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Triassic correlation of the Southeast Asian mainland
ELSEVIER
Palaeogeography, Palaeoclimatology, Palaeoecology 143 (1998) 285–291
Triassic correlation of the Southeast Asian mainland Vu Khuc a,Ł , Dang Tran Huyen b a
b
Geological Museum of Vietnam, 6 Pham Ngu Lao, Hanoi, Vietnam Research Institute of Geology and Mineral Resources, Dong Da, Hanoi, Vietnam Accepted 23 July 1998
Abstract The Triassic in Southeast Asia is represented mainly by marine sediments. From many areas these sediments furnish abundant fossil collections, composed mostly of bivalves and ammonoids. Based on those groups, biostratigraphic scales have been compiled to make possible the correlation of the Triassic sequences of different Southeast Asian areas. Twelve assemblage zones have been distinguished, among them four are Lower Triassic, four are Middle Triassic and four are Upper Triassic. Triassic faunas from Southeast Asia have many species in common with analogous assemblages from south China and the Himalayas. 1998 Elsevier Science B.V. All rights reserved. Keywords: Triassic; fauna; biostratigraphy; palaeobiogeography; Southeast Asia
1. Introduction In some large areas of the Southeast Asian mainland, Triassic sequences are composed of all seven stages of this system. They are represented mainly by marine sediments, bearing abundant fossils, composed mostly of bivalves and ammonoids with a few brachiopods, foraminiferans, conodonts, corals and algae. In some areas, continental facies appeared in the Carnian, but in most cases in the Norian or Rhaetian. Continental sediments yield fresh-water bivalves and phyllopods. The coal-bearing formations contain plant remains and, locally, fossils of coleopterids. Triassic fossils in the Southeast Asian mainland have been studied since the first decade of this century, beginning with the description of Triassic
Ł Corresponding
author.
bivalves from the Malay Peninsula (Newton, 1900) and of Triassic ammonoids and bivalves from north Vietnam (Mansuy, 1908) (Fig. 1). Up to now, almost all the Triassic basins of the region have been more or less investigated, and accumulated data allow us to carry out this synthetic work in order to provide the biostratigraphic base for various applied geological works.
2. Triassic assemblage zones of the Southeast Asian mainland 2.1. Lower Triassic The Lower Triassic is represented by the following facies: carbonate in Myanmar and the extreme north of Vietnam, carbonate with interbeds of terrigenous rocks in north Malaysia, volcanogenic rocks passing upward to terrigenous rocks in north-
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V. Khuc, D. Tran Huyen / Palaeogeography, Palaeoclimatology, Palaeoecology 143 (1998) 285–291
east and northwest Vietnam, and terrigenous rocks in the remaining areas. Good sections of the Lower Triassic have been found in northeast and northwest Vietnam, Shan State of Myanmar, north Thailand and the northern part of the Central Belt of Malaysia. Based on those of northeast Vietnam (Vu Khuc, 1990), four assemblage zones have been distinguished, as follows. 2.1.1. Induan (1) Ophiceras–Claraia stachei Assemblage Zone (A.Z.). Distribution: Lang Son and Ha Giang Provinces of northeast Vietnam, Son La Province of northwest Vietnam and Song Be Province of south Vietnam. Characteristic species: Ophiceras cf. O. commune, Glyptophiceras langsonense, Lytophiceras sp., Claraia stachei, C. wangi, C. clarai, C. yunnanensis, C. griesbachi, C. vietnamica, Eumorphotis inaequicostata, Lingula tenuissima. (2) Koninckites–Claraia concentrica A.Z. Distribution: Lang Son Province of northeast Vietnam. Characteristic species: Koninckites cf.K. vidarbha, Euflemingites sp., Claraia concentrica, C. aurita, C. gervilliaeformis, C. kiparisovae, Eumorphotis venetiana. 2.1.2. Olenekian (3) Flemingites–Paranorites A.Z. Distribution Lang Son Province of northeast Vietnam and Song Be Province of south Vietnam. Characteristic species: Flemingites aff. F. flemingianus, F. cf. F. rursiradiatus, Paranorites praestans, Owenites carinatus, Pseudowenites oxynotus, Ussuria lenticularis, Lanceolites bicarinatus, Meekoceras cf. M. yukiangense, Neospathodus dieneri, N. waageni, Eumorphotis spinicosta, Entolium discites microtis. (4) Tirolites–Columbites A.Z. Distribution: Lang Son Province of northeast Vietnam, Lai Chau and Son La Provinces of northwest Vietnam. Characteristic species: Tirolites idrianus, Anakashmirites nivalis, Dieneroceras sp., Columbites cf. C. parisianus, Preflorianites sp., Bakevellia albertii, B. exporrecta, Unionites fassaensis, Neoschizodus ovatus, Costa-
Fig. 1. Distribution of the Triassic fossil localities in the SE Asian mainlaind.
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toria costata, Hoernesia socialis, Worthenia turbo, Naticella costata. In Thailand, according to Chonglakmani (1981), the Lower Triassic is undivided and described as the Claraia–Ophiceras beds, bearing: Lytophiceras cf. L. chamunda, Discophiceras cf. D. subkyokticum, Claraia stachei, C. radialis, C. concentrica, C. intermedia, C. yunnanensis. In the northern part of the Central Belt of the Malaya Peninsula the Lower Triassic has been recognized with the presence of Claraia concentrica, C. intermedia multistriata in the lower part, and Owenites, Arctoceras, Paranannites, Prosphingites in the upper part (Khoo, 1988). In the northern Shan State of Myanmar, the Lower Triassic is also undivided, the lower part of it furnishing Glytophiceras, Ophiceras and Vishnuites, together with (?) Owenites, Kashmirites and Aspenites (U and U, 1988). 2.2. Middle Triassic The Middle Triassic in the Southeast Asian mainland is represented by two sequence types: carbonate passing upward to terrigenous sediments of deepwater facies in northwest Vietnam, and volcanogenic rocks passing upward to terrigenous sediments of shallow-water facies in the remaining parts. Good sections of the Middle Triassic have been studied in north Vietnam, north Thailand and the Central Belt of the Malaya Peninsula. Based on those of north Vietnam the following four assemblage zones of Middle Triassic age have been distinguished. 2.2.1. Anisian (5) Balatonites–Costatoria curvirostris A.Z. Distribution: Lang Son, Son La, Thanh Hoa Provinces of north Vietnam, Dong Nai Province of south Vietnam. Characteristic species: Paracrochordiceras sp., Acrochordiceras cf. A. fischeri, Balatonites balatonicus, B. lemoinei, Cuccoceras cuccense, C. annamiticum, Frechites sp., Costatoria curvirostris, C. proharpa, C. chegarperahensis, Entolium discites, Posidonia mimer. (6) Paraceratites–Daonella elongata A.Z. Distribution: Lang Son, Son La, Thanh Hoa Provinces of north Vietnam. Characteristic species: Paraceratites subtrinodosus, Daonella elongata, D. sturi,
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Daonellopecten desmoornatus, Holcorhynchia bogumilorum, Adygella hoangmaiensis. (7) Kellnerites–Mentzelia A.Z. Distribution: Lang Son, Son La and Thanh Hoa Provinces of north Vietnam. Characteristic species: Kellnerites samneuaensis, Mentzelia mentzelii, Aulacothyris angusta.
chegarperahensis and Neoschizodus cf. N. laevigatus elongatus. The Ladinian Daonella A.Z. is composed of Daonella indica, D. lommeli, D. pichleri, whereas the synchronous Costatoria A.Z. consists of Costatoria quinquicostata and C. pahangensis. 2.3. Upper Triassic
2.2.2. Ladinian (8) Protrachyceras–Daonella indica A.Z. Distribution: Lang Son, Son La, Hoa Binh Provinces of north Vietnam. Characteristic species: Protrachyceras costulatum, P. villanovae, Rimkinites tonkinensis, Procladiscites cf. P. brancoi, Daonella indica, D.. bulogensis, D. lommeli, D. pichleri, Posidonia wengensis, Zittelihalobia planicosta. There is a synchronous faunal assemblage characterizing the shallow-water facies in Lang Son and Thanh Hoa Provinces of north Vietnam. It includes: Costatoria goldfussi, C. inaequicostata, C. ngeanensis, Trigonodus sandbergeri, T. tonkinensis, T. trapezoidalis, Entolium tridentini, Mysidioptera incurvostriata, Schafhauetlia plana, Cercomya magna, Hoernesia magnissima, Pleuromya habacensis, Langsonella elongata. According to Chonglakmani (1981), the Middle Triassic in north Thailand is characterized by two assemblage zones as follows: Hollandites– Leiophyllites A.Z. of Anisian age, and the Daonella indica A.Z. with its contemporary Costatoria A.Z. of Ladinian age. The Hollandites–Leiophyllites A.Z. includes the following characteristic species: Hollandites cf. H. ravana, H. cf. H.roxburghii, Beyrichites srikanta, Balatonites sp., Leiophyllites cf. L. pitamaha. The Daonella indica A.Z. consists of: Daonella indica, D. bulogensis, D. susdanai, Retidaonella multilineata, Posidonia kedahensis, P. wengensis, P. cf. P. cycloidalis. The synchronous Costatoria assemblage of the shallow-water facies comprises: Costatoria goldfussi mansuyi, C.. maethaensis, Elegantinia elegans, Trigonodus tonkinensis, T. costatus, Mysidioptera cf. M. cainalli. In the Central Belt of the Malaya Peninsula, two assemblage zones of Middle Triassic can be distinguished (Khoo, 1988): Anisian Paraceratites–Costatoria chegarperahensis and Ladinian Daonella with the synchronous Costatoria A.Z. The Paraceratites–Costatoria chegarperahensis A.Z. is characterized by Paraceratites cf. P. trinodosus, Frechites sp., Costatoria
The Upper Triassic in the Southeast Asian mainland begins mostly with shale of deep-water facies bearing in abundance thin-shelled Carnian halobiids. Only in northeast Vietnam, this part is composed of continental red beds. Since the Norian, the sequence is strongly differentiated. In northeast Vietnam and north of central Vietnam it is characterized by a paralic coal-bearing formation; in Laos and northwest Vietnam it is composed of marine sediments passing upward to paralic coal-bearing beds; meanwhile, in Myanmar it is represented by marine sediments. The presence of the Norian–Rhaetian in Thailand and Malaysia is still under discussion. Good sections of the Upper Triassic are exposed in north Vietnam, upper Laos, north Myanmar, north Thailand and in the Central Belt of the Malaya Peninsula. Based on the sections in north Vietnam, four assemblage zones have been distinguished in the Upper Triassic. 2.3.1. Carnian (9) Discotropites–Zittelihalobia superba A.Z. Distribution: Lai Chau, Son La, Hoa Binh and Ninh Binh Provinces. Characteristic species: Discotropites gemmellaroi, Sagenites? attenuatus, Arcestes cf. A. esinensis, Zittelihalobia praesuperba, Z. cordillerana vietnamica, Z. sonlaica, Halobia tropitum, H. charlyana. (10) Margaritropites–Halobia talauana A.Z. Distribution: Son La, Lai Chau, Hoa Binh and Ninh Binh Provinces. Characteristic species: Margaritropites phongthoensis, Halobia talauana, H. styriaca, H. substyriaca, H. austriaca, Zittelihalobia posterolaevis, Z. rugosa, Indigirohalobia pluriradiata. The Rhaetina A.Z., distributed in Lai Chau Province, represents a synchronous coral reef facies. It includes mostly brachiopods, such as Rhaetina complanata, R. bamaensis, Laballa cf. L. suessi, Sinucosta songdae, Aulacothyropsis bisinuata, Sulcorhynchia (?) vietnamica.
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2.3.2. Norian (11) Burmesia–Halobia norica A.Z. Distribution: Lai Chau, Son La, Hoa Binh and Ninh Binh Provinces. This zone is characterized by four components: (1) Norian ammonoids and halobiids — Juvavites magnus, Cyrtopleurites bicrenatus, Paratibetites tornquisti, Parathisbites sopcopensis, Halobia norica, H. distincta, Zittelihalobia sublaevis; (2) species also known from Rhaetian Rhaetavicula contorta Beds of Europe — Gervillia praecursor, Trigonia zlambachensis, Ostrea haidingeriana; (3) species also known from the Napeng Beds of Myanmar — Burmesia lirata, Prolaria sollasi, Costatoria (Napengocosta) napengensis, Thracia prisca, Palaeocardita singularis and; (4) endemic species — Songdaella graciosa, Mesopinna choboensis, Mesoneilo perlonga, Vietnamicardium vietnamicum. 2.3.3. Rhaetian (12) Cardinia–Unionites damdunensis A.Z. Distribution: Lai Chau, Son La, Hoa Binh and Ninh Binh Provinces. Characteristic species: Cardinia nachamensis, C. ovoidea, Gervillia inflata, Unionites damdunensis, U. convexa, Isocyprina ewaldi, Vietnamicardium vietnamicum, V. altum, Langvophorus garandi, L. choboensis. The synchronous flora is characterized by Dictyophyllum nathorstii, Clathropteris meniscioides, Neocalamites hoerensis, Thaumatopteris remauryi, Goeppertella microloba, Asterotheca cottoni, Taeniopteris jourdyi, Pterophyllum bavieri. In some parts of the Southeast Asian mainland, the Carnian component of the Upper Triassic sections is expressed more clearly than in others. In north Thailand, it is divided into the Paratrachyceras Beds and Halobia parallela–H. charlyana Beds (Chonglakmani, 1981). The first is characterized by Paratrachyceras cf. P. aon, P. cf. P. regoledanum, Joanites maehuatensis, J. honghoiensis, Buchites sp, Halobia cf. H. subcomata, Daonella piyasini, Posidonia lampangensis, whereas the second is characterized by Halobia parallela, H. charlyana, H. austriaca, H. wangchinensis, H. phraeensis, H. moluccana, H. talauana, Zittelohalobia ingavatae. In the Central Belt of Malaysia, the Carnian has been recognized as only the Halobia–Paratrachyceras Beds. After Khoo (1988), they are characterized by Halo-
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bia talauana, H. aotii, Zittelihalobia comata, Paratrachyceras regoledanum, Posidonia cf. P. kedahensis. The presence of Carnian in Myanmar has not been firmly approved on a good paleontological basis. It has been described in the thick Shan Dolomite Group and Thanbaya Formation in northwest Myanmar, but the collected fauna consists of only badly preserved imprints of Halobia? sp. and Halobia cf. H. comata together with Paragondolella polygnathiformis and Bathysiphon (U and U, 1988). The Norian in Thailand has been recognized in a thick terrigenous formation with the Indopecten Beds and Halobia distincta Beds. The faunal composition of each of them is still poor. The Indopecten Beds are characterized by Indopecten seinaamensis and Schafhauetlia maemokensis, but the Halobia distincta Beds by the index species and Palaeocardita singularis (Chonglakmani, 1981). The stratigraphic position of those beds has been clearly indicated. The presence of the Norian in Malaysia has not been paleontologically demonstrated. The presence of the Rhaetian in Southeast Asia is still a problem for discussion, but the find of Rhaetavicula contorta in the Napeng Beds of Myanmar may be a good basis for the recognition of this stage in the region. The well-known Napeng fauna is characterized by some typical species of the Rhaetavicula contorta Beds of Europe, together with a number of endemic species. In Vietnam, the Rhaetian is marked by a coal-forming period. Under the coal-bearing beds, the Norian is represented by a marine sequence beginning with transgressive members containing a series of ammonoids from the late-early Norian Juvavites magnus to middle Norian Cyrtopleurites, and then Parathisbites. The upper Norian is marked by a member of regressive sediments bearing degenerate halobiids. Therefore, the Burmesia–Halobia norica A.Z. has been considered as equivalent to the entire Norian stage, and because of that the coal-bearing beds with the Cardinia– Unionites damdunensis A.Z. have been assigned to the Rhaetian (Vu Khuc et al., 1991). Based on the above-described biostratigraphy of the Triassic in different territories of the Southeast Asian mainland, a scheme of Triassic biostratigraphic zones of this region can be presented (Table 1).
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Table 1 Triassic biostratigraphic zones of the SE Asian mainland Age
Vietnam, Laos, Cambodia
T3 r
Cardinia–Unionites damdunensis (D Dictyophyllum–Clathropteris) Burmesia–Halobia norica
T3 n T3 c
T2 l
T2 a
T1
Margaritropites–Halobia talauana (D Rhaetina) Discotropites–Zittelihalobia superba Protrachyceras–Daonella indica (D Costatoria goldfussi– Trigonodus) Kellnerites–Mentzelia Paraceratites–Daonella elongata Balatonites–Costatoria curvirostris Tirolites–Columbites Flemingites–Paranorites Koninckites–Claraia concentrica Ophiceras–Claraia stachei
Thailand (Chonglakmani, 1981)
Malaysia (Khoo, 1988)
Myanmar (U and U, 1988) Rhaetavicula–Burmesia Beds
Indopecten Beds Halobia distincta Beds Halobia parallela Beds
?
H. charlyana Beds Paratrachyceras Beds
Halobia–Paratrachyceras Beds
Daonella indica Beds (D Costatoria Beds)
Daonella Beds (D Costatoria quinquicostata Beds)
Hollandites– Leiophyllites Beds
Paraceratites– Costatoria chegarperahensis Beds
Paraceratites– Neogondolella mombergensis Beds
Claraia–Ophiceras Beds
Owenites–Claraia Beds
Owenites–Ophiceras Beds
3. Fauna of Triassic basins in the Southeast Asian mainland The fauna from the Triassic basins of the Southeast Asian mainland has many genera and species in common with analogous assemblages from south China (Kwangsi, Yunnan, Guizhou). Some endemics have been found only in this region. In the Early Triassic, we note the coexistence of different Claraia and Eumorphotis species during Induan time in various basins of the region (Yin, 1981; Vu Khuc, 1990). Among Claraia species, C. concentrica and C. yunnanensis are characteristic for those basins (Yunnan, north Vietnam, Thailand). In the Middle Triassic, the noticeable feature of faunal assemblages of the region is the abundant presence of various small-sized Costatoria both in the Anisian and in the Ladinian (Kobayashi and Tamura, 1968, 1984; Vu Khuc, 1990). Besides, it is worthy to pay attention to the early appearance in the Ladinian of halobiids in this area, e.g., Parahalobia (Yunnan; Yin and Hsue, 1938), and especially, Zittelihalobia planicosta (Yunnan, northwest Vietnam)
Halobia–Paragondolella polygnathiformis Beds
of large size and with well-developed shell ornamentation (Chen, 1980; Guo, 1985). Characteristic taxa of the region are Langsonella, Asoella, and the twisted Hoernesia? magnissima. In the Late Triassic, the Norian fauna of the studied region has the greatest endemism. Although there are some European species from the Rhaetavicula contorta Beds (Healey, 1908; Vu Khuc et al., 1991), the Norian assemblage is full of endemics: Prolaria, Datta, Langvophorus, Costatoria (Napengocosta), Songdaella, Mesopinna, Vietnamicardium and Mesoneilo. Moreover, the cosmopolitan Monotis that has been found in adjacent areas (Kalimantan, northern Himalayas) is absent in the assemblage. All these facts affirm the existence in the Triassic of a specific biogeographic province in the Southeast Asian mainland, the East Tethyan Province (Nakazawa, 1977). However, in the Norian this province was subdivided, and a new subprovince appeared in the territory of southwest China, northwest Vietnam, northern Laos and Myanmar. It is the Shan–Red River subprovince of the East Tethyan biogeographic province.
V. Khuc, D. Tran Huyen / Palaeogeography, Palaeoclimatology, Palaeoecology 143 (1998) 285–291
Acknowledgements This paper is a contribution to IGCP Projects 306 (Stratigraphic correlation in SE Asia) and 359 (Correlation of Tethyan, Pacific and Gondwanan Permo– Triassic) and to the 30th IGC in Beijing (August, 1996). The authors would like to express their deep thanks to their Chinese colleagues Profs Drs Yin Hongfu, Hou Hongfei and Xiang Liwen, who have given them favourable facilities for attending the 30th IGC and presenting the results of their researches.
References Chen, C.C., 1980. Marine Triassic Lamellibranch Assemblages from SW China. Riv. Ital. Paleont. 85, 1189–1196. Chonglakmani, C., 1981. The Systematics and Biostratigraphy of Triassic Bivalves and Ammonoids of Thailand. Ph.D. thesis, Univ. of Auckland, Auckland. Guo, F.X., 1985. Fossil bivalves from Yunnan. Yunnan Sci. and Techn. Publ., Kunming. Healey, M., 1908. Fauna of the Napeng Beds of Upper Burma. Pal. Indica, 2=4, New Delhi. Khoo, H.P., 1988. Malaysia. ESCAP Atlas of stratigraphy, VII. Triassic of Asia, Australia and the Pacific. United Nations,
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New York. Kobayashi, T., Tamura, M., 1968. Myophoria in Malaya with a note on the Triassic Trigoniacea. Geol. Paleontol. SE Asia 5, 83–137. Kobayashi, T., Tamura, M., 1984. The Triassic Bivalvia of Malaysia, Thailand and adjacent areas. Geol. Paleontol. SE Asia 25, 201–227. Mansuy, H., 1908. Contribution a` la carte ge´ologique de l’Indochine. Paleontol., Serv. Geol. Indoch., Ha Noi. Nakazawa, K., 1977. On Claraia of Kashmir and Iran. J. Paleontol. Soc. India 20, 191–204. Newton, R.B., 1900. On marine Triassic Lamellibranchs discovered in the Malaya Peninsula. Proc. Malacol. Soc. London. U, T.N., U, C.S., 1988. Burma. ESCAP Atlas of stratigraphy, VII. Triassic of Asia, Australia and the Pacific. United Nations, New York. Vu Khuc, 1990. Characteristic assemblages of the Triassic fauna of Viet Nam. ESCAP Atlas of stratigraphy, IX. Triassic biostratigraphy and paleogeography of Asia, 59. United Nations, New York, pp. 48–53. Vu Khuc, Vu Chau, Trinh Dzanh, Dang Tran Huyen, Nguyen Dinh Huu, Trinh Tho, 1991. Paleontological Atlas of Viet Nam. Science and Technics Publisher, Hanoi. Yin, H.F., 1981. Paleogeographical and stratigraphical distribution of the Lower Triassic Claraia and Eumorphotis. Acta Geol. Sin. 3, 161–169. Yin, T.H., Hsue, T.H., 1938. In: Chen, C.C. (Ed.), 1976. The Lamellibranch Fossils of China. Nanjing Inst. Geol. Paleontol., Science Press, Beijing, p. 224.
Palaeogeography, Palaeoclimatology, Palaeoecology 143 (1998) 285–291
Triassic correlation of the Southeast Asian mainland Vu Khuc a,Ł , Dang Tran Huyen b a
b
Geological Museum of Vietnam, 6 Pham Ngu Lao, Hanoi, Vietnam Research Institute of Geology and Mineral Resources, Dong Da, Hanoi, Vietnam Accepted 23 July 1998
Abstract The Triassic in Southeast Asia is represented mainly by marine sediments. From many areas these sediments furnish abundant fossil collections, composed mostly of bivalves and ammonoids. Based on those groups, biostratigraphic scales have been compiled to make possible the correlation of the Triassic sequences of different Southeast Asian areas. Twelve assemblage zones have been distinguished, among them four are Lower Triassic, four are Middle Triassic and four are Upper Triassic. Triassic faunas from Southeast Asia have many species in common with analogous assemblages from south China and the Himalayas. 1998 Elsevier Science B.V. All rights reserved. Keywords: Triassic; fauna; biostratigraphy; palaeobiogeography; Southeast Asia
1. Introduction In some large areas of the Southeast Asian mainland, Triassic sequences are composed of all seven stages of this system. They are represented mainly by marine sediments, bearing abundant fossils, composed mostly of bivalves and ammonoids with a few brachiopods, foraminiferans, conodonts, corals and algae. In some areas, continental facies appeared in the Carnian, but in most cases in the Norian or Rhaetian. Continental sediments yield fresh-water bivalves and phyllopods. The coal-bearing formations contain plant remains and, locally, fossils of coleopterids. Triassic fossils in the Southeast Asian mainland have been studied since the first decade of this century, beginning with the description of Triassic
Ł Corresponding
author.
bivalves from the Malay Peninsula (Newton, 1900) and of Triassic ammonoids and bivalves from north Vietnam (Mansuy, 1908) (Fig. 1). Up to now, almost all the Triassic basins of the region have been more or less investigated, and accumulated data allow us to carry out this synthetic work in order to provide the biostratigraphic base for various applied geological works.
2. Triassic assemblage zones of the Southeast Asian mainland 2.1. Lower Triassic The Lower Triassic is represented by the following facies: carbonate in Myanmar and the extreme north of Vietnam, carbonate with interbeds of terrigenous rocks in north Malaysia, volcanogenic rocks passing upward to terrigenous rocks in north-
0031-0182/98/$ – see front matter 1998 Elsevier Science B.V. All rights reserved. PII: S 0 0 3 1 - 0 1 8 2 ( 9 8 ) 0 0 1 1 8 - 7
286
V. Khuc, D. Tran Huyen / Palaeogeography, Palaeoclimatology, Palaeoecology 143 (1998) 285–291
V. Khuc, D. Tran Huyen / Palaeogeography, Palaeoclimatology, Palaeoecology 143 (1998) 285–291
east and northwest Vietnam, and terrigenous rocks in the remaining areas. Good sections of the Lower Triassic have been found in northeast and northwest Vietnam, Shan State of Myanmar, north Thailand and the northern part of the Central Belt of Malaysia. Based on those of northeast Vietnam (Vu Khuc, 1990), four assemblage zones have been distinguished, as follows. 2.1.1. Induan (1) Ophiceras–Claraia stachei Assemblage Zone (A.Z.). Distribution: Lang Son and Ha Giang Provinces of northeast Vietnam, Son La Province of northwest Vietnam and Song Be Province of south Vietnam. Characteristic species: Ophiceras cf. O. commune, Glyptophiceras langsonense, Lytophiceras sp., Claraia stachei, C. wangi, C. clarai, C. yunnanensis, C. griesbachi, C. vietnamica, Eumorphotis inaequicostata, Lingula tenuissima. (2) Koninckites–Claraia concentrica A.Z. Distribution: Lang Son Province of northeast Vietnam. Characteristic species: Koninckites cf.K. vidarbha, Euflemingites sp., Claraia concentrica, C. aurita, C. gervilliaeformis, C. kiparisovae, Eumorphotis venetiana. 2.1.2. Olenekian (3) Flemingites–Paranorites A.Z. Distribution Lang Son Province of northeast Vietnam and Song Be Province of south Vietnam. Characteristic species: Flemingites aff. F. flemingianus, F. cf. F. rursiradiatus, Paranorites praestans, Owenites carinatus, Pseudowenites oxynotus, Ussuria lenticularis, Lanceolites bicarinatus, Meekoceras cf. M. yukiangense, Neospathodus dieneri, N. waageni, Eumorphotis spinicosta, Entolium discites microtis. (4) Tirolites–Columbites A.Z. Distribution: Lang Son Province of northeast Vietnam, Lai Chau and Son La Provinces of northwest Vietnam. Characteristic species: Tirolites idrianus, Anakashmirites nivalis, Dieneroceras sp., Columbites cf. C. parisianus, Preflorianites sp., Bakevellia albertii, B. exporrecta, Unionites fassaensis, Neoschizodus ovatus, Costa-
Fig. 1. Distribution of the Triassic fossil localities in the SE Asian mainlaind.
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toria costata, Hoernesia socialis, Worthenia turbo, Naticella costata. In Thailand, according to Chonglakmani (1981), the Lower Triassic is undivided and described as the Claraia–Ophiceras beds, bearing: Lytophiceras cf. L. chamunda, Discophiceras cf. D. subkyokticum, Claraia stachei, C. radialis, C. concentrica, C. intermedia, C. yunnanensis. In the northern part of the Central Belt of the Malaya Peninsula the Lower Triassic has been recognized with the presence of Claraia concentrica, C. intermedia multistriata in the lower part, and Owenites, Arctoceras, Paranannites, Prosphingites in the upper part (Khoo, 1988). In the northern Shan State of Myanmar, the Lower Triassic is also undivided, the lower part of it furnishing Glytophiceras, Ophiceras and Vishnuites, together with (?) Owenites, Kashmirites and Aspenites (U and U, 1988). 2.2. Middle Triassic The Middle Triassic in the Southeast Asian mainland is represented by two sequence types: carbonate passing upward to terrigenous sediments of deepwater facies in northwest Vietnam, and volcanogenic rocks passing upward to terrigenous sediments of shallow-water facies in the remaining parts. Good sections of the Middle Triassic have been studied in north Vietnam, north Thailand and the Central Belt of the Malaya Peninsula. Based on those of north Vietnam the following four assemblage zones of Middle Triassic age have been distinguished. 2.2.1. Anisian (5) Balatonites–Costatoria curvirostris A.Z. Distribution: Lang Son, Son La, Thanh Hoa Provinces of north Vietnam, Dong Nai Province of south Vietnam. Characteristic species: Paracrochordiceras sp., Acrochordiceras cf. A. fischeri, Balatonites balatonicus, B. lemoinei, Cuccoceras cuccense, C. annamiticum, Frechites sp., Costatoria curvirostris, C. proharpa, C. chegarperahensis, Entolium discites, Posidonia mimer. (6) Paraceratites–Daonella elongata A.Z. Distribution: Lang Son, Son La, Thanh Hoa Provinces of north Vietnam. Characteristic species: Paraceratites subtrinodosus, Daonella elongata, D. sturi,
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Daonellopecten desmoornatus, Holcorhynchia bogumilorum, Adygella hoangmaiensis. (7) Kellnerites–Mentzelia A.Z. Distribution: Lang Son, Son La and Thanh Hoa Provinces of north Vietnam. Characteristic species: Kellnerites samneuaensis, Mentzelia mentzelii, Aulacothyris angusta.
chegarperahensis and Neoschizodus cf. N. laevigatus elongatus. The Ladinian Daonella A.Z. is composed of Daonella indica, D. lommeli, D. pichleri, whereas the synchronous Costatoria A.Z. consists of Costatoria quinquicostata and C. pahangensis. 2.3. Upper Triassic
2.2.2. Ladinian (8) Protrachyceras–Daonella indica A.Z. Distribution: Lang Son, Son La, Hoa Binh Provinces of north Vietnam. Characteristic species: Protrachyceras costulatum, P. villanovae, Rimkinites tonkinensis, Procladiscites cf. P. brancoi, Daonella indica, D.. bulogensis, D. lommeli, D. pichleri, Posidonia wengensis, Zittelihalobia planicosta. There is a synchronous faunal assemblage characterizing the shallow-water facies in Lang Son and Thanh Hoa Provinces of north Vietnam. It includes: Costatoria goldfussi, C. inaequicostata, C. ngeanensis, Trigonodus sandbergeri, T. tonkinensis, T. trapezoidalis, Entolium tridentini, Mysidioptera incurvostriata, Schafhauetlia plana, Cercomya magna, Hoernesia magnissima, Pleuromya habacensis, Langsonella elongata. According to Chonglakmani (1981), the Middle Triassic in north Thailand is characterized by two assemblage zones as follows: Hollandites– Leiophyllites A.Z. of Anisian age, and the Daonella indica A.Z. with its contemporary Costatoria A.Z. of Ladinian age. The Hollandites–Leiophyllites A.Z. includes the following characteristic species: Hollandites cf. H. ravana, H. cf. H.roxburghii, Beyrichites srikanta, Balatonites sp., Leiophyllites cf. L. pitamaha. The Daonella indica A.Z. consists of: Daonella indica, D. bulogensis, D. susdanai, Retidaonella multilineata, Posidonia kedahensis, P. wengensis, P. cf. P. cycloidalis. The synchronous Costatoria assemblage of the shallow-water facies comprises: Costatoria goldfussi mansuyi, C.. maethaensis, Elegantinia elegans, Trigonodus tonkinensis, T. costatus, Mysidioptera cf. M. cainalli. In the Central Belt of the Malaya Peninsula, two assemblage zones of Middle Triassic can be distinguished (Khoo, 1988): Anisian Paraceratites–Costatoria chegarperahensis and Ladinian Daonella with the synchronous Costatoria A.Z. The Paraceratites–Costatoria chegarperahensis A.Z. is characterized by Paraceratites cf. P. trinodosus, Frechites sp., Costatoria
The Upper Triassic in the Southeast Asian mainland begins mostly with shale of deep-water facies bearing in abundance thin-shelled Carnian halobiids. Only in northeast Vietnam, this part is composed of continental red beds. Since the Norian, the sequence is strongly differentiated. In northeast Vietnam and north of central Vietnam it is characterized by a paralic coal-bearing formation; in Laos and northwest Vietnam it is composed of marine sediments passing upward to paralic coal-bearing beds; meanwhile, in Myanmar it is represented by marine sediments. The presence of the Norian–Rhaetian in Thailand and Malaysia is still under discussion. Good sections of the Upper Triassic are exposed in north Vietnam, upper Laos, north Myanmar, north Thailand and in the Central Belt of the Malaya Peninsula. Based on the sections in north Vietnam, four assemblage zones have been distinguished in the Upper Triassic. 2.3.1. Carnian (9) Discotropites–Zittelihalobia superba A.Z. Distribution: Lai Chau, Son La, Hoa Binh and Ninh Binh Provinces. Characteristic species: Discotropites gemmellaroi, Sagenites? attenuatus, Arcestes cf. A. esinensis, Zittelihalobia praesuperba, Z. cordillerana vietnamica, Z. sonlaica, Halobia tropitum, H. charlyana. (10) Margaritropites–Halobia talauana A.Z. Distribution: Son La, Lai Chau, Hoa Binh and Ninh Binh Provinces. Characteristic species: Margaritropites phongthoensis, Halobia talauana, H. styriaca, H. substyriaca, H. austriaca, Zittelihalobia posterolaevis, Z. rugosa, Indigirohalobia pluriradiata. The Rhaetina A.Z., distributed in Lai Chau Province, represents a synchronous coral reef facies. It includes mostly brachiopods, such as Rhaetina complanata, R. bamaensis, Laballa cf. L. suessi, Sinucosta songdae, Aulacothyropsis bisinuata, Sulcorhynchia (?) vietnamica.
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2.3.2. Norian (11) Burmesia–Halobia norica A.Z. Distribution: Lai Chau, Son La, Hoa Binh and Ninh Binh Provinces. This zone is characterized by four components: (1) Norian ammonoids and halobiids — Juvavites magnus, Cyrtopleurites bicrenatus, Paratibetites tornquisti, Parathisbites sopcopensis, Halobia norica, H. distincta, Zittelihalobia sublaevis; (2) species also known from Rhaetian Rhaetavicula contorta Beds of Europe — Gervillia praecursor, Trigonia zlambachensis, Ostrea haidingeriana; (3) species also known from the Napeng Beds of Myanmar — Burmesia lirata, Prolaria sollasi, Costatoria (Napengocosta) napengensis, Thracia prisca, Palaeocardita singularis and; (4) endemic species — Songdaella graciosa, Mesopinna choboensis, Mesoneilo perlonga, Vietnamicardium vietnamicum. 2.3.3. Rhaetian (12) Cardinia–Unionites damdunensis A.Z. Distribution: Lai Chau, Son La, Hoa Binh and Ninh Binh Provinces. Characteristic species: Cardinia nachamensis, C. ovoidea, Gervillia inflata, Unionites damdunensis, U. convexa, Isocyprina ewaldi, Vietnamicardium vietnamicum, V. altum, Langvophorus garandi, L. choboensis. The synchronous flora is characterized by Dictyophyllum nathorstii, Clathropteris meniscioides, Neocalamites hoerensis, Thaumatopteris remauryi, Goeppertella microloba, Asterotheca cottoni, Taeniopteris jourdyi, Pterophyllum bavieri. In some parts of the Southeast Asian mainland, the Carnian component of the Upper Triassic sections is expressed more clearly than in others. In north Thailand, it is divided into the Paratrachyceras Beds and Halobia parallela–H. charlyana Beds (Chonglakmani, 1981). The first is characterized by Paratrachyceras cf. P. aon, P. cf. P. regoledanum, Joanites maehuatensis, J. honghoiensis, Buchites sp, Halobia cf. H. subcomata, Daonella piyasini, Posidonia lampangensis, whereas the second is characterized by Halobia parallela, H. charlyana, H. austriaca, H. wangchinensis, H. phraeensis, H. moluccana, H. talauana, Zittelohalobia ingavatae. In the Central Belt of Malaysia, the Carnian has been recognized as only the Halobia–Paratrachyceras Beds. After Khoo (1988), they are characterized by Halo-
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bia talauana, H. aotii, Zittelihalobia comata, Paratrachyceras regoledanum, Posidonia cf. P. kedahensis. The presence of Carnian in Myanmar has not been firmly approved on a good paleontological basis. It has been described in the thick Shan Dolomite Group and Thanbaya Formation in northwest Myanmar, but the collected fauna consists of only badly preserved imprints of Halobia? sp. and Halobia cf. H. comata together with Paragondolella polygnathiformis and Bathysiphon (U and U, 1988). The Norian in Thailand has been recognized in a thick terrigenous formation with the Indopecten Beds and Halobia distincta Beds. The faunal composition of each of them is still poor. The Indopecten Beds are characterized by Indopecten seinaamensis and Schafhauetlia maemokensis, but the Halobia distincta Beds by the index species and Palaeocardita singularis (Chonglakmani, 1981). The stratigraphic position of those beds has been clearly indicated. The presence of the Norian in Malaysia has not been paleontologically demonstrated. The presence of the Rhaetian in Southeast Asia is still a problem for discussion, but the find of Rhaetavicula contorta in the Napeng Beds of Myanmar may be a good basis for the recognition of this stage in the region. The well-known Napeng fauna is characterized by some typical species of the Rhaetavicula contorta Beds of Europe, together with a number of endemic species. In Vietnam, the Rhaetian is marked by a coal-forming period. Under the coal-bearing beds, the Norian is represented by a marine sequence beginning with transgressive members containing a series of ammonoids from the late-early Norian Juvavites magnus to middle Norian Cyrtopleurites, and then Parathisbites. The upper Norian is marked by a member of regressive sediments bearing degenerate halobiids. Therefore, the Burmesia–Halobia norica A.Z. has been considered as equivalent to the entire Norian stage, and because of that the coal-bearing beds with the Cardinia– Unionites damdunensis A.Z. have been assigned to the Rhaetian (Vu Khuc et al., 1991). Based on the above-described biostratigraphy of the Triassic in different territories of the Southeast Asian mainland, a scheme of Triassic biostratigraphic zones of this region can be presented (Table 1).
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Table 1 Triassic biostratigraphic zones of the SE Asian mainland Age
Vietnam, Laos, Cambodia
T3 r
Cardinia–Unionites damdunensis (D Dictyophyllum–Clathropteris) Burmesia–Halobia norica
T3 n T3 c
T2 l
T2 a
T1
Margaritropites–Halobia talauana (D Rhaetina) Discotropites–Zittelihalobia superba Protrachyceras–Daonella indica (D Costatoria goldfussi– Trigonodus) Kellnerites–Mentzelia Paraceratites–Daonella elongata Balatonites–Costatoria curvirostris Tirolites–Columbites Flemingites–Paranorites Koninckites–Claraia concentrica Ophiceras–Claraia stachei
Thailand (Chonglakmani, 1981)
Malaysia (Khoo, 1988)
Myanmar (U and U, 1988) Rhaetavicula–Burmesia Beds
Indopecten Beds Halobia distincta Beds Halobia parallela Beds
?
H. charlyana Beds Paratrachyceras Beds
Halobia–Paratrachyceras Beds
Daonella indica Beds (D Costatoria Beds)
Daonella Beds (D Costatoria quinquicostata Beds)
Hollandites– Leiophyllites Beds
Paraceratites– Costatoria chegarperahensis Beds
Paraceratites– Neogondolella mombergensis Beds
Claraia–Ophiceras Beds
Owenites–Claraia Beds
Owenites–Ophiceras Beds
3. Fauna of Triassic basins in the Southeast Asian mainland The fauna from the Triassic basins of the Southeast Asian mainland has many genera and species in common with analogous assemblages from south China (Kwangsi, Yunnan, Guizhou). Some endemics have been found only in this region. In the Early Triassic, we note the coexistence of different Claraia and Eumorphotis species during Induan time in various basins of the region (Yin, 1981; Vu Khuc, 1990). Among Claraia species, C. concentrica and C. yunnanensis are characteristic for those basins (Yunnan, north Vietnam, Thailand). In the Middle Triassic, the noticeable feature of faunal assemblages of the region is the abundant presence of various small-sized Costatoria both in the Anisian and in the Ladinian (Kobayashi and Tamura, 1968, 1984; Vu Khuc, 1990). Besides, it is worthy to pay attention to the early appearance in the Ladinian of halobiids in this area, e.g., Parahalobia (Yunnan; Yin and Hsue, 1938), and especially, Zittelihalobia planicosta (Yunnan, northwest Vietnam)
Halobia–Paragondolella polygnathiformis Beds
of large size and with well-developed shell ornamentation (Chen, 1980; Guo, 1985). Characteristic taxa of the region are Langsonella, Asoella, and the twisted Hoernesia? magnissima. In the Late Triassic, the Norian fauna of the studied region has the greatest endemism. Although there are some European species from the Rhaetavicula contorta Beds (Healey, 1908; Vu Khuc et al., 1991), the Norian assemblage is full of endemics: Prolaria, Datta, Langvophorus, Costatoria (Napengocosta), Songdaella, Mesopinna, Vietnamicardium and Mesoneilo. Moreover, the cosmopolitan Monotis that has been found in adjacent areas (Kalimantan, northern Himalayas) is absent in the assemblage. All these facts affirm the existence in the Triassic of a specific biogeographic province in the Southeast Asian mainland, the East Tethyan Province (Nakazawa, 1977). However, in the Norian this province was subdivided, and a new subprovince appeared in the territory of southwest China, northwest Vietnam, northern Laos and Myanmar. It is the Shan–Red River subprovince of the East Tethyan biogeographic province.
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Acknowledgements This paper is a contribution to IGCP Projects 306 (Stratigraphic correlation in SE Asia) and 359 (Correlation of Tethyan, Pacific and Gondwanan Permo– Triassic) and to the 30th IGC in Beijing (August, 1996). The authors would like to express their deep thanks to their Chinese colleagues Profs Drs Yin Hongfu, Hou Hongfei and Xiang Liwen, who have given them favourable facilities for attending the 30th IGC and presenting the results of their researches.
References Chen, C.C., 1980. Marine Triassic Lamellibranch Assemblages from SW China. Riv. Ital. Paleont. 85, 1189–1196. Chonglakmani, C., 1981. The Systematics and Biostratigraphy of Triassic Bivalves and Ammonoids of Thailand. Ph.D. thesis, Univ. of Auckland, Auckland. Guo, F.X., 1985. Fossil bivalves from Yunnan. Yunnan Sci. and Techn. Publ., Kunming. Healey, M., 1908. Fauna of the Napeng Beds of Upper Burma. Pal. Indica, 2=4, New Delhi. Khoo, H.P., 1988. Malaysia. ESCAP Atlas of stratigraphy, VII. Triassic of Asia, Australia and the Pacific. United Nations,
291
New York. Kobayashi, T., Tamura, M., 1968. Myophoria in Malaya with a note on the Triassic Trigoniacea. Geol. Paleontol. SE Asia 5, 83–137. Kobayashi, T., Tamura, M., 1984. The Triassic Bivalvia of Malaysia, Thailand and adjacent areas. Geol. Paleontol. SE Asia 25, 201–227. Mansuy, H., 1908. Contribution a` la carte ge´ologique de l’Indochine. Paleontol., Serv. Geol. Indoch., Ha Noi. Nakazawa, K., 1977. On Claraia of Kashmir and Iran. J. Paleontol. Soc. India 20, 191–204. Newton, R.B., 1900. On marine Triassic Lamellibranchs discovered in the Malaya Peninsula. Proc. Malacol. Soc. London. U, T.N., U, C.S., 1988. Burma. ESCAP Atlas of stratigraphy, VII. Triassic of Asia, Australia and the Pacific. United Nations, New York. Vu Khuc, 1990. Characteristic assemblages of the Triassic fauna of Viet Nam. ESCAP Atlas of stratigraphy, IX. Triassic biostratigraphy and paleogeography of Asia, 59. United Nations, New York, pp. 48–53. Vu Khuc, Vu Chau, Trinh Dzanh, Dang Tran Huyen, Nguyen Dinh Huu, Trinh Tho, 1991. Paleontological Atlas of Viet Nam. Science and Technics Publisher, Hanoi. Yin, H.F., 1981. Paleogeographical and stratigraphical distribution of the Lower Triassic Claraia and Eumorphotis. Acta Geol. Sin. 3, 161–169. Yin, T.H., Hsue, T.H., 1938. In: Chen, C.C. (Ed.), 1976. The Lamellibranch Fossils of China. Nanjing Inst. Geol. Paleontol., Science Press, Beijing, p. 224.