Arc-continent collision and orogenesis in western Tasmanides: insights from reactivated basement structures and formation of an ocean-continent transform boundary off western Tasmania

• Published in: Gondwana Research
• Other Authors: Commonwealth of Australia (Geoscience Australia) (owner), Commonwealth of Australia (Geoscience Australia) (pointOfContact), EGD (hasAssociationWith), GGIBSON (custodian), Gibson, G.M. (author), Ireland, T.R. (author), Manager Client Services (distributor), Manager Client Services (custodian), Morse, M.P. (author), Nayak, G. (author)
• Format: Text
• Language: unknown
• Published: Australian Ocean Data Network
• Subjects: geoscientificInformation; External Publication; Article; continental margins; cultural boundaries; structural geology; marine; AU-NSW; AU-TAS; AU-VIC; EARTH SCIENCES; Published_External; Antarc*; Antarctica; Victoria Land
• Online Access: https://researchdata.edu.au/arc-continent-collision-western-tasmania/687559; https://pid.geoscience.gov.au/dataset/ga/70061; https://doi.org/10.1016/j.gr.2010.11.020

Maintenance and Update Frequency: unknown Statement: Unknown 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) optimally oriented for reactivation during 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 emplaced westwards over late Neoproterozoic passive margin sequences deposited during Rodinia breakup. Following a change to transcurrent motion along the Gondwana margin, Tasmania migrated northward along the Avoca fault system. This process arrested with entry of continental crust (Selwyn block) into a subduction zone located along the Heathcote-Governor fault systems, precipitating a second collision event accompanied by south-vergent thrusting, blueschist facies metamorphism and tectonic reworking of the already accreted Cambrian arc-forearc complex and underlying passive margin sequences.