Ocean Plate Stratigraphy in East and Southeast Asia

Journal of Asian Earth Sciences 24 (2005) 679–702 www.elsevier.com/locate/jaes

Ocean Plate Stratigraphy in East and Southeast Asia Koji Wakitaa,*, Ian Metcalfeb a

Institute of Geology and Geoinformation, National Institute of Advanced Industrial Science and Technology, Tsukuba 305-8567, Japan b Asia Centre, University of New England, Armidale, NSW 2351, Australia Received 15 March 2003; accepted 11 April 2004

Abstract Ancient accretionary wedges have been recognised by the presence of glaucophane schist, radiolarian chert and me´lange. Recent techniques for the reconstruction of disrupted fragments of such wedges by means of radiolarian biostratigraphy, provide a more comprehensive history of ocean plate subduction and successive accretion of ocean floor materials from the oceanic plate through offscraping and underplating. Reconstructed ocean floor sequences found in ancient accretionary complexes in Japan comprise, from oldest to youngest, pillow basalt, limestone, radiolarian chert, siliceous shale, and shale and sandstone. Similar lithologies also occur in the me´lange complexes of the Philippines, Indonesia, Thailand and other regions. This succession is called ‘Ocean Plate Stratigraphy’ (OPS), and it represents the following sequence of processes: birth of the oceanic plate at the oceanic ridge; formation of volcanic islands near the ridge, covered by calcareous reefs; sedimentation of calcilutite on the flanks of the volcanic islands where radiolarian chert is also deposited; deposition of radiolarian skeletons on the oceanic plate in a pelagic setting, and sedimentary mixing of radiolarian remains and detrital grains to form siliceous shale in a hemipelagic setting; and sedimentation of coarse-grained sandstone and shale at or near the trench of the convergent margin. Radiolarian biostratigraphy of detrital sedimentary rocks provides information on the time and duration of ocean plate subduction. The ages of detrital sediments becomes younger oceanward as younger packages of OPS are scraped off the downgoing plate. OPS reconstructed from ancient accretionary complexes give us the age of subduction and accretion, direction of subduction, and ancient tectonic environments and is an important key to understanding the paleoenvironment and history of the paleo-oceans now represented only in suture zones and orogenic belts. q 2004 Elsevier Ltd. All rights reserved. Keywords: Accretionary complex; Me´langes; Tethys

1. Introduction Ancient accretionary complexes have been recognized in the orogenic belts of the Asian region (Hutchison, 1989; Metcalfe, 1988, 1990, 1996, 2000; Sengo¨r and Natal’in, 1996). These were recognised by the presence of glaucophane schist, radiolarian chert and me´lange composed of polymict clasts within a scaly matrix. Recent developments in the study of Paleozoic and Mesozoic radiolarian biostratigraphy gives us a new technique for the reconstruction of disrupted fragments in

* Corresponding author. Tel.: C81-29-861-2469; fax: C81-29-8613742. E-mail address: [email protected] (K. Wakita). 1367-9120/$ - see front matter q 2004 Elsevier Ltd. All rights reserved. doi:10.1016/j.jseaes.2004.04.004

the orogenic belts. We can reconstruct the original stratigraphy of the protolith of me´langes by means of radiolarian biostratigraphy. The sequence of lithologies in reconstructed sequences from me´langes and from ancient accretionary complexes is similar. The stratigraphical succession reconstructed from the me´langes and accretionary complexes is here called ‘Ocean Plate Stratigraphy’ (OPS). These successions provide evidence for the history of the ocean plate from its initiation at a mid-ocean ridge to subduction at an oceanic trench, with the successive accretion of oceanic materials from the oceanic plate through offscaping and underplating to form an accretionary complex (Matsuda and Isozaki, 1991; Isozaki and Blake, 1994; Wakita, 1988a,b, 2000a). This paper firstly reviews research on Jurassic accretionary complexes in Japan, and defines ‘Ocean Plate

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Fig. 1. Distribution of continental terranes, accretionary complexes and sutures in East and Southeast Asia. Names of major accretionary complexes and sutures are: 1. Samarka; 2. Khabarovsk; 3. Nadanhata; 4. Akiyoshi; 5. Mino-Tamba; 6. North Shimanto; 7. Palawan; 8.Luk-Ulo; 9.Bentong-Raub; 10. YarlungZangbo. The reconstructed OPS of the accretionary complexes and sutures are shown in Fig. 8 with same numbers.

Stratigraphy’. Secondly, recent work on Ocean Plate Stratigraphy in East and Southeast Asia (Russian Far East, China, Philippines, Indonesia, Malaysia and Thailand) (Fig. 1) is summarised, including specific contributions by the authors in central Japan, central Java, and Northern Thailand. The importance and implications of Ocean Plate Stratigraphy for tectonics and amalgamation of continental terranes in Asia are also discussed.

2. Definition of Ocean Plate Stratigraphy (OPS) Ocean Plate Stratigraphy was first defined by Isozaki et al. (1990) as ‘Oceanic Plate Stratigraphy’. We here re-name this as ‘Ocean Plate Stratigraphy’ to include the stratigraphy of any tectonic ocean basin with an ocean plate basement, including marginal basins. Ocean Plate Stratigraphy is an

idealised stratigraphic succession of the ocean floor, reconstructed from the protoliths of me´langes or ancient accretionary complexes. It is usually reconstructed by means of radiolarian, conodont and fusulinid microfossil biostratigraphy. Radiolarians are the most useful because they occur throughout the Phanerozoic and in various lithologies, argillaceous, siliceous or calcareous. Fig. 2 shows an idealised stratigraphic column of Ocean Plate Stratigraphy reconstructed from protoliths of Paleozoic to Mesozoic accretionary complexes in Japan. These successions have similar lithologies, even though they are of different ages. The lower part of the OPS comprises basalt, limestone and chert, whereas the upper part is of chert, siliceous shale and turbidite in ascending order. The ideal succession of the OPS is pillow basalt, limestone, radiolarian chert, siliceous shale, and shale and sandstone in ascending order. The age range represented by chert is

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Fig. 2. Standard OPS reconstructed for a Jurassic accretionary complex in Japan.

much longer than that for the detrital clastic rocks. On the other hand, the detrital clastic part of the OPS is thickest because of a higher rate of sedimentation in detrital sediments compared to pelagic chert.

3. History of Oceanic Plate recorded in the OPS Ocean Plate Stratigraphy is commonly composed of pillow basalt, limestone, chert, siliceous shale, and detrital turbidite in ascending order. The basal pillow basalts have an alkaline–basalt chemical composition indicating an origin as seamounts. The basalt is often overlain by reefal limestone and passes into reef detritus, which often occurs on the flanks of seamounts or on the surrounding oceanic floor (Okamura, 1991; Sano, 1988a,b; Sano and Kojima, 2000). Radiolarian siliceous skeletons are deposited slowly

on the ocean floor as ‘marine snow’ after the death of the organism and are diagenetically altered to chert. Layers of calcareous detrital fragments occur interbedded with siliceous radiolarian oozes on or near the flanks of seamounts, forming limestones interbedded with chert. Radiolarian chert overlies the limestone and chert, interbedded with very thin shale films, and the deposit is called ‘bedded’, or ‘ribbon-bedded’ chert. A very slow rate of sedimentation is estimated from the age ranges and thicknesses of ribbon-bedded radiolarian chert. These cherts include no detrital grains derived from a continental provenance. The slow sedimentation rate and lack of continentderived grains indicate that ribbon-bedded radiolarian cherts are pelagic sediments deposited on the oceanic floor. The age range of chert in an OPS sequence documents the age of the ocean floor and its duration, from birth at a mid-ocean ridge to death at the trench.

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Fig. 3. Formation and disruption processes of Ocean Plate Stratigraphy.

Oceanic radiolarian chert grades upwards into siliceous shale, which consists mainly of fine-grained detritus and radiolarian remains. The greater proportion of radiolarians, and a slower sedimentation rate than normal detrital sediments, indicate a hemipelagic environment on the offshore side of the trench near the continental margin. The siliceous shale is successively covered by shale, interbedded with thin sandstone layers, which is followed by a sandstone-dominated turbidite sequence. The younger turbidite sequence includes proximal massive coarsegrained sandstones. Both the shale-dominated and sandstone-dominated sequences are flysch-type sedimentary rocks deposited by turbidity currents near or at the trench. These Ocean Plate Stratigraphy successions record the geologic history of the ocean floor from its formation at the mid-ocean ridge to subduction at the convergent plate margin (Fig. 3). Volcanic islands, created near shallow oceanic ridges just after the oceanic plate was born, were covered by reef limestone following subsidence below sea level as the plate spread away from the ridge. This produced the basalt overlain by reef limestone seen in the lower part of the succession. Alternatively, within-plate volcanism, related to a hot-spot, may have produced volcanic islands (such as the Hawaiian-Emperor Chain) which results in a basalt–reef limestone couplet. These two possibilities can be distinguished by the geochemical signature of the basalts. Limestone interbedded with chert is a rock facies formed in the ocean, near or on the flanks of volcanic islands/ seamounts, probably close to the carbonate compensation depth (CCD). Ribbon-bedded radiolarian chert is formed from radiolarian ooze deposited on the oceanic floor below the CCD, and records the travel history of any particular segment of oceanic plate following subsidence of

the volcanic islands/seamounts, until their arrival at the subduction trench at the continental margin. Siliceous muds, overlying radiolarian cherts were deposited in the hemipelagic region just before the oceanic plate arrived at the trench. The oceanic plate segment, covered by radiolarian chert and siliceous mud, is then covered by flysch-type trench-fill sediments on its arrival in the trench. The upper parts of the Ocean Plate Stratigraphy are scraped off at the toe of the accretionary wedge and stacked tectonically in the accretionary prism. On the other hand, the lower parts of the OPS are accreted into the accretionary prism by an underplating process. In particular, the upper parts of accreted volcanic islands (seamounts) were scraped off along deep-seated decollements. These accreted sediments were deformed and disrupted by multiple processes.

4. Reconstruction of Ocean Plate Stratigraphy: an example from the Jurassic accretionary complex of Japan Jurassic accretionary complexes are major components of the Japanese Islands. Equivalents extend north to Sikhote-Alin and northeast China (Kojima, 1989), and Western Philippines (Isozaki et al., 1988; Faure and Ishida, 1990; Zamoras and Matsuoka, 2001). They are composed of basalt, limestone, chert, siliceous shale, mudstone, sandstone and conglomerate. The Jurassic accretionary complexes can be divided into coherent and me´lange units. The coherent units are composed of imbricated thrust sheets, each several hundred meters thick (e.g. Yoshida and Wakita, 1999). Each sheet, 100–500 m thick, consists of a coherent stratigraphic

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sequence of Early Triassic siliceous claystone, Middle Triassic to Early Jurassic radiolarian ribbon-chert, Middle Jurassic siliceous mudstone and Middle to Late Jurassic turbidite, in ascending order. The ages of each lithology were determined by extensive radiolarian biostratigraphic work (e.g. Yao et al., 1980; Kimura and Hori, 1993). The reconstructed succession corresponds to the upper part of the OPS. The me´lange unit, characterised by blocks of various lithologies in a sheared mudstone matrix, may be subdivided into two types, i.e. sandstone–chert me´lange and basalt–limestone me´lange. The sandstone–chert me´lange includes clasts of siliceous claystone, radiolarian chert, siliceous mudstone and turbidite within a dark gray terrigenous mudstone. The basalt–limestone me´lange includes various sized clasts mainly of basalt, limestone and chert of Permian age, within a carbonaceous muddy matrix (Sano, 1988a,b; Wakita, 1991). The matrix, deep black in color, yields very few detrital grains but has a high (O10%) carbonaceous content (Wakita, 1988b). The sandstone–chert me´lange is a chaotic mixture derived mainly from the dismembered upper OPS. On the other hand, the basalt–limestone me´lange is produced from the dismembered lower OPS (Fig. 4). The two types of the me´langes are the end members of various me´lange types in the Jurassic accretionary complex of the Mino terrane. Most of the me´langes of the Mino terrane are mixtures of the two types of me´lange, i.e. sandstone–chert me´lange and basalt– limestone me´lange.

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4.1. Tectonically stacked OPS The Jurassic accretionary complexes of Japan contain well-preserved upper OPS which were tectonically stacked during the process of off-scraping at the Jurassic convergent margin. The sequence observed in the Inuyama area, central Japan is composed of Early Triassic siliceous claystone, Middle Triassic to Early Jurassic chert, Middle Jurassic siliceous shale and Middle to Late Jurassic turbidites in ascending order. Extensive studies of the stratigraphy, paleontology, sedimentology, structural geology, and paleomagnetism have been carried out on the rocks of the Mino Terrane exposed along the Kiso River in the Inuyama area (e.g. Kondo and Adachi, 1975; Yao et al., 1980; Mizutani and Koike, 1982; Shibuya and Sasajima, 1986; Matsuda and Isozaki, 1991; Kimura and Hori, 1993; Ando et al., 2001). The rocks consist of Early Triassic carbonaceous– siliceous claystone, Middle Triassic to Early Jurassic radiolarian bedded chert, Middle Jurassic siliceous mudstone, Middle Jurassic black mudstone and Middle Jurassic (?) turbidite. This chert–clastic rock sequence, about 200–300 m in thickness, represents the upper part of the ocean plate stratigraphy (OPS). The rock formations are cut by many thrusts parallel to the bedding planes, and the rock succession, or part of the succession, occurs repeatedly in the Inuyama area. The stack of thrust sheets is folded into an EW-trending and westward-plunging synform (Fig. 4).

Fig. 4. Geologic Map of the stacked upper OPS in Inuyama area, central Japan. Inset is a detailed map of the geology and structure along the Kiso River in the area outlined on the main map.

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The lowermost unit of the OPS in this area is carbonaceous–siliceous claystone. The claystone is composed of alternating beds of carbonaceous black shale and greenish gray siliceous claystone. Dolomite layers and lenses are occasionally interbedded with the claystone. Lower Triassic conodonts were reported from this claystone at many localities in Japan (Igo, 1979). The claystone is known to occur above the black shale accumulated across the Permian– Triassic boundary (Isozaki, 1997c), although the boundary formation is missing in this area due to thrusting. The claystone is covered by reddish brown radiolarian chert. The chert formation consists of 2–5 cm thick chert beds with thin siliceous shale partings. The rhythmical bedding is interpreted as formed by the cyclic deposition of a slow, but continuous accumulation of siliceous shale, and the fast, episodic blooming of radiolarians (Hori et al., 1993). Yao (1982) carried out a radiolarian biostratigraphic study on the chert at this locality, and established four radiolarian assemblage zones, ranging in age from Middle Triassic to Early Jurassic. This zonation has become the standard for the Japanese radiolarian zones for this time interval. Subsequently, Sugiyama (1997) subdivided the Lower Triassic to Early Jurassic into 20 radiolarian zones by analyzing the claystone– chert formations in this area. Correlation of the radiolarian zones with international zonation schemes, and the examination of the co-occurring conodonts have permitted the correlation of the radiolarian zones in this area with the international radiolarian zonation. The radiolarian chert gradually passes into siliceous mudstone, indicating the approach of the oceanic plate to the subduction zone. In the Inuyama area, the boundary between the chert and siliceous mudstone is correlated approximately with the boundary between the Lower and Middle Jurassic. The siliceous mudstone is dark brown, brownish gray, and greenish gray in color, and is massive to weakly bedded. Abundant radiolarian fossils have been reported from the mudstone, and exceptionally wellpreserved radiolarians occur in manganese–carbonate nodules and in bands of siliceous mudstone (Ichikawa and Yao, 1976; Yao, 1972, 1979; Mizutani and Koike, 1982). The siliceous mudstone is covered by black mudstone indicating that fine-grained terrigenous clastic materials were reaching the oceanic plate. The black mudstone also includes radiolarian fossils dated as of upper Middle Jurassic age (Kimura and Hori, 1993). The mudstone is intruded by sandstone dikes and sills, the composition of the sandstone being identical to that of the turbidite sandstone described below, indicating that the sandstone dikes and sills were derived from subducted water-rich turbidite under high pore water pressure. All the rocks are capped by proximal turbidites composed of coarse-grained sandstone and mudstone. By the time of deposition of the turbidite, the oceanic plate had arrived at the trench. The Middle Jurassic ammonite, Choffatia sp., was found in the clastic rocks in this area

(Sato, 1974). Generally speaking, sandstones in the Mino Terrane are graywackes rich in quartz and feldspar with accessory biotite, garnet, zircon, tourmaline and opaques (Mizutani, 1957, 1959). 4.2. Upper OPS reconstructed from me´lange Sandstone–chert me´langes commonly occur in the Jurassic accretionary complex of Japan. The me´langes are chaotic mixtures of clasts of various rock types within a shale matrix. The major rock types of clasts are sandstone, chert, and siliceous shale. Wakita (1984) reconstructed the protolith of the me´lange of the Mino Terrane, by means of radiolarian biostratigraphy. He investigated the ages and lithologies of the various types of rock included as clasts in the me´langes, and reconstructed the stratigraphic column of the protolith from which the me´lange clasts were derived (Wakita, 1984) (Fig. 5). The reconstructed succession consists of radiolarian chert (Middle Triassic to Middle Jurassic), siliceous shale (Late Jurassic to earliest Cretaceous) and shale and sandstone (earliest Cretaceous) in ascending order (Fig. 5). This succession is similar to the tectonically stacked OPS, typically observed in the Inuyama area, central Japan. It also corresponds to the upper part of the Ocean Plate Stratigraphy. Late Triassic or younger basalt including kaersutite and biotite are intercalated in chert beds (Wakita, 1984, 1988b). This might have been a local event related to hot spot activity on the oceanic floor. The sandstone–chert me´lange is composed of various types of mixtures derived from upper and middle parts of the OPS such as sandstone, mudstone, siliceous mudstone, chert, and P–T boundary claystone. The mixture is subdivided into two parts, i.e. a mixture of the upper part of the OPS, and a mixture of the middle part of the OPS. The former is characterized by clasts of sandstone, siliceous mudstone and chert within a dark gray terrigenous mudstone matrix. The matrix contains terrigenous fragments, quartz, feldspars, micas, and various rock fragments. The latter contains the P–T boundary siliceous claystone and chert blocks within black claystone, which is a mixture of the P–T boundary carbonaceous claystone and Jurassic terrigenous mudstone. The OPS was detached from the subducting oceanic plate along a decollement surface (Fig. 3). The decollement was located at the position of the P–T boundary claystone, so that the upper and middle parts of the OPS were scraped off above this level. Disruption and mixing of neighboring materials occurred in and along the decollement zone. The uppermost turbidites are overlain tectonically by the P–T boundary claystone which occupies the lowermost level of the overthrust sheet, and became disrupted into broken formations. On the other hand, the P–T boundary siliceous claystone and Early Triassic chert were detached from the underlying OPS and mixed with highly sheared carbonaceous claystone matrix.

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Fig. 5. Reconstruction of OPS from the earliest Cretaceous me´lange of the Mino Terrane in the Kanayama area, central Japan by means of radiolarian biostratigraphic technique (Wakita, 1988a).

4.3. Lower OPS reconstructed from me´lange Lower parts of the OPS are preserved in the basalt– limestone me´lange of the Mino Terrane. Basalt and limestone was detached from subducting seamounts and accreted mainly in the lower part of the accretionary prism during the underplating process (Fig. 3). Permian chert was detached from the lower part of the OPS, and mixed with basalt and limestone in the basalt–limestone me´langes. The basalt–limestone me´lange unit is composed of various types of mixtures derived from the lower parts of the OPS such as chert, P–T boundary claystone, limestone

and basalt. The matrix does not contain terrigenous fragments such as quartz and feldspars, but has a high carbon content (O15%). The carbonaceous claystone was derived from the P–T boundary siliceous and carbonaceous claystone part of the OPS. Basalt of the Jurassic accretionary prism was metamorphosed to prehnite–pumpellyite–pumpellyite–actinolite facies (Hashimoto and Saito, 1970). This indicates that the seamount body was subducted deeply enough to be metamorphosed to these grades, and incorporated into the accretionary prism. Therefore the basalt–limestone me´langes are considered to be products of the underplating

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processes. The upper part of the subducting seamounts were cut off and accreted into the deeper part of the accretionary wedge and mixed with adjacent mudstone and chert. The matrix of the basalt–limestone me´langes is more sheared and deformed than that of the sandstone–chert me´langes because the former was detached in the deeper part of the accretionary wedge during the underplating process.

5. Ocean Plate Stratigraphy (OPS) of the Western Pacific Margin 5.1. Japan Accretionary complexes are the main components of the pre-Tertiary tectonic units in Southwest Japan (Wakita, 1989, 1997; Isozaki et al., 1990; Ichikawa

et al., 1990). Three main complexes are recognized, i.e. the Permian accretionary complex of the Chugoku Terrane, the Jurassic (to earliest Cretaceous) accretionary complex of the Chichibu-Tamba-Mino Terrane, and Cretaceous (to Paleogene) accretionary complex of the Shimanto Terrane. The Permian accretionary complex, the main component of the Chugoku Terrane, contains sandstone, shale, chert, basalt and limestone. They are chaotic mixtures of Middle to Late Permian trench-fill sediments, Middle Permian pelagic sediments (chert) and accreted remnants of Carboniferous to Permian seamounts (Fig. 6). Chert, basalt and limestone occur as allochthonous blocks incorporated into flysch and me´langes during subduction. Jurassic accretionary complexes are the dominant tectonic units in Japan. They occur in the Mino-Tamba, Chichibu, Sambagawa and North Kitakami terranes.

Fig. 6. Arrangement and reconstructed OPS of three major accretionary complexes in Japan. Permian AC: Permian accretionary complex of the Akiyoshi Terrane, Jurassic AC: Jurassic accretionary complexes of the Tamba, Mino, Ashio and Chichibu Terranes, Cretaceous AC: Cretaceous accretionary complex of the Shimanto Terrane.

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The accretionary complexes are composed mainly of Jurassic to earliest Cretaceous accretionary flysch and me´langes associated with allochthonous blocks of Permian to Triassic chert, limestone and basalt (Fig. 6). One of the most famous accretionary complexes in Japan is that of the Shimanto Terrane, which was the first to be reported as an ancient analogue to an accretionary prism. The complex is subdivided into Cretaceous and Paleogene parts. The subduction complex of the Shimanto Terrane extends to Central Hokkaido through offshore Northeast Japan. This complex is composed mainly of thick coarse-grained turbidites, tectonically intercalated with relatively thin me´lange zones. The turbidites are tectonically imbricated by north-dipping thrust faults. The me´langes are highly sheared due to tectonic mixing, and occur in a thin tectonic zone between two flysch units. Ocean Plate Stratigraphy is recognized in the reconstructed succession from the me´langes (Taira et al., 1988). The reconstructed OPS from the me´lange of the Northern Shimanto Belt is as follows (Taira et al., 1988). Oceanic basalt is older than Valanginian, chert ranges from Hauterivian to Cenomanian, hemipelagic siliceous shale ranges from Turonian to Santonian, and flysch is younger than Santonian. The reconstructed OPS in Fig. 6 is based on recent biostratigraphic data as well as Taira et al.’s (1988) original data. 5.2. Philippines Jurassic accretionary complexes are reported from North Palawan, the Calamian Islands and South Mindoro Island in the Philippines (Isozaki et al., 1988; Faure and Ishida, 1990; Zamoras and Matsuoka, 2001). They are components of the North Palawan Block (Isozaki et al., 1988) and are composed of chert, limestone, siliceous mudstone and turbidite (Zamoras and Matsuoka, 2001). The protolith stratigraphy of the accretionary complex has been reconstructed by several researchers (Cheng, 1989, 1992; Tumanada, 1991, 1994; Yeh, 1992; Yeh and Cheng, 1996, 1998; Tumanda-Mateer et al., 1996; Zamoras and Matsuoka, 2000, 2001) by means of radiolarian biostratigraphy. The complex of Busuanga Island is the most recently and best investigated among the accretionary complexes of the North Palawan Block. This complex is divided into three belts, the Northern, Middle and Southern Busuanga Belts. Zamoras and Matsuoka (2001) described the stratigraphic succession of the three belts as follows. The Northern Busuanga Belt is composed of Middle Permian to Middle Jurassic chert followed by Bathonian– Callovian siliceous mudstone and Callovian turbidite. The Middle Busuanga Belt has Bajocian–lower Bathonian cherts, a siliceous mudstone interval from upper Bathonian to lower Oxfordian, and turbidites of Oxfordian age. The Southern Busuanga Belt covers a transition from lower-middle Tithonian chert to upper

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Tithonian–Berriasian siliceous mudstone and turbidite of Lower Cretaceous age (Fig. 7). The accretionary complex of the North Palawan Block is considered to be the southwestern extension of the Jurassic– Early Cretaceous accretionary complexes of Japan (Isozaki et al., 1988; Kojima and Kametaka, 2000; Zamoras and Matsuoka, 2001). 5.3. Russian Far East and Northeast China Jurassic to Early Cretaceous accretionary complexes are distributed in the Sikote-Alin area, Russian Far East and in the Nadanhata area, Northeast China (Kojima, 1989; Mizutani and Kojima, 1992; Kojima and Kametaka, 2000). They are composed of limestone, basalt, gabbro, chert, siliceous shale, me´langes and turbidites. Extensive biostratigraphic research has revealed an OPS protolith for the complexes as shown in Fig. 8. The accretionary complexes of the Samarka and Khabarovsk terranes in the Sikhote-Alin area, and the complex of the Nadanhata area are well investigated by means of micropaleontology. Chert contains Late Devonian to Triassic conodonts and radiolarians, Carboniferous to Permian fusulinids are included in limestone, and middle to late Jurassic radiolarians from the siliceous shale in the Samarka Terrane (Kemkin and Khanchuk, 1994; Kojima and Kametaka, 2000). Late Carboniferous foraminifera, Permian coral, fusulinids and conodonts and late Triassic conodonts, pelecypods, ammonoids, etc. occur in limestone, late Early to Late Triassic conodonts and radiolarians are contained in chert and middle to Late Jurassic radiolarians were extracted from siliceous shale and turbidites in the Khabarovsk Terrane (Natal’in and Zyabrev, 1989; Kojima et al., 1991; Wakita et al., 1992; Matsuoka, 1995; Zyabrev and Matsuoka, 1999). Middle Carboniferous to Early Permian fusulinids are reported from limestone, Middle to Late Triassic radiolarians and Late Triassic to Early Jurassic radiolarians were extracted from chert and siliceous shale of the Nadanhata Terrane, respectively (Mizutani et al., 1986; Kojima and Mizutani, 1987).

6. Ocean Plate Stratigraphy (OPS) of the Paleo-Tethyan suture zones The Palaeo-Tethys ocean is represented in East and Southeast Asia by a number of suture zones corresponding to both the main ocean and Palaeo-Tethyan marginal basins (Fig. 9). The main Palaeo-Tethys ocean is represented by the Lancangjian, Changning–Menglian, Chiang Mai, and Bentong-Raub suture zones (Metcalfe, 1988, 1996, 2000). The Jinshajiang, Ailaoshan and Nan-Uttaradit sutures have recently been re-interpreted as probably representing a marginal Palaeo-Tethyan back-arc basin (Ueno and Hisada, 1999; Wang et al., 2000; Metcalfe, 2002). Sutures that

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Fig. 7. Reconstructed OPS in Busuanga Island, North Palawan Block, Philippines (Zamoras and Matsuoka, 2001).

represent the main Palaeo-Tethys preserve accretionary prisms and me´langes from the off-scrapings of PalaeoTethyan ocean floor. Depending on the stratigraphic location of the detachment surface of off-scraped ocean floor, thrust slices in the accretionary complexes preserve partial or complete ocean plate stratigraphies. Partial OPS

also tends to be highly disrupted by subsequent tectonic activity and reactivation along the suture zones, especially strike-slip faulting. Me´langes preserve fragments of the OPS as clasts and microfossil (especially radiolarian) biostratigraphic studies have allowed some reconstruction of OPS in Palaeo-Tethyan suture zones of the region.

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Fig. 8. Reconstructed OPS in East and Southeast Asia. See the localities in Fig. 1 with the same numbers.

In Thailand, the Nan-Uttaradit and Sra Kaeo Suture Zones have traditionally been interpreted as representing the main Palaeo-Tethys ocean between the Sibumasu and Indochina Gondwanaland-derived terranes (Hada et al., 1999; Singharajwarapan and Berry, 2000). Recent discoveries of oceanic and seamount rock associations in the Chiang Mai–Chiang Dao area of western Thailand, interpreted as remnants of the main Palaeo-Tethys (Metcalfe, 2002), and re-interpretation of the Nan-Uttaradit suture as representing a back-arc basin which opened in the Carboniferous (Ueno and Hisada, 1999; Wang et al., 2000; Metcalfe, 2002), require a re-interpretation of the tectonic framework of Thailand and adjacent regions. Assessments of the OPS of suture zones in this region, together with new isotope geochronological and geochemical investigations will provide vital information on the genesis and tectonic setting of the ocean basins that these suture zones represent. 6.1. Main Palaeo-Tethys Ocean in South West China, Thailand and Malaysia 6.1.1. Changning–Menglian Suture Zone In SW China, the main Palaeo-Tethys ocean is represented by the Changning–Menglian Suture Zone which forms the boundary between the Sibumasu and

Simao terranes and which marks the remarkable Gondwana–Cathaysia Late Palaeozoic biogeographic divide. The suture is a narrow north–south oriented zone of dismembered basic–ultrabasic volcanic and intrusive igneous rocks and associated deep-marine sedimentary rocks that are interpreted as representing a segment of the main Palaeo-Tethys in East Asia (Huang et al., 1984; Zhang et al., 1984; Wu and Zhang, 1987; Liu et al., 1991, 1996; Wu, 1993; Fang et al., 1994; Wu et al., 1995; Fang and Feng, 1996; Zhong Dalai et al., 2000; Feng, 2002). The suture can be traced from Menglian northwards through Laochong, Tongchangia to Changning and ophiolitic me´lange includes blocks of harzburgite, cumulate websterite, gabbro, basalt, limestone and chert in a mud–silt grade matrix. Associated basalts are of mid-ocean ridge and ocean-island types (Wu et al., 1995) and remnants of limestone capped seamounts have been identified in the zone (Liu et al., 1991). Oceanic ribbon-bedded chert–shale sequences have yielded graptolites, conodonts and radiolarians, indicating ages ranging from Lower Devonian to Middle Triassic (Duan et al., 1982; Qin et al., 1980; Wu and Zhang, 1987; Wu and Li, 1989; Liu et al., 1991; Feng and Ye, 1996; Kuwahara, et al., 1997) (Fig. 10). Limestone blocks and lenses dominantly found within the basalt sequence of the suture and interpreted as seamount caps, have yielded fusulinids indicative of Lower Carboniferous

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Fig. 9. Distribution of continental blocks, fragments and terranes, and principal sutures of Southeast Asia (modified after Metcalfe, 1990) and East Asia (inset). Terrane abbreviations in inset map: WB, West Burma; KL, Kunlun; QD, Qaidam; AL, Ala Shan; QS, Qamdao-Simao; QI, Qiangtang; L, Lhasa; SI, Simao Terrane; SWB, S.W. Borneo; SG, Songpan Ganzi accretionary complex. Numbered microcontinental blocks: 1. Hainan Island terranes; 2. Sikuleh; 3. Paternoster; 4. Mangkalihat; 5. West Sulawesi; 6. Semitau; 7. Luconia; 8. Kelabit-Longbowan; 9. Spratley Islands-Dangerous Ground; 10. Reed Bank; 11. North Palawan; 12. Paracel Islands; 13. Macclesfield Bank; 14. East Sulawesi; 15. Bangai-Sula; 16. Buton; 17. Obi-Bacan; 18. Buru-Seram; 19. West Irian Jaya. C–M: Changning–Menglian Suture.

to Upper Permian ages (Duan et al., 1982; Wu et al.,1995; Ueno et al., 2003). The suture is truncated to the north of Changning by the Chongshan metamorphic belt and almost certainly continues northwards as the Lancangjiang suture to the west of Deqin. This suture zone preserves basic and ultrabasic MORB volcanics (including pillow basalts) and intrusives, withinplate ocean island basalts, shallow-water limestones interpreted as seamount caps, interbedded radiolarian cherts and pelagic limestones, oceanic ribbon-bedded radiolarian cherts, siliceous shales and mudstones, and shale–sandstone turbiditic rhythmites (‘flysch’).

Basic-ultrabasic volcanic and intrusive igneous rocks of the Changning–Menglian suture zone include basalt, diabase, gabbro, meta-peridotite, and ultrabasic cumulates with an age range from (?Devonian) Lower Carboniferous to Upper Permian (Zhong Dalai et al., 2000; Feng, 2002). The volcanics mainly represent seamount/ocean island settings. Oceanic ribbon-bedded radiolarian cherts, as disrupted fault-bounded packages, as parts of more complete partial OPS in accretionary complexes, and as clasts in both tectonic and sedimentary me´langes range in age from Upper Devonian to Lower Triassic (Fig. 10).

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Fig. 10. Reconstructed OPS for the main Palaeo-Tethys ocean and for the Palaeo-Tethyan back-arc basin developed between the Simao Block and South China/Indochina.

6.1.2. Chiang Mai Suture Zone The belt of oceanic and seamount rock associations in western Thailand (Figs. 10 and 11) includes packages of basalts (in places pillow basalts), ribbon-bedded cherts dated by radiolarians as Devonian, Carboniferous, Permian and Triassic (Caridroit et al., 1990, 1992; Caridroit, 1991, 1993; Sashida et al., 1993; Sashida and Igo, 1999; Metcalfe, 2002), interbedded pelagic limestones and bedded chert, pelagic mudstones, rhythmic mudstones and greywacke turbidites and massive turbiditic sandstones, and shallow-marine Lower Carboniferous (Vise´an) to Upper Permian (Dorashamian) limestones with fusulinids, interpreted as carbonate caps to sea mounts (Ueno and Igo, 1997). Examples of coherent partial ocean-plate stratigraphy (OPS) have also been discovered in this area by the authors, representing thrust slices of the Palaeo-Tethyan ocean floor preserved in the accretionary complex. One such example of lower OPS exposed in a road cutting south of Chiang Mai at 18830.7 0 N/ 99805.60 0 E comprises pillow basalts overlain by chert, interbedded chert and pelagic limestone, siliceous shale/ argillites. These Palaeo-Tethyan rock associations distributed in the Chiang Dao–Chiang Mai region are interpreted as representing a segment of the main Palaeo-Tethys ocean suture, here termed the Chiang Mai Suture, following Cooper et al. (1989), Charusiri et al. (1997) and Metcalfe (2002) (Fig. 9). The Chiang Mai Suture corresponds to the Chiang

Mai Volcanic Belt of Macdonald and Barr (1978) and Barr et al. (1990) and the Inthanon Zone of Barr and Macdonald (1991) and other authors. It is interpreted to equate and be contiguous with the Bentong-Raub Suture of Peninsular Malaysia (Metcalfe, 2000). The rock associations of the Chiang Mai Suture in the Chiang Mai and Chiang Dao area equate well with similar rock suites of the same ages in the Changning–Menglian Suture in western Yunnan to the north (Liu et al., 1991; Fang et al., 1994; Fang and Feng, 1996; Wu et al., 1995) with which it is here considered to be contiguous (Figs. 9 and 10) following Wu et al. (1995). The eastern boundary of the Sibumasu Terrane in northern Thailand therefore lies further to the west than previously interpreted, and central north Thailand, between the Chiang Mai and Nan-Uttaradit sutures, forms the southern tip of the Simao Terrane, no longer regarded as part of Indochina, but as a separate South China/Indochina-derived terrane produced by back-arc spreading in the Carboniferous. 6.1.3. Bentong-Raub Suture Zone The Bentong-Raub Suture Zone (Fig. 9) is located between the Sibumasu Terrane and the East Malaya Block (?Indochina Terrane) in Peninsular Malaysia. The suture zone represents the main Palaeo-Tethys ocean basin which opened in the Devonian and closed in the Triassic (Metcalfe, 2000). The Ocean Plate Stratigraphy of

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Fig. 11. Sketch map showing the Chiang Mai, Nan-Uttaradit and Sra Kaeo suture zones of Thailand, the southern part of the Simao Terrane, and the distribution of volcanic arc rocks, basalts, ultramafic and mafic rocks and seamount carbonates in northern Thailand (from Metcalfe, 2002).

the Palaeo-Tethys preserved in this suture zone includes some, but not voluminous serpentinites, volcaniclastic rocks, ribbon-bedded radiolarian cherts, limestones, siliceous mudstones, and sandstone–shale turbidite sequences and me´lange. Serpentinites occur as sporadic small bodies and are interpreted as representing oceanic peridotites, and other mafic/ultra-mafic igneous rocks, including pillow basalts (Metcalfe, 2000). The age of these serpentinites is not known, except that they are associated with, and occur as bodies within a Permian–Triassic me´lange.

Ribbon-bedded oceanic radiolarian cherts occur as faultbounded packages in accretionary complex thrust slices and also as clasts in me´lange (Metcalfe, 2000). They range in age from Devonian to Permian, and up to Middle Triassic (Fig. 10) if Semanggol foredeep cherts are included (Metcalfe, 1992; Spiller and Metcalfe, 1993, 1995a,b; Sashida et al., 1993, 1995; Metcalfe and Spiller, 1994; Basir Jasin 1994, 1995; Spiller, 1996; Basir Jasin and Che Aziz Ali, 1997; Metcalfe et al., 1999). Limestones occur as clasts, large blocks and knockers in me´lange. Large limestone bodies are relatively pure white

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limestone, but are recrystallized and have not yielded agediagnostic fossils. Smaller limestone clasts in me´lange have yielded conodonts and fusulinids dating them as Permian (Metcalfe, 2000). These limestones may represent disrupted parts of seamount cap limestones that are more completely preserved in the contiguous Chiang Mai and Changning– Menglian sutures to the north (Fig. 10). 6.2. Palaeo-Tethyan back-arc basin in China and Thailand The Jinshajiang, Alaioshan, Nan-Uttaradit and Sra Kaeo suture zones of SW China and Thailand preserve significant ophiolites and have a different OPS to suture zones interpreted to represent the main Palaeo-Tethys (see above and Fig. 10). The age range of oceanic cherts is more restricted, from Upper Carboniferous to Middle Triassic, basic igneous rocks have supra-subduction zone geochemical signatures, and remnants of oceanic seamounts appear to be absent. 6.2.1. Jinshajiang–Alaioshan Suture Zone Wang et al. (2000) reviewed the tectonostratigraphy, age and evolution of the Jinshajiang–Alaioshan Suture Zone and interpreted this as a back-arc basin which opened in the Lower Carboniferous, separating the Simao Block from South China. Remnants of OPS in this suture zone include radiolarian cherts of Upper Carboniferous, and Lower and Upper Permian ages associated with basic volcanics, voluminous Carboniferous–Permian ophiolites, and clastic turbidite sequences of Upper Permian to Middle Triassic age (Fig. 10). Ages for plagiogranites in the ophiolites are Lower Carboniferous (Wang et al., 2000). 6.2.2. Nan-Uttaradit Suture Zone The Nan-Uttaradit Suture Zone (Fig. 11), traditionally regarded as representing the main Palaeo-Tethys, has recently been re-interpreted as representing a segment of the back-arc basin which opened in the Carboniferous between the Simao Block and South China/Indochina (Ueno and Hisada, 1999; Wang et al., 2000; Metcalfe, 2002). A Permo-Triassic accretionary complex contains Carboniferous to upper Permian blocks. Provenance evidence from widespread Permo-Triassic volcaniclastics, combined with structural and other indicators indicate westwards subduction of the marginal basin in PermoTriassic times (Singharajwarapan and Berry, 2000). Upper Permian radiolarian cherts are known, but to date there are no known Carboniferous or Devonian ribbon-bedded cherts known from the Nan-Uttaradit suture. Middle Triassic chert clasts are known from basal conglomerates in the Jurassic overlap sequence. Turbidite sequences, interpreted as forearc deposits by Singharajwarapan and Berry (2000), range in age from Late Permian to early Late Triassic.

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6.2.3. Sra Kaeo Suture Zone The Sra Kaeo Suture Zone in SE Thailand (Fig. 11) comprises a western chert–clastic sequence and an eastern Thung Kabin me´lange (Hada et al., 1999). The chert–clastic sequence comprises alternating thrust slices of Middle to Upper Triassic red bedded chert and clastic turbidites. At one locality, the red bedded cherts of Middle Triassic age directly overlie pillow basalts. This sequence is interpreted as an accretionary complex. The Thung Kabin me´lange is a serpentinite matrix me´lange, including clasts of greenstone (including pillow lavas), chert, and limestone. The chert clasts are of Lower, Middle and Upper Permian ages. Ages of limestone clasts, based on fusulinids, are Lower and Middle Permian in age (Hada et al., 1999; Fig. 11). Unfortunately, there is little direct age control on the basic igneous rocks of the suture. Reconstructed OPS suggests that this basin probably opened in the Carboniferous and closed in the Triassic. Further work (especially geochemical and geochronological) is required to confirm whether this suture represents a back-arc basin, and is therefore contiguous with the Nan-Uttaradit and Jinshajiang–Alaioshan sutures, or if it represents the main Palaeo-Tethys. On currently available information, we favour the former interpretation. 6.2.4. Songpan Ganzi accretionary complex The Songpan Ganzi accretionary complex (Fig. 1) is not a suture zone but a remnant of the Paleo-Tethys (Metcalfe, 1996, 1999). As thick piles of Triassic flysch sediments caused by collision between South and North China Blocks cover the hemiplagic and pelagic sediments of Paleo-Tethys ocean, we have little information on OPS in the Songpan Ganzi accretionary complex.

7. Ocean Plate Stratigraphy (OPS) of Ceno-Tethyan suture zones The Yarlung-Zangbo suture zone is located between the Lhasa Block and the Indian Block which collided with each other in Paleogene time. Yang et al. (2000, 2002) reviewed recent results of radiolarian biostratigraphy in Southern Tibet. Radiolarians occurred mainly in ophiolite and sedimentary me´lange belts. The chert of the ophiolite belt yields Jurassic and Cretaceous radiolarians, whereas the chert and siliceous shale of the sedimentary me´lange belt contains radiolarians ranging in age from Middle Triassic to Late Cretaceous (Yang et al., 2000, 2002). Matsuoka et al. (2002) obtained more detailed OPS succession from the Xialu Chert of the Yarlung-Zangbo ophiolite. The OPS is composed of pelagic chert ranging in age from Middle Jurassic (Aalenian) to Lower Cretaceous (Barremian), and siliceous shale of Aptian age (Fig. 8). Although there is no information concerning the lower and upper portions of the OPS, we can recognize the typical Ceno-Tethyan OPS in their results, consistent with a Triassic

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rather than a Permian rifting and separation of the Lhasa Block from Indian Gondwana.

8. Ocean Plate Stratigraphy (OPS) of the Indian Ocean margin Cretaceous accretionary complexes are distributed in Central Java, South Sulawesi, Southeast Kalimantan and Sumatra, Indonesia. They are the Luk Ulo Complex (Askin, 1974; Wakita et al., 1994b), the Bantimala Complex (Wakita et al., 1994a, 1996), the Meratus Complex (Wakita et al., 1998) and the Woyla Group (Wajzer et al., 1991; Barber, 2000), respectively. They are composed mainly ofme´langes, including clasts of radiolarian chert, limestone and pillow lava, high P/T metamorphic rocks, and ultramafic rocks. An Ocean Plate Stratigraphy has been reconstructed in several Cretaceous accretionary complexes of Indonesia (Wakita, 2000b). 8.1. Luk-Ulo Complex, Central Java Ocean Plate Stratigraphy is typically recognized in the Luk-Ulo Complex of central Java. The complex is composed of crystalline schist, phyllite, marble, rhyolite, dacite, basic to ultramafic rocks, limestone, chert, siliceous shale, shale, sandstone and conglomerate. They are represented as tectonic slices and blocks bounded by faults. Metamorphic and igneous rocks, except for pillow basalt, are tectonically mixed with sedimentary components in post-accretionary processes. In the sedimentary rocks, sandstone and shale are dominant, whereas chert, limestone and conglomerate are locally recognized. Sandstone, pale brown, gray and reddish brown in color, is usually interbedded with shale of gray or reddish brown color. The dominant rock type among the sandstones is volcaniclastic arenite, which consists mostly of fragments of plagioclase and intermediate to basic volcanic rocks. Pebbly shale, locally recognized, grades into shale interbedded with sandstone. Basalt is pillow basalt or pillow breccia. The lava is aphyric, or includes small phenocrysts of augite and sometimes pseudomorphs of olivine. Limestone, light gray in color, is interbedded with chert of reddish brown color. Alternating beds of limestone and chert conformably overlie pillow basalt, and include Early Cretaceous radiolarians in the chert. The chert is mostly reddish brown, but locally gray, light greenish gray and black in color and grades into siliceous shale toward the stratigraphic top in some localities. The chert and siliceous shale sometimes yield radiolarians of Early to Late Cretaceous age (Wakita et al., 1994). The original succession of this sedimentary-volcanic suite survives along the Cacaban River. It consists of pillow basalt, alternations of limestone and chert, radiolarian chert, siliceous shale, sandstone and shale in ascending order. Similar successions are reconstructed by means of radiolarian biostratigraphy (Fig. 12). The succession represents a typical Ocean Plate Stratigraphy which is similar to that of the PreTertiary accretionary complexes in Japan. The ages of each

Fig. 12. Reconstructed OPS in Cretaceous accretionary complex, central Java, Indonesia (modified from Wakita et al., 1994).

rock type are different in different localities. The oldest OPS is recognized in the Mucar River, followed by younger OPS reconstructed in the Cacaban, Sigoban and Medana Rivers (Fig. 12). 8.2. Bantimala Complex, Southwest Sulawesi The Bantimala Complex of Southwest Sulawesi is a tectonic assemblage of ultramafic rocks, high P/T schist and me´langes. The me´lange includes radiolarian chert of Albian to Cenomanian age. Although the oceanic assemblage of the complex is lithologically similar to the OPS, the radiolarian chert is overlying not pillow basalt but high P/T schist. Therefore, it is difficult to regard the chert assemblage of the Bantimala Complex as a part of the OPS. 8.3. Meratus Complex of South Kalimantan The Meratus Complex of South Kalimantan consists of me´lange, chert, siliceous shale, limestone, basalt, ultramafic

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rocks and schist. The complex is unconformably covered by Late Cretaceous sedimentary-volcanic formations. The chert yields radiolarians ranging from early Middle Jurassic to late Early Cretaceous (Wakita et al., 1998).

Radiolaria of Aalenian age have been obtained from cherts correlated with the Woyla Group from the Indarung area near Padang, West Sumatra (McCarthy et al., 2001).

8.4. Woyla Group of Sumatra

9. Arrangement of Ocean Plate Stratigraphy (OPS) in accretionary prisms

The Oceanic assemblage of the Woyla Group has been recognized in the Natal and Aceh areas, Sumatra Island, Indonesia (Wajzer et al., 1991; Barber, 2000). In the Natal area this includes massive spilitic lava, turbidite, and me´lange containing fragments of chert, limestone and volcanics in a cherty siltstone matrix (Wajzer et al., 1991). The Woyla Group of the Aceh area yields an oceanic assemblage of serpentinized harzburgite, metagabbro, mafic to intermediate volcanics, volcaniclastic sandstone, manganiferous slate, and radiolarian chert from which no agediagnostic radiolaria have yet been obtained (Barber, 2000).

Fig. 13. Younging polarity of the arrangement of the tectonic units in Jurassic accretionary complex of central Japan (modified from Matsuoka, 1984) Radiolarian assemblage zones are the same as in Fig. 5. Ya: Yamanokami belt; Ko: Kobiura belt; NI: Nishiyama belt; I, NII: Nishiyama belt; II, NIII: Nishiyama belt III.

Accretionary complexes usually grow from the continental side to the ocean side because of the oceanward migration of subduction sites. In Japan, Permian to present accretionary complexes are temporally arranged oceanward (Fig. 6). Even in a single accretionary complex, individual tectonic units of the complex become younger oceanward. Ancient accretionary complexes are divided into several tectonic units characterized by specific age and lithology. These tectonic units are divided by out-of-sequence thrusts developed in the accretionary process. As older tectonic units moved upward along the out-of-sequence thrusts and were overthrust onto a younger tectonic unit, younger tectonic units prograded toward the ocean side. In ancient accretionary complexes, Matsuoka (1984, 1992) clearly showed the arrangement of the offscraped

Fig. 14. Paleooceanography of western Pacific region in Jurassic time.

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OPS in the Shikoku area, Southwest Japan. The upper OPS is tectonically stacked in a duplex unit. The age of clastic rocks of the OPS sequence becomes gradually younger toward the Pacific (Fig. 13). On the other hand, the age of the lowest part of the accreted OPS is Lower Triassic. This is because the decollement which cut the OPS at the toe of the ancient accretionary prism was developed at the P–T boundary claystone level which is fragile and slippery.

10. Reconstruction of Paleo-ocean environment 10.1. Panthalassa Ocean The Paleo-Pacific Ocean ‘Panthalassa’ was extended to the east of the Asian Continent in the Paleozoic and Mesozoic Eras. We can recognize accretionary complexes of various ages in Japan, such as Permian, Jurassic,

Fig. 15. Palaeogeographic reconstructions of the Tethyan region for (a) Early Carboniferous, (b) Early Permian, (c) Late Permian and (d) Late Triassic showing relative positions of the East and South-east Asian terranes and distribution of land and sea. Also shown is the distribution of the Early Permian cold-water tolerant conodont Vjalovognathus, and the Late Permian Dicynodon locality on Indochina in the Late Permian. SC: South China; T: Tarim; I: Indochina; Em: East Malaya; WS: West Sumatra; NC: North China; SI: Simao; S: Sibumasu; WB: West Burma; QI: Qiangtang; L: Lhasa; WC: Western Cimmerian Continent.

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Fig. 16. Palaeogeographic reconstructions for Eastern Tethys in (a) Late Jurassic, (b) Early Cretaceous, (c) Late Cretaceous and (d) Middle Eocene showing distribution of continental blocks and fragments of South-east Asia-Australasia and land and sea. SG: Songpan Ganzi accretionary complex, SC: South China, QS: Qando-Simao, SI: Simao, QI: Qiangtang, S: Sibumasu, I: Indochina, EM: East Malaya, WSu: West Sumatra; L: Lhasa, WB: West Burma; SWB: South West Borneo, SE: Semitau, NP: North Palawan and other small continental fragments now forming part of the Philippines basement Si: Sikuleh, M: Mangkalihat, WS: West Sulawesi, PB: Philippine Basement, PA: Incipient East Philippine arc; PS: Proto-South China Sea; Z: Zambales Ophiolite; Rb: reed Bank; MB: Macclesfield Bank. PI: Paracel Islands; Da: Dangerous Ground, Lu: Luconia, Sm: Sumba. M numbers represent Indian Ocean magnetic anomalies.

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Cretaceous, Paleogene, and Neogene to present complexes. The presence of these accretionary complexes suggests that subduction of oceanic plates has occurred along the eastern margin of the Asian continent since late Paleozoic times. The formation of accretionary complexes of Permian, Jurassic and Cretaceous ages are related to the subduction of different oceanic plates, i.e. Farallon, Izanagi and Kula oceanic plates, respectively (Isozaki, 1996b, 1997a,b; Maruyama et al., 1997). The fragments of OPS of Farallon, Izanagi and Kula plates are recognized in the Permian, Jurassic and Cretaceous accretionary complexes of Japan which are shown in Fig. 6. The age range of pelagic chert in the reconstructed OPS indicates the length of time for which each oceanic plate existed. The Farallon, Izanagi and Kula plates survived for at least 60, 200, and 50 Ma, respectively. The Farallon Plate was born sometime before the Carboniferous and subducted to form an accretionary wedge along the Eastern Asian margin in late Permian time. The subduction of the ocean plate ceased just after the accretion of huge seamounts capped by fusulinacean limestone. The Izanagi Plate was born in late Devonian time and subducted from Early Jurassic to Early Cretaceous time. In Late Carboniferous to Early Permian time, seamounts were formed near the oceanic ridge, and were covered by calcareous reefs. The Izanagi Plate experienced a superanoxia event at the Permian/Triassic boundary transition (Isozaki, 1993, 1994, 1996a, 1997c). In late Triassic or early Jurassic time, volcanic activity occurred at a hot spot with alkaline basalt extruded onto pelagic siliceous oozes. The pelagic sediments and volcanic seamounts on the Izanagi Plate were accreted to the continental margin, together with detrital sediments derived from the continental margin in Jurassic and early Cretaceous time (Fig. 14). Records of the remnants of the Kula Plate are limited. Most of the Kula Plate was subducted into the deeper parts of the accretionary wedge or has disappeared into the mantle. The OPS are recorded in a thin tectonic zone of me´langes. The OPS indicates that the Kula Plate had a short history of only about 50 Ma. The plate was formed in Late Jurassic or Early Cretaceous time and subducted in the late Cretaceous. The plate is considered to have been hot enough at the time of subduction to heat up the surrounding sediments. In the Cenozoic, the Pacific and Philippine Plates were subducted along the East Asian continental margin where marginal seas have been developed since Miocene times.

of terranes successively separated from Gondwanaland (Fig. 15). In addition, there were other Tethyan marginal basins which opened and closed at various times. The reconstructed OPS for the main Palaeo-Tethys ocean shows that ocean floor spreading occurred from Upper Devonian to Middle Triassic times, and that subduction of the ocean basin along its northern margin probably occurred from the Carboniferous to the Early Triassic. Limestone capped oceanic seamounts of Upper Carboniferous to Upper Permian age were incorporated into the accretionary complex and me´langes at the subduction zone. The reconstructed OPS for the back-arc basin represented by the Jinshajiang–Alaioshan, Nan-Uttaradit and Sra Kaeo sutures indicates that this Palaeo-Tethyan marginal basin opened in the Carboniferous, when the Simao Terrane separated from South China/Indochina, and closed in the late Triassic. Information on OPS of Meso-Tethyan suture zones is meagre at best and requires further studies to elucidate the detailed history of this ocean basin. Indications are that it opened in the Middle Permian, when the Cimmerian Continental strip separated from Gondwanaland, and that it closed in the Jurassic–Cretaceous (Fig. 16). Indications from preserved OPS in the Ceno-Tethyan Yarlung-Zangbo suture indicate that the Ceno-Tethys opened in the Triassic, contrary to the earlier Permian separation which has been proposed by some workers. This ocean closed following the main breakup of Gondwanaland and the arrival of India and Australia in the Cenozoic (Fig. 16).

Acknowledgements We express our thanks to Dr Anthony J. Barber of the University of London for his critical review of the manuscript. We also wish to acknowledge Dr Atsushi Matsuoka of the Niigata University for his recent publications on radiolarian biostratigraphic research from Tibet and the Philippines. Thanks also go to Dr Satoru Kojima of the Gifu University for his suggestions concerning the geology of the Jurassic accretionary complex in the Mino Terrane and in the Russian Far East. I. Metcalfe acknowledges support from the Australian Research Council for work on East and Southeast Asia.

References 10.2. Tethyan Oceans Metcalfe (1990, 1996, 1998) has demonstrated that the Tethys Ocean is in fact represented by multiple Tethyan ocean basins, including three main oceanic Tethyan ocean basins, the Palaeo-Tethys, Meso-Tethys and Ceno-Tethys, which opened when three continental slivers or collages

Ando, A., Kodama, K., Kojima, S., 2001. Low-latitude and Southern Hemisphere origin of Anisian (Triassic) bedded chert in the Inuyama area, Mino Terrane, central Japan. Journal of Geophysical Research 106, 1973–1986. Askin, S., 1974. The geological evolution of central Java and vicinity in the light of the new-global tectonics. Ph.D. Thesis, Bandung Institute of Technology.

K. Wakita, I. Metcalfe / Journal of Asian Earth Sciences 24 (2005) 679–702 Barber, A.J., 2000. The origin of the Woyla Terranes in Sumatra and the Late Mesozoic evolution of the Sundaland margin. Journal of Asian Earth Sciences 18, 713–738. Barr, S.M., Macdonald, A.S., 1991. Toward a late Paleozoic–early Mesozoic tectonic model for Thailand. Journal of Thai Geosciences 1, 11–22. Barr, S.M., Tantisukrit, C., Yaowanoiyothin, W., Macdonald, A.S., 1990. Petrology and tectonic implications of Upper Paleozoic volcanic rocks of the Chiang Mai Belt, northern Thailand. Journal of Southeast Asian Earth Sciences 4, 37–47. Basir Jasin, 1994. Middle Triassic radiolaria from the Semanggol Formation, northwest Peninsular Malaysia. Warta Geologi 20, 279–283. Basir Jasin, 1995. Occurrence of bedded radiolarian chert in the Kubang Pasu Formation, north Kedah, Peninsular Malaysia. Warta Geologi 21, 73–79. Basir Jasin, Che Aziz Ali, 1997. Lower Permian Radiolaria from the Pos Blau area, Ulu Kelantan, Malaysia. Journal of Asian Earth Sciences 15, 327–339. Caridroit, M., 1991. Taxonomic study on Carboniferous and Permian Radiolaria from NW Thailand. Paleontologic, stratigraphic and tectonic significances. Abstracts. Sixth Meeting, International Association of Radiolarian Paleontologists (INTERRAD VI), 21. Caridroit, M., 1993. Permian Radiolaria from NW Thailand, In: Thanasuthipitak, T. (Ed.), Proceedings of the International Symposium on Biostratigraphy of Mainland Southeast Asia: Facies and Paleontology, vol. 1, pp. 83–96. Caridroit, M., Fontaine, H., Jongkanjanasoontorn, Y., Suteethorn, V., Vachard, D., 1990. First results of a palaeontological study of Northwest Thailand. CCOP Technical Secretariat, 337–350. Caridroit, M., Vachard, D., Fontaine, H., 1992. Datations par radiolaires (Carbonife`re, Permie`n et Trias) en Thailande nord-occidentale. Mise en evidence de nappe de charriage et dolistostromes. Acade´mie des Sciences Compte Rendu Paris 314, 515–520. Charusiri, P., Kosuwan, S., Imsamut, S., 1997. Tectonic evolution of Thailand, from Bunopas (1981)’s to a new scenario Proceedings, GOTHAI’97, vol. 1. Department of Mineral Resources, Thailand, pp. 414–420. Cheng, Y., 1989. Upper Paleozoic and Lower Mesozoic radiolarian assemblages from the Busuanga Islands, Northern Palawan Block, Philippines. Bulletin of National Museum of Natural Science (Taiwan) 1, 129–175. Cheng, Y., 1992. Upper Jurassic Pantanelliidae (Pantaneliinae Pessagno, 1992 and Vallupinae Pessagno and Macleod, 1987) from the Busuanga Islands, Philippines. Bulletin of National Museum of Natural Science (Taiwan) 3, 1–49. Cooper, M.A., Herbert, R., Hill, G.S., 1989. The structural evolution of Triassic intermontane basins in Northeast Thailand. In: Thanasuthipitak, T., Ounchanum, P. (Eds.), Proceedings of International Symposium on Intermontane Basins: Geology and Resources. Chiang Mai University, Thailand, pp. 231–242. Duan, Y., Xiao, Y., Hong, Y., Liu, Y., Zhao, Z., 1982. 1:200,000 scale geological map (Menglian) and technical report (in Chinese). Fang, N., Feng, Q. (Eds.), 1996. Devonian to Triassic Tethys in Western Yunnan. China University of Geosciences Press, China, p. 135. Fang, N., Liu, B., Feng, Q., Jia, J., 1994. Late Palaeozoic and Triassic deepwater deposits and tectonic evolution of the Palaeotethys in the Changning–Menglian and Lacangjiang belts, southwestern Yunnan. Journal of Southeast Asian Earth Sciences 9, 363–374. Faure, M., Ishida, I., 1990. The Mid-Upper Jurassic olistostrome of the west Philippines: a distinctive keymarker for the North Palawan Block, Philippines. Journal of Southeast Asian Earth Sciences 4, 61–67. Feng, Q.-L., 2002. Stratigraphy of volcanic rocks in the Changning– Menglian Belt in southwestern Yunnan, China. Journal of Asian Earth Sciences 20, 657–664. Feng, Q., Ye, M., 1996. Permian radiolarian sedimentary assemblage and paleoecology in south and southwest China. In: Xiangfu, L. (Ed.),

699

Devonian to Triassic Tethys in Western Yunnan, China. China University of Geosciences Press, Wuhan, pp. 106–112. Hada, S., Bunopas, S., Ishii, K., Yoshikura, S., 1999. Rift-drift history and the amalgamation of Shan-Thai and Indochina/East Malaya blocks. In: Metcalfe, I. (Ed.), Gondwana Dispersion and Asian Accretion. Balkema, Rotterdam, pp. 67–87. Hashimoto, M., Saito, Y., 1970. Metamorphism of Paleozoic greenstones of the Tamba Plateau, Kyoto Prefecture. Journal of Geological Society of Japan 76, 1–6. Hori, R.S., Cho, C.F., Umeda, H., 1993. Origin of cyclicity in Triassic– Jurassic radiolarian bedded chert of the Mino accretionary complex from Japan. The Island Arc 2, 170–180. Huang, J., Chen, G., Chen, B., 1984. Preliminary analysis of the TethysHimalayan tectonic domain. Acta Geologica Sinica 58, 1–17. (in Chinese with English abstract). Hutchison, C.S., 1989. Geological evolution of South-east Asia Oxford Monographs on Geology and Geophysics, vol. 13. Clarendon Press, Oxford. 368 p. Ichikawa, K., Yao, A., 1976. Two new genera of Mesozoic cyrtoid radiolarians from Japan. In: Takayanagi, T., Saito, T. (Eds.), Progress in Micropaleontology. Micropaleontology Press, pp. 110–117. Ichikawa, K., Mizutani, S., Hara, H., Hada, S., Yao, A., 1990. PreCretaceous Terranes of Japan. Publication of IGCP Project No. 224. Pre-Jurassic Evolution of Eastern Asia. 413 p. Igo, H., 1979. Conodont biostratigraphy and restudy of geological structure at the eastern part of the Mino Belt. In: Biostratigraphy of Permian and Triassic Conodonts and Holothurian Sclerites in Japan, Prof. M. Kanuma Commemorative Volume, pp. 103–113. Isozaki, Y., 1993. Superanoxia across the P/T boundary and mass extinction. Eos (Transactions of American Geophysical Union) 74, 330. Isozaki, Y., 1994. Superanoxia across the Permo-Triassic boundary: record in accreted deep-sea pelagic chert in Japan. In: Embry, E.F., Beauchamp, B., Glass, D.J. (Eds.), Global Environments and Resources. Canadian Society of Petroleum Geologists, Memoir vol. 17, pp. 805–812. Isozaki, Y., 1996a. P–T boundary superanoxia and oceanic stratification in Panthlassa. In: Noda, H., Sashida, K. (Eds.), Prof. H. Igo Commemorative Volume on Geology and Paleontology of Japan and Southeast Asia. Gakujyutsu Tosho Insatsu Co. Ltd, Tokyo, pp. 29–41. Isozaki, Y., 1996b. Anatomy and genesis of a subduction-related orogen: a new view of geotectonic subdivision and evolution of the Japanese Islands. The Island Arc 5, 289–320. Isozaki, Y., 1997a. Contrasting two types of orogen in Perm-Triassic Japan: accretionary versus collisional. The Island Arc 6, 2–24. Isozaki, Y., 1997b. Jurassic accretion tectonics of Japan. The Island Arc 6, 25–51. Isozaki, Y., 1997c. Permian–Triassic Boundary superanoxia and stratified superocean: records from lost deep sea. Science 276, 235–238. Isozaki, Y., Blake Jr., M.C., 1994. Biostratigraphic constraints on formation and timing of accretion in a subduction complex: an example from the Franciscan Complex of Northern California. Journal of Geology 102, 283–296. Isozaki, Y., Amiscaray, E.A., Rillon, A., 1988. Permian, Triassic and Jurassic bedded radiolarian cherts in North Palawan Block, Philippines: evidence of Late Mesozoic subduction-accreton. Report No. 3, IGCP Project 224. Pre-Jurassic Evolution of Eastern Asia, 99–115. Isozaki, Y., Maruyama, S., Furuoka, F., 1990. Accreted oceanic materials in Japan. Tectonophysics 181, 179–205. Kemkin, I.V., Khanchuk, A.I., 1994. Jurassic accretionary prism in the southern Sikhote Alin. Geology of Pacific Ocean 10, 831–846. Kimura, K., Hori, R., 1993. Offscraping accretion of Jurassic chert–clastic complexes in the Mino-Tamba Belt, central Japan. Journal of Structural Geology 15, 145–161. Kojima, S., 1989. Mesozoic terrane accretion in Northeast China, SikhoteAlin and Japan regions. Palaeogeography, Palaeoclimatology, Palaeoecology 69, 213–232.

700

K. Wakita, I. Metcalfe / Journal of Asian Earth Sciences 24 (2005) 679–702

Kojima, S., Kametaka, M., 2000. Jurassic accretionary complexes in East Asia. Memoir of Geological Society of Japan 55, 61–72 (in Japanese with English abstract). Kojima, S., Mizutani, S., 1987. Triassic and Jurassic Radiolaria from the Nadahada Range, Northeast China. Transaction and Proceedings of the Palaeontological Society of Japan, N.S. 148, 256–275. Kojima, S., Wakita, K., Okamura, Y., Natal’in, B.A., Zyabrev, S.V., Zhang, Q.L., Shao, J.A., 1991. Mesozoic radiolarians from the Khabarovsk Complex, eastern USSR: their significance in relation to the Mino Terrane, central Japan. Journal of Geological Society of Japan 97, 549–551. Kondo, N., Adachi, M., 1975. Mesozoic strata of the area north of Inuyama, with special reference to the Sakahogi conglomerate. Journal of the Geological Society of Japan 81, 373–386. Kuwahara, K., Yao, A., An, T., 1997. Paleozoic and Mesozoic complexes in the Yunnan area, China (Part 1): Preliminary report of Middle–Late Permian radiolarian assemblages. Journal of Geosciences, Osaka City University 40, 37–49. Liu, B., Feng, Q., Fang, N., 1991. Tectonic evolution of the Palaeo-Tethys in Changning–Menglian Belt and adjacent regions, western Yunnan. Journal of China University of Geosciences 2, 18–28. Liu, B., Feng, Q., Fang, N., Jia, J., He, F., Yang, W., Liu, D., 1996. Tectonopaleogeographic framework and evolution of the Paleotethyan archipelagoes ocean in Changning–Menglian Belt, western Yunnan, China. In: Long, X. (Ed.), Devonian to Triassic Tethys in Western Yunnan, China. China University of Geosciences Press, Wuhan, pp. 1–12. Macdonald, A.S., Barr, S.M., 1978. Tectonic significance of a Late Carboniferous volcanic arc in northern Thailand. In: Nutalaya, P. (Ed.), Proceedings of the Third Regional Conference on Geology and Mineral Resources of Southeast Asia, Bangkok. Asian Institute of Technology, Thailand, pp. 151–156. Maruyama, S., Isozaki, Y., Kimura, G., Terabayashi, M., 1997. Paleogeographic maps of the Japanese Islands: plate tectonic synthesis from 750 Ma to the present. The Island Arc 6, 121–142. Matsuda, T., Isozaki, Y., 1991. Well-documented travel history of Mesozoic pelagic chert in Japan: from remote ocean to subduction zone. Tectonics 10, 475–499. Matsuoka, A., 1984. Togano Group of the Southern Chichibu Terrane in the western part of Kochi Prefecture, Southwest Japan. Journal of Geological Society of Japan 90, 455–477 (in Japanese with English abstract). Matsuoka, A., 1992. Jurassic–Early Cretaceous tectonic evolution of the Southern Chichibu terrane, southwest Japan. Palaeogeography, Palaeoclimatology, Palaeoecology 96, 71–88. Matsuoka, A., 1995. Jurassic and Lower Cretaceous radiolarian zonation in Japan and in the western Pacific. The Island Arc 4, 140–153. Matsuoka, A., Yang, Q., Kobayashi, K., Takei, M., Nagahashi, T., Zeng, Q., Wang, Y., 2002. Jurassic–Cretaceous radiolarian biostratigraphy and sedimentary environments of the Ceno-Tethys: records form the Xialu Chert in the Yarlung-Zangbo Suture Zone, Southern Tibet. Journal of Asian Earth Sciences 20, 277–287. McCarthy, A.J., Basir Jasin, Haile, N.S., 2001. Middle Jurassic age of radiolarian chert: its implications for stratigraphical relations near Indarung, Padang District, West Sumatra. Journal of Asian Earth Sciences 19, 31–44. Metcalfe, I., 1988. Origin and assembly of Southeast Asian continental terranes. In: Audley-Charles, M.G., Hallam, A. (Eds.), Godwana and Tethys Special Publication 37. Geological Society of London, pp. 101–118. Metcalfe, I., 1990. Allochthonous terrane processes in Southeast Asia. Philosophical Transactions of the Royal Society of London, Series A 331, 625–640. Metcalfe, I., 1992. Nature, regional significance and age of the Bentong– Raub suture of the Malay Peninsula. Second International Symposium on Gondwana Dispersion and Asian Accretion: Geological Evolution of Eastern Tethys, Kochi, Japan, Abstracts. Kochi University, pp. 45–48.

Metcalfe, I., 1996. Pre-Cretaceous evolution of SE Asian terranes. In: Hall, T., Blundell, D. (Eds.), Tectonic Evolution of Southeast Asia Geological Society Special Publication 106, pp. 97–122. Metcalfe, I., 1998. Palaeozoic and Mesozoic geological evolution of the SE Asian region, multidisciplinary constraints and implications for biogeography. In: Hall, R., Holloway, J.D. (Eds.), Biogeography and Geological Evolution of SE Asia. Backhuys Publishers, Amsterdam, The Netherlands, pp. 25–41. Metcalfe, I., 1999. Gondwana dispersion and Asian accretion: an overview. In: Metcalfe, I. (Ed.), Gondwana Dispersion and Asian Accretion. Balkema, Rotterdam, pp. 9–28. Metcalfe, I., 2000. The Bentong–Raub Suture Zone. Journal of Asian Earth Sciences 18, 691–712. Metcalfe, I., 2002. Permian tectonic framework and palaeogeography of SE Asia. Journal of Asian Earth Sciences 20, 551–566. Metcalfe, I., Spiller, F.C.P., 1994. Correlation of the Permian and Triassic in Peninsular Malaysia: new data from conodont and radiolarian studies. In: Angsuwathana, P., Wongwanich, T., Tansathian, W., Wongsomsak, S., Tulyatid, J. (Eds.), Proceedings of the International Symposium on Stratigraphic Correlation of Southeast Asia. Department of Mineral Resources, Bangkok, Thailand, p. 129. Metcalfe, I., Spiller, F.C.P., Liu, B., Wu, H., Sashida, K., 1999. The PalaeoTethys in Mainland East and Southeast Asia: contributions from radiolarian studies. In: Metcalfe, I. (Ed.), Gondwana Dispersion and Asian Accretion. Balkema, Rotterdam, pp. 259–281. Mizutani, S., 1957. Permian sandstones in the Mugi area, Gifu Prefecture, Japan. Journal of Earth Sciences, Nagoya University 5, 135–151. Mizutani, S., 1959. Clastic plagioclase in Permian greywacke from the Mugi area, Gifu Prefecture, central Japan. Journal of Earth Sciences, Nagoya University 7, 108–136. Mizutani, S., Koike, T., 1982. Radiolarians in the Jurassic siliceous shale and in the Triassic bedded chert of Unuma, Kagamigahara City, Gifu Prefecture, Central Japan, News of Osaka Micropaleontologists Special Volume No. 5. Mizutani, S., Kojima, S., 1992. Mesozoic radiolarian biostratigraphy of Japan and collage tectonics along the eastern continental margin of Asia. Palaeogeography, Palaeoclimatology, Palaeoecology 96, 3–22. Mizutani, S., Kojima, S., Shao, J.A., Zhang, Q.L., 1986. Mesozoic radiolarians from the Nadahatda area, Northeast China. Proceedings of Japan Academy, Series B 62, 337–340. Natal’in, B., Zyabrev, S.V., 1989. Structure of Mesozoic rocks of the Amur River Valley. International Symposium on Tectonics, Energy and Mineral Resources of North-west Pacific Field Trip Guidebook. Institute of Tectonics and Geophysics, USSR Academy of Science, Khabarovsk p. 48. Okamura, Y., 1991. Large-scale melange formation due to seamount subduction: an example from the Mesozoic accretionary complex in central Japan. Journal of Geology 99, 661–674. Qin, D., He, C., Yang, J., Li, H., Chen, K., Yang, Z., Wang, Z., Wang, J., 1980. 1:200,000 scale geological map (Baoshan) and technical report (in Chinese). Sano, H., 1988a. Permian oceanic-rocks of Mino Terrane, central Japan. Part I. Chert facies. Journal of Geological Society of Japan 94, 697–709. Sano, H., 1988b. Permian oceanic-rocks of Mino Terrane, central Japan. Part II. Limestone facies. Journal of Geological Society of Japan 94, 963–976. Sano, H., Kojima, S., 2000. Carboniferous to Jurassic oceanic rocks of Mino-Tamba-Ashio Terrane, southwest Japan. Memoirs of Geological Society of Japan 55, 123–144 (in Japanese with English abstract). Sashida, K., Igo, H., 1999. Occurrence and tectonic significance of Paleozoic and Mesozoic radiolaria in Thailand and Malaysia. In: Metcalfe, I. (Ed.), Gondwana Dispersion and Asian Accretion. Balkema, Rotterdam, pp. 175–196. Sashida, K., Igo, H., Hisada, K., Nakornsri, N., Ampornmaha, A., 1993. Occurrence of Paleozoic and Early Mesozoic radiolaria in Thailand (preliminary report). Journal of Southeast Asian Earth Sciences 8, 97–108.

K. Wakita, I. Metcalfe / Journal of Asian Earth Sciences 24 (2005) 679–702 Sashida, K., Adachi, S., Igo, H., Koike, T., Ibrahim, B.A., 1995. Middle and Late Permian radiolarians from the Semanggol Formation, Northwest Peninsular Malaysia. Transactions and Proceedings of the Palaeontological Society of Japan. New Series 177, 43–58. Sato, T., 1974. A Jurassic ammonite from near Inuyama, north of Nagoya. Transactions and Proceedings of the Palaeontological Society of Japan, N.S. 96, 427–432. Sengo¨r, A.M.C., Natal’in, B.A., 1996. Palaeotectonics of Asia: fragments of a synthesis. In: Yin, A., Harrison, T.M. (Eds.), Tectonic Evolution of Asia. Cambridge University Press, Cambridge. Shibuya, H., Sasajima, S., 1986. Paleomagnetism of red cherts: a case study in the Inuyama area, central Japan. Journal of Geophysical Research 91, 14105–14116. Singharajwarapan, S., Berry, R., 2000. Tectonic implications of the Nan Suture Zone and its relationship to the Sukhothai Fold Belt, Northern Thailand. Journal of Asian Earth Sciences 18, 663–673. Spiller, F.C.P., 1996. Late Paleozoic radiolarians from the Bentong-Raub Suture Zone, Peninsular Malaysia. The Island Arc 5, 91–103. Spiller, F.C.P., Metcalfe, I., 1993. Late Palaeozoic radiolarians from the Bentong–Raub suture zone, Peninsular Malaysia: initial findings. Third International Symposium of IGCP 321 Gondwana Dispersion and Asian Accretion. Abstracts of Papers, pp. 67–69. Spiller, F.C.P., Metcalfe, I., 1995a. Late Palaeozoic radiolarians from the Bentong–Raub Suture Zone and Semanggol Formation, Peninsular Malaysia: initial findings. Journal of Southeast Asian Earth Sciences 11, 217–224. Spiller, F.C.P., Metcalfe, I., 1995b. Palaeozoic and Mesozoic radiolarian biostratigraphy of Peninsular Malaysia. In: Tran, V.T. (Ed.), Proceedings of the International Symposium on the Geology of Southeast Asia and Adjacent Areas Journal of Geology (Vietnam), Series B, 5/6, pp. 75–86. Sugiyama, K., 1997. Triassic and Lower Jurassic radiolarian biostratigraphy in the siliceous claystone and bedded chert units of the southeastern Mino Terrane, Central Japan. Bulletin of the Mizunami Fossil Museum 24, 79–193. Taira, A., Katto, J., Tahiro, M., Okamura, M., Kodama, K., 1988. The Shimanto Belt in Shikoku, Japan: evolution of Cretaceous to Miocene accretionary prism. Modern Geology 12, 5–46. Tumanda, F., 1991. Radiolarian biostratigraphy in central Busuanga Island, Palawan, Philippines. Journal of Geological Society of Philippines 46, 49–104. Tumanda, F., 1994. Permian radiolaria from Busuanga Island, Palawan, Philippines. Journal of Geological Society of Philippines 49, 119–193. Tumanda-Mateer, F., Sashida, K., Igo, H., 1996. Some Jurassic radiolarians from Busuanga Island, Calamian Island Group, Palawan, Philippines. In: Noda, H., Sashida, K. (Eds.), Prof. Hisayoshi Igo Commemorative Volume on Geology and Paleontology of Japan and Southeast Asia, pp. 165–192. Ueno, K., Hisada, K., 1999. Closure of the Paleo-Tethys caused by the collision of Indochina and Sibumasu. Chikyu Monthly 21, 832–839 (in Japanese). Ueno, K., Igo, H., 1997. Late Paleozoic foraminifers from the Chiang Dao area, northern Thailand: geologic age, faunal affinity, and palaeobiogeographic implications. Proceedings of the 13th International Congress on the Carboniferous and Permian, Krakow, Poland, 1997, pp. 339–358. Ueno, K., Wang, Y., Wang, X., 2003. Fusulinoidean faunal succession of a Paleo-Tethyan oceanic seamount in the Changning–Menglian Belt, West Yunnan, Southwest China: an overview. Island Arc 12 (2), 145– 161. Wajzer, M.R., Barber, A.J., Hidayat, S., Suharsono, 1991. Accretion, collision and strike–slip faulting: the Woyla Group as a key to the tectonic evolution of North Sumatra. Journal of Southeast Asian Earth Sciences 6, 447–461. Wakita, K., 1984. Geology of Hachiman district, Quadrangle Series, scale 1:50,000, Geological Survey of Japan 89p.

701

Wakita, K., 1988a. Origin of chaotically mixed rock bodies in the Early Jurassic to Early Cretaceous sedimentary complex of the Mino Terrane, central Japan. Bulletin of Geological Survey of Japan 39, 675–757. Wakita, K., 1988b. Early Cretaceous me´lange in the Hida-Kanayama area, central Japan. Bulletin of the Geological Survey of Japan 39, 367–421. Wakita, K., 1989. Accretion tectonics in Japan. Bulletin of Geological Survey of Japan 40, 251–253. Wakita, K., 1991. Geology of the Tanigumi district, with Geological Sheet Map at 1:50,000, Geological Survey of Japan 53p (in Japanese with English abstract). Wakita, K., 1997. The Geology of Japan: a Guide for the CD-ROM Digital Geologic Map of East and Southeast Asia. CCOP Technical Bulletin 26, 47–57. Wakita, K., 2000a. Melanges of the Mino terrane. Memoir of Geological Society of Japan 55, 145–163 (in Japanese with English abstract). Wakita, K., 2000b. Cretaceous accretionary: collision complexes in central Indonesia. Journal of Asian Earth Sciences 18, 739–749. Wakita, K., Kojima, S., Okamura, Y., Natal’in, B.A., Zyabrev, S.V., 1992. Triassic and Jurassic Radiolaria from the Khabarovsk Complex, eastern Russia. News of Osaka Micropaleontologists, Special Volume 8, 9–19. Wakita, K., Munasri Sopaheluwakan, J., Zulkarnain, I., Miyazaki, K., 1994a. Early Cretaceous tectonic events implied in the time-lag between the age of radiolarian chert and its metamorphic basement in Bantimala area, South Sulawesi, Indonesia. The Island Arc 3, 90–102. Wakita, K., Munasri Sopaheluwakan, J., Widoyoko, B., 1994b. Cretaceous radiolarians form the Luk-Ulo Melange Complex in the Karangsambung area, central Java, Indonesia. Journal of Southeast Asian Earth Sciences 9, 29–43. Wakita, K., Munasri Sopaheluwakan, J., Zulkarnain, I., Miyazaki, K., 1996. Tectonic Evolution of the Bantimala Complex, South Sulawesi, Indonesia. In: Hall, R., Blundell, D (Eds.), Tectonic Evolution of Southeast Asia. Geological Society of London, Special Publication 106, pp. 353–364. Wakita, K., Miyazaki, K., Zulkarnain, I., Sopaheluwakan, J., Sanyoto, P., 1998. Tectonic implication of new age data for the Meratus Complex of South Kalimantan, Indonesia. The Island Arc 7, 202–222. Wang, X., Metcalfe, I., Jian, P., He, L., Wang, C., 2000. The Jinshajiang– Ailaoshan suture zone, tectono-stratigraphy, age and evolution. Journal of Asian Earth Sciences 18, 675–690. Wu, G., 1993. Late Paleozoic tectonic framework and Paleotethyan evolution in Western Yunnan. Scientia Geologica Sinica 2, 129–149. Wu, H., Li, H., 1989. Carboniferous and Permian radiolaria in the Menglian area, western Yunnan (in Chinese with English abstract). Acta Micropalaeontologica Sinica 6, 337–343. Wu, H., Zhang, Q., 1987. Carboniferous and Permian radiolarites of Western Yunnan-relict of the Paleo-Tethys. Acade´mie des Sciences Comptes Rendus Paris 3, 90–96. Wu, H., Boulter, C.A., Ke, B., Stow, D.A.V., Wang, Z., 1995. The Changning–Menglian suture zone; a segment of the major CathaysianGondwana divide in Southeast Asia. Tectonophysics 242, 267–280. Yang, Q., Matsuoka, A., Wang, Y., Kobayashi, K., Nagahashi, T., Zeng, Q., 2000. A Middle Triassic radiolarian assemblage from Quxia, Lhaze County, southern Tibet. Scientific Reports, Niigata University, Series E (Geology) 15, 73–79. Yang, Q., Matsuoka, A., Wang, Y., 2002. Progress in Radiolarian micropaleontological studies in Southern Tibet. Acta Micropalaeontologica Sinica 19, 105–111. Yao, A., 1972. Radiolarian fauna from the Mino Belt in the northern part of the Inuyama area, central Japan. Part I. Spongosaturnalids. Journal of Geoscience, Osaka City University 15, 21–64. Yao, A., 1979. Radiolarian fauna from the Mino Belt in the northern part of the Inuyama area, central Japan. Part II: Nassellaria 1. Journal of Geoscience, Osaka City University 22, 21–72. Yao, A., 1982. Middle Triassic to Early Jurassic radiolarians from the Inuyama area, central Japan. Journal of Geoscience, Osaka City University 25, 53–70.

702

K. Wakita, I. Metcalfe / Journal of Asian Earth Sciences 24 (2005) 679–702

Yao, A., Matsuda, T., Isozaki, Y., 1980. Triassic and Jurassic radiolarians from the Inuyama area, central Japan. Journal of Geosciences, Osaka City University 23, 135–154. Yeh, K., 1992. Triassic Radiolaria from Uson Island, Philippines. Bulletin of National Museum of Natural Sciences (Taiwan) 3, 51–91. Yeh, K., Cheng, Y., 1996. Jurassic radiolarians from the northwest coast of Busuanga Island, North Palawan Block, Philippines. Micropaleontology 42, 93–124. Yeh, K., Cheng, Y., 1998. Radiolarians from the Lower Jurassic of the Busuanga Island, Philippines. Bulletin of National Museum of Natural Sciences (Taiwan) 11, 1–65. Yoshida, F., Wakita, K., 1999. Geology of the Gifu district, With Geological Sheet Map at 1:50,000, Geological Survey of Japan, 71 p (in Japanese with English abstract).

Zamoras, L.R., Matsuoka, A., 2000. Early Late Jurassic radiolarians from the clastic unit in Busuanga Island, North Palawan, Philippines. Science Report of Niigata University, Series E (Geology) 15, 91–109. Zamoras, L.R., Matsuoka, A., 2001. Malampaya Sound Group: a Jurassic– Early Cretaceous accretionary complex in Busuanga Island, North Palawan Block (Philippines). Journal of the Geological Society of Japan 107, 316–336. Zhang, Z.M., Liou, J.G., Coleman, R.G., 1984. An outline of plate tectonics of China. Geological Society of America Bulletin 95, 295–312. Zhong Dalai, et al., 2000. Paleotethysides in West Yunnan and Sichuan. Science Press Beijing/VSP Utrecht, China. 248pp. Zyabrev, S.V., Matsuoka, A., 1999. Late Jurassic (Tithonian) radiolarians from a clastic unit of the Khabarovsk Complex (Russian Far East): significance for subduction accretion timing and terrane correlation. The Island Arc 8, 30–37.