Authors / CoAuthors
Goncharov, A. | Kennard, J. | Becker, L.
Abstract
The Bedout High in the offshore Roebuck/Canning Basin at the Australian NW Margin (NWAM) has recently been re-interpreted as a massive impact structure that appears to be associated with the global Permian/Triassic extinction event. This impact may have significantly modified the crustal structure in the region. Depth conversion of the reflection seismic data suggests that depth to basement in this area is ~ 3.5 km, and the Bedout High stands more than 4 km above the surrounding sedimentary basins. The basement and crust in the Roebuck/Canning Basin have a number of features that make it distinctly different from other basins at the NWAM. Rapid crustal thinning (from 34 to 12 km thick crust over a distance of 100 km) and the presence of a thick layer of magmatic underplating in the lower crust are among these features. The protracted thermal/fluid events associated with this underpalting may have rendered the Roebuck Basin ?sterile? of Triassic-Jurassic sourced hydrocarbons which are ubiquitous across other parts of the NW Australian margin. Interval velocities for Top Permian - Lower Carboniferous (pre-impact interval) and for Base Jurassic ? Top Permian (post-impact interval) sections display similar correlation with total sediment thickness: in both cases lower velocities correspond to thinner sediment, unlike at other basement highs in the region. OBS-derived interval velocities appear to be up to 10% higher than the stacking-derived ones, consistent with fine velocity stratification of this part of the section. However, existing seismic data do not allow an accurate estimate of the size of the area affected by the meteorite impact, and to measure any effects or controls it may have exerted on rifting, thermal, sedimentation and hydrocarbon maturation regimes in the area. Further multidisciplinary research is necessary to answer these questions.
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nonGeographicDataset
eCat Id
61163
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
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Keywords
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- External PublicationConference Paper
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- AU-WA
- Australian and New Zealand Standard Research Classification (ANZSRC)
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- Earth Sciences
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- Published_Internal
Publication Date
2004-01-01T00:00:00
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geoscientificInformation
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[-22.0, -14.0, 114.0, 122.0]
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