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The Cretaceous and Cenozoic Tectonic Evolution of Southeast Asia

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The Cretaceous and Cenozoic Tectonic Evolution of Southeast Asia EGU Journal Logos (RGB) Open Access Open Access Open Access Advances in Annales Nonlinear Processes Geosciences Geophysicae in Geophysics Open Access Open Access Natural Hazards Natural Hazards and Earth System and Earth System Sciences Sciences Discussions Open Access Open Access Atmospheric Atmospheric Chemistry Chemistry and Physics and Physics Discussions Open Access Open Access Atmospheric Atmospheric Measurement Measurement Techniques Techniques Discussions Open Access Open Access Biogeosciences Biogeosciences Discussions Open Access Open Access Climate Climate of the Past of the Past Discussions Open Access Open Access Earth System Earth System Dynamics Dynamics Discussions Open Access Geoscientific Geoscientific Open Access Instrumentation Instrumentation Methods and Methods and Data Systems Data Systems Discussions Open Access Open Access Geoscientific Geoscientific Model Development Model Development Discussions Open Access Open Access Hydrology and Hydrology and Earth System Earth System Sciences Sciences Discussions Open Access Open Access Ocean Science Ocean Science Discussions Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Open Access Solid Earth Discuss., 5, 1335–1422, 2013 Open Access www.solid-earth-discuss.net/5/1335/2013/ Solid Earth Solid Earth SED doi:10.5194/sed-5-1335-2013 Discussions © Author(s) 2013. CC Attribution 3.0 License. 5, 1335–1422, 2013 Open Access Open Access This discussion paper is/has been under review for the journal Solid Earth (SE). The Cryosphere The Cretaceous and Please refer to the correspondingThe Cryosphere final paper in SE if available. Discussions Cenozoic tectonic evolution of The Cretaceous and Cenozoic tectonic Southeast Asia evolution of Southeast Asia S. Zahirovic et al. S. Zahirovic, M. Seton, and R. D. Müller Title Page EarthByte Group, School of Geosciences, The University of Sydney, Sydney, NSW 2006, Australia Abstract Introduction Received: 2 August 2013 – Accepted: 11 August 2013 – Published: 21 August 2013 Conclusions References Correspondence to: S. Zahirovic ([email protected]) Tables Figures Published by Copernicus Publications on behalf of the European Geosciences Union. J I J I Back Close Full Screen / Esc Printer-friendly Version Interactive Discussion 1335 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | Abstract SED Tectonic reconstructions of Southeast Asia have given rise to numerous controversies which include the accretionary history of Sundaland and the enigmatic tectonic origin of 5, 1335–1422, 2013 the Proto South China Sea. We assimilate a diversity of geological and geophysical ob- 5 servations into a new regional plate model, coupled to a global model, to address these The Cretaceous and debates. Our approach takes into account terrane suturing and accretion histories, the Cenozoic tectonic location of subducted slabs imaged in mantle tomography in order to constrain the evolution of opening and closure history of paleo-ocean basins, as well as plausible absolute and Southeast Asia relative plate velocities and tectonic driving mechanisms. We propose a scenario of rift- 10 ing from northern Gondwana in the Late Jurassic, driven by northward slab pull, to de- S. Zahirovic et al. tach East Java, Mangkalihat, southeast Borneo and West Sulawesi blocks that collided with a Tethyan intra-oceanic subduction zone in the mid Cretaceous and subsequently accreted to the Sunda margin (i.e. southwest Borneo core) in the Late Cretaceous. In Title Page accounting for the evolution of plate boundaries, we propose that the Philippine Sea Abstract Introduction 15 Plate originated on the periphery of Tethyan crust forming this northward conveyor. We implement a revised model for the Tethyan intra-oceanic subduction zones to recon- Conclusions References cile convergence rates, changes in volcanism and the obduction of ophiolites. In our Tables Figures model the northward margin of Greater India collides with the Kohistan-Ladakh intra- oceanic arc at ∼ 53 Ma, followed by continent-continent collision closing the Shyok and J I 20 Indus-Tsangpo suture zones between ∼ 42 and 34 Ma. We also account for the back-arc opening of the Proto South China Sea from J I ∼ 65 Ma, consistent with extension along east Asia and the emplacement of supra- subduction zone ophiolites presently found on the island of Mindoro. The related rifting Back Close likely detached the Semitau continental fragment from east China, which accreted to Full Screen / Esc 25 northern Borneo in the mid Eocene, to account for the Sarawak Orogeny. Rifting then re-initiated along southeast China by 37 Ma to open the South China Sea, resulting in Printer-friendly Version the complete consumption of Proto South China Sea by ∼ 17 Ma when the collision of the Dangerous Grounds and northern Palawan blocks with northern Borneo choked Interactive Discussion 1336 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | the subduction zone to result in the Sabah Orogeny and the obduction of ophiolites in Palawan and Mindoro. We conclude that the counterclockwise rotation of Borneo was SED accommodated by oroclinal bending consistent with paleomagnetic constraints, the 5, 1335–1422, 2013 curved lithospheric lineaments observed in gravity anomalies of the Java Sea and the 5 curvature of the Cretaceous Natuna paleo-subduction zone. We complete our model by constructing a time-dependent network of continuously closing plate boundaries The Cretaceous and and gridded paleo-ages of oceanic basins, allowing us to test our plate model evo- Cenozoic tectonic lution against seismic tomography. In particular, slabs observed at depths shallower evolution of than ∼ 1000 km beneath northern Borneo and the South China Sea are likely to be Southeast Asia 10 remnants of the Proto South China Sea basin. S. Zahirovic et al. 1 Introduction Title Page Southeast Asia is an accretionary mosaic of continental fragments, seamounts, ex- otic terranes and intra-oceanic island arcs that were welded to the Asian continent, Abstract Introduction presently delineated by suture zones and remnants of ancient Tethyan and proto- Conclusions References 15 Pacific ocean basins that once separated them (Şengör et al., 1988; Metcalfe, 2011; Veevers, 2004; Stauffer, 1983) (Fig. 1). The tectonic framework of Southeast Asia is Tables Figures inherited from the long-term convergence between the Australian, (proto-) Pacific and Eurasian plates and the cyclical Gondwana-derived terrane detachment and subse- J I quent accretion onto Eurasia and the Sundaland core (Acharyya, 1998; Golonka, 2004; J I 20 Stampfli and Borel, 2002; Hall, 2002; Metcalfe, 2006; Veevers et al., 1991). The north- ern Gondwana margin, as the origin for many of the Asian continental fragments, was Back Close a passive boundary for much of the Mesozoic, with periodic rifting events that carried continental slivers on the Tethyan conveyors to be accreted to the Eurasian margin Full Screen / Esc (Audley-Charles, 1988; Veevers et al., 1991; Seton et al., 2012). Printer-friendly Version 25 The Sundaland core, forming much of the Sunda shelf and continental promontory in Southeast Asia (Fig. 2), is largely comprised of the Cimmerian terranes that rifted from Interactive Discussion Gondwana at early Permian times (Metcalfe, 2011) and accreted diachronously along 1337 Discussion Paper | Discussion Paper | Discussion Paper | Discussion Paper | the Eurasian margin during the Triassic and Jurassic (Golonka, 2007; Metcalfe, 1999; Seton et al., 2012; Stampfli and Borel, 2002) to open the MesoTethys at the expense SED of the PaleoTethys (Table 1). A Late Jurassic rifting episode along northern Gondwana 5, 1335–1422, 2013 likely detached continental fragments including West Sulawesi, Mangkalihat, East Java, 5 parts of Borneo (Hall, 2011; Metcalfe, 2011; Wakita, 2000) and other potential micro- continents such as Sikuleh, Natal, Lolotoi and Bengkulu (Acharyya, 1998; Metcalfe, The Cretaceous and 1996), to open the NeoTethys. However, the origin of these blocks on the northern Cenozoic tectonic Gondwana margin is controversial, in particular whether they all originated from the evolution of Argo Abyssal Plain, hence the “Argoland” name applied to blocks originating here, Southeast Asia 10 on the northwest Australian shelf, or whether some of these blocks originated from the New Guinea or even Greater Indian passive margin. In addition, the nature of the micro- S. Zahirovic et al. continents on Sumatra has been disputed and recent studies have argued that these are more likely to be accreted intra-oceanic island arcs with no continental basement Title Page or affinity (Barber, 2000; Barber and Crow, 2003, 2009). 15 Although oceanic crust adjacent to the northwest Australian shelf records Abstract Introduction NeoTethyan seafloor spreading, only dismembered fragments of obducted oceanic crust in suture zones gives a glimpse of the older Meso- and Paleo- Tethyan oceanic Conclusions References domains (Seton et al., 2012). For example, the only remnant of the latest Jurassic Tables Figures seafloor spreading is contained in the obducted basement of the Irian ophiolite, likely 20 preserved in an embayment along New Guinea (Hill and Hall, 2003). The lack of J I preserved seafloor spreading histories results in uncertain origins of many terranes presently found in Southeast Asia. As a result, we flag instances where alternative tec- J I tonic scenarios can explain the piecemeal data coverage in the absence of conclusive Back Close pre-breakup
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