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Session 10. Oral Presentation for: A new perspective on regional structural architecture across the offshore Otway Basin

Chris Nicholson A *
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A Geoscience Australia, Canberra, ACT, Australia.

* Correspondence to: Chris.Nicholson@ga.gov.au

Australian Energy Producers Journal 64 https://doi.org/10.1071/EP23331
Published: 7 June 2024

© 2024 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of Australian Energy Producers. This is an open access article distributed under the Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International License (CC BY-NC-ND)

Abstract

Presented on Wednesday 22 May: Session 10

Geoscience Australia has undertaken a regional seismic mapping study of the offshore Otway Basin extending across the explored inner basin to the frontier deep-water region. Seismic interpretation covers over 18,000 line-km of new and reprocessed data acquired in the 2020 Otway Basin seismic program and over 40,000 line-km of legacy 2D seismic data. We present new basin-scale isochore maps that show the distribution of the Cretaceous depocentres. Maps for the Lower Cretaceous Crayfish and Eumeralla supersequences, together with those recently published for the Upper Cretaceous Shipwreck and Sherbrook supersequences, complete the set of isochore maps for the main tectonostratigraphic basin intervals. Mapping of basement-involved faults has revealed structural fabrics that have influenced depocentre development. The tectonostratigraphic development of depocentres and maps of deep crustal units delineate crustal thinning trends related to late Cretaceous extension phases. This work highlights the need to review and update structural elements. For example, the boundary between the Otway and Sorell basins is now geologically constrained. The refinements to the tectonostratigraphic evolution of the Otway Basin presented here have important implications for the distribution and potential maturity of petroleum systems, especially with regard to heat flow associated with crustal extension.

To access the Oral Presentation click the link on the right. To read the full paper click here

Keywords: basement, basin boundaries, Eumeralla Supersequence, Otway Basin, reflection MOHO, Sherbrook Supersequence, Shipwreck Supersequence, structural architecture, top lower laminated crust.

Biographies

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Chris Nicholson graduated with a BSc (Hons) in Geology from the Australian National University in 2000. He joined Geoscience Australia in 2004 as Basin Analyst and Structural Geologist working on regional prospectivity studies of Australia’s offshore basins. Chris is a member of PESA and SEAPEX, and is a past president of PESA ACT.