Title Arc-continent collision and orogenesis in western Tasmanides; insights from reactivated basement structures and formation of an ocean-continent transform boundary off western Tasmania
Author Gibson, G.M.; Morse, M.P.; Ireland, T.R.; Nayak, G.K.
Author Affil Gibson, G.M., Geoscience Australia, Canberra, Australia. Other: Chinese Academy of Sciences, China; Australian National University, Australia
Source Island arcs; their role in growth of accretionary orogens and mineral endowment, edited by R.A. Glen, C.D. Quinn and W. Xiao. Gondwana Research, 19(3), p.608-627. Publisher: Elsevier on behalf of International Association for Gondwana Research, Amsterdam and Kochi, International. ISSN: 1342-937X
Publication Date Apr. 2011
Notes In English. 108 refs. GeoRef Acc. No: 309729
Index Terms Australasia--Tasman orogenic zone; Australia--Tasmania; Antarctica--Wilson Terrane; Antarctica; Australasia; Australia; back-arc basins; basement; basins; crust; deep-seated structures; Delamerian Orogeny; faults; island arcs; lower Paleozoic; Paleozoic; passive margins; plate collision; plate tectonics; reconstruction; rifting; Ross Orogeny; strike-slip faults; subduction; Tasman orogenic zone; Tasmania Australia; Tasmanides; transform faults; Victoria Land; Wilson Terrane
Abstract Crustal architecture in formerly contiguous basement terranes in SE Australia, Tasmania and northern Victoria Land is a legacy of late Neoproterozoic-Cambrian subduction-related processes, culminating in formation of the Delamerian-Ross Orogen. Structures of Delamerian-Ross age were subsequently reactivated during late Mesozoic- Cenozoic Gondwana breakup, strongly influencing the geometry of continental rifting and providing clues about the origins and configuration of the pre-existing basement structures. An ocean-continent transform boundary developed off western Tasmania follows the trace of an older Paleozoic strike-slip structure (Avoca-Sorell fault system) optimally oriented for reactivation during the final separation of Australia from Antarctica. This boundary cuts across rocks preserving an earlier record of arc-continent collision during the course of which continental crust was subducted to mantle depths and Cambrian mafic-ultramafic island arc rocks were thrust westwards over late Neoproterozoic-Cambrian passive margin sequences. Collision was accompanied by development of a foreland basin into which 520-600Ma arc-derived detrital zircons were shed. Following a reversal in subduction polarity, and change to transcurrent motion along the Gondwana margin, Tasmania migrated northward along the proto-Avoca fault system before entering a subduction zone located along the Heathcote-Governor fault system, precipitating a second collision, south- vergent thrusting, and tectonic reworking of the already accreted Cambrian arc-forearc assemblages and underlying passive margin sequences.
URL http://hdl.handle.net/10.1016/j.gr.2010.11.020
Publication Type journal article
Record ID 91376