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

Open-File Report 2007-1047-SRP-109

By:
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DOI: 10.3133/ofr20071047SRP109

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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.

Geospatial Extents

Additional Publication Details

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
Other Geospatial:
Antarctica
Additional Online Files(Y/N):
N