Journal of Asian Earth Sciences 18 (2000) 691–712 www.elsevier.nl/locate/jseaes The Bentong–Raub Suture Zone I. Metcalfe Asia Centre, University of New England, Armidale, NSW 2351, Australia Received 7 February 2000; accepted 25 July 2000 Abstract It is proposed that the Bentong–Raub Suture Zone represents a segment of the main Devonian to Middle Triassic Palaeo-Tethys ocean, and forms the boundary between the Gondwana-derived Sibumasu and Indochina terranes. Palaeo-Tethyan oceanic ribbon-bedded cherts preserved in the suture zone range in age from Middle Devonian to Middle Permian, and me´lange includes chert and limestone clasts that range in age from Lower Carboniferous to Lower Permian. This indicates that the Palaeo-Tethys opened in the Devonian, when Indochina and other Chinese blocks separated from Gondwana, and closed in the Late Triassic (Peninsular Malaysia segment). The suture zone is the result of northwards subduction of the Palaeo-Tethys ocean beneath Indochina in the Late Palaeozoic and the Triassic collision of the Sibumasu terrane with, and the underthrusting of, Indochina. Tectonostratigraphic, palaeobiogeographic and palaeomagnetic data indicate that the Sibumasu Terrane separated from Gondwana in the late Sakmarian, and then drifted rapidly northwards during the Permian–Triassic. During the Permian subduction phase, the East Malaya volcano-plutonic arc, with I-Type granitoids and intermediate to acidic volcanism, was developed on the margin of Indochina. The main structural discontinuity in Peninsular Malaysia occurs between Palaeozoic and Triassic rocks, and orogenic deformation appears to have been initiated in the Upper Permian to Lower Triassic, when Sibumasu began to collide with Indochina. During the Early to Middle Triassic, A-Type subduction and crustal thickening generated the Main Range syn- to post-orogenic granites, which were emplaced in the Late Triassic–Early Jurassic. A foredeep basin developed on the depressed margin of Sibumasu in front of the uplifted accretionary complex in which the Semanggol “Formation” rocks accumulated. The suture zone is covered by a latest Triassic, Jurassic and Cretaceous, mainly continental, red bed overlap sequence. ᭧ 2000 Elsevier Science Ltd. All rights reserved. Keywords: Bentong–Raub Suture Zone; Semantan basin; Permian–Triassic boundary 1. Introduction or alternatively as the “Raub–Bentong Line”. Mitchell (1977), furthermore, interpreted the zone of “folded slates, radiolarian The belt of Lower Palaeozoic rocks that extends from the cherts and flysch, with vertical or overturned isoclinal folds, Malay Peninsula northwards through Thailand, Burma and and minor ophiolitic bodies” (his Zone 2) as representing China was termed the Yunnan–Malaya Geosyncline by oceanic crust and sediments, forming an accretionary complex Burton (1967). Jones (1968, 1973) further interpreted the produced by eastwards subduction. Establishment of this zone stratigraphy and north–south facies belts of the Malayan as a suture zone representing the site of a former ocean now portion as representing “miogeosynclinal” shelf or platform seems beyond doubt, and it is now generally referred to as the facies in the west, and “eugeosynclinal” facies (containing Bentong–Raub Suture Zone. The north–south trending radiolarian cherts, basic igneous rocks and thick sections of Bentong–Raub Suture extends from Thailand through Raub deep-marine clastics) in central Malaya. He also suggested and Bentong to the east of Malacca, Peninsular Malaysia. the former presence of a large continental landmass to the Southwards extension of the suture is controversial (see west, which has since rifted away (now interpreted as Gond- below). This suture represents the main Palaeo-Tethys wanaland). Hutchison (1973a) placed the data in a plate- Ocean which was destroyed by collision of the Sibumasu tectonics context and interpreted the “eugeosyncline” as a and Indochina continental terranes of Southeast Asia (Fig. 1). former trench in a subduction system. Hutchison (1975), in This paper presents an overview of the Bentong–Raub his paper on ophiolites in Southeast Asia, named the central Suture Zone, and reviews the evidence for the age-duration Malayan zone the “Bentong–Raub ophiolite line”, which of the Palaeo-Tethys Ocean which it represents, and the age then became widely quoted as the “Bentong–Raub Line”, of suturing of the Sibumasu and Indochina terranes. Impli- cations for palaeogeographic reconstructions of the region E-mail address: [email protected] (I. Metcalfe). are also discussed. 1367-9120/00/$ - see front matter ᭧ 2000 Elsevier Science Ltd. All rights reserved. PII: S1367-9120(00)00043-2 692 I. Metcalfe / Journal of Asian Earth Sciences 18 (2000) 691–712 KAZAKSTAN NORTHEAST CHINA (COMPOSITE) 102E TARIM THAILAND QD AL NORTH L. Perm., KL CHINA QI QS SG L. Carb. U. Perm., L SOUTH M. Trias. INDIA CHINA (Tourn) WB SI ? ? SIBUMASU Alor Star INDOCHINA 0 600 km B CENTRAL BELT e n L t SWB M. Trias. o e Gunong b n EASTERN Semanggol i g r 5N F 5N a BELT Cameron L. Perm., u U. Perm l Kuala Highlands t WESTERN Z Kangsar Fig. 10 o n BELT L. Carb. e R ?L. Carb. a (Visean) u Raub INDOCHINA b U. Dev. Jengka U. Dev. L. Perm. TERRANE (Fam) Bentong L. Perm. (PART) L. Carb. Sheared (Tourn) Diamictite SIBUMASU L. Carb. S (Visean) u TERRANE t Bahau u r U. Dev., (PART) e L. Carb. N Malacca Suture Zone Rocks Muar Semanggol Formation Radiolarian locality with age 0 50 100 150 km 102E Fig. 1. Western, Central and Eastern “Belts” of Peninsular Malaysia and distribution of suture zone rocks (oceanic ribbon-bedded cherts, argillites, me´lange, serpentinites) and ribbon-bedded cherts, argillites and turbidites of the Semanggol Formation. Radiolarian localities and ages are also shown (after Metcalfe et al., 1999). Inset map shows the distribution of principal continental terranes and sutures of East and Southeast Asia. WB West Burma, SWB South West Borneo, S Semitau Terrane, HT Hainan Island terranes, L Lhasa Terrane, QI Qiangtang Terrane, QS Qamdo-Simao Terrane, SI Simao Terrane, SG Songpan Ganzi accretionary complex, KL Kunlun Terrane, QD Qaidam Terrane, AL Ala Shan Terrane (after Metcalfe, 1998). 2. Geological setting of the Bentong–Raub Suture Zone The traditionally recognised suture is exposed as an approximately 20 km wide zone bordering the eastern Peninsular Malaysia has traditionally been divided into limit of the Main Range granitoids in Peninsular Malay- three north–south-trending zones based on differences of sia and comprises me´lange, oceanic ribbon-bedded stratigraphy, mineralisation and structure. These zones cherts, schist, and discontinuous, narrow, elongate have been variously referred to as the Western, Central bodies of serpentinised mafic–ultramafic rocks, inter- and Eastern “Belts” “Zones” or “Domains”. In addition, preted as ophiolite (Hutchison, 1975, 1989; Tjia, 1987, some authors recognise a Northwestern “Zone” or 1989a,b). An occurrence of sheared diamictite, here “Domain” (Fig. 1). interpreted as possibly tectonic me´lange, was reported SIBUMASU TERRANE INDOCHINA TERRANE (Western Belt of Peninsular Malaysia) (Central & Eastern Belts of Peninsular Malaysia) 1. 2. 3. 4. SIBUMASU TERRANE INDOCHINA TERRANE 5. 6. 7. Langkawi South Perlis Kanthan, Kuala Lumpur, Trengganu/ West & Central South Pahang, Palaeo Palaeo and N.W. Malaya and North Kedah Kinta Valley, Perak Selangor Biogeographical province Biogeographical province East Pahang Pahang /faunal affinities Climate Climate /faunal affinities Johore, Singapore Yunnan, Kwangsi Panti Sst Cretaceous ? ? ? ? Warm vv vv Warm Laurasia Tembeling Gp/ Tembeling Gp/ Tebak Fm I. Metcalfe / Journal of Asian Earth Sciences 18 (2000) 691–712 Saiong Beds Saiong Beds Saiong Beds Ryoseki Type vv Gagau Gp vv Gagau Gp Ulu Endau Beds (Continental) (Continental) (Continental) v Sedili v Ryoseki Type v Volcanics Jurassic Tethyan Warm Warm Laurasia Tethyan Kerum Fm Yunnan v v v Semantan Fm/ Jurong Fm Turbidites Laurasia Triassic Eastern Tethyan Warm Warm v Gemas Fm Tethyan v v Kodiang/ Semanggol Eastern Tethys Jerus Lst Chuping "Fm." Lst. Eastern Tethyan Tethyan South China, Indochina v Linggiu Fm Permian Warm v Kanthan Sibumasu Province Warm Tethyan Gua Musang Fm Kenny Hill N. W. Australia Aring Fm v Sumalayang Lst. Limestone 18 Cathaysian v Singa Fm. Formation Gondwanaland Cool O v Dohol Fm (Glacial-marine) Kubang Pasu/ Arctic-Eurasian Cool Euramerican v Sagor Fm Raub Group/ Carboniferous Kati Fm. Eastern Australia Warm China Panching Lst ? Arctic-Eurasian Kepis Fm (shallow-marine) Warm Mersing N. W. Australia China v Charu Fm v Beds ? ? ? Eastern THAILAND 102E Devonian Warm Kuala Lumpur Gondwanaland INDOCHINA Setul Lst Fm. Kanthan Limestone (Peritidal, 1 TERRANE Mahang Limestone subtidal) (PART) Silurian Fm. B Warm e S. China 2 n t o n g ? Hawthornden S. China (Pagoda Fm) 5N 5N ? ? Schist S. China 3 5 Ordovician Australia, Tibet, N. China Warm S. China, R a Dinding u Argentina b Machinchang Jerai Schist N. W. Australia Warm 6 Fm. Fm. ? ? Cambrian 4 SIBUMASU S u ? ? t TERRANE u r (PART) e Suture Zone Rocks 7 Precambrian 1300-1800 Ma 1300-1800 Ma 1300-1800 Ma 1300-1800 Ma 0 150 km 900-1400 Ma 900-1400 Ma 900-1400 Ma (not exposed) (not exposed) (not exposed) (not exposed) (not exposed) (not exposed) (not exposed) 102E Interbedded Shale, v vvv Volcanics Bedded Brachiopods Gastropods Schist Limestone Sandstone Plants Trilobites Sandstone, Siltstone vvv v Volcaniclastics Chert Fusulines Conodonts Bivalves Proterozoic Glacial-marine Stratigraphic Dolomite Shale/Mudstone Conglomerate Vertebrates basement diamictites Break Stromatoporoids Nautiloids Small forams Fig. 2. Representative generalised stratigraphic collumns and biogeographic affinities for the Peninsular Malaysia parts of the Sibumasu and Indochina terranes. Partly after Metcalfe (1988, 2000c). 693 694 I. Metcalfe / Journal of Asian Earth Sciences 18 (2000) 691–712 SIBUMASU CANNING BASIN M JURASSIC E 205 L TRIASSIC M E 252 L PERMIAN E 298 S W CARBON- N IFEROUS V T 354 L DEVONIAN M E 410 PRI LUD SILURIAN WEN X X LLY 434 X A X ORDO- C LLN VICIAN A 490 TR L M CAMBRIAN E 545 Limestone Sandstone Conglomerate Mixed Stratigraphic Shale clastics Break X X Evaporites Glacial-marine X (salt) diamictites Fig.