A new perspective on regional structural architecture across the offshore Otway Basin
Chris Nicholson A * , Steve Abbott A , George Bernardel A and Yvette Poudjom Djomani AA
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. |
Steve Abbott holds a PhD degree in sedimentary geology from James Cook University. He joined Geoscience Australia in 2013 where he works as a Basin Analyst on regional studies of Australia’s offshore basins. Steve is a member of PESA and SEPM, and is past president of PESA ACT. |
George Bernardel gained his BSc (Honours) in Geophysics from the University of Sydney in 1986. He joined Geoscience Australia in 1995 where he works as a Basin Analyst on Australia’s offshore basins. He is currently mapping Cretaceous–Cenozoic sequences and structure across the offshore Otway Basin. |
Yvette Poudjom Djomani completed a PhD in geophysics at the University of Paris XI (France) and earned an MBA from the Australian Institute of Business (Adelaide). She joined Geoscience Australia in 2016 where she works as a Potential Field Geophysicist. Yvette is currently working on depth to basement modelling of the Deep-water Otway Basin. She is a member and Treasurer of ASE. |
Abstract
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.
Keywords: basement, basin boundaries, Eumeralla Supersequence, Otway Basin, reflection MOHO, Sherbrook Supersequence, Shipwreck Supersequence, structural architecture, top lower laminated crust.
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. |
Steve Abbott holds a PhD degree in sedimentary geology from James Cook University. He joined Geoscience Australia in 2013 where he works as a Basin Analyst on regional studies of Australia’s offshore basins. Steve is a member of PESA and SEPM, and is past president of PESA ACT. |
George Bernardel gained his BSc (Honours) in Geophysics from the University of Sydney in 1986. He joined Geoscience Australia in 1995 where he works as a Basin Analyst on Australia’s offshore basins. He is currently mapping Cretaceous–Cenozoic sequences and structure across the offshore Otway Basin. |
Yvette Poudjom Djomani completed a PhD in geophysics at the University of Paris XI (France) and earned an MBA from the Australian Institute of Business (Adelaide). She joined Geoscience Australia in 2016 where she works as a Potential Field Geophysicist. Yvette is currently working on depth to basement modelling of the Deep-water Otway Basin. She is a member and Treasurer of ASE. |
References
Abbott S, Cubitt C, Bernardel G, Nicholson C, Nguyen D (2024) Shipwreck and Sherbrook Supersequence Regional Gross Depositional Environments, offshore Otway Basin. Australian Energy Producers Journal 64, S302-S307.
| Crossref | Google Scholar |
Gibson GM, Morse MP, Ireland TR, Nayak GK (2011) Arc–continent collision and orogenesis in western Tasmanides: Insights from reactivated basement structures and formation of an ocean–continent transform boundary off western Tasmania. Gondwana Research 19, 608-627.
| Crossref | Google Scholar |
Gunning M, Wilkinson S, Chau P, Mitchell C, Badry J (2024) Post-stack 3D merging to fast-track regional interpretation - offshore Otway Basin case study. Australian Energy Producers Journal 64, S388-S392.
| Crossref | Google Scholar |
Moore AMG, Stagg HMJ, Norvick MS (2000) Deep-water Otway Basin: A new assessment of the tectonics and hydrocarbon prospectivity. The APPEA Journal 40, 66-84.
| Crossref | Google Scholar |
Nicholson C, Abbott S, Bernardel G, Gunning ME (2022) Stratigraphic framework and structural architecture of the Upper Cretaceous in the deep-water Otway Basin – implications for frontier hydrocarbon prospectivity. The APPEA Journal 62, S467-S473.
| Crossref | Google Scholar |
Peron-Pinvidic G (2022) The seismic reflection Moho across the mid-Norwegian continental rifted margin. Communications Earth & Environment 3, 133.
| Crossref | Google Scholar |
Schenk O, Karvelas A, West T, Kornpihl D (2021) Otway Basin Regional Study report. Available at https://www.ga.gov.au/nopims/releases/otway-basin-regional-study-report
