Authors / CoAuthors
Gibson, G.M. | Totterdell, J.M. | Goncharov, A. | Mitchell, C.H. | Whitaker, A.J. | Stacey, A.R. | Morse, M.P. | Nayak, G.K.
Abstract
Continental rifting and the separation of Australia from Antarctica commenced in the Middle-Late Jurassic and progressed from west to east through successive stages of crustal extension, basement-involved syn-rift faulting and thermal subsidence until the Cenozoic. Early syn-rift faults in the Bight Basin developed during NW-SE directed extension and strike mainly NE and E-W, parallel to reactivated basement structures of Paleoproterozoic or younger age in the adjacent Gawler craton. This extension was linked to reactivation of NW-striking basement faults that predetermined not only the point of breakup along the cratonic margin but the position and trend of a major intracontinental strike-slip shear zone along which much of the early displacement between Australia and Antarctica was accommodated. Following a switch to NNE-SSW extension in the Early Cretaceous, the locus of rifting shifted eastwards into the Otway Basin where basin evolution was increasingly influenced by transtensional displacements across reactivated north-south-striking terrane boundaries of Paleozoic age in the Delamerian-Ross and Lachlan Orogens. This transtensional regime persisted until 55 Ma when there was a change to north-south rifting with concomitant development of an ocean-continent transform boundary off western Tasmania and the South Tasman Rise. This boundary follows the trace of an older Paleozoic structure optimally oriented for reactivation as a strike-slip fault during the later stages of continental breakup and is one of two major basement structures for which Antarctic equivalents are readily identified. Some ocean floor fracture zones lie directly along strike from these reactivated basement structures, pointing to a link between basement reactivation and formation of the ocean floor fabrics. Together with the two basement structures, these fabrics serve as an important first order control on palaeogeographic reconstructions of the Australian and Antarctic conjugate margins.
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nonGeographicDataset
eCat Id
73252
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
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Keywords
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- External Publication
- ( Theme )
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- continental margins
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- crustal structure
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- plate tectonics
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- structural geology
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- tectonic history
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
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2012-01-19T00:00:00
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