Controls on the locus of intraplate deformation in central Australia

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doi: 10.1016/S0012-821X(98)00159-9
Authors:Sandiford, Mike; Hand, Martin
Author Affiliations:Primary:
University of Adelaide, Department of Geology and Geophysics, Adelaide, South Aust., Australia
Volume Title:Earth and Planetary Science Letters
Source:Earth and Planetary Science Letters, 162(1-4), p.97-110. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0012-821X
Publication Date:1998
Note:In English. 52 refs.; illus., incl. sects., 1 table, geol. sketch map
Summary:The locus of intraplate deformation in central Australia changed from the presently preserved southern margin of the Amadeus Basin during the late Neoproterozoic to early Phanerozoic Petermann Orogeny to the northern margin in the late Phanerozoic Alice Springs Orogeny. Immediately prior to each event the thickness of the Amadeus basin sediments varied from as little as 1.5 km in the central parts of the basin to as much as 7 km in the vicinity of the presently preserved margins of the basin with the locus of deformation mimicking the locus of maximum sedimentary thicknesses at the onset of each orogenic event. As such these orogenies represent extreme examples of basin inversion; a process observed in many intracratonic basins worldwide. We show that differential burial of the central Australian Proterozoic basement complexes beneath the Amadeus basin is capable of producing variations in Moho temperature of up to 30°C prior to the Petermann Orogeny and up to 110°C prior to the Alice Springs Orogeny. For a "Brace-Goetze" model of lithospheric rheology, the variations in Moho temperature equate to variations in effective lithospheric strain rate of 1-4 orders of magnitude, implying that variations in thickness of the sedimentary blanket may have played a primary role in localising Phanerozoic intraplate deformation in central Australia. An appealing aspect of this model lies in its corollary: that the removal of the sedimentary blanket during denudation of the orogen will be accompanied by dramatic cooling and strengthening of the lithosphere. This may provide a plausible explanation for the long-term persistence of the extraordinary gravity anomalies (∼150 mGal) developed during these central Australian intraplate orogenies. Abstract Copyright (1998) Elsevier, B.V.
Subjects:Alice Springs Orogeny; Basins; Burial; Continental crust; Controls; Cratons; Crust; Gravity anomalies; Heat flow; Heat sources; Intraplate processes; Lithosphere; Mohorovicic discontinuity; Neoproterozoic; Orogeny; Paleozoic; Precambrian; Proterozoic; Radioactivity; Rheology; Sedimentary cover; Temperature; Thermomechanical properties; Upper Precambrian; Amadeus Basin; Australasia; Australia; Northern Territory Australia; South Australia; Central Australia; Petermann Orogeny
Abstract Numbers:99M/3121
Record ID:1998073279
Copyright Information:GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands
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