Gondwana Research 19 (2011) 47–60

Contents lists available at ScienceDirect

Gondwana Research

journal homepage: www.elsevier.com/locate/gr

Paleo-environments and tectonic setting of the Mesozoic Thung Yai Group in Peninsular , with a new record of Parvamussium donaiense Mansuy, 1914

Wirote Saengsrichan a,b,c,1, Thasinee Charoentitirat b,c, Assanee Meesook a, Ken-ichiro Hisada d, Punya Charusiri b,c,⁎ a Department of Mineral Resources, Rama VI Road, 10400, Thailand b Department of Geology, Faculty of Science, Chulalongkorn University, Bangkok 10330, Thailand c Earthquake and Tectonic Geology Research Unit, Chulalongkorn University, Bangkok 10330, Thailand d Division of Earth Evolution Sciences, Graduate School of Life and Environmental Science, University of Tsukuba, Tsukuba, Ibaraki 305-8571, Japan article info abstract

Article history: The Thung Yai Group extends over a large area of peninsular Thailand, along the eastern margin of the Shan Received 23 August 2009 Thai block. Bound by angular unconformities 300 m thick dominantly detritic brackish to non-marine Accepted 17 May 2010 deposits with few intercalated limestone beds between Triassic marine and Tertiary non-marine sediments, Available online 27 May 2010 represent the Thung Yai Group that comprises four formations: Khlong Min, Lam Thap, Sam Chom, and Phun Phin Formations. In the Ao Luk–Plai Phraya (ALPP) area, the Khlong Min and Lam Thap formations yield Keywords: marine, brackish-water and non-marine fossil assemblages. These include trace fossils and for the first time Jurassic–Cretaceous Paleo-environments in peninsular , the bivalve Parvamussium donaiense Mansuy, 1914. Based on fossil Tectonic setting determinations, the Thung Yai Group has a late Early Jurassic to Early Cretaceous age. Our new observations help unravel the tectonic history of Mesozoic Peninsular Thailand. After the complete Thung Yai Group closure of the Paleotethys in the Late Triassic, renewed inundation, from the late Early Jurassic to the early Peninsular Thailand Middle Jurassic, brought a regime of shallow to open marine and lagoon sedimentation over northwestern, Parvamussium donaiense western and southern peninsular Thailand, in the eastern part of Sundaland bordering the Mesotethys to the west. © 2010 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved.

1. Introduction Charusiri et al., 2002; Meesook et al., 2005)(Fig. 2). Our focus of interest here relates to extensive on-shore petroleum exploration. Mainland Southeast Asia comprises three major terranes: Western The present study area is part of the Ao Luk and Plai Phraya Burma, Shan–Thai and Indochina (Burrett, 1974; Stauffer, 1974; districts (ALPP) that coverapproximately400km2 within the Hutchison, 1975; Gatinsky et al., 1978; Bunopas, 1981; Burrett et al., Songkhla basin in the northern part of the , southern 1990; Barber and Crow, 2003; Metcalfe, 2006, 2010). Thailand peninsular Thailand (Fig. 1). Geomorphologically an intramontane consists in the west of the eastern part of the Shan–Thai terrane and sub-basin, the area of the ALPP is bound to the east by the Phanom in the east of the western part of the Indochina terrane. The Benja Range culminating at 1340 m above mean sea level (msl) and intervening tectonic units (Fig. 1) are the Lampang–Chiang Rai unit, west of it, the undulating terrains of the northwest–southeast for the eastern part of Shan–Thai, and the Nakhon Thai unit, for the trending, about 500 m high Phanom Hills extend. western part of Indochina (Charusiri et al., 2002, 2006; Hara et al., The Mesozoic sequences in Thailand comprise marine, brackish and 2009). Our study area belongs to the southern part of eastern Shan– continental facies (Meesook and Grant-Mackie, 1996). Exclusively Thai terrane, west of the Pattani suture (Charusiri et al., 2002), which marine in western Thailand, the most fully developed Jurassic sediments is considered to connect southward with the Bentong–Raub suture, in occur in the Mae Hong Son–Kanchanaburi basin of northwest and west . The latter suture resulted from the collision of the Indochina Thailand. In peninsular Thailand, the Chumphon basin to the north and and Shan–Thai terranes (Bunopas, 1981; Hahn et al., 1986; Panjasa- the Songkhla basin, further south contain Jurassic marine sediments. watwong, 1991) mostly during Late Triassic times (Metcalfe, 1989; With exception of the continental basins in northeastern Thailand, most marine and brackish Jurassic basins are elongated north trending, normal fault or strike-slip bound (Fig. 1). In the Songkhla basin, the Ao ⁎ Corresponding author. Department of Geology, Faculty of Science, Chulalongkorn Luk–Plai Phraya (ALPP) area comprises the Thung Yai Group that University, Bangkok 10330, Thailand. Fax: +66 22185464. E-mail address: [email protected] (P. Charusiri). encompasses four formations: Khlong Min, Lam Thap, Sam Chom, and 1 Deceased. Phun Phin Formations. The Khlong Min and Lam Thap Formations yield

1342-937X/$ – see front matter © 2010 International Association for Gondwana Research. Published by Elsevier B.V. All rights reserved. doi:10.1016/j.gr.2010.05.006 48 W. Saengsrichan et al. / Gondwana Research 19 (2011) 47–60

Fig. 1. Map of Thailand showing major tectonic units, distribution of the Jurassic–Cretaceous sedimentary rocks, associated basins, and major tectonic features (modified after Polachan and Sattayarak, 1989; Charusiri et al., 2002). bivalves and some other macrofossils that provide age constraints for bivalves occur. Brackish-water heterodont bivalves among them stratigraphic correlation and the establishment of the continuity of show ecological and taxonomical diversifications (Kondo et al., lithologic units. Their relations with the better-known non-marine 2006). These play an important role in the evaluation of their paleo- Khorat Group to the east are also considered. environment and the delineation of their paleo-biogeography (Arias, Besides the first discovery of the Jurassic bivalve Parvamussium 2008). All fossils cited in the text are part of collections during donaiense Mansuy, 1914 in the Songkhla basin, other Mesozoic fieldwork by the authors, unless otherwise indicated. W. Saengsrichan et al. / Gondwana Research 19 (2011) 47–60 49

Fig. 2. Map of southern peninsular Thailand showing regional distribution of mainly clastic sedimentary rocks belonging to the Thung Yai Group (modified after Raksaskulwong, 1994; Teerarungsigul, 1999).

The prime objective of this paper is to contribute a detailed Previously, Sanansiang (1977) had mapped the Mesozoic rocks lithostratigraphy and paleontology of the Mesozoic sediments in the exposed mostly in the Chumphon– and Trang Ao Luk–Plai Phraya (ALPP) basin, using simultaneously tectonic, areas as a single unit (Fig. 1). Subsequently, Asama et al. (1981) paleo-environmental, lithostratigraphic and paleontological data. described six species of fossil plants from clastic strata of the Trang area and found these to be different from those of the Khorat Group 2. General stratigraphic setting in northeastern Thailand (Kon'no and Asama, 1973) but closely similar to those of the Early Cretaceous Gagau Group in the Malayan Mesozoic rocks in southern peninsular Thailand were first peninsula (western Malaysia). reported by Kobayashi and Tokuyama (1959) with the discovery of Raksaskulwong et al. (1989) established the Mesozoic stratigraphy Triassic marine bivalve, Halobia sp. Hayami (1960) described some in the Thung Yai–Klong Thom area, recognizing five formations: Sai bivalves in argillaceous sandstone at the Hadd Sai Ri beach, Pak Nam Bon, Lam Thap, Khlong Min, Sam Chom, and Phun Phin in ascending Chumphon Bay, , and proposed a probable order. Jurassic age for his Eomiodon chumphonensis Hayami, 1960. The Khlong Min Formation that yields the Jurassic fossils reported The systematic geological mapping in southern Thailand at a scale in this paper, was originally regarded as a member of the Tertiary Sin of 1:250,000 commenced as a project of the Department of Mineral Pun Formation, containing the bivalve Corbula njalindungensis (Martin Resources in 1989 with special emphasis on Mesozoic sediments. 1919), which is indicative for the Miocene (Beets, 1981). In the Bang 50 W. Saengsrichan et al. / Gondwana Research 19 (2011) 47–60

Hian area, Krabi and Surat Thani Provinces, Tantiwanit et al. (1989) sandstone. Zuoqi (1993) studied the palynology of the red-beds of subdivided the Mesozoic sequence into two formations: Sai Bon and peninsular Thailand and found a spore-pollen assemblage in sand- Lam Thap. The Sai Bon Formation consists mainly of red brown clastics stone and shale beds that consists predominantly of gymnosperm and dolomitic limestone with abundant foraminifera and bivalves, pollens, of Late Jurassic age. Further to the north, ammonite and while the Lam Thap Formation is chiefly composed of red beds, arkosic bivalve fossils indicative of the Early Bajocian (Middle Jurassic) were

Fig. 3. Geologic map and cross-sections showing the distribution, ages and simple structures of major rock units in the Ao Luk–Plai Phraya area, Krabi Province. W. Saengsrichan et al. / Gondwana Research 19 (2011) 47–60 51 abundantly found in fine-grained clastic rocks of the Khao Lak overlies with an angular unconformity the marine Triassic Sai Bon Formation, in the Chumphon Province, about 80 km north (Meesook Formation that itself overlies unconformably the Paleozoic basement. and Grant-Mackie, 1994; Meesook et al., 2005, 2006a). The same However, Nakanart and Mantajit (1983) used the term “Trang authors also reported mudstone and sandstone of the Phra Bat Formation” for Middle Miocene laminated shale, changing laterally Formation in the Chian Yai and Hua Sai areas, Nakhon Si Thammarat to argillaceous limestone and grading to glauconitic siltstone, in Province, were of Toarcian (Early Jurassic) age. Buffetaut et al. (1994) petroleum wells of the Andaman Sea. reported vertebrate fossils in Mesozoic non-marine clastic rocks at In his revision of the lithostratigraphic nomenclature of non- several localities in the peninsular Thailand and assigned these to the marine Mesozoic rocks in peninsular Thailand, Raksaskulwong Jurassic. (2002), used the term “Thung Yai Group” that he subdivided into Raksaskulwong (1994) erected the Trang Group for the non- the four formations Khlong Min, Lam Thap, Sam Chom, and Phun Phin marine Mesozoic sequences exposed in the Chumphon to Trang areas Formations in ascending order. (Fig. 2), subdividing it into the four formations of Chumphon redbed, Khlong Min, Khao Sam Chom and Phun Phin in ascending order. 3. Structure Teerarungsigul (1999)studying in detail the non-marine Mesozoic sediments in the Thung Yai–Klong Thom area, Nakhon Si Thammarat A regional north–south strike of the Mesozoic and pre-Mesozoic and Krabi Provinces, recognized within the Trang Group (Raksaskul- strata prevails between Chumphon and Trang (Fig. 2). However, north wong, 1994) the four formations of Khlong Min, Lam Thap, Sam Chom, of Surat Thani, the northeast-trending reactivation of the Klong Marui and Phun Phin, in ascending order. The Khlong Min Formation strike-slip fault (KMF in Figs. 1–4), with sinistral movement, may have

Fig. 4. Landsat TM5 image (A) and interpretation map (B) showing distribution of rock units, their major structures, faults and fractures. Note that the major northeast trending Klong Marui Fault (KMF) is located in the upper left corner of the map. 52 W. Saengsrichan et al. / Gondwana Research 19 (2011) 47–60 subsequently obscured this folding trend, as this fault also reaches the In the study area, the four gentle north-trending synclines of study area. Our regional reconnaissance survey also indicates that Kanjanapayont (2002) correspond to the Chumphon, Ta Pi, Krabi East other large lateral faults of similar trend, such as the Fault and Trang synclines. The ALPP basin is located southwest of the Ta Pi (RNF in Figs. 1 and 2) and the Surat Thani Fault (STF see Figs. 1 and 2), syncline. Based on our regional field survey (Fig. 3) and stratigraphic show left-lateral movements. investigation (Fig. 5) in conjunction with aerial photography and Kanjanapayont (2002) proposed a structural model of upper remote-sensing (Fig. 4), the major open syncline has beds dipping peninsular Thailand, with special reference to the Krabi and Surat about 20°–30° and extends from the Krabi Province in the south to the Thain Provinces. For him the Mesozoic stratigraphic units form a large in the north. The general axial trend is north– first-order syncline and four lower-order gentle synclines, transected south with a gentle plunge (5°–15°) to the north. The result of remote- by strike-slip faults and fractures. These structures formed before the sensing reveals that most of the lineaments are northeast-southwest. deposition of the Tertiary sedimentary units. Since then, no major They mainly follow the northeast-trending Klong Marui Fault folding has taken place, except for the formation of fault-controlled (see also Figs. 1–4). The minor joints are mainly north–south and Tertiary basins. northwest-southeast.

Fig. 5. Composite stratigraphic column of Upper Paleozoic–Mesozoic rocks in the study area and its vicinity (modified after Poonpun, 2002) (U=unconformity). W. Saengsrichan et al. / Gondwana Research 19 (2011) 47–60 53

4. Lithostratigraphy Thammarat Province, Klong Thom, Ao Luk and Plai Phraya areas of the Krabi Province and Wang Vi Set area of the . The age of Sediments ranging from the Carboniferous to the Quaternary fill the group is Late Early Jurassic to Cretaceous (Teerarungsigul, 1999; the ALPP area (Fig.3). A composite lithologic columnar section shows Raksaskulwong, 2002). the rock units of the study area (Fig. 5). The marine sequence of the Khlong Min Formation, totalizes a The Upper Paleozoic consists of the more than 500 m greenish grey thickness of about 200 m. It is well exposed between km 8–25 of the pebbly mudstone and sandstone sequences of the Ko Yao Noi Krabi–Khanom road (Highway no. 44), in particular at km 10+300 on Formation that belongs to the Kaengkrachan Group. The group covers the western side of highway at Ban Khao Ngam, Ao Luk District, and at about 30% of the total area mapped area, extends to the western, the Huai Luk reservoir (see Figs. 3 and 5). The sequence includes southern, and eastern parts of the study area. In the central part greenish grey, thin- to medium-bedded mudstone, intercalated with characteristic thinly bedded to massive fossiliferous limestones, rep- ripple cross-laminated sandstone (Figs. 6, 7A, and B) and fossiliferous resent the Ratburi Group that yields fossil assemblages of predom- limestone with common invertebrate and vertebrate fossils. The inantly corals, bivalves, brachiopods, bryozoans and foraminifers. strata exposed at the Huai Luk reservoir (Fig. 6B), Plai Phraya District, The Mesozoic succession includes the Sai Bon Formation and are composed chiefly of greenish grey to reddish brown, thin- to Thung Yai Group. thick-bedded mudstone intercalated with fossiliferous limestone, The more than 150 m-thick Sai Bon Formation consists of brown to ripple cross-laminated sandstone (Fig. 7C) with abundant inverte- reddish brown sandstone interbedded with siltstone, greyish mud- brate and plant remains. stone and greyish limestone with Triassic fossils, such as foraminifers, The Lam Thap Formation is more than 100 m thick at Khao Chong bivalves, brachiopods (Teerarungsigul, 1999). Mai Dam, east of Khao Hua Sing To and Huai Luk reservoir in the ALPP The Thung Yai Group consists chiefly of about 700 m greyish area of the Krabi and Surat Thani Provinces (Fig. 5). It comprises brown shales and reddish brown, fine-grained sandstones and mainly two lithofacies (Figs. 6A and 7D), the medium- to thick- conglomerates. The group is well exposed in the Wiang Sa area of bedded arkosic sandstones and intercalated siltstone with greyish the Surat Thani Province, the Thung Yai area of the Nakhon Si mudstone. The mainly brown or reddish brown medium- to coarse-

Fig. 6. Stratigraphy of the Thung Yai Group. (A) Columnar section of the Khlong Min (lower) and Lam Thap (upper) formations, at km 10+300 along Highway no. 44 (Krabi– Khanom). (B) Columnar section of the brackish Jurassic sedimentary rocks of the Khlong Min Formation at the Huai Luk reservoir, Plai Phraya District, Krabi Province. 54 W. Saengsrichan et al. / Gondwana Research 19 (2011) 47–60

Fig. 7. (A) Road-cut at km 10+300 on Highway no. 44 (Krabi–Khanom), Krabi Province showing west-dipping, dark grey mudstone (Md); specimen BH1 in sandstone (Ss) of the upper part of the Khlong Min Formation (KMF); unconformably overlain by sandstone of the Lam Thap Formation (LTF). (B) Close-up of a bedding plane of siltstone of the Khlong Min Formation that shows trace fossils and ripple marks with the paleocurrent to the west. (C) Open-pit outcrop of south-west dipping, thinly-bedded mudstone (Md) with specimen BH2 interbedded with thickly bedded sandstone (Ss) and fossiliferous limestone (Ls) near the top of the Khlong Min Formation at Huai Luk reservoir. (D) Road-cut outcrop of the Lam Thap Formation showing durable thickly-bedded arkosic sandstone (Ss) interbedded with less durable siltstone (St) at km 10+300 on Highway no. 44 (Krabi–Khanom), Ao-Luk District, Krabi Province. grained, subangular to subrounded sandstone of moderate sphericity The Sam Chom and Phun Phin formations are barren. A Cretaceous consists in general of 30% feldspar and 70% quartz grain with siliceous age is probable on the base of their stratigraphic position. cements and iron oxide coating (Fig. 8). Based on paleontological data the age range of the Thung Yai Group is late Early Jurassic to Early Cretaceous (Table 2). 5. Age constrains 6. Paleo-environments Age constraints are provided by the stratigraphic and paleonto- logical data (Asama et al., 1981; Zuoqi, 1993; Buffetaut et al., 1994; 6.1. Khlong Min Formation Meesook, 1994; Teerarungsigul, 1999; Meesook et al., 2005; Meesook et al., 2006a) that confer early Middle Jurassic to Late Cretaceous ages In southern peninsular Thailand, particularly the ALPP study area, to the Thung Yai Group. marine to brackish bivalves occur abundantly in dark grey claystones The Khlong Min Formation yields the Jurassic bivalves P. donaiense and grey limestones of the Khlong Min Formation. The marine Mansuy, Astarte sp., Protocardia sp., Modiolus sp., gastropods, conchos- bivalves P. donaiense, Protocardia sp., Modiolus sp., Hudsonella sp., traceans, the palynomorphs Classopollis sp. and Dicheiopollis sp., wood Juranomia sp., Phraemytilus sp., Eomiodon cf. securiformis and fragments (Zuoqi, 1993) and non-marine vertebrates, hybodont sharks, Actinostreon sp. occur in association with ostracods, palynomorphs lepidotes-like actinopterigians, lung fishes, temnospondyle amphibians, and some vertebrates, suggesting shallow to brackish environments. mesosuchian crocodilians and cryptodiran turtles (Buffetaut et al., The record of P. donaiense for the first time in southern peninsular 1994). Plant fossils, are also found in this area. These fossils assign Thailand is of major importance, since this bivalve occurs abundantly an Early to early Middle Jurassic age to the Khlong Min Formation. Near in northwestern Thailand (Kemper, 1976; von Braun and Jordan, the township of Ban Sai Thong, approximately 6 km north of Chumphon, 1976; Charoenprawat et al., 1985; Beauvais, 1988, 1989; Fontaine and along the Klong Hua Wang Phranang Tak canal, a faunal assemblage Suteethorn, 1988; Meesook, 1994; Kozai et al., 2006). Moreover, as of the bivalves Actinostreon sp., Protocardia sp., Myrene sp., Eomiodon the species P. donaiense occurs in Vietnam (Vu et al., 1991) and in sp., with the trace fossils Skolithos sp. and Thalassinoides sp. is abundant Tibet (Yin and Grant-Mackie, 2005) the significance of this species is and similar to that of Ban Map Ching and the ALPP study area. stratigraphical as well as paleogeographical, indicating the Toarcian– The Lam Thap Formation contains fern-like leaves such as Filicales, Aalenian over a large area. Other fossils encompass marine to brackish Bennettitales and Coniferales indicative of Early Cretaceous age (Asama bivalves (Fig. 9) from locality BH2 of the Khlong Min Formation in the et al., 1981). The non-marine bivalve Unio cf. heilongjiangensis Sha and ALPP basin (Fig. 6B), occur in mudstone intercalated with sandstone Fuersich (1993) occurs in thinly bedded conglomeratic limestones. and fossiliferous limestone. These are Modiolus sp. (D in Fig. 9), Astarte W. Saengsrichan et al. / Gondwana Research 19 (2011) 47–60 55

Fig. 8. Parvamussium donaiense (Mansuy, 1914), from the mudstone of the Khlong Min Formation at km 10+300, Highway 44 (Krabi–Khanom), Ao Luk District, Krabi Province: (A) RV, external mould; (B) LV, internal mould; (C) Paratype D, RV, internal mould; (D) Paratype A, LV, external mould; (E) RV, internal and external mould; (F) LV, external mould.

sp. (C in Fig. 9), Protocardia sp. (A in Fig. 9), Hudsonella sp., Juranomia sp., Phraemytilus sp., Eomiodon cf. securiformis, Actinostreon sp., Table 1 Myrene sp., Trigonia sp. and a scleractinian coral (F in Fig. 9). Trace Dimensions of Parvamussium donaiense measurements. fossils are Skolithos sp. and Thalassinoides sp. Gastropods, ostracods, Specimen Valve Length (L) (mm) Height (H) (mm) L/H concostrachan, palynomorph, vertebrate hard parts (G in Fig. 9) and plant remains (H in Fig. 9), also occur in this area. Holotype Right valve 12.00 14.00 0.86 Paratype A Left valve 6.00 8.50 0.71 Paratype B Left valve 7.50 9.00 0.83 6.2. Lam Thap Formation Paratype C Right valve 7.00 8.50 0.82 Paratype D Right valve 7.50 8.00 0.94 The Lam Thap Formation yields the non-marine bivalve Unio cf. Paratype E Left valve 6.50 7.50 0.87 fl Paratype F Left valve 10.00 11.50 0.87 heilongjiangensis, suggesting a Lower Cretaceous uviatile or lacus- Paratype G Left valve 7.00 8.50 0.82 trine fresh water environment. This occurrence in southern Thailand Paratype H Left valve 6.50 8.00 0.81 enables the comparison of the Lam Thap Formation with the Sao Khua Paratype I Right valve 7.50 9.00 0.83 Formation of the Khorat Group in northeastern Thailand (Meesook Paratype J Left valve 7.50 8.50 0.88 et al., 2006b). The same bivalve and associated non-marine mollusks 56 W. Saengsrichan et al. / Gondwana Research 19 (2011) 47–60

Table 2 pas, 1981; Charusiri, 1989). Permian and Triassic radiolarian-bearing Bivalve biozonation of the Khlong Min and Lam Thap Formations, at the km 10+300 cherts in Malaysia support such collision tectonics, being part of the along the Highway no. 44 (Krabi–Khanom) and Huai Luk reservoir, Ao Luk and Plai Phraya area, Krabi Province. Indosinian orogeny (Metcalfe, 1988, 1989) and so does the contrast- ing I-type granite intrusion in Thailand (Charusiri, 1989) and the sinistral movement of major northeast-trending Ranong and Klong Marui strike-slip faults (Fig. 1)(Garson and Mitchell, 1970; Charusiri et al., 2002). Acartoon(Fig. 10) displays the post-Permian plate tectonic reconstruction of southern Thailand. It suggests the complete closure of Paleotethys in western peninsular Thailand by Late Triassic times. Particularly in the ALPP study area, a limestone conglomerate un- conformably underlying the Sai Bon Formation (A in Fig. 10A) supports a sedimentological response to the tectonic warping resulting from Early to Middle Triassic compression of Shan–Thai. The ingression of the shelf deposition of the Nathawi Formation (Grant-Mackie et al., 1980)ontheeasternShan–Thai side, suggests that down warping may have opened passages for the Paleotethys into the Songkhla and Yala–Pattani basins (B and C in Fig. 10A). In Late Triassic to Early Jurassic times, strong collision with westward up-thrusting along the Pattani suture (C in Fig. 10B), accompanied by uplift in Khao Nam Kang (B in Fig. 10B), contributed to a regional westward tilting of the Shan–Thai block and the closure of Paleotethys in the Songkhla and Yala–Pattani basins. The Yala and Pin Yoe Granites (Fig. 10B and C) of S- and I-types, respectively, intruded most basins. However, as tectonic tilting developed, a Mesotethys Sea filled the ALPP depression with the marine clastic sediments of the Sai Bon Formation, triggering renewed subsidence in the basin (A in Fig. 10B). Subsequently, progressive Middle to Late Jurassic tectonic uplift developed as the result of on-going compressive tectonics by the approach of the Western Burma block. In the mean time, extensive erosion and denudation of the uplifted highlands generated wide- occur in South China (Li and Grant-Mackie, 1993), Korea (Chang et al., spread non-marine siliciclasts (e.g. Sadao Red Beds and Lam Thap 2000; Kozai et al., 2005), and southwest Japan (Matsukawa et al., Formation, A in Fig. 10D) that spilled over the uplifted basins. This hit 2006). We therefore suggest that during Late Jurassic–Cretaceous the ALPP basin of western peninsular Thailand only later, as marine times, Thailand, South China, Korea and Southwest Japan shared deposition continued in the clastic sequences of the Khlong Min similar paleoclimatic conditions. Formation (Thung Yai Group) (Fig. 10D). Further uplift, occurring in For Teerarungsigul (1999) the Khlong Min and Lam Thap the Late Jurassic to Early Cretaceous, can explain the absence by formations represent shallow marine to lagoonal environments, denudation of Upper Jurassic sequences in the study and nearby areas. replaced later by meandering rivers, probably in semi-arid conditions. Once the subduction of the oceanic plate of the Western Burma block In western and northwestern Thailand shallow marine environments beneath western Shan–Thai took place, Late Cretaceous–Early prevailed during the Early to early Middle Jurassic (Toarcian–Early Tertiary, S-type dominated, felsic magmatism occurred in peninsular Bajocian) and non-marine fluvial to fluvio-lacustrine deposits Thailand (Charusiri et al., 2002). Contemporaneous with progressive dominated in northeast Thailand. The presence of similar faunal and tectonic stress, compression of the ALPP and nearby basins formed floral assemblages in the Khlong Min Formation, particularly in the large synclines and reactivated the sinistral movement along the ALPP basin, indicates that the Early to early Middle Jurassic shallow Ranong, Klong Marui, and Krabi Surat Thani Faults. seaway possibly extended to peninsular Thailand, eventually becom- ing non-marine in the Early Cretaceous. After the Early Cretaceous, the 8. Conclusion whole of Thailand was covered with continental sediments as the red beds of the Khorat Group in northeastern Thailand (Meesook et al., The 300 m thick clastic sequence of the Thung Yai Group extends 2006a) and the Lam Thap, Sam Chom and Phun Phin formations in to the eastern Shan Thai terrane in peninsular Thailand, consisting of the south (this study). the Khlong Min and Lam Thap formations. The older 200 m thick Khlong Min Formation includes greenish grey, thin- to medium- 7. Tectonic setting bedded mudstone intercalated with ripple, cross-laminated sand- stone and fossiliferous limestone with common invertebrate and There is a wide consensus that both the Shan–Thai and Indochina vertebrate fossils. The younger, more than 100 m-thick Lam Thap terranes were originally parts of Gondwana. After rifting, drifting and Formation comprises two lithofacies including medium- to thick- collision, these terranes amalgamated to Eurasia before the end of the bedded arkosic sandstones and siltstones intercalated with greyish Triassic (Bunopas and Vella, 1978; Gatinsky et al., 1978; Macdonald mudstones with common bivalves. The Thung Yai Group overlies and Barr, 1978; Hahn, 1982; Chonglakmani, 1983; Sengor, 1984; unconformably clastic Triassic and underlies unconformably Tertiary Chonglakmani et al., 1985; Metcalfe, 1988, 1989; Charusiri, 1989; semi-consolidated deposits. Based on faunal and floral assemblages, Hutchison, 1989; Burrett et al., 1990; Hada, 1990, and Panjasawat- marine, brackish to non-marine Mesozoic strata of the Thung Yai wong, 1991; Hirsch et al., 2006). Eastward subduction of the oceanic Group in southern peninsular Thailand has an age range from late lithosphere may perhaps have taken place in the easternmost part of Lower Jurassic to Upper Cretaceous. Lithofacies and fossil assemblages the Shan–Thai terrane, and eastward oceanic subduction beneath of the Khlong Min Formation point to lagoonal environments during Indochina may have taken place almost contemporaneously (Buno- the brief marine ingression of the Mesotethys from late Early to early W. Saengsrichan et al. / Gondwana Research 19 (2011) 47–60 57

Fig. 9. Jurassic fossil assemblages of the Khlong Min Formation. (A) Protocardia sp.; (B) Trigonia sp.; (C) Astarte sp., (D) Modiolus sp., (E) Gastropod, (F) Scleractinian Coral, (G) vertebrate bone, (H) Plant remains. 58 W. Saengsrichan et al. / Gondwana Research 19 (2011) 47–60

Fig. 10. Tectonic model illustrating the meso-tectonic stage during Middle Triassic to Early Cretaceous for southern peninsular Thailand (modified after Charusiri et al., 2002). Note A = Ao Luk–Plai Phraya Basin, B = Songkhla Basin, C = Yala–Pattani Basin, ST = Shan–Thai Block, IC = Indochina Block, WB = Western Burma Block, KMF = Klong Marui Fault, STF = Surat Thani Fault.

Middle Jurassic, the depositional environment gradually changing to Acknowledgements the meandering river system of the Lam Thap Formation. Character- istic for the brief marine incursion in the Jurassic is the presence of We dedicate this paper to the memory of our beloved colleague the bivalves P. donaiense, Modiolus sp., and Astarte sp. in siltstone late Wirote Saengsrichan. We owe grateful acknowledgements to beds of the Khlong Min Formation that witness a Mesotethyan Chommada Srinuan for map preparation, report, and field investiga- ingression during the Early and Middle Jurassic. Changes in the tion, to Wattana Tansathian and Terapon Wongprayoon for field environment were due to subsequent compressive interaction with guidance and recommendations. We extend our sincere thanks to the Western Burma block, resulting in the uplift of the western Shan– Surachet Poonpun, Pitak Thiamwong and Sakda Khundee for their Thai terrane and the disappearance of the Upper Jurassic sequence support with previous geological data and satellite image preparation. in this area. We also thank Jirapha Homhuek and Phanomrung Songchaeng for The lower and upper contacts of the Thung Yai Group with the preparing the manuscript. We thank Prasert Lekngam and Chamlong underlying clastic Triassic and the overlying semi-consolidated Ketsathit for fieldwork. Last, but not least, we would like to thank the Tertiary deposits are unconformable. Bureau of Geological Survey, Department of Mineral Resources and W. Saengsrichan et al. / Gondwana Research 19 (2011) 47–60 59

Department of Geology, Faculty of Science, Chulalongkorn University western flank of road-cut outcrop on the Highway no. 44 (km 10+ for all nontechnical facilities. Parts of this research have been 300), Ao Luk District, Krabi Province. supported by the Evolution of Mesozoic Biodiversity in Thailand (BRT R_245007) granted to AM and WS and by GISTDA, Thailand Age granted to PC. We are indebted to our reviewers Prof. J. Grant-Mackie (Auckland Toarcian–Early Bajocian (late Lower–early Middle Jurassic). University) and Ana Marquez-Aliaga (University of Valencia, Spain), for their constructive comments. Distribution

Appendix A. Parvamussium donaiense Parvamussium donaiense (Mansuy) occurs in the Pa Lan, Mae Sot, and Umphang areas of the westernmost part of Thailand (Fontaine and The systematic classification and morphological terms used in this Suteethorn, 1988; Kozai et al., 2006), Vietnam (Vu et al., 1991) and study are those of Cox et al. (1969) for Bivalvia, modified after Waller outside Sundaland, the species was also identified in Tibet (Yin (1978). and Grant-Mackie, 2005).

Phylum MOLLUSCA References Class BIVALVIA Linne, 1758 Arias, C., 2008. Palaeogeography and biogeography in the Early Jurassic Panthalassa and Subclass PTERIOMORPHA Beurlen, 1944 Tethys Ocean. Gondwana Research 14, 306–335. Order OSTREOIDA Vaught, 1989 Asama, K., Nakornsri, N., Hinthong, C., Sinsakul, S., 1981. Some younger Mesozoic plants from Trang. Geology and Palaeontology of Southeast Asia 22, 35–48. Suborder PECTININA Vaught, 1989 Barber, A.J., Crow, M.J., 2003. An evaluation of plate tectonic models for the Superfamily PECTINACEA Rafinesque development of Sumatra. Gondwana Research 6, 1–28. Family PROPEAMUSSIIDAE Vaught, 1989 Beauvais, L., 1988. Jurassic corals and coral-bearing limestones of Thailand and Burma. CCOP Technical Bulletin 20, 204–210. Genus Parvamussium Sacco, 1987 Beauvais, L., 1989. Jurassic corals from the circum-Pacific area. Association of the Subgenus Parvamussium s.s. Australasian Palaeontologists, Memoir 8, 291–302. Beets, C., 1981. Note on Mollusca from the Lower Mentawir Beds, Balikpapan Bay area, Parvamussium donaiense Mansuy, 1914 (Fig. 8A–F) Kalimantan (East Borneo). Scripta Geologica 59, 1–12 (1 fig., Leiden, June 1981). Beurlen, K., 1944. Beitrage zur Stammesgeschichte der Muscheln: Bayer. Akademie der – – Diagnosis Wissenschaften, Sitzungsber 1 2, 133 145. Buffetaut, E., Tong, H., Suteethorn, V., 1994. First post-Triassic labyrinthodont amphibian in Southeast Asia: a temnospondyl intercentrum from Jurassic of Thailand. Neues Small- to medium-size species of Parvamussium, characterized Jahrbuch für Geologie und Paläontologie Monatshefte 11, 659–666. by subequilateral outline, faint concentric plicae on right valve, Bunopas, S., 1981. Paleogeographic history of western Thailand and adjacent parts of – southeastern Asia— A plate-tectonics interpretation. Ph.D thesis, Victoria Univer- weak radial riblets on left valve, and six to seven sharp straight sity of Wellington, New Zealand. internal ribs which extend nearly to valve margin. Material: A total Bunopas, S., Vella, P., 1978. Late Palaeozoic and Mesozoic structural evolution of of 11 specimens encompassing six complete, five incomplete , a plate tectonics model. In: Nutalaya, P. (Ed.), Proceedings of the Third Regional Conference on Geology and Mineralogy Resources of Southeast internal and external moulds and casts of the left and right valves Asia. Bangkok, Thailand, pp. 133–140. from locality BH1, from the Khlong Min Formation; locality BH1 Burrett, C.F., 1974. Plate tectonics and the fusion of Asia. Earth and Planetary Science (Fig. 6A), grid reference 0476676E 0942352 N, Ban Mak quadrangle Letters 21 (2), 181–189. – (4725I), along Highway no. 44 (km 10+300), Ao Luk District, Krabi Burrett, C., Long, J., Stait, B., 1990. Early Middle Palaeozoic biogeography of Asia terranes derived from Gondwana. In: McKerro, W.S., Scottese, C.R. (Eds.), Province. Palaeogeography and Biogeography: Geological Society Memoir, 12, pp. 163–174. Chang, K.H., Park, S.O., Chang, S., 2000. Upper Mesozoic unconformity-bounded units of Korean Peninsula within Koguryo Magmatic Province. In: Okada, H., Mateer, N.J. Description (Eds.), Cretaceous Environments of Asia. Elsevier, Amsterdam, pp. 91–111. Charoenprawat, A., Dhamdusdi, V., Sripongpan, P., Paksamut, N., 1985. Geology of Small- to medium-sized, rarely exceeding 14 mm in height, Changwat Mae Hong Son and Ban Huai Pong Quadrangles, , Thailand. Geological Survey Division, Department of Mineral resources, Geologic subcircular in outline, inequivalve, nearly equilateral, slightly convex, Quadrangle Maps 4547I and 4547II scale 1: 50,000. slightly higher than long. Test thin, apical angle exclusive of auricle Charusiri, P., 1989. Lithophile Metallogenic Epochs of Thailand: A Geological and about 115°, beak not projecting above straight hinge line; auricles Geochronological Investigation. Ph.D. Thesis, Queen's University, Kingston, Ontario, Canada. unequal, anterior usually larger than posterior; byssal notch unde- Charusiri, P., Daorerk, V., Archiblad, D., Hisada, K., Ampaiwan, T., 2002. Geotectonic veloped; surfaces of right valves generally smooth but with faint evolution of Thailand: a new synthesis. Journal of the Geological Society of Thailand concentric threads; left valves with weak spaced radial riblets 1, 1–20. Charusiri, P., Imsamut, S., Zhuang, Z., Ampaiwan, T., Xu, X., 2006. Paleomagnetism of the approximately corresponding to internal ribs; interspaces of external earliest Cretaceous to early late Cretaceous sandstones, Khorat Group, Northeast ribs with numerous faint radial threads in some specimens but lacking Thailand: implications for tectonic plate movement of the Indochina block. any concentric ornament on left valves; 6–7 internal ribs very sharp Gondwana Research 9, 310–325. Chonglakmani, C., 1983. The marine Mesozoic stratigraphy of Thailand. In: Nutalaya, P. and straight, extending from umbo nearly to valve margin, gradually (Ed.), Proceedings of the Workshop on Stratigraphic Correlation of Thailand and strengthening ventrally. Malaysia. Haad Yai, Thailand, pp. 105–127 (Technical Paper 1). Chonglakmani, C., Meesook, A., Suteetorn, V., 1985. Jurassic stratigraphy of Thailand. In: Thanvarachorn, P., Hokjaroen, S., Youngme, W. (Eds.), Proceedings of the Dimensions Conference on Geology and Mineral Resources Development of the Northeast Thailand. Thailand, Khon Kaen University. (Table 1, in mm): The average size is 7.7 mm length, 9.1 mm Cox, L.R., Newell, N.D., Boyd, D.W., Branson, C.C., Casey, R., Chavan, A., Coogan, A.H., Dechaseaux, C., Fleming, C.A., Haas, F., Hertlein, L.G., Kauffman, E.G., Keen, A.M., height, and range of L/H ratio 0.85, but individual specimens may Larocque, A., McAlester, A.L., Moore, R.C., Nuttall, C.P., Parkin, B.F., Puri, H.S., Smith, reach 12 mm in length, 14 mm in height, with a L/H ratio of 0.85. L.A., Soot-Ryen, T., Stenzel, H.B., Trueman, E.R., Turner, R.D., Weir, J., 1969. The Geological Society of America and the University of Kansas. In: Moore, R.C. (Ed.), Treatise on Invertebrate Paleontology. : Part N, Mollusca 6, Bivalvia, Vol. 1, 2 y 3. Occurrence University of Kansas, Lawrence, Kansas. Fontaine, H., Suteethorn, V., 1988. Late Paleozoic and Mesozoic fossils of West Thailand and their environments. CCOP Technical Bulletin 20, 217. Common in dark grey mudstones, and rare in fossiliferous Garson, M.S., Mitchell, A.H.G., 1970. Transform faulting in the Thai Peninsula. Nature, limestone of the Khlong Min Formation at the Ban Khao Ngam, London 22, 45–47. 60 W. Saengsrichan et al. / Gondwana Research 19 (2011) 47–60

Gatinsky,Y.G.,Mishima,A.V.,Vinogradov,I.V.,Kovalev,A.A.,1978.Themain Meesook, A., Sha, J., Teerarungsigul, N., Poonpun, S., 2006b. Non-marine Jurassic rocks metallogenic belts of Southeast Asia as a result of different geodynamic conditions of Thailand. A summary. Progress in Natural Science, Marine and Non-marine interference. In: Nutalaya, P. (Ed.), Proceedings of the Third Regional Conference on Jurassic. : Boundary Events and Correlation., 16. National Natural Science Foundation Geology and Mineral Resources of Southeast Asia. Bangkok, AIT. and Chinese Academy of Sciences of China, Beijing, China, pp. 153–162 (special issue). Grant-Mackie, J.A., Sawata, H., Arpornsuwan, S., Arrykul, S., Chutatis, V., Pungrassami, T., Metcalfe, I., 1988. Origin and assembly of Southeast Asian Continental terranes. In: 1980. Some Triassic and associated strata of southern Thailand. Report of Triassic Audley-Charles, M.G., Hallam, A. (Eds.), Gondwana and Tethys: Geological Society Study Team No. 1, Prince of Songkla University, Geological Research Project, 9, p. 85. of London, Special Publication, 37, pp. 101–118. Hada, S., 1990. Geology of the Nan-Chanthaburi suture zone: (I) stratigraphy and Metcalfe, I., 1989. Triassic sedimentation in the central basin of peninsular Malaysia. In: geologic structure. In: Charusiri, P., Pisutha-Arnond, V., Jaupongsakul, S. (Eds.), Thanasuthipitak, T., Ounchanum, P. (Eds.), Proceedings of the International Proceedings of the Technical Conferences on Development Geology for Thailand Symposium on Intermontane Basins: Geology and Resouces. Chiang Mai, Thailand, into the Year 2000. Department of Geology, Chulalongkorn University, Bangkok, pp. 173–186. Thailand. Metcalfe, I., 2006. Paleozoic and Mesozoic tectonic evolution and palaeogeography of Hahn, L., 1982. Stratigraphy and marine ingressions of the Mesozoic Khorat Group in East Asian crustal fragments: the Korean Peninsula in context. Gondwana Research Northeastern Thailand. Geologisches Jahrbuch, Reihe B43, 7–35. 9, 24–46. Hahn, L., Koch, K.E., Witte Kindt, H., 1986. Outline of the geology and mineral potential Metcalfe, I., 2010— this issue. Tectonic framework and Phanerozoic evolution of of Thailand. Geologische Jahrbuch, Reihe B59, 3–49. Sundaland. Gondwana Research, doi:10.1016/j.gr.2010.02.016. Hara, H., Wakita, K., Ueno, K., Kamata, Y., Hisada, K., Charusiri, P., Charoentitirat, C., Nakanart, A., Mantajit, N., 1983. Stratigraphic correlation of the Andaman Sea, preprint. Chaodumrong, P., 2009. Nature of accretion related to Paleo-Tethys subduction Conference, Geology and Mineral Resources of Thailand, Bangkok, Thailand. recorded in northern Thailand: constraints from mélange kinematics and illite Panjasawatwong, Y., 1991. Petrology, geochemistry, and tectonic implications of crystallinity. Gondwana Research 16, 310–320. igneous rocks in the Nan Suture, Thailand and an empirical study of the effects of Hayami, I., 1960. Two Jurassic Pelecypods from West Thailand. Trans. Proc. Palaeonto- Ca/Na, Al/Si and H2O on plagioclase-melt equilibria at 5–10 kb pressure. Ph.D. logical Society of Japan 38, 284. thesis, University of Tasmania, Hobart, Australia. Hirsch, F., Ishida, K., Kozai, T., Meesook, A., 2006. The welding of Shan–Thai. Geosciences Polachan, S., Sattayarak, N., 1989. Strike-slip tectonics and the development of Tertiary Journal 10 (3), 195–204. basins in Thailand. In: Thanasuthipitak, T., Ounchanum, P. (Eds.), Proceedings of the Hutchison, C.S., 1975. Ophiolite in Southeast Asia. Bulletin of the Geological Society of International Symposium on Intermontane Basins: Geology and Resources. : America 86, 797–806. Department of Geological Sciences. Chiang Mai University, Chiang Mai, pp. 243–253. Hutchison, C.S., 1989. Geological evolution of Southeast Asia. Oxford University Press, Poonpun, S., Thiumwong, P., Saengsrichan, W., 2002. Geology of limestone in the Ban Oxford Monographs on Geology and Geophysics 13, 368. Mak and Ban Bang Hian Quadrangles, Ao Luk and Plai Phraya Districts, Krabi Kanjanapayont, P., 2002. Geologic Structural Model Illustrated by the Mesozoic Province. Department of Mineral Resources, Bangkok Thailand, Geologic Quadran- Stratigraphic Units in the Upper Southern Thailand, with Special Reference to gle Maps 4725I and 4726II, scale 1:50,000. Changwat Krabi and Surat Thani. Thesis, Chulalongkorn University, Bangkok, Raksaskulwong, L., 1994. Trang Group, Geological Survey Division, Department of Thailand, M.Sc. Mineral Resources (unpublished, in Thai with English abstract). Kemper, E., 1976. The foraminifera in the Jurassic limestone of west Thailand. Raksaskulwong, L., 2002. Thung Yai Group: Jurassic–Cretaceous transition and Geologisches Jahrbuch, Reihe B 21, 129–153. continental deposits in Southern Thailand. Geological Survey Division. Department Kobayashi, T., Tokuyama, A., 1959. The Halobiidae from Thailand. Journal of Faculty of of Mineral Resources, Bangkok, Thailand (Report no. 260/2545). Science, University of Tokyo 12, 27–30. Raksaskulwong, L., Teerarungsigul, N., Thanphisit, K., 1989. Geology of Thung Kon'no, E., Asama, K., 1973. Mesozoic plants from Khorat, Thailand. Geology and Yai, Ban Nua Klong and Ban Thang Laung Quadrangles. Geological Survey Division, Palaeontology of Southeast Asia, Tokyo University 12, 149–172. Department of Mineral Resources, Bangkok, Thailand, Geologic Quadrangle Kondo, Y., Kozai, T., Kikuchi, N., Sukawara, K., 2006. Ecologic and taxonomic Maps 4825 III and 4825 II, scale 1:50,000. diversification in the Mesozoic brackish water bivalve faunas in Japan, with Sacco, F., 1987. 1 molluschi dei terreni terziarii del Piemonte e della Liguria. Musei emphasis on infaunalization of heterodonts. Gondwana Research 10, 316–327. Zoologia Anatomia comp. R. Univ. Torino, boll. 12, 99–102. Kozai, T., Ishida, K., Hirsch, F., Park, Sun-Ok, Chang, Ki-Hong, 2005. Early Cretaceous non- Sanansiang, S., 1977. Geologic map of Nakhon Si Thammarat Quadrangle. Geological marine mollusc faunas of Japan and Korea. Cretaceous Research 26 (1), 97–112. Survey Division, Department of Mieneral Resources, Geologic Quadrangle Map NC Kozai, T., Hirsch, F., Ishida, K., Meesook, T., 2006. Faunal affinity of Toarcian–Aalenian 47-15, scale 1:250, 000. (Early Jurassic) bivalves from Mae Sot and Umphang (), Northwestern Sengor, A.M.C., 1984. The Cimmeride orogenic system and the tectonics of Eurasia. Thailand. Geosciences Journal 10 (3), 205–215. Geological Society of America Special Paper 195, 88p. Li, X., Grant-Mackie, J.A., 1993. Jurassic sedimentary cycles and eustatic sea level Sha, J., Fuersich, F.T., 1993. Biostratigraphy of the Upper Jurassic–Lower Cretaceous changes in southern tibet. Paleogeography Paleoclimatology and Paleoecology 101 bivalves Buchia and Aucellina of eastern Heilongjiang, northeast China. Geological (1–2), 27–48. Magazine 130, 533–542. Linne, C., 1758. Systema nature per regna tria nature: edit. Decima (Holmiae) 824. Stauffer, P., 1974. Malaya and Southeast Asia in the pattern of continental drift. Bulletin. Macdonald, A.S., Barr, S.M., 1978. Tectonic significance of the Late Carboniferous Geological Society of Malaysia 7, 84–138. volcanic arcs in northern Thailand: geochemistry and tectonic significance. Tantiwanit, W., Bupasiri, W., Kamchoo, A., Boonchoo, W., 1989. Annual report, Geology Bulletin. Geological Society of Malaysia 17, 209–244. of Amphoe Panom and Ban Bang Haen Quadrangles, Geologic Quadrangle Mansuy, H., 1914. Description d' especes nouvelles des terranes paleozoique du Tonkin. Maps 4726 I and 4726 II, scale 1:50,000. Geological Survey Division, Department IV. Gisement liasiquedes schistes de Trian. V. Etude des faunes, des feuilles de Phu of Mineral Resources. Nhoquan et Sontay (Tonkin). Mem. Serv. Geol. Ind. 3, 2. Teerarungsigul, N., 1999. Lithostratigraphy of Non-marine Mesozoic Rocks: Thung Yai- Matsukawa, Matsukawa, M., Lockley, M., Jianjun, L., 2006. Cretaceous terrestrial biotas Klong Thom Area, in Southern Part of Thailand. Thesis, Chulalongkorn University, of East Asia, with special reference to dinosaur-dominated ichnofaunas: towards a Bangkok, Thailand, M.Sc. synthesis. Cretaceous Research 27, 3–21. Vaught, K.C., 1989. A classification of the living mollusca. In: Abbutt, R.T., Boss, K.J. Meesook, A., 1994. Marine Jurassic Stratigraphy and Bivalve Paleontology of Thailand. (Eds.), Am. Malacologists, Inc, Melbourne, Florida, p. 32902 (U.S.A.). Ph.D thesis, University of Auckland, New Zealand. von Braun, E., Jordan, R., 1976. The stratigraphy and palaeontology of the Mesozoic Meesook, A., Grant-Mackie, J.A., 1994. Biostratigraphic correlation of marine Jurassic sequence in the Mae Sot area in western Thailand. Geologisches Jahrbuch, Reihe B, rocks within Thailand and Southeast Asia. Proceedings of the International Heft 21, 5–51. Symposium on: Stratigraphic Correlation of Southeast Asia, pp. 160–169 (Bangkok, Vu, Khuc, Vu, Chau, Trinh, D., Dang, T.H., Nguyen, D.H., Trinh, T., 1991. Paleontological Atlas Thailand). of Vietnam. : Mollusca, vol. 3. Science and Technics Publishing House, Hanoi (207. p). Meesook, A., Grant-Mackie, J.A., 1996. Marine Jurassic lithostratigraphy of Thailand. Waller, T.R., 1978. Morphology, morphoclines and a new classification of the Journal of Southeast Asian Earth Sciences 14 (5), 377–391. Pteriomorphia. In: Yonge, C., Thompson, T. (Eds.), Evolutionary Systematics of Meesook, A., Teerarungsigul, N., Saengsrichan, W., 2005. Mesozoic stratigraphy and Bivalve Mollusks: Philos. Trans. R. Soc., ser. B, 284, 1001, pp. 345–365 (Mollusca: faunal aspects of Thailand. Final Report, Submitted to the Project Entitled, the Bivalvia). Evolution of Mesozoic Biodiversity in Thailand, Bureau of Geological Survey. Yin, J., Grant-Mackie, J., 2005. Late Triassic–Jurassic bivalves from volcanic sediments of Department of Mineral Resources, Bangkok, Thailand. the Lhasa block. New Zealand Journal of Geology & Geophysics 2005 (48), 555–576. Meesook, A., Sha, J., Saengsrichan, W., Teerarungsigul, N., 2006a. Lithostratigraphy and Zuoqi, L., 1993. The discovery and significance of the Late Jurassic sporopollen faunal aspects of marine Jurassic rocks in Thailand. Progress in Natural Science, assemblage in peninsular Thailand. In: Thanasuthipitak, T. (Ed.), Proceedings of the Marine and Non-marine Jurassic. : Boundary Events and Correlation, 16. National International Symposium on Biostratigraphy of Mainland Asia. Facies and Natural Science Foundation and Chinese Academy of Sciences of China, Beijing, Palaeontology, Chiang Mai, pp. 361–380. China, pp. 119–152 (special issue).