post-collisional tectonic escapes in indonesia

PROCEEDINGS PIT IAGI RIAU 2006 The 35th IAGI Annual Convention and Exhibition

Pekanbaru – Riau, 21 – 22 November 2006

POST-COLLISIONAL TECTONIC ESCAPES IN INDONESIA : FASHIONING THE CENOZOIC HISTORY

Awang Harun Satyana1

1BPMIGAS

ABSTRACT

Post-collisional tectonic escape refers to the lateral escape or extrusion of fault-bounded geological blocks as a result of collision or compression away from the collision zone and towards free edge of oceanic margin. While the collision zone is represented by fold-thrust belts, the tectonic escape is accommodated by large strike-slip faults and rifting and spreading of basement. There are five significant collisional events fashioning the Cenozoic tectonics of Indonesia. The first was collision of India to Eurasia started at 50 or 45 Ma (early-middle Eocene). The collision resulted in the Himalayan Fold-Thrust Belt and was followed by the escape of the Sundaland southeastwards through major strike-slip faults and the formation of sedimentary basins in the Sundaland as well as the opening of marginal seas of the South China Sea and Andaman Sea. The faults occupied and reactivated Mesozoic sutures within the Sundaland. The faults are Red River Fault-Sabah Shear, Tonle-Sap-Mekong (Mae Ping) Fault, Three Pagoda Fault-Malay-Natuna-Lupar Line-Adang Fault, and the Sumatran Faults. The second collision occurred at about 25 Ma (late Oligocene) when an oceanic island arcs constructed on the southern margin of the Philippine Sea Plate collided with the northern margin of Australia Continent. The collision resulted in fold-thrust belt of the Papua Central Ranges and was followed by tectonic escapes of strike-slip faults and basin formation. The faults are Sorong-Yapen Fault, Waipoga Fault, Gauttier Offset, and Apauwar-Nawa Fault. Opening of the North Irian Basin in northern Papua also shows the post-collision tectonic escapes. The third collision was the collision of the Bird’s Head microcontinent with Papua at 10 Ma (late Miocene). The Lengguru Fold-Thrust Belt marks the collision zone. Strike-slip faults away from the collision zone like the Tarera-Aiduna, Sorong, Waipoga, and Ransiki Faults may demonstrate the post-collision tectonic escape. The Bintuni Basin located just to the west of the Lengguru Fold-Thrust Belt is a foreland basin developing as a response to post-collision extensional structure. The fourth collision occurred from 11 to 5 Ma (late Miocene to earliest Pliocene) when the Buton-Tukang Besi and the Banggai-Sula microcontinents collided East Sulawesi ophiolite. The microcontinents were detached from the Bird’s Head of Papua and escaped westwards by the Sorong Fault. The collision has formed Batui Fold-Thrust Belt and was followed by post-collision tectonic escapes in forms of rotation of arms of Sulawesi, formation of major strike-slip faults of Palu-Koro, Kolaka, Lawanopo, Hamilton, Matano, and Balantak Faults, and the opening of the Gulf of Bone. More recent transtensional movement is responsible for the opening of pull-apart basins of Poso, Matano and Towuti Lakes, as well as the Palu Depression. The last collision commenced at about 3 Ma (mid-Pliocene) when northern margin of Australia Continent collided Banda Island Arc. The collision resulted in foreland fold-thrust belt from Timor, Tanimbar to Seram. Lateral extension is observed to follow the arc-continent collision indicating a tectonic escape. Major strike-slip faults were formed sub-paralleling the Timor Island and may relate to the escape of the Sumba Island westwards. Extensional crustal collapse followed the arc-continent collision and has resulted in the formation of the Weber Deep, Savu Basin, and opening of the Banda Sea .



The cases in Indonesia show that tectonic escape is a widespread process and may have been very important in the evolution of convergent region like Indonesia. The concept of tectonic escape can contribute to the understanding of the process by which continents are assembled and slivered.

INTRODUCTION

The term ‘tectonic escape’/ ‘escape tectonics’ / ‘extrusion tectonics’ and related to ‘indentation tectonics’ refers to the lateral motion of fault-bounded geological blocks following collision (indentation), hence the terminology is ‘post-collision tectonic escape’. The motion is away from the collision zone. Strike-slip and extensional/rifting structures accommodate the lateral motion. Tectonic escape has been elemental in continental evolution throughout recorded earth-history. Indonesia holds a critical position in the development of the idea of the escape tectonics and provide a good evidence of it (Satyana, 2003). The classic example of escape tectonics and from which the idea was developed has long been held to be the eastward extrusion of parts of Southeast Asia as a response to the collision and northward motion of India into Eurasia. This paper will describe a number of examples and evidence of tectonic escapes from widespread geographic areas in Indonesia during Cenozoic era. The tectonic escapes have “fashioned” (gave shape or form, altered, transformed, made, constructed) Indonesian tectonics. Older than Cenozoic era, tectonic escape could have operated, but recognition of the extent to which it has operated may be difficult due to problem of complicated overprinting. Knowledge of escape tectonics may lead to the understanding of regional tectonic evolution and to the prediction and recognition of rifted structures of sedimentary basins which may become the sites for petroleum accumulations and coal deposits.

ESCAPE TECTONICS : THE ORIGIN OF THE IDEA

Work about escape tectonics or extrusion tectonics commenced with Molnar and

Tapponnier’s 1975 publication on the Cenozoic tectonics of Asia. They highlighted the results of India’s collision with Eurasia and the ensuing deformation within Indochina and Sunda. These crustal gymnastics were elegantly modeled by Tapponnier et al. (1982) using an indentation machine and layered plasticine. (Figure 1) The processes by which continents are assembled and modified are currently well understood. Molnar and Tapponnier (1975), Tapponnier et al. (1982), and Burke and Sengör (1986) investigated the effect of collision of continents or microcontinents as well as island arcs to the development of tectonics in continents. They concluded that there exists a range of phenomena, associated mainly with continental collision and dominated by strike-slip faulting called extrusion tectonics by Tapponnier et al. (1982) or escape tectonics/ tectonic escape by Burke and Sengör (1986). The term “escape tectonics” (“extrusion tectonics”) refers to the lateral escape or extrusion of fault-bounded geological blocks as a result of collision or compression. This extrusion can occur on all scales, ranging from small-scale faults, with only centimeters or meters of displacement, to large-scale crustal faults, with hundreds kilometers of displacement . The classic example of escape tectonics has long been held to be the eastward and southeastward escape or extrusion of parts of Southeast Asia as a response to the collision and northward motion of India into Eurasia. Initial collision of India with Eurasia occurred about 50 million years ago. Geophysical evidence, derived from the pattern of magnetic stripes in the Indian Ocean, indicates that the northward motion of India, with respect to Asia, slowed down from about 10 cm a year to about 5 cm a year at this time. This lower rate continues to the present day. As a result, almost 2500 km of convergence between the two has occurred since the collision, shortening and



thickening the crust to produce the Himalayan Mountains and the Tibetan Plateau. Estimates of the amount of crustal mass beneath the Tibetan Plateau are, however, about 30 percent too little to account for all the shortening that must have taken place. In addition, many of the large earthquakes that affect the region occur, not at the boundary between the Indian and Eurasian plates, but within the Eurasian plate. In the 1970s a number of workers drew on these lines of evidence, and on the recognition of large-scale strike-slip faults (hundreds of kilometers in length) in Southeast Asia from the newly available satellite imageries. As a result, they proposed that the balance of the missing material from India-Asia collision must have been extruded or “escaped” eastwards from which extrusion or escape tectonics terminology was derived.

ESCAPE TECTONICS : MECHANISM Lateral extrusion occurs when a rigid plate collides with a softer or semi-rigid plate. Because of the difference in rigidity, the softer plate can be expelled out to the sides of the collision boundary. Supporting evidence for this extrusion model was obtained by Tapponnier et al. (1982) from a series of laboratory experiments using a rigid indenter (representing India) and plasticine (representing Asia) which produced a series of ‘slip lines’ of material motion, generated by the indenter penetrating into the Asian plate, in a pattern strikingly similar to the pattern of faults observed in Southeast Asia (Figure 1). Because buoyant continental (or arc) material generally moves during collision toward a nearby oceanic margin where less buoyant lithosphere crops out, the process of major post-collision strike-slip faults is called towards a ‘free oceanic edge or face’ readily subductable during arc or continental collision (Burke and Sengör, 1986). In the case of India-Asia collision, the strike-slip faulting occurred eastwards and southeastwards towards the free oceanic face of subduction zone of oceanic plates along the Western Pacific margins. The distribution and sense of strike-slip faults following the collision bear a striking resemblance

to the geometry of slip lines in the well-known plasticity problem of plane indentation. Tectonic escape promotes : (1) pervasive strike-slip faulting late in orogenic history which breaks up mountain belts across strike and may juxtapose unrelated sectors in cross section, (2) rifting and the formation of rift-basins with thinning of thickened crusts, and (3) localized compressional mountains and related foreland-through basins. Nowadays, the group of researchers make an effort to link internal shortening of Tibetan Plateau with extrusion of related features. By compiling recent studies on Cenozoic deformation, magmatism and seismic structure, they formulate a time-dependent model for the growth of Tibetan plateau (Tapponnier et al. 2001). They introduced successive intracontinental subduction zones playing a dynamic role on maintaining stepwise growth and rise of the plateau in three main phases younging northward. In their model, strike-slip faults develops at weakly welded sutures where oblique subduction is partitioned. In first order approximation, model seems working but there is still no solid data indicating the postulated intracontinental subduction zones.

REGIONAL TECTONICS OF INDONESIA The tectonics of Indonesia is complex but very interesting due its position in plates convergence. Three provinces compose the Indonesian Archipelago : western Indonesia, central Indonesia, and eastern Indonesia. (Figures 2, 3). The western Indonesia (Sumatra-Natuna-Kalimantan-Java-Bali) is situated on the southeastern extension of the Eurasian Plate. This extension manifests the extrusion of Eurasian Plate due to the collision with India. The eastern Indonesia (Papua-Timor) shows extension of Australian Plate by rifting and drifting. The central Indonesia (Sulawesi-Halmahera-Moluccas-Flores-Lombok) represents island arcs formed due to the interaction of plates (Eurasia, Pacific, Indian-Australia). Indonesia is bounded to the south and west by the Indian-Australian Plate and to the north and east by the Philippine and Pacific Plates (Figure 3). The margins of the plates are in collision,



resulting in the consumption of plates along the subduction zones, the creation of volcanic arcs, and the formation of compressional and oblique slip structures. The Indonesian Archipelago therefore represents an immensely complicated triple junction, involving a complex pattern of small marginal ocean basins and microcontinental blocks bounded by subduction zones, extensional margins, and major transcurrent faults. On the basis of geological and geophysical characteristics, Simandjuntak and Barber (1996) distinguished five regions of crust of different origins in Indonesian region. The regions are : (1) southeastern promontory of the Eurasian plate forming the Sundaland continental craton in Sumatra, West Java and Western Kalimantan; (2) Philippine Sea oceanic plate in the northeast; (3) Australian continental craton extending into the Indonesian region in Papua and the Arafura and Sahul Platforms; (4) Indian oceanic plate in the southwest; and (5) transition zone, marking the zone of current plate interaction with active seismicity and volcanism extending through western Sumatra, eastern Java and the Banda arcs to northern Papua and through Sulawesi and the Moluccas to Mindanao in the Philippines. In this zone, subduction is still active, with the development of thrusts, transcurrent and extensional faults. This region is also characterized by allocthonous continental micro-plates with Tertiary and Mesozoic sediments overlying Paleozoic basement, juxtaposed against Cretaceous and Tertiary terranes. The present physiography of the Indonesian archipelago can be attributed directly to the Neogene orogenic events. Simandjuntak and Barber (1996) subdivided these events into six orogenies : (1) Sunda orogeny in Java and Nusa Tenggara, (2) Barisan orogeny in Sumatra, (3) Talaud orogeny in the North Moluccas, (4) Sulawesi orogeny in Sulawesi, (5) Banda orogeny in the Banda Arc and (6) Melanesian orogeny in Papua. These events include : plate convergence with subduction beneath the margins of Sundaland to produce a Cordilleran type of orogeny, a unique arc-arc collision in the Moluccas, formation of sliver plates in Eastern Indonesia, collision of arcs with microcontinents like in Sulawesi and with major continental blocks like in Timor, construction of mountain belts, transpression and

transtension along major strike-slip faulting, obduction and construction of foreland fold and thrust belts, back-arc thrusting, and reversal of subduction polarity.

TECTONIC ESCAPES IN INDONESIA Escape tectonics fashions the tectonics of Indonesia and is responsible for the physiography and present distribution of islands in the Indonesian Archipelago. The areas in Indonesia observed with tectonic escapes will be described in terms of their contribution to the development and evolution of Indonesian tectonics.

India-Eurasia Collision and Sundaland Tectonic Escapes

Collision of India and presence of major shears

The Tertiary and present configuration of geology and tectonics of Southeast Asia has been strongly controlled by the collision of India sub-continent to the Eurasian Plate starting at 50 or 45 Ma. In their well known extrusion model, Tapponnier and his co-workers (such as : Molnar and Tapponnier, 1975; Tapponnier et al., 1982; Peltzer and Tapponnier, 1988) argued that during the collision, continental blocks to the east and southeast of the collision zone -including Sundaland where most parts of Sumatra-Natuna-Kalimantan are contained - were extruded (escaped) hundreds of km (550-700 km – Murphy, 2002a) southeastwards and eastwards as India indented the Eurasia. The convergence rate between India and Eurasia dropped sharply between anomalies A22 and A21 (50.3 – 47.8 Ma) and an Indian Ocean spreading ridge reorganized between 43.9-41.1 Ma (Packham, 1996). The decreasing rate of convergence and spreading reorganization indicate the events of collision of India to Eurasia occurred between 50.3 to 41.1 Ma. Most authors favor the collision date of India to Eurasia between 50 and 45 Ma. Hutchison (1996) subdivided the history of Indian collision into ‘soft collision’ at anomaly 22 (53 Ma – Early Eocene) and ‘hard collision’ at 40 Ma (Late Eocene). The soft collision is not considered powerful enough to have produced the major



Southeast Asian shears, but the Late Eocene hard collision would have been. The early convergence of India with Eurasia must have emphasized movements on the pre-existing faults. Sengör (1984), Hutchison (1996), and Pulunggono et al. (1999) suggested that the escape tectonics made use of pre-existing zones of weakness such as old suture zones, and shear zones which already existed before the collision. The remnants of these movements are preserved in major strike-slip faults or shears. Regional strike-slip faults (shears) in Sundaland and Southeast Asia was discussed by Wood (1985) (Figure 4). He subdivided the region into the South China, Indochina, and Sunda sub-plates bordered by major parallel NW-SE trending shear systems : (1) Red River-Sabah, (2) Thai-Burma-Natuna-Lupar-Adang, and (3) Sumatran Shears. Slight extension on these major strike-slip faults led to the localization of major Cenozoic basins within shear zones. Pulunggono et al. (1999) considered that dextral strike-slip faults induced by India-Eurasia collision expressed as reactivated movements along the existing pre-Tertiary WNW-ESE (NE 300°) trending shears. The possibility of extrusion of segments of Sundaland to the southeast (or ESE) along those WNW-ESE series of shears is not impossible. Reconstruction studies of Sundaland before and after the collision of India to Eurasia are provided by Daines (1985), Gatinsky et al. (1984), Gatinsky (1986), Hutchison (1996), Hall (1995, 1996) and Murphy (2002b). Daines (1985) proposed that as collision progressed, grabens formed prior to strike-slip movement on the old sutures. Rapid left-lateral movement on the Red River Fault resulted in extension of the South China Basin. During the extrusion process, the suture acted as a profound zone of weakness which allowed propagation of the regional strike-slip system of the Malay-Natuna-Lupar shear zone. This suture/shear zone separates Sunda from Indochina. The Malay Basin shear zone developed along the pre-existing Jurassic suture, and depending on the differences in the rate of movement along the Red River and Malay Basin shear zones, extension or compression could have been produced in Kalimantan. As left-lateral movement occurred on the Altyn Tagh fault located to the north of the collision zone, the

direction of slip changed on the Red River and Malay Basin shear zones. The rotation of Indochina caused a change in the orientation of the spreading axis in the South China Basin. Whereas right-lateral movement on the Red River Fault is a direct result of eastward displacement of China, right-lateral movement on the Malay Basin shear zone is due to the continued clockwise rotation of Indochina and Sunda. The stress regime in the old grabens was strongly compressive during this phase. Gatinsky et al. (1984), Gatinsky (1986), and Hutchison (1996) provided a series of palinspastic maps for Southeast Asia from Paleozoic to the present day based on palaeomagnetic studies. From Early Paleogene to the Recent (60 Ma-0 Ma) the major events are the Eocene collision of India with Eurasia and the opening of the South China Sea. The collision propagated major shear faults eastwards and southeastwards as the squeezed terrains attempted to escape from the collision zone (Molnar and Tapponnier, 1975). The West Kalimantan basement has been driven south to equatorial latitudes by the opening of the South China Sea (Haile, 1979; Taylor and Hayes, 1983). These events pushed many microcontinents southwards from the South China shelf towards Kalimantan. The Neogene map of Gatinsky et al. (1984) suggests that Southeast Asia may be divided into several independent sub-plates. The southeast China sub-plate is moving eastwards and is detaching from Eurasia along the seismically active north-south Qujiang Fault, while strike-slip motion along the Red River Fault is right-lateral. The Indochina sub-plate is thought to be independently moving towards the northwest with respect to the southeast China sub-plate, causing present-day compressional seismicity in the Indo-Burman Ranges and extensional tectonics behind it in the South China Sea region. The boundary zone between the Indochina and the Central Sunda subplate lies along the axis of the Tonle Sap-Mekong Basin, and the extensional tectonics along this predominantly strike-slip fault system may be held responsible for the Pliocene-Pleistocene alkaline basaltic province which extends along its length from the Mekong Delta northwestwards into northern Thailand. The tendency for the Central Sunda subplate to move



southeastwards is shown by extension behind it in the Andaman Sea, and important southeast-directed faults in the South China Sea and in the Malay Peninsula. Extension on these predominantly strike-slip faults has resulted in important shear basins such as the Malaya Basin and the fault planes passing through the Malay Peninsula. Murphy (2002b) proposed 45 Ma as the inception of the India-Eurasia collision. The collision destroyed the final remnants of the Tethys Ocean. At 40 Ma (Figure 5), the western Sunda margin became a pure transform margin by clockwise rotation of the fringing elements brought about by the northward passage of India into ‘hard collision’ with Eurasia. The first internal Tertiary basin formation within Sunda took place in Sumatra and western Java. Post-collision escape/extrusion tectonics commenced at 36 or 38 Ma when major changes took place in Sundaland. Sunda was split into three major blocks by extrusion from the India-Eurasia collision (Figure 5). The three blocks were : (1) South China (SOCH), north of the Red River Fault, attached to Eurasia, (2) Indochina (INCH), south of the red River Fault, east of the Sagaing Fault, north of the Three Pagoda-SW Malay Faults, and (3) South and West Sunda (SOWS), bounded by the Three Pagoda Fault, the eastern margin of the Khorat Arch (on the Vietnam shelf), the eastern side of the Natuna Ridge and adjacent parts of the core of Borneo and the right-lateral Sumatran Fault, with extensions to the Sagaing Fault. Initially, SOWS escaped at a rate somewhat faster than did Indochina. This, together with a slight degree of clockwise rotation of SOWS, opened the Sunda Rift basins in southern South China Sea. Formation of the modern South China Sea commenced with the extrusion of INCH and SOWS along the left-lateral Red River Fault. Extrusion of INCH and SOWS, together with slab pull at the trenches along NW Borneo and the Sulu Sea, was the apparent driving mechanism for the South China Sea opening. Continued extrusion at 30 Ma of the SOWS block led to compression along its leading edge (Figure 5). Moderate folding arched Sumatra, producing open folds in the forearc and backarc positions.

The Java forearc was also folded. The Sumatran Fault gradually converted from transtensional to transpressional movement. In the South China Sea, oceanic crust was inserted commencing at 32.8 Ma. Deltas built out from the Sunda Shelf in NW and central Borneo. At 25 Ma, deltas spread southwards in the Sumatra and West Java basins, marking the inception of the Neogene wedge, major reservoirs for hydrocarbons. Between 20 and 15 Ma tectonic differentiation in Southeast Asia intensified. The Barisan Range in Sumatra was compressed and uplifted as a consequence of clockwise rotation of Sunda about a pole of rotation in the Assam Syntaxis. Spreading at the South China Sea ceased at about 16.8 Ma as a result of the collision of the drifted microcontinents of South China Sea with NW Borneo. Central Kalimantan was uplifted and became the source of sediments for circum-Borneo until Java. In the Murphy (2002)’s reconstruction, post-collision escape tectonics between 35 Ma and 15 Ma has extruded Sundaland 550-700 km and right-lateral movement along the Sumatran fault/Andaman/Sagaing system is paired with left-lateral movement along the Red River Fault-West Baram Line.

Support from palaeomagnetic data The collision of India into Eurasia and related tectonic escapes in Southeast Asia are supported by palaeomagnetic data (like Richter and Fuller, 1996) . The available Mesozoic and Cenozoic palaeomagnetic data from the Indochina and Sibumasu (Siam-Burma-Malaysia-Sumatra) blocks qualitatively support the predictions of laboratory models of Tapponnier et al. (1982). However, ambiguities regarding the tectonic significance of these palaeomagnetic data remain. Many of the tectonic conclusions are based upon several key sampling localities or well preserved chronostratigraphic successions and very little is known about the intervening regions or time periods. With regard to the actual palaeomagnetic analyses, it has proved difficult to discriminate between primary and secondary magnetizations. Despite these difficulties, palaeomagnetism remains one of the few direct records of ancient plate motions available to us.



The palaeomagnetic and geological data from Sundaland suggest several modifications to the extrusion tectonic model (Richter and Fuller, 1996). Northern Sundaland has only rotated 25° -30° clockwise with respect to South China during the Tertiary. The total southeastward translation of the Indochina block was only 300-500 km. The extruding blocks are composed of smaller rigid blocks which are separated by extensional and transtensional zones which have accommodated the formation of rifted basins. Deformation of the Sibumasu block resulted from oblique subduction of the Indian Ocean plate, whereas deformation of the Indochina block was dominated by extrusion driven by convergence between the Indian Craton and Eurasia. The extruding blocks could not simply override plate boundaries located to the south and east and was partially or completely coupled to them. Thus, extrusion worked with northward subduction of Indian oceanic crust and northward motion and clockwise rotation of the Philippine Sea Plate to drive the counter-clockwise rotation of Kalimantan.

Basin development due to the collision

The Eocene collision between India and Eurasia corresponded temporally with the initiation of much of the basin evolution in SE Asia. Daly et al. (1987) detailed the evolution of these basins. The basin systems of Sumatra, Java, Malaysia, Thailand, and Kalimantan were initiated during the Eocene. In Sumatra, there are two basin systems, which at present are found in fore-arc and back-arc settings. The back-arc basins include the North Sumatra, Central Sumatra, and South Sumatran Basins. The northern basin extends some distance offshore to the north as the Mergui Basin. These basins are bounded by broad strike-slip fault zones to the north and south – the Malacca and Sumatran/Semangko Fault Zones, respectively. These fault zones express the tectonic escapes due to collision. The basins appear to have the geometry of large scale pull-apart basins generated by dextral strike-slip displacements on the two fault zones. Rift sediments in these basins are dated as Mid to Late Eocene. Murphy (2002b) proposed 40 Ma as the commencement of the first internal Tertiary basin formation within Sunda (Figure 5). Five basins

had their inception in north-trending rifts with an east-west extensional direction : North, Central, and South Sumatra and the Sunda and Arjuna Basins. The origin of these basins may be related to a slightly transtensional Sumatra fault, but evidence is not conclusive, nor is there a clear linkage to the India-Eurasia Collision. The pre-Tertiary framework of Sumatra consists of a mosaic of continental and oceanic microplates accreted in the late Triassic when the Mergui, Malacca and East Malaya micro-plates joined together to form Sundaland. Further accretion involving the west coast Woyla Terranes followed in the late Mesozoic (Pulunggono and Cameron, 1984). Pulunggono et al., (1999) showed the role of Sumatran Faults to the development of Sumatran basins. Presence of Sumatran Fault as response to escape tectonics of Indian collision had considerably overprinted the pre-Tertiary framework of Sumatra. The growth of the Sumatran Fault System has considerably modified the end-Mesozoic boundaries. The major zones of weakness of basement accretion rifted when back-arc basins of Sumatra developed in Early Tertiary. The major Tertiary (N-S) rift system of onland Sumatra were initiated during the Eocene, probably also under roll-back conditions of the obliquely subducting Indian oceanic plate under Sundaland, and rifting phase was well underway during the Late Eocene. Eo-Oligocene rifting took place along the old N-S set of basement “weak zones” or megashears of Mesozoic age and along the NE 30-40º faults. In conjunction, movements along the existing pre-Tertiary WNW-ESE megashears (reactivation) took place and were expressed as Late Eocene strike-slip movements. In contrast to the strike-slip basins, the forearc basins of Sumatra appear to have an essentially extensional origin. Their generation corresponds with the marked decrease in the convergence velocity of the Indian plate with Eurasia. Basin development in Natuna area are related to rifting as consequence of escape tectonics when South-West Sunda extruded at 35 Ma at a rate faster than Indochina together with slight clockwise rotation of South-West Sunda. Daines (1985) demonstrated the development of these basins. Basins in Natuna (East and West Natuna Basins) initiated when South China Sea



commenced to develop in Oligocene time. The first phase was one of crustal extension, lasting from 40-29 Ma which resulted in basin development. The second phase commenced about 29 Ma and was dominated by transpression resulting basin inversion until about 10 Ma. The two deformation periods are interpreted to be the result of escape tectonics and clockwise rotation of Indochina-Sunda of India-Eurasia collision. Pre-collision reconstruction of Eurasia suggests that an extensive Jurassic suture, separating Indochina and Sunda, was responsible for allowing the propagation of the major escaped strike-slip fault zone of Malay-Natuna-Lupar Shear Zone, which consequently facilitated basin development in the area. Strike-slip movement ceased in the West Natuna Basin at approximately 10 Ma when right-lateral movement became concentrated on the Red River Fault, although movement is still occurring on the northern extension of the shear zone in western Thailand-southeastern Burma. In Kalimantan, major shear related to the India collision is the Lupar-Adang Fault (Satyana, 1994; Satyana, 1996; Satyana et al., 1999). It is a transversal trending major structural element traversing the island of Kalimantan from the Natuna Sea through the island to the Strait of Makassar as long as 1350 km. The trace of this Kalimantan megashear occupies the northern border of the Schwaner and Semitau terranes. Kalimantan is made up of a variety of accreted terranes : continental, oceanic and transitional. The Lupar-Adang Fault occupies the suture of these terranes (Satyana, 1996). Initiation of basins in Kalimantan (Barito, Kutei, Tarakan, Makassar Strait) appears to relate to back-arc extension that occurred at 50 Ma (Satyana, 2003) Murphy, 2002b) along the SW Pacific margin. These basins do not appear to relate directly to the deformation caused by the collision of India. However, Melawi and Ketungau Basins located to the southeast of the Lupar Line are pull-apart basins related to Lupar-Adang Fault, therefore the basins express the rifted escape tectonics. Basins in Java (like Sunda, West Java, East Java Basins) may also not relate to strike-slip faulting due to India collision, but indeed it is related to India collision. They may relate to roll back movement of the Indian oceanic slab beneath Java

because of decreasing rate of convergence rate due to India collision. The velocity decrease would cause the subducting slab to sink (to roll back), with consequent decoupling of the slab and creation of an extensional environment in the arc region. Combination of escape tectonics and rollback movement due to decreasing convergence rate are another possible mechanism (Morley, 2001). The process of escape tectonics is continuing at the present time. Palaeomagnetic data for Sumatra (Ninkovich, 1976) and for Kalimantan (Fuller et al., 1999) have proven that extrusion tectonics is indeed ongoing today. A Late Cenozoic clockwise rotation of about 20° of Sumatra relative to Java was earlier suggested by Ninkovich (1976) based on the sharp change of curvature of the Sunda Trench at the Sunda Strait. Such a rotation requires the existence of an important shear or dislocation zone lying in the Sunda Strait. Right-lateral displacement in Recent time along the Red River Fault has resulted in displaced drainages, although the rate of movement is relatively slow (2-5 mm per year). Further, the active tectonics of Burma demonstrate a change from thrust fault movements to strike-slip, and this reflects the transition from subduction to collision and strike-slip motion as India penetrated into Eurasia past Burma. The Andaman Sea also shows the current process of escape tectonics. The basin was formed by strike-slip pull-apart rifting since Early Miocene. The Andaman Sea continues to open until present time in a highly oblique sense, in response to oblique subduction of the Indian Plate.

Challenge to role of India collision in Tertiary

evolution of SE Asia

The absence of elements of transtensional and transpression tectonism in seismic data of Paleogene of Southeast Asia leads Longley (2002) concluded that collision of India to Eurasia in Eocene did not control the Paleogene evolution of Southeast Asia. Seismic study in the offshore Red River Fault area by Rangin et al. (1995) clearly shows that this fault did not act as a major strike-slip fault during the Paleogene as the extrusion tectonics model requires. Extrusion tectonics also fails to explain the origin of the backarc basins of Sumatra and Java, the origin of the Malay Basin, the oceanic spreading history of the South China



Sea and the collision of rifted blocks along the margin of Northwest Borneo. Longley (1997, 2002) proposed an alternative model relating the Paleogene evolution of the region principally to a regional (Indian, Southern and Pacific Ocean) middle Eocene plate reorganization caused by the Indian-Eurasian plate collision. Longley (1997) considered that extrusion tectonics only played a role since 21 Ma (mid-Early Miocene) as Neogene modifier to the basins formed by the Paleogene events. However, interpretation of the opening history of the South China Sea based on ocean floor magnetic anomalies (Taylor and Hayes, 1980, 1983), reconstructions of South China Sea (Briais et al., 1993), reconstruction of Southeast Asia (Hall, 1995, 1996; Murphy, 2002b), demonstrated that Red River and Three Pagoda Faults have moved since Oligocene time. Briais et al. (1993) suggested about 550 km of movement on the Red River Fault with left-lateral motion between 32-15 Ma and some dextral movement since the late Miocene. The movement of these faults has extruded Indochina southeastwards.

Central Papua-Northern Australia Collision

and Northern Papua Tectonic Escapes

In the late Paleogene (25 Ma – Hall, 1995, 1996) or very early Neogene (Simandjuntak and Barber, 1996), the northern promontory of the Australian Continent collided with an oceanic island arcs constructed on the southern margin of the Philippine Sea Plate (Hall, 1996). McAdoo and Haebig (2000) stated that the collision may have begun as early as the Late Cretaceous. They also observed that the collision appears to be oblique, commencing in the west of Papua and gradually progressing eastwards through time. This collision trapped Indian oceanic crust between the northern margin of the Australian Continent and the island arcs . The oceanic crust which underlay the oceanic island arc subsequently uplifted as the result of the collision with the Australia (presently southern Papua) forming the Central Ranges of Papua and Papua New Guinea composed of major ophiolite complex (Figure 6). To the south of the Central Ranges, the Australian passive margin sediments are deformed by thin-skinned thrust tectonics into foreland fold and thrust belt, with folding imbrication and duplexing. At deeper

levels seismicity indicates that the underlying Australian continental crust is also involved in the thrusting (Abers and McCaffrey, 1988) leading Hobson et al. (1997) concluded that style of the deformation of southern Central Ranges is inverted thick-skinned tectonics. The whole collision belt is being thrust southwards over the northern margin of the Australian Continent. The southern margin of the overthrust belt is marked by the Asmat Thrust (Simandjuntak and Barber, 1996). Following the collision, strike-slip faulting and extension structures - geologic patterns interpreted here to represent escape tectonics - were formed (Figure 6). The Yapen-Sorong Fault system – a major left-lateral fault trending west-east - initiated in the Early Miocene time (20 Ma – Hall, 1995, 1996) which subsequently moved terranes of the Philippine Sea Plate arc and northern margin of the Australian Continent westwards. During the mid-Miocene (15 Ma), splays of the Sorong Fault developed sequentially. The Tukang Besi and Buton platform were detached from the Bird’s Head of Papua and was carried west on the Philippine Sea Plate to collide with East Sulawesi (Garrard et al., 1988; Davidson, 1991; Satyana, 2006). Some researchers have suggested that as much as 600 km horizontal displacement occurred. In addition to the Yapen-Sorong Fault System, there are other major strike-slip faults in northern Papua which their origins may relate to post-collision escape tectonics : (1) Waipoga Fault Zone, (2) Gauttier Offset, and (3) Apauwar-Nawa Fault Zone. McAdoo and Haebig (2000) summarized these fault zones. The Waipoga Fault Zone is the large, left-lateral fault forming the southeastern edge of Cenderawasih Bay. The fault trends SW-NE and appears to be truncated by the Yapen Fault through the splay of Yapen Fault namely the Naufi Fault. The Gautier Offset is an offset in the trend of the Gauttier Mountains, probably as left-lateral fault striking SW-NE. Is seems to be related to the same stress regime causing the Waipoga Fault Zone. The Gauttier Offset also offsets the North Papua Basin axis. The Apauwar-Nawa Fault Zone strikes NNW-SSE and is clearly evident on radar imagery. The fault is left-lateral and displaced by the Gauttier



Offset. Motion of the Apauwar-Nawa Fault seems to be more of a thrust than a strike-slip. Opening of the rifts in northern Papua and northern Papua New Guinea also indicates post-collision tectonic escapes. McAdoo and Haebig (2000) described the complex of the basins to the north of the Central Ranges collision zone under the name of North Irian Basin. The complex of this basin may continue to Papua New Guinea as Markham Valley and Ramu Basin. The North Irian Basin is located at a hybrid of forearc basin and subduction-related accretionary prisms. The North Irian Basin is an elongated basin 600 to 700 km long and 200 to 250 km wide with its long axis trending generally east-west. The basin contains over 25,000 ft of Tertiary-aged clastic and carbonate sediments in several localized depocenters, most notably the Waropen, Teer River, Waipoga, and Meervlakte. Rapid subsidence has created asymmetric basin fills dominated by turbidites.

The Bird’s Head-Papua Collision and the

Bird’s Head Tectonic Escapes

The Bird’s Head of Papua (called Western Irian Jaya by some authors) presents a tectonic puzzle on its origin and a unique present position (Figure 7). Pigram and Panggabean (1984) advocated that the Bird’s Head is a microcontinent rifted from the Gondwana (Australia) in the Early Jurassic, drifted towards its present position, and re-united with the Australian Continent (Papua) in the Neogene through microcontinent-continent collision. Other workers (for example : Dow and Sukamto, 1984; Dow et al., 1985) argued that the Bird’s Head is not a microcontinent and has always been in its present position relative to the Australian Continent, representing a large remnant of mostly undeformed continental crust protruding into the Pacific Plate. In his tectonic reconstruction, Hall (1995, 1996) proposed that the Bird’s Head is a microcontinent forming a single block at the end of Oligocene separated from Australia during the Mesozoic. The microcontinent had been located never apart from the northern margin of Australia (Papua). Palaeomagnetic results suggest that the microcontinent was at least 10° N of the north Australian margin in the late Cretaceous (Wensink

et al., 1989). The Bird’s Head and the northern Australia continent drifted together northwards to their present position. In 10 Ma (Late Miocene) the Bird’s Head collided Papua and translated northwards since then to its present position along a strike-slip fault at the Aru Basin edge (Figure 7). The Lengguru Fold-Thrust Belt, located in between the Bird’s Head and Papua, is critical in the tectonic evolution of the Bird’s Head and Papua. The origin of the Lengguru Fold-Thrust Belt has been a matter of debate. Pigram et al. (1982) and Pigram and Panggabean (1983) argued that the Lengguru Fold-Thrust Belt indicates a site of collision between the Bird’s Head microcontinent and northern Australia (Papua) continent. Dow et al. (1985) proposed that the Lengguru Fold-Thrust Belt was formed by the southwestward thrusting of a thick sedimentary section over the continental crust of the Bird’s Head as a result of the southwesterly movement of the Pacific plate. In this context, the Bird’s Head is considered has remained fixed relative to the Australian continent. Sulaeman et al. (1990) interpreted that Lengguru Fold-Thrust Belt was probably part of the Central Range of Papua Fold-Thrust Belt prior to the Late Tertiary movements. The sinistral movement along the Sorong Fault combined with obduction of ophiolite in North Papua have dragged the western fold-thrust belt or currently the northern tip of the Lengguru Fold-Thrust Belt to the east resulting in arcuate belts of Lengguru. Hobson et al. (1997) supported Dow et al. (1985)’s interpretation saying that the Central Range of Papua and the Lengguru Fold-Thrust Belt may define the axis of an exhumed and inverted Triassic rift and the change of their trends from Central Range to Lengguru may be inherited from the initial geometry of the rift system. The Triassic rift in the Lengguru Fold-Thrust Belt was uplifted when the Pacific-Australian plate convergence became oblique. The Lengguru Fold-Thrust Belt occupies a triangular area about 300 km long by 100 km wide at the south and 30 km at the north (Dow et al., 1985). The Lengguru Fold-Thrust Belt is bordered by major faults : the Ransiki-Wandamen Fault to the east, the Tarera-Aiduna to the south, and the Arguni Thrust to the west. The belt is characterized by prominent strike ridges up to 50



km long, formed of resistant New Guinea limestones. It is composed of Mesozoic clastics conformably overlain by Tertiary limestones, folded and faulted in NW-SE trends, almost all of the western limbs are cut by parallel thrusts replacing synclines. The intensity of folding and faulting in the fold-thrust belt increases to the northeast. Taken into account the interpretation from Pigram et al. (1982), Pigram and Panggabean (1983) and Hall (1995, 1996) that the Lengguru Fold-Thrust Belt marks a collision zone of the Bird’s Head microcontinent and Papua, then post-collision tectonic escapes in the Bird’s Head area can be derived (Figure 7). Firstly, the presence of west-east trending major left-lateral faults to the north and south of the Bird’s Head namely the Sorong Fault and the Tarera-Aiduna Fault may response to the post-collision tectonic escapes. Connection to the Sorong Fault from the Lengguru Fold-Thrust Belt is via left-lateral Ransiki Fault to the northeast of the Lengguru Fold-Thrust Belt. The Tarera-Aiduna Fault is a left-lateral fault terminates the Lengguru Fold-Thrust Belt abruptly to the south. The fault is straight, steeply dipping merging to the east with faults of the Weyland overthrust. Both the Sorong and Tarera-Aiduna Faults are well defined by seismic data as vertical zones, up to several kilometers wide, of massive chaotic material devoid of reflectors and become the sites for diapiric shales. The left-lateral Waipoga Fault trending SW-NE from the eastern border of the Cenderawasih Bay to the west of the Aru Trough may also relate to the post-collision tectonic escape of the Bird’s Head collision. The Bintuni Basin located just to the west of the Lengguru Fold-Thrust Belt is a foreland basin developing as a response to post-collision extensional collapse (Pigram et al., 1982; Charlton, 1991).

Buton-Tukang Besi – Banggai-Sula – East Sulawesi Collisions and Sulawesi Tectonic

Escapes

Sulawesi Islands in Central Indonesia provides a good place to examine collision and post-collision escape tectonics (Figures 7, 8). The islands were assembled by collision of terranes and have been modified by post-collision escape tectonics. Sulawesi Island has been collided by

microcontinents of Buton-Tukang Besi and Banggai-Sula. Satyana (2006) recently discussed the evolution of Sulawesi collision and post-collision tectonic escape. Different authors have different interpretations on the mode and timing of collision of Buton-Tukang Besi and Banggai-Sula microcontinents. Hall (1996) reconstructed the detachment of the microcontinents from the Bird’s Head of Papua, their transfer to the west, and their collisions with eastern Sulawesi. At 20 Ma (Early Miocene), these microcontinents were dismembered from the Bird’s Head by Sorong Fault splay. At 15 Ma, a strand of Sorong Fault propagated westward, at 11 Ma Buton-Tukang Besi collided with Sulawesi. Collision of Buton-Tukang Besi with Sulawesi locked the strand of the Sorong Fault and requiring a development of a new fault strand which caused the detachment of Banggai-Sula microcontinent. Banggai-Sula drifted northward and collided with Sulawesi ophiolite. Overthrusting of the ophiolite onto the western edge of Banggai-Sula microcontinent occurred in the latest Miocene (Davies, 1990) indicating that collision of the Sula platform with East Sulawesi must have occurred at 5 Ma (end of Miocene) (Figure 8). The collision of East Sulawesi ophiolite and Banggai-Sula microcontinent is marked by overthrusting of the ophiolite, formation of the Batui-Balantak fold and thrust belt and emplacement of the Kolokolo melange. The development of duplex structure in Nambo and Balantak areas is related closely to the forward migration of the Batui Thrust during and/or subsequent to the collision (Simandjuntak, 1987). The K-shaped Sulawesi Island is considered as a response to post-collision rotation of the curvatures of four arms of Sulawesi from being convex eastward to being concave eastward (Figure 7). This rotation expresses the tectonic escape. This rotation has been partly proved by palaeomagnetism. Opening of the Gulf of Bone is due to rotation of Southeast Arm. Associated with the rotation, or following shortly after, was the development of major strike-slip faults crossing the island like Palu-Koro, Kolaka, Lawanopo, Hamilton, Matano, and Balantak Faults. More recent transtensional movement is responsible for



opening pull-apart basins of Poso, Matano and Towuti Lakes, as well as the Palu depression. Frontal to the collision of Banggai-Sula microcontinent is the development of strike-slip faults in East Arm (Figure 7) : the Balantak, Toili, Ampana, and Wekuli Faults (Simandjuntak, 1987, 1993). The lateral motions detached East Arm of Sulawesi and escaped the rocks apart from the compressional collision eastward into the oceanic free edge/face in the East-Sangihe subduction zone. Extension structures which are almost parallel to the convergence direction are observed in the East Arm of Sulawesi until offshore Banggai-Sula area. Peleng Island is deformed intensively by normal faults. Normal faults of the grabens sometime reactivate the short limbs of the folds of the Batui-Balantak fold and thrust belt. It can be inferred that the eastern half of East Sulawesi collision zone is undergoing extension driven by slab-pull at the East Sangihe trench. In summary, collision of the Buton-Tukang Besi and Banggai-Sula microcontinents to Eastern Sulawesi took place during the Miocene. Collision of the microcontinents resulted in obduction of the East Sulawesi ophiolites onto the microcontinental blocks, formation of foreland Batui-Balantak fold and thrust belt, and emplacement of Kolokolo melange. Post-collision tectonic escapes followed afterwards. They started with rotation of arms of Sulawesi, opening of the Gulf of Bone, formation of Sulawesi’s major strike-slip faults, and occurrences of extension fractures.

Australia Collision and Banda Arc Tectonic

Escapes

Many of the best examples of young arc-continent collision are found in eastern Indonesia, where the northern margin of Australia has been in collision in the late Neogene with a succession of island arc systems (Figure 10). The Banda Arc is the youngest of these collision zones and forms the present plate boundary in this region (Charlton, 1991). As a result of Pliocene collision between the Banda Arc and the northwestern margin of the Australian continent, Australian crust now underlies the outer slope of the Timor-Tanimbar Trough. The geology of Timor-Tanimbar shows

the structural characteristics of a foreland fold-thrust belt, consisting of thrust-imbricated sequences of the Australian outer continental margin. The initiation of collision of Australian continental margin with the Banda Arc is various among authors but most believe Pliocene is the important period for this. Richardson and Blundell (1996) based on multichannel reflection profiles across the Banda Arc-Timor Trough-Australian NW Shelf concluded a timing of 2.4 Ma as the age of initiation of the collision of the Australian continental margin with the arc and seem to be active at the present day at the northern end of the collision zone. This convergence has shortened, thickened, and uplifted both oceanic and continental materials of this region. The thrust belts in Timor-Tanimbar generated by the collision are estimated to be no older than 2.4 Ma. In an arc-continent collision, oceanic crust in front of continental plate will be subducted prior to collision. As collision occurred, subduction will cease when partially subducted continental lithosphere decouple from subducting oceanic lithosphere and is rebounding isostatically toward the surface. The decoupling area of lithosphere near the continent-ocean boundary is marked by reverse fault of lithospheric slab (Figures 11, 12). Lateral extension is a phenomenon observed following the arc-continent collision. This marks a post-collision tectonic escape. Detailed examination of the stratigraphy of Tanimbar shows that subduction probably ceased as a result of the arc-continent collision during late Pliocene time. Tanimbar island is rising, this upward movement will need to be compensated by a lateral extension. Timor also shows good evidence of compressive, collision-related deformation overprinted by late-stage extension associated with rapid uplift (Figure 12). Other examples of extensional crustal collapse following arc-continent collision include the eastern Banda Arc (the Weber Deep and the Kai islands) and southern Seram. The Weber Deep at the eastern extremity of the Banda Arc is anomalously deep fore-arc basin (its maximum depth in excess of 7000 meters makes it the deepest point on the Earth’s sea floor not in a



subduction trench). To the east, the western half of the Kai islands is a Banda fore-arc-type arc-continent collision complex comparable to Tanimbar and Timor. A similar tectonic history is observed in this region – probable Pliocene arc-continent collision is overprinted by young extension in the Weber fore-arc basin (Figures 11, 12). The collision of the northern margin of Australia with the Banda Arc may also relate to the extension of the Banda Sea. The Banda basin has been extending rapidly between 5 and 0 Ma (Hall, 1996). Therefore, both the north and south Banda Sea can be interpreted as having an extensional origin and to have opened during the late Neogene. These interpretations are consistent with the age of young volcanics dredged in the Banda Sea (Réhault et al., 1995). Burke and Dewey (1974), in considering the consequences of the headland and embayment structure of Atlantic type margins for arc-continent collision predicted that strike-slip motion mainly in the accretionary prism of the arc would be a common condition early during collision where a headland had impinged on an arc, but embayment still faced a trench. Burke and Sengör (1986) considered that this geometry exists at Timor where strike-slip faults trending west-east and parallel with Timor island escaped Sumba island westwards from the Timor collision and that the Savu Basin represents a late Neogene rift formed in the escape process (Figure 10).

CONCLUSIONS

• Tectonic escape or extrusion tectonics is the

movement of fault-bounded package of rocks or crustal mass following collision of crustal plates away from the collision zone and towards free-edge of nearby oceanic margin. The movement of escapes are accommodated by major strike-slip faults, rifting and spreading of basement. Collision and post-collision tectonic escape have played significant roles in assembling and slivering continents.

• Collision and post-collision tectonic escapes

have fashioned the Cenozoic geological evolution of Indonesia. Five periods of

collisions are identified and their post-collisional tectonic escapes are discussed : (1) India-Eurasia collision at 45 Ma and tectonic escapes in the Sundaland, (2) Central Papua-northern Australia collision at 25 Ma and tectonic escapes in northern Papua, (3) Bird’s Head-Papua collision at 10 Ma and tectonic escapes in the Bird’s Head, (4) Buton Tukang Besi-Banggai Sula - East Sulawesi collisions at 11-5 Ma and tectonic escapes in Sulawesi, and (5) northern Australia-Banda Arc collision at 3 Ma and tectonic escapes in the Banda Arc.

• Major strike-slip faults in Indonesia resulted

from post-collision tectonic escapes are among others : Natuna-Lupar-Adang Fault, Sumatran Fault, Sorong-Yapen Fault, Tarera-Aiduna Fault, Palu-Koro Fault, and Matano Fault. The faults may detach and/or escape crustal mass like Sundaland, Banggai-Sula, and Sumba. Rifting of basins like the formation of sedimentary basins in Sumatra, Natuna, North Irian and Savu, and spreading of marginal seas like South China Sea, Andaman Sea, and Banda Sea also demonstrates escape tectonics.

ACKNOWLEDGMENTS

I thank Rudhy L. Tarigan (Medco) who always shared his collections of published and unpublished materials on regional geology of Southeast Asia and made discussions on some aspects of regional geology of Indonesia. I acknowledge the Managers of Exploration BPMIGAS to have given the sponsorship to publish this study.

REFERENCES

Abers, G. and McCaffrey, R., 1988, Active deformation in the New Guinea fold and thrust belt : seismological evidence for strike-slip faulting and basement-involved thrusting, Journal of Geophysical Research, vol. 93, pp. 13,332-13,354. Briais, A., Patriat, P., and Tapponnier, P., 1993, Updated interpretation of magnetic anomalies and reconstructions of the South China basins : implications for the Tertiary evolution of



Southeast Asia, Journal of Geophysical Research, vol. 98, pp. 6299-6328. Burke, K. and Dewey, J., 1974, Hot spots and continental break up : implications for collisional orogeny, Geology, vol. 2, pp. 57-60. Burke, K. and Sengör, A.M.C., 1986, Tectonic escape in the evolution of the continental crust in Barazangi, M. and Brown, L. (eds), Reflection Seismology, American Geophysical Union Geodynamic Series, no. 14, pp. 41-53. Charlton, T.R., 1991, Postcollision extension in arc-continent collision zones, eastern Indonesia, Geology, vol. 19, pp. 28-31. Daines, S.R., 1985, Structural history of the West Natuna Basin and the tectonic evolution of the Sunda region, Proceedings Indonesian Petroleum Association 14th Annual Convention, vol. 1, pp. 39-61. Daly, M.C., Hooper, B.G.D., and Smith, D.G., 1987, Tertiary plate tectonics and basin evolution in Indonesia, Proceedings Indonesian Petroleum Association 16th Annual Convention, vol. 1, pp. 399-428. Daly, M.C., Cooper, M.A., Wilson, I., B.G.D., Smith, D.G. and Hooper, B.G.D., 1991, Cenozoic plate tectonics and basin evolution in Indonesia, Marine and Petroleum Geology, vol. 8, pp. 2-21. Davidson, J.W., 1991, The geology and prospectivity of Buton island, S.E. Sulawesi, Indonesia, Proceedings Indonesian Petroleum Association 20th Annual Convention, pp. 209-233. Davies, I.C., 1990, Geological and exploration review of the Tomori PSC, Eastern Indonesia, Proceedings Indonesian Petroleum Association 19th Annual Convention, pp. 41-67. Dow, D.B. and Sukamto, R., 1984, Western Irian Jaya : the end product of oblique plate convergence in the Late Tertiary, Tectonophysics, vol. 106, pp. 109-139. Dow, D.B., Robinson, G.B., and Ratman, N., 1985, New hypothesis for the formation of Lengguru foldbelt, Indonesia, American

Association of Petroleum Geologists Bulletin, vol. 69, pp. 203-214. Fuller, M., Ali, J.R., Moss, S.J., Frost, G.M., Richter, B., and Mahfi, A., 1999, Palaeomagnetism of Borneo, Journal of Southeast Asian Earth Sciences, vol. 17, pp. 3-24. Garrard, R.A., Supandjono, J.B., and Surono, 1988, The geology of the Banggai-Sula microcontinent, Eastern Indonesia, Proceedings Indonesian Petroleum Association 17th Annual Convention, pp. 23-52. Gatinsky, Y.G., 1986, Geodynamics of Southeast Asia in relation to the evolution of ocean basins, Palaeogeography, Palaeoclimatology, Palaeoecology, vol. 55, p. 127-144. Gatinsky, Y.G., Hutchison, C.S., Nguyen, Nguyen, Minh, N.N., and Tri, T.V., 1984, Tectonic evolution of Southeast Asia, 27th International Geology Congress Reports 5, Colloquium 5, Tectonics of Asia, pp. 225-240. Haile, N.S., 1979, Rotation of Borneo microplate completed by Miocene : palaeomagnetic evidence, Newsletter of the Geological Society of Malaysia, vol. 5, pp. 19-22. Hall, R., 1995, Plate tectonic reconstruction of the Indonesian region, Proceedings Indonesian Petroleum Association 24th Annual Convention, vol. 1, pp. 71-84. Hall, R., 1996, Reconstructing Cenozoic SE Asia in Hall, R. and Blundell, D. (eds), Tectonic Evolution of Southeast Asia, Geological Society Special Publication No. 106, pp. 153-184. Hobson, D.M., Adnan, A., Samuel, L., 1997, The relationship between Late Tertiary basins, thrust belts and major transcurrent faults in Irian Jaya : implications for petroleum systems throughout New Guinea in Howes, J.V.C. and Noble, R.A., eds, Proceedings IPA Petroleum Sytems of SE Asia and Australasia Conference, Jakarta, Indonesia, May 1997, Indonesian Petroleum Association (IPA), Jakarta, pp. 261-284.



Hutchison, C.S., 1996, Geological Evolution of South-East Asia, Geological Society of Malaysia, 368 ps. Longley, I.M., 1997, The tectonostratigraphic evolution of SE Asia, in Fraser, A.J., Matthews, S.J., and Murphy, R.W., eds, The Petroleum Geology of SE Asia, Geological Society Special Publication, no. 126, pp. 311-339. Longley, I.M., 2002, Extrusion tectonics – give it up ! – it does not explain the Tertiary evolution of SE Asia, Indonesian Petroleum Association Newsletter, June 2002, pp. 16-19. McAdoo, R.L. and Haebig, J.C., 2000, Tectonic elements of the North Irian basin, Proceedings Indonesian Petroleum Association 27th Annual Convention, vol. 1, pp. 545-562 Molnar, P. and Tapponnier, P., 1975, Cenozoic tectonics of Asia : effects of a continental collision, Science, vol. 189, pp. 419-426. Morley, C.K., 2001, Combined escape tectonics and subduction rollback-back arc extension : a model for the evolution of Tertiary rift basins in Thailand, Malaysia and Laos, Journal of the Geological Society London, vol. 158, pp. 461-474. Murphy, R.W., 2002a, Southeast Asia (over?) simplified, Indonesian Petroleum Association Newsletter, June 2002, pp. 14-15. Murphy, R.W., 2002b, Southeast Asia reconstruction with a non-rotating Cenozoic Borneo, Indonesian Petroleum Association Newsletter, June 2002, pp. 22-29. Netherwood, R.E., 2000, A geological overview of Indonesia, Reservoir Optimization Conference : Indonesia 2000, Schlumberger. Ninkovich, D., 1976, Late Cenozoic clockwise rotation of Sumatra, Earth and Planetary Science Letters, no. 29, pp. 269-275. Packham, G., 1996, Cenozoic Southeast Asia : reconstructing its aggregation and reorganization in Hall, R. and Blundell, D., eds, 1996, Tectonic Evolution of Southeast Asia, Geological Society Special Publication, no. 106, pp. 123-152.

Peltzer, G. and Tapponnier P., 1988, Formation of strike-slip faults, rifts, and basins during the India-Asia collision : an experimental approach, Journal of Geophysical Research, vol. 93, pp. 15,085-15,117. Pigram, C.J. and Panggabean, H., 1983, Rifting of the northern margin of the Australian continent and the origin of some microcontinents in Eastern Indonesia, Tectonophysics, vol. 107, pp. 331-353. Pigram, C.J., Robinson, G.P., Tobing, S.L., 1982, Late Cenozoic origin for the Bintuni basin and adjacent Lengguru foldbelt, Irian Jaya, Proceedings Indonesian Petroleum Association 11th Annual Convention, vol. 1, pp. 109-126. Pulunggono, A. and Cameron, N.R., Sumatran microplates, their characteristics and their role in the evolution of the Central and South Sumatra Basins, Proceedings Indonesian Petroleum Association 13th Annual Convention, vol. 1, pp. 121-144. Pulunggono, A., Abdullah, C.I., Noeradi, D., Suparka, E., Djuhaeni, Samuel, L., 1999, Sumatran megashears : their crucial role in (tertiary) sedimentary basin development, in Darman, H. and Sidi, F.H., eds, Tectonics and Sedimentation of Indonesia, Indonesian Sedimentologists Forum, Special Publication No. 1, p. 29-34. Rangin, C., Klein, M., Roques, D., Le Pichon, X., and van Trong, L., 1995, The Red River fault system in the Tonkin Gulf, Vietnam, Tectonophysics, vol. 243, pp. 209-222. Réhault, J.P., Villeneuve, M., Honthaas, C., Bellon, H., Malod, J.A., 1995, New geological samplings along a transect across the southeast Banda Sea basin (Indonesia), in Tectonics of SE Asia Conference Abstracts, Geological Society, p. 45. Richardson, A.N. and Blundell, D.J., 1996, Continental collision in the Banda arc in Hall, R. and Blundell, D., eds, 1996, Tectonic Evolution of Southeast Asia, Geological Society Special Publication, no. 106, pp. 47-60.



Richter, B. and Fuller, M., 1996, Palaeomagnetism of the Sibumasu and Indochina bocks : implications for the extrusion tectonic model in Hall, R. and Blundell, D., eds, 1996, Tectonic Evolution of Southeast Asia, Geological Society Special Publication, no. 106, pp. 203-224. Satyana, A.H., 1994, The Northern Massifs of the Meratus Mountains, South Kalimantan : nature, evolution, and tectonic implications to the Barito structures, Indonesian Association of Geologists, 23rd Annual Convention, vol. 1, pp. 457-470. Satyana, A.H., 1996, Adang-Lupar Fault, Kalimantan : controversies and new observations on the trans-Kalimantan megashear, Proceedings Indonesian Association of Geologists, 25th Annual Convention, vol. 3, pp. 124-143. Satyana, A.H., Imanhardjo, D.N., Surantoko, 1999, Tectonic controls on the hydrocarbon habitats of the Barito, Kutei and Tarakan Basins, Eastern Kalimantan, Indonesia : major dissimilarities in adjoining basins, Journal of Asian Earth Sciences, 17, pp. 99-122. Satyana, A.H., 2003, Accretion and dispersion of Southeast Sundaland : the growing and slivering of a continent, Proceedings Joint Convention of Indonesian Association of Geologists (IAGI), 31st Annual Convention and Indonesian Association of Geophysicists (HAGI), 28th Annual Convention, Jakarta, December 2003. Sengör, A.M.C., 1984, The Cimmeride orogenic system and the tectonics of Eurasia, Geological Society of America Special Paper, no. 195. Simandjuntak, T.O., 1987, Sedimentology and tectonics of the collision complex in the East Arm of Sulawesi, Indonesia, Geosea Congress VI, 6-12 July 1987, Jakarta, 123 ps. Simandjuntak, T.O., 1993, Struktur rangkap (duplex), sesar sungkup dan sesar jurus mendatar di Lengan Timur Sulawesi, Geological Research and Development Centre (GRDC) Bull., no. 16, pp. 27-44.

Simandjuntak, T.O. and Barber, A.J., 1996, Contrasting tectonic styles in the Neogene orogenic belts of Indonesia in Hall, R. and Blundell, D., eds, 1996, Tectonic Evolution of Southeast Asia, Geological Society Special Publication, no. 106, pp. 185-201. Sulaeman, A., Sjapawi, A., Sosromihardjo, S., 1990, Frontier exploration in the Lengguru foldbelt Irian Jaya, Indonesia, Proceedings Indonesian Petroleum Association 19th Annual Convention, vol. 1, pp. 85-105. Tapponnier, P., Peltzer, G., Le Dain, A.Y., Armijo, R., and Cobbold, P., 1982, Propagating extrusion tectonics in Asia : new insights from simple experiments with plasticine, Geology, vol. 10, pp. 611-616. Taylor, B. and Hayes, D.E., 1980, The tectonic evolution of the South China Basin, in Hayes, D.E., ed., The Tectonic and Geologic Evolution of Southeast Asian Seas and Islands, Geophysical Monograph, no. 23, American Geophysical Union, Washington, pp. 89-104. Taylor, B. and Hayes, D.E., 1983, Origin and history of the South China Basin, in Hayes, D.E., ed., The Tectonic and Geologic Evolution of Southeast Asian Seas and Islands, Geophysical Monograph, no. 27, American Geophysical Union, Washington, pp. 23-56. Wensink, H., Hartosukohardjo, S., Suryana, Y., 1989, Palaeomagnetism of Cretaceous sediments from Misool, northeastern Indonesia, Netherlands Journal of Sea Research, vol. 24, pp. 287-301. Wood, B.G.M., 1985, The mechanics of progressive deformation in crustal plates – a working model for Southeast Asia, Geological Society of Malaysia Bulletin, vol. 18, pp. 55-99.

post-collisional tectonic escapes in indonesia

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