Crustal architecture of the oblique-slip conjugate margins of George V Land and southeast Australia

Open-File Report 2007-1047-SRP-109
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Abstract

A conceptual, lithospheric-scale cross-section of the conjugate, oblique-slip margins of George V Land, East Antarctica, and southeast Australia (Otway Basin) has been constructed based on the integration of seismic and sample data. This cross-section is characterised by asymmetry in width and thickness, and depth-dependent crustal extension at breakup in the latest Maastrichtian. The broad Antarctic margin (~360 km apparent rift width) developed on thick crust (~42 km) of the Antarctic craton, whereas the narrow Otway margin (~220 km) developed on the thinner crust (~31 km) of the Ross–Delamerian Orogen. The shallow basement (velocities ~5.5 km.s-1) and the deep continental crust (velocities >6.4 km.s-1) appear to be largely absent across the central rift, while the mid-crustal, probably granitic layer (velocities ~6 km.s-1) is preserved. Comparison with published numerical models suggests that the shallow basement and deep crust may have been removed by simple shear, whereas the mid-crust has been ductilely deformed.

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Publication type Report
Publication Subtype USGS Numbered Series
Title Crustal architecture of the oblique-slip conjugate margins of George V Land and southeast Australia
Series title Open-File Report
Series number 2007-1047-SRP-109
DOI 10.3133/ofr20071047SRP109
Year Published 2007
Language English
Publisher U.S. Geological Survey
Publisher location Reston, VA
Description 6 p.
Larger Work Type Report
Larger Work Subtype USGS Numbered Series
Larger Work Title Antarctica: A Keystone in a Changing World--Online Proceedings for the Tenth International Symposium on Antarctic Earth Sciences. Santa Barbara, California, U.S.A.--August 26 to September 1, 2007
Other Geospatial Antarctica
Additional Online Files (Y/N) N
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