Authors / CoAuthors
Wellman, P.
Abstract
The Eastern Highlands form a broad arch, with similar cross sections along its length, and varying altitude of its axis. At least on the western margin in Queensland and near Sydney, most of the uplift was by warping. Mesozoic sediments preserved on the summit and flanks of the highlands prove that most of the uplift was after the Early Cretaceous in Queensland, after the mid Triassic near Sydney, and after the Triassic in Tasmania. Uplift of the highlands was most likely initiated at the time of change of the sedimentation pattern and tectonics, 95 Ma ago, as suggested by Jones and Veevers, except that uplift is thought to have started in the Jurassic in Tasmania. Denudation rates vary with local relief. The Cainozoic average rate for Queensland and New South Wales is near 3 m.Ma-1, and for Victoria and Tasmania 5-7 m.Ma-1. Gravity studies show that the Eastern Highlands are on relatively weak lithosphere, so the denudation would have resulted in denudation isostatic rebound of the local area, and the total amount of tectonic uplift is given approximately by the smoothed altitude of the present highlands. In general, the amount of denudation is smaller than the total amount of tectonic uplift. The timing of the tectonic uplift is not well determined, but most is earlier than mid Cainozoic, and there is evidence that possibly one third of it was during the late Cainozoic. The early tectonic uplift is thought to be due to removal of the lower lithosphere from beneath the highlands at the time of rifting to form the Tasman and Coral Seas, leading to uplift both by crustal underplating, and by the short and long-term effects of crustal heating. Later tectonic uplift is thought to be caused by crustal underplating associated with Cainozoic basaltic volcanism.
Product Type
document
eCat Id
81225
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
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Keywords
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- GA PublicationJournal
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- QLDSANSWVICTAS
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_External
Publication Date
1987-01-01T00:00:00
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unknown
Topic Category
geoscientificInformation
Series Information
BMR Journal of Australian Geology and Geophysics 10:3:277-286
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Unknown
Parent Information
Extents
[-43.92, -10.96, 140.4, 155.69]
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Spatial Resolution
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