Authors / CoAuthors
Norvick, M.S.
Abstract
A variety of alternative reconstructions are considered for the northern margins of the Australian plate. The simplest solution involves Hall's (2002) configuration for the microplates in the Greater Birds Head. Prior to the early Permian, the Greater Birds Head is thought to have lain adjacent to northern Australia from Timor to the Kai islands. After Meso-Tethys breakup in the Sakmarian, it then rotated away during the Permian to Middle Triassic to form the proto-Banda Sea and the spreading centre was then abandoned. From the Middle Triassic to the Oligocene, the Greater Birds Head was probably a relatively stable promontory of northern Australia and was then fragmented, tectonised and incorporated into the SE Asian island arc system during the late Oligocene to Holocene. The palaeogeographic maps are updated to incorporate these new plate models. The tectonostratigraphic evolution of northern Australia is divided into several phases. During the Carboniferous to Sakmarian pre-breakup phase, the Westralian Superbasin was characterised by rifting, deltas and various types of glacial sedimentation. After the Sakmarian Meso-Tethys breakup, there were large amounts of deltaic clastic sedimentation, lasting until Argoland drifted away in the Late Jurassic. The New England Orogeny overlapped with the first part of this phase on the NE margin until the Middle Triassic. There was a long period of post-breakup marine rift basin formation in NW Australia from the Oxfordian to the Valanginian. Indian Ocean breakup then led to rapid thermal subsidence. The rest of the Cretaceous was characterised by passive tectonics with largely fine-grained sedimentation on the NW margin, and increasing volcanicity and rifting on the NE side of the continent. Shifting areas of rifting and breakup, largely in a backarc setting affected the NE margins in the latest Cretaceous to early Eocene. Carbonate progradation started in the Westralian Superbasin in the Paleocene. The Eocene to Holocene history has been marked by passive carbonate progradation on the NW margin and multiple collisions in the N and NE. Many of the tectonic models put forward in this study are very difficult to substantiate using the data currently available and alternative scenarios are a strong possibility. The way forward is now to formulate research programmes that would help to narrow down these alternatives and better document the history of this very complex margin.
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nonGeographicDataset
eCat Id
82539
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Keywords
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- GA PublicationReport
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_External
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2003-01-01T00:00:00
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Report
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