mottled clay

10.3 23.2

3. Kampung Bakong Kechik Ball clay Mottled clay

2.4 14.4

4. Pengkalan Kubur Ball clay 1.2

5. Bukit Pak Junus Ball clay Mottled clay

4.6 10.0

Total: Ball clay Mottled clay

20.3 51.5

The mottled ball clay occurs mainly at the upper part of the deposit. Its thickness ranges

from 0.2 to 8.0 m with an average of 2.3 m. This red clay has medium plasticity and medium to good green strength. The fired colour at 1,1000C is light pink to light red. The clay is comparable with some of the ball clays used for local tile, vitrified clay pipe, art ware and brick industries.

The unmottled ball clay layers have an average thickness of 1.2 m. The clay, light grey in colour, has generally medium to good green strength and medium to good plasticity. Its Si02 content ranges from 48.0 to 62.2%. The A12O3 content ranges from 24.5 to 33.6% and the Fe2O3 content ranges from 1.14 to 2.6%. The fired colour at 1,1000C is predominantly off-white. The clay is comparable with some ball clays currently being used by the local tile, sanitary ware, tableware and artware industries.

The minimum reserve of the clay deposit based on a 200 m grid bore hole spacing is estimated at 33.5 million tonnes, comprising 23.2 million tonnes of mottled ball clay and 10.3 million tonnes of unmottled ball clay. The overburden is estimated to be 44 million tonnes.

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Kampung Geretak Tiga and Kampung Padang Lichin ball clays

Result of a follow-up clay investigation in these areas, a deposit covering 77 hectares has been discovered. Two types of ball clay, namely mottled ball clay and unmottled ball clay were identified. The ball clays occur as lenses (Zainol Abidin et al., 1995b).

The mottled ball clay occurs mainly at the upper part of the deposit. The thickness of the clay ranges from 0.1 to 6.5 m with an average of 2.3 m. The clay, largely red in colour, has medium plasticity and good green strength. The fired colour at 1,1000C is light pink. The clay is comparable with those used for the local tile, vitrified clay pipe, art ware and brick industries.

The unmottled ball clay layers have a thickness of up to 4.0 m. The clay, light grey in colour, has medium to good green strength and medium plasticity. Its SiO2 content ranges from 46.5 to 56.5%. The A12O3 content ranges from 27.9 to 35.0% and the Fe203 content ranges from 1.23 to 2.26%. The fired colour at 1,1000C is predominantly off-white. The clay is comparable with those currently being used for the local tile, sanitary ware, table and art ware industries.

The minimum measured reserve of the deposit is estimated at 5.7 million tonnes comprising 3.9 million tonnes of mottled ball clay and 1.8 million tonnes of unmottled ball clay. The overburden is estimated to be 8.7 million tonnes.

Kampung Bakong Kechik ball clays

Follow-up ball clay investigation in this area has resulted in the delineation of a deposit covering 292 hectares in the Kampung Bakong Kechik area, Pasir Mas. Two types of ball clay, namely mottled ball clay and unmottled ball clay were identified. The ball clays occur as lenses.

The mottled ball clay occurs mainly at the upper part of the deposit. The thickness of the clay ranges from 0.5 to 8.0 m with an average of 3.3 m. The clay, largely red in colour, has medium to high plasticity and medium to good green strength. The fired colour at 1,1000C ranges from light brown to red. The clay is comparable with those used for the local tile, vitrified clay pipe, art ware and brick industries.

The unmottled ball clay layers have an average thickness of 1.9 m. The clay, light grey in colour; has generally good green strength and medium plasticity. Its Si02 content ranges from 51.6 to 69.6%. The A12O3 content ranges from 21.3 to 30.7% and the Fe203 content ranges from 1.15 to 2.37%. The fired colour at 1,1000C is predominantly off white. The clay is comparable with those currently being used for the local tile, sanitary ware, tableware and art ware industries.

The minimum measured clay reserve of the deposit based on a 200 m grid borehole spacing is estimated at 16.8 million tonnes comprising 14.4 million tonnes of mottled ball clay and 2.4 million tonnes of unmottled ball clay. The overburden is estimated to be 3.6 million tonnes (Zainol Abidin et al., 1995c).

Pengkalan Kubur area ball clay

A reconnaissance survey revealed two potential areas (on the basis of quality, thickness and extent of the unmottled ball clay deposit) at Kampong Kajang Sebidang–Kampong Kubang Sawa–Kampong Palas Merah and Kampong Ninchang in Tumpat District. The unmottled ball clays occur as lenses. The total reserve is 1.2 million tonnes (Mohd Suhaili Ismail et al., 1993).

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At the Kampong Kajang Sebidang–Kampong Kubang Sawa–Kampong Palas Merah area, the unmottled ball clay layers have thicknesses ranging from 1.3 m to 2.1 m and the colour is light grey. Its SiO2 content ranges from 53.0 to 56.8 %. The Fe2O3 content ranges from 1.32 - 1.79 % and the TiO2 content ranges from 0.58 - 0.89 %. The fired colour at 1,100 0C is off-white.

At the Kampong Ninchang area, the ball clay layers have an average thickness of 1.1 m and are light grey in colour. Its SiO2 content is high (65.2 %). The Fe2O3 and TiO2 contents are 1.64 % and 0.74 % respectively. The fired colour at 900 0C, 1,000 0C and 1,100 0C is off-white.

Bukit Pak Junus area ball clay

Follow-up ball clay investigation in this area has resulted in the delineation of a deposit covering 362 hectares in the Bukit Pak Junus area, Pasir Mas (Zainol Abidin et al., 1994). Two types of ball clay, namely, mottled ball clay and unmottled ball clay were identified. The ball clays occur as lenses.

The mottled ball clay occurs mainly at the upper part of the deposit. The thickness of the clay ranges form 0.2 to 6.4 m with an average of 1.9 m. The clay, largely red in colour, has medium to high plasticity and medium to good green strength. The fired colour at 1,1000C ranges form pink to mainly orange and reddish brown. The clay is comparable with those used for the local tile, vitrified clay pipes, art ware and brick industries.

The unmottled ball clay layers have an average thickness of 1.32 m. The clay, light grey in colour, has generally good green strength and medium plasticity. Its Si02 content ranges from 53.0 to 70.7%. The A1203 content ranges from 17.5 to 31.0% and the Fe203 content ranges from 0.96 to 2.46%. The fired colour at 1,1000C is predominantly off-white. The clay is comparable with those already used for the local tile, sanitary ware, tablewares and art ware industries.

The measured reserve of the clay deposit is estimated at 14.6 million tonnes comprising 10 million tonnes of mottled ball clay and 4.6 million tonnes of unmottled ball clay. The overburden is estimated to be 15 million tonnes.

5.2.4 Crystalline limestone

Outcrops of crystalline limestone are observed at Gunung Reng, close to Sungai Tadoh. It occurs as lenses trending N-S and continuing near the border area. In the southern part, these rocks can also be observed at the Gua Setir area. The rock is light grey to grey, thin bedded to massive. Sometimes it shows light- and dark-banded layers. Detailed study is recommended in the near future to determine the potential of this rock for dimension stone and others such as cement, calcium carbonate powder, quick lime and hydrated lime industries.

The Gunung Reng area may have the potential to be developed for the tourism industry due to its beautiful panoramic scene.

5.2.5 Barite

In Malaysia, barite deposit was discovered only at Bukit Pencuri in the District of Tanah Merah which is associated with hematite. The percentage of BaSO4 analysed from three samples collected is shown below:

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BaSO4 (%) Fe2O (%) Specific Gravity Sample 1 57.6 38.1 4.5 Sample 2 64.6 32.5 4.6 Sample 3 79.2 7.11 4.0

The barite ore can be used as a weighting agent in drilling fluid for oil-well exploration.

Currently, this mine is closed. There was no production recorded from this abandoned mine.

6. Discussion and conclusion

Discussion

i. Lithostratigraphically, the Silurian-Devonian Tiang schist/Ban Sa formation (SDts/bs) is considered as the oldest rock unit in the Transect area. The rock unit crops out at two localities i.e. in the west, it forms a north-south belt from Ai Ku Sa stream (Thailand) to Bukit Luat Lantai down to Kuala Sungai Machang (Malaysia), and in the east it is restricted to stream outcrops near Ban Sa and road-cut outcrops at Ban Ba La, the southern part of Waeng District, Narathiwat Province, Thailand. It consists mainly of medium- to thick-banded paragneiss and augen gneiss with subordinate amphibolite schist, schist and hornfels. No fossils were found within this rock unit.

ii. The succession of Carboniferous-Permian clastic rocks can be subdivided into two formations in ascending order: the Mangga/Ai Ka Po/Ka Lu Bi formation (CPmg/ak/kl) and the Taku schist/Buke Ta formation (CPtk/bt).

a. In Malaysia, the Mangga/Ai Ka Po/Ka Lu Bi formation (CPmg/ak/kl) is represented by the Mangga formation (CPmg), a low grade metamorphic sequence that was subdivided into 4 facies: argillaceous (CPmgag), arenaceous (CPmgar), pyroclastic (CPmgpy), and calcareous (CPmgcl) facies. The argillaceous facies consists mainly of metamorphosed siliceous shale, slate, phyllite, metasiltstone and hornfels. The arenaceous facies consists of metasandstone and metagraywacke interbedded with minor metasiltstone and schist. The pyroclastic facies is composed mainly of rhyolitic tuff occurring as lenses within arenaceous and argillaceous strata. The calcareous facies consists of impured marble and pure white marble that occur as lenses within the argillaceous, arenaceous and pyroclastic facies. The rock units are exposed at the upper reaches of Sungai Machang extending southeastwards to Kampung Gunung.

b. In Thailand, the Mangga/Ai Ka Po/Ka Lu Bi formation (CPmg/ak/kl) is represented by the Ai Ka Po formation (CPak) and the Ka Lu Bi formation (CPkl). The Ai Ka Po formation is exposed as a narrow N-S trending ridge. This formation is composed mainly of thin- to thick-bedded, tuffaceous sandstone, quartzite and metaconglomerates. The Ka Lu Bi formation (CPkl) is the gradational fining upward sequence from the former formation. The succession, well exposed at low relief terrain, consists of cycles of thin- to medium-bedded, shales, sandstones and conglomerates with quartz vein and dyke at the lower part. In the upper part, sharp, even, very thin bedded or rhythmic sequence of shales and siltstones are intercalated with very fine-grained sandstones.

c. The Taku schist/Buke Ta formation (CPtk/bt) is well distributed in the southeastern part of the Transect area within Malaysia, whereas in Thailand, it

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is locally distributed at Ban Buke Ta and Mae Nam Kolok. These rock units comprise predominantly schists, which are wholly crystalline and generally completely schistosed. Mica schist is the main rock type, which consists of quartz-mica schist, mica-garnet schist and quartz-mica-garnet.

Local deformation and low-grade metamorphism took place in the shear and contact zones, and metamorphosed the original rocks to slate, phyllite, phyllitic shale and spotted slate. No fossil has been found in these formations and the thickness of the succession is still indeterminable. However, evidences shown by the intrusion of the well-dated Triassic granite and the stratigraphic position of the rocks enable the working group to assume that the age of the rocks is Carboniferous-Permian.

iii. The Permian-Triassic succession of the Ai Ba Lo formation (PTrab) is confined to the northwestern part of the Transect area (within Thailand). It mainly consists of sharp, even, thin- bedded cherts with recrystalline radiolarian intercalated with stringering shale beds and rare volcaniclastic sediments. The succession obviously exhibits instability of the basin during the time of deposition because of igneous activities. Stratigraphically, the age of these chert strata is considered as belonging to the Permian-Triassic Period.

iv. The Permian-Triassic succession of the Telong formation (PTrtl) is confined to the central-south and central part of the Transect area in Malaysia i.e. in Kampung Legeh and extends eastwards to the Tanah Merah area. The Telong formation consists mainly of argillite, low-grade metasedimentary and metavolcanic rocks. It can be divided into four facies namely: argillaceous (PTrtlag), arenaceous (PTrtlar), calcareous (PTrtlcl) and volcanic facies (PTrtlpy). No fossils were found so far in the Transect area. However, based on the bivalves and foraminifera reported found in the same lithology unit to the south of the Transect area, the age of this formation may be assumed as Permian-Triassic.

v. The term Bu Yong formation (Trby) is introduced by the Working Groups after the Bu Yong road cut and the stream across the rock formation in the Ku Mung-Bu Yong area, Cha Nae District on the western side of Narathiwat Province, Thailand. The Triassic submarine fanglomerate or the Bu Yong formation (Trby) is not observed in Malaysia. It is unconformably underlain by the Carboniferous-Permian and Permian-Triassic rocks. It crops out in the central part of the Transect area. The Bu Yong formation consists of massive to thick-bedded, conglomerates, conglomeratic sandstones, with both matrix- and clast-supported types. Clasts are made up of sandstones, quartz, cherts, and volcanic rocks.

vi. The Panau beds (Kpn) are locally exposed at Bukit Panau and Bukit Jambul about 10 km north of the Tanah Merah town (in Malaysian side) located in the eastern part of the Transect area. Nonconformity between the Triassic granite and the overlying sandstone of Panau beds can be observed at an abandoned rock quarry at the foothill of Bukit Panau. The age of this rock unit is evidently younger than Triassic and is believed to be Cretaceous; based on plant fragments found in the fine-grained sandstone beds at the foothill of Bukit Panau.

vii. The unconsolidated sediments within the Transect area were deposited in both marine and non-marine environments. The Working Group has recognised three formations (in descending order) i.e. Gula Formation/Tak Bai formation (Qhgl/tb), Beruas Formation/Sungai Kolok formation (Qhbr/sk) and Simpang Formation/Waeng formation (Qpsk/wg). a. The marine Holocene sediments of the Gula Formation/Tak Bai formation are

subdivided (from top to bottom) into five members: Recent beach member

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(Qhrbgl/tb), Matang Gelugor Member/Old beach member (Qhmtobgl/tb), Peat swamp member (Qhpbstb), Teluk Intan Member/Tidal flat (Qhtitfgl/tb), and Bagan Datoh Member/Shallow marine members (Qhbdsmgl/tb). However, the Peat swamp member is only exposed extensively in Thailand.

b. The non-marine Holocene sediments of the Beruas Formation/Sungai Kolok formation can be subdivided into four members: Natural levee member, Abandoned channel member, Floodplain member and Pengkalan member. However, the Pengkalan member is only observed in Malaysia. It is mainly characterised by silty clay, sand, and gravel with abundant mottles and iron concretions.

c. The non-marine Pleistocene deposits consist of the Colluvium/Terrace and Former floodplain members of the Simpang Formation/Waeng formation which is dominantly characterised by gravel, sand, silt, and laterite.

viii. The Permo-Triassic volcanic rocks are subdivided into two sub-units: the intermediate volcanic association of the Tanah Merah/Muno Volcanics (PTrvtn/mn) and the Ku Mung volcanic complex (PTrvkm). In Malaysia, the Tanah Merah/Muno volcanic (PTrvtn/mn) is composed of andesite flow, andesitic tuff and agglomerate but predominantly pyroclastics. It is mostly extrusive in nature, probably contemporaneous with the deposition of the associated sediments and pyroclastics. In Thailand, the Tanah Merah/Muno volcanic (PTrvtn/mn) is only represented by a small hill in Ban Mu No, near Mae Nam Kolok at the east of the Transect area. It comprises strongly sheared and altered andesite, andesitic tuff and agglomerate. Serpentinite and relicts of ultramafic and mafic rocks with podiform chromite deposit of the Ku Mung volcanic complex (PTrvkm) are located as a narrow NE-SW trending body in the central part of the Transect area. Pillow (lava) basalt, basaltic andesite and gabbro are well exposed along Mae Nam Sai Buri located in the central part of the Transect area. The unit is closely related with the Ai Ba Lo formation (PTrab).

ix. The Temangan Ignimbrite (Trvtg) presents a prominent ridge about 10 km long and 800 m wide, trending approximately N-S. The nature of the contact can be observed in the Temangan area, which shows the N-S trending ridge cutting the shale and sandstone. This evidence suggests an intrusive nature for the ignimbrite, which intruded along the Lebir Fault zone (Aw, 1967). However, the rock unit is currently not found in Thailand. The ignimbrite forms a hard massive outcrop with minor flow structure. The texture on the whole is quite homogenous and there is no visible change either laterally or vertically.

Conclusion

i. Problems on the discontinuity among time rock unit boundaries between the Paleozoic rocks to Quaternary deposits, and the extension of granitic rocks (including the mineral association), in both the Malaysian and Thai sides have been satisfactorily resolved.

ii. Historically, marine sedimentation took place continuously throughout the Paleozoic and Early Mesozoic Eras, but nevertheless, the large breaks can be observed due to instability of the depositional basins during the Devonian-Carboniferous and Early Triassic.

iii. The Paleozoic rock sequences were intruded by the two bodies of granitic rocks. The N-S trending granitic rocks in the central part of the Transect area consist of the

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equigranular to porphyritic biotite-hornblende granite with muscovite occuring as secondary mineral resulting from the alteration of K-feldspar and/or biotite. Many phases of granitic rock types are also found in the eastern flank of the Ba Tu Ta Mong-Jeli granitic belt. The other belt is located as a N-S trending body in the western part of the Transect area, consisting of porphyritic biotite-muscovite granite including aplite and pegmatite with associated Sn-deposit. Structurally, the Paleozoic succession is characterised by strongly deformed close fold especially in the Silurian-Devonian succession. Triassic rock sequence generally exhibits open fold. The strike-slip, normal, reverse and thrust faults are conspicuous with three main N-S, NW-SE and NE-SW directions.

iv. The N-S trending quartz dykes and some other igneous stocks intruded the country rocks, especially in the Kalai area in the northern part of the Transect area close to the Malaysian-Thai border. The contact metamorphism resulted from the igneous intrusion and its association with the late stage mineralisations can be observed in the country rocks.

v. Based on the geochemical exploration results carried out earlier in the Transect area (especially in Malaysia), it is believed that mineral deposits with remaining reserves are still widespread. However, many parts of high potential areas in both the Malaysian and Thai sides have been reserved for watershed and forest areas. Therefore, no immediate exploitation of the economic minerals can be done and renewals of the existing mining leases will have to follow very tight procedures. Security is another important issue that has caused the problem in mining in the proximity of the Malaysia-Thailand border. In the future, when mineral prices increase and the mining technology developed to a high efficiency in order to minimize environmental impacts, the situation of appropriate cooperation, integration of planning and management among the authorities concerned under the government’s initiation will hopefully be improved. Then, the mining industry may make resume in both countries.

7. Acknowledgements

The Malaysian and Thai Working Groups would like to thank the Malaysia-Thailand Border Joint Geological Survey Committee for their support and encouragement, the Minerals and Geoscience Department Malaysia and Department of Mineral Resources, Thailand for support and funding of this project. Thanks are also due to the Malaysian police and army officials, and to the Thai military, provincial and border police officials for their help, especially in security matters.

Thanks are extended to Director of the Geological Survey Division, Department of Mineral Resources, Thailand, Director of Technical Services Division, Minerals and Geoscience Department, Malaysia and Director of Minerals and Geoscience Department Kelantan State for their encouragements during the study.

Last but not least to all Department of Mineral Resources, and Minerals and Geoscience Department staffs especially from Kelantan State Office for their support and assistance during the field work.

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9. Appendices

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Appendix 1: List of samples in the Batu Melintang-Sungai Kolok Transect on the Malaysian side.

Sample no. Northing Easting Locality Description Unit

JMG/MT2/A/3767/R1 5o 41.034’ 101o 43.62’ East-West Highway Quartz-mica schist Tiang schist

JMG/MT2/A/3867/R2a Granite of the Jeli igneous complex

JMG/MT2/A/3867/R2b Microdiorite(?).

JMG/MT2/A/3867/R2c 5o 42.247’ 101o 50.277’ Near Jeli town, Jeli Microgabbro(?) Kemahang granite

JMG/MT2/A/3867R2d1 Aplite(?)

JMG/MT2/A/3867/R2d2 Microgranite(?)

JMG/MT2/A/3767/R3a Hornfels Mangga Formation

JMG/MT2/A/3767/R3b 5o 42.857’ 101o 45.375’ Km 105.2 East-West Highway

(junction to FELCRA Tumbi Rapat) Bedded hornfels Mangga Formation

JMG/MT2/A/3767/R4 5o 41.288’ 101o 43.662’ Km 100.8 East-West Highway (Bukit Taboh) Schist Tiang schist

JMG/MT2/A/3767/R5 5o 41.034’ 101o 43.620’ East-West Highway Quartz-mica schist Tiang schist

JMG/MT2/A/3767/R6 5o 46.600’ 101o 43.747’ Abandoned Kalai gold mine Hornfels Mangga Formation

JMG/MT2/A/R7 5o 46.880’ 101o 45.568’ Sungai Paku Duduk Granite Kemahang Granite

JMG/MT2/B/3867/R1 Sungai Golok Schist Telong Formation

JMG/MT2/B/3867/R2 Lanchang River Schist. Telong Formation

JMG/MT2/B/3867/R3 Schist Taku schist

JMG/MT2/B/3867/R4 5o 50.5’ 101o 53.7’ Kolok River, near Bukit Bunga

Granite Minor granitic intrusion

JMG/MT2/B/3867/R5 5o 49.554’ 101o 52.972’ Kampung Renap Sheared granite Kemahang Granite

- 68 - Sample no. Northing Easting Locality Description Unit

JMG/MT2/B/3867/R6 5o 53.775’ 101o 56.313’ Kampung Rahmat Sandstone Telong Formation

JMG/MT2/B/3867/R7 Granite Kemahang Granite

JMG/MT2/B/3867/R8 Granite Kemahang Granite

JMG/MT2/B/3867/R9

5o 49.640’ 101o 56.154’ Sebarang Bina Quarry

Granite Kemahang Granite

JMG/MT2/B/3867/R10 5o 56.595’ 101o 59.478’ Kampung Gual Rimau Highly weathered volcanic rock Telong Formation

JMG/MT2/B/3867/R11 5o 56.174’ 102o 00.491’ Kampung Tandak Tuffaceous shale Telong Formation

JMG/MT2/B/3867/R12 5o 52.132’ 102o 00.361’ Felda Kemahang Granite Kemahang Granite

JMG/MT2/C/3967/R1 5o 53.177’ 102o 10.383’ Foot of Bukit Panau Sandstone Panau beds

JMG/MT2/C/3867/R2 5o 53.622’ 102o 10.631’ Top of Bukit Panau Cross laminated fine-grained sandstone Panau beds

JMG/MT2/C/3867/R3 5o 52.719’ 102o 04.239’ Bukit Penchuri abandoned quarry Barite with iron-oxide coating Telong Formation

JMG/MT2/C/3967/R4 5o 51.632’ 102o 11.658’ Sungai Bagan Estate Granite Boundary Range Granite

JMG/MT2/C/3867/R5 5o 53.978’ 101o 59.727’ Felda Kemahang 3 Metasandstone Telong Formation

JMG/MT2/C/3867/R6 5o 53.794’ 102o 00.606’ Felda Kemahang 3 Metargillite Telong Formation

JMG/MT2/C/3967/R7 5o 55.239’ 102o 05.974’ Kampung Bukit Perah Highly weathered argillite Telong Formation

JMG/MT2/D/3967/R1 5o 41.995’ 102o 09.078’ Near Temangan town Ignimbrite Temangan Ignimbrite

JMG/MT2/D/3966/R2 5o 41.773’ 102o 08.949’ Near Temangan town Ignimbrite Temangan Ignimbrite

JMG/MT2/D/3967/R3a Grey, medium-grained equigranular granite

JMG/MT2/D/3967/R3b 5o 52.342’ 102o 15.185’ Timor-Barat Quarry, Bukit Buloh Pink, medium-grained

equigranular granite

Boundary Range granite

JMG/MT2/D/3967/R4 5o 46.351’ 102o 09.571’ Tanah Merah-Machang main road Greenish, fine to medium-grained andesite Tanah Merah volcanics

- 69 - Sample no. Northing Easting Locality Description Unit

JMG/MT2/D/3966/R5 5o 40.387’ 102o 13.778’ FELCRA Berangan Mek Nab Hornfels Telong Formation

JMG/MT2/D/3966/R6 5o 39.595’ 102o 11.691’ FELCRA Ladang Temangan Hornfelsic metasandstone Telong Formation

JMG/MT2/D/3867/R7 5o 43.914’ 102o 01.162’ Hujan Waterfall, Ulu Kusial Quartz-mica schist Taku schist

JMG/MT2/D/3867/R8 5o 47.011’ 102o 02.221’ Kampung Jelakong Pak Lembek Hornfelsic metasediments Telong Formation

JMG/MT2/D/3867/R9 5o 46.529’ 102o 01.729’ Lata River Granodiorite(?) Kemahang Granite

JMG/MT2/D/3866/R10 5o 40.128’ 102o 55.556’ Gua Setir Light grey, crystalline limestone Telong Formation

JMG/MT2/D/3867/R11 5o 40.460’ 102o 02.320’ Road to Kampung Perala Fine to medium-grained granitic rock Minor intrusion

JMG/MT2/D/3967/R12 5o 45.400’ 102o 15.800’ Highway to Pasir Putih Coarse-grained equigranular biotite granite

Boundary Range Granite

JMG/MT2/D/3967/R13 5o 42.856’ 102o 13.454’ Abandoned quarry near Kampung Jambu Lawar

Coarse-grained equigranular granite Boundary Range Granite

JMG/MT2/D/3967/R14 5o 48.582’ 102o 09.336’ Doctor’s quarters, Tanah Merah District Hospital Andesite Tanah Merah volcanics

JMG/MT2/D/3967/R15 5o 45.400’ 102o 15.800’ Sungai Jibok, near Temangan Andesite Tanah Merah volcanics

JMG/MT2/D/3966/R16 5o 40.3’ 102o 18.9’ Near abandoned Temangan Iron Mine Indurated shale Telong Formation

JMG/MT2/D/3967/R17 5o 42.8’ 102o 10.2’ Kampung Pangkal Chuit-Temangan trunk road Andesite Tanah Merah volcanics

JMG/MT2/D/3967/R18 5o 49.3’ 102o 9.5’ Near Bukit Maka, Tanah Merah Andesite Tanah Merah volcanics

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Appendix 2: List Of The Malaysian Working Group (Minerals and Geoscience Department Malaysia)

Consultant Field Geologists Mr. Yunus bin Abdul Razak Mr. Mohammed Hatta bin Abdul Karim Dr. Chow Weng Sum

Mr. Loh Chiok Hoong Mr. Ibrahim bin Amnan Mr. Lai Kok Hoong Mr. Askury bin Abdul Kadir

Field Geologists Mr. Mohd Sari bin Hassan Head of Sector A Mr. Mohd Badzran bin Mat Taib Head of Sector B Mr. Mohamad Hussein bin Hj. Jamaluddin Mr. Mat Niza bin Abdul Rahman Mr. Azmi bin Ismail

Head of Sector C Head of Sector D

Mr. Zaidi bin Daud Mr. Ab. Rashid bin Ahmad Mr. Ahmad Zamani bin Samat

Technical Assistants

Mr. Nai Pian a/l Nai Wan Mr. Khalid bin Mat Hashim

Mr. Ibrahim bin Wan Mr. Abdul Ghani bin Awang

GIS

Mr. Mustafar bin Hamzah

Mrs. Norsham binti Samsudin

Drivers Mr. Nanjon a/l Rajoo Mr. Zamberi bin Dollah Mr. Ismail bin Mr. Selim bin Sulaiman Mr. Abu Bakar bin

Mr. Md Razuki bin Hanapi Mr. Razlan bin Daud Mr. Razman bin Ismail Mr. Zarbani bin Mat Junos Mr. Ramli bin Awang

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Appendix 3: List of The Thai Working Group (Department of Mineral Resources Thailand)

Consultant Field Geologists

Dr. Thanis Wongwanich Mr. Somkiat Maranate Mr. Lertsin Raksaskulwong Mr. Adichat Surinkum

Mr. Sirote Sulyapongse Dr. Assanee Meesook Dr. Sunya Sarapirome Mr. Kampon Maneeprapun

Field Geologists Mr. Somboon Khositanont Head of Igneous Sector Mr. Naramase Teerarungsigul Head of Geologic and Quaternary Sectors Mr. Suvapak Imsamut Head of Stratigraphic Sector Mr. Thawatchai Tepsuwan Head of Mineral Resources Sector Mr. Winut Puthiang Mr. Nitmit Sornklang Mr. Kitti Khaowiset Ms. Surasak Meetuwong

Technical Assistants Mr. Thawin Kleemla Senior Sergeant Major Kiatisak Sonklin

Mr. Santi Srichum Ms. Bareeya Ketpuk

GIS Dr. Sunya Sarapirome Mr. Wanida Romruen

Ms. Wilai Wechsri

Drivers Mr. Suthep Jungsamrarn Mr. Chamlong Ketsathit Mr. Kumpol Pongpankum Mr. Worakot Thani Mr. Prathum Pramoenchai

Mr. Kasem Lek-ngarm Mr. Pojanamai Kasemsilp Mr. Chom Ketkaew Mr. Wiwat Charnchuwong Mr. Thaworn Jittakharm