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Towards a regional understanding of Sherbrook Supersequence Gross Depositional Environments, offshore Otway Basin

Created 17/10/2025

Updated 17/10/2025

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The Sherbrook Supersequence (Campanian–Maastrichtian) is the youngest of four Cretaceous supersequences in the Otway Basin and was deposited during a phase of crustal extension. Supersequence thickness is typically less than 1000 ms TWT across the inboard platform. Beyond the platform edge up to 2 800 ms TWT of Sherbrook sediments were deposited in the deep-water Morum and Nelson sub-basins. Analysis of wireline-logs and cores from wells yielded fluvial, deltaic, coastal shelf gross depositional environments (GDEs). As the number of regionally mappable seismic facies is much less than the number of well-based GDEs, the integration of well-based environmental interpretations with seismic facies resulted in three main regional GDE (RGDE); Fluvial Plain, Coastal/Delta Plain, and Shelf. The Fluvial Plain and Coastal/Deltaic RGDEs are almost entirely restricted to the inboard platform areas of the basin. The mud-prone Shelf RGDE is widespread across the deep-water part of the basin where it forms the depocentres of the Morum and Nelson sub-basins. The Shelf RGDE is well imaged on the Otway 2020 2D seismic data that was acquired over the deep-water Otway Basin. In the Morum Sub-basin, the Shelf RGDE is strongly influenced by growth on extensional faults. In contrast, the Shelf RGDE in the Nelson Sub-bsin is a relatively unstructured progradational complex. The presence of mass-transport and incision complexes are consistent with active tectonism during Sherbrook deposition. Reservoir rocks in the deep-water basin are best developed in the Coastal/Deltaic RGDE where it encroaches into the Morum Sub-basin, and where the Austral 3 petroleum system was potentially active within the Sherbrook Supersequence.  This presentation was given at the 2023 Australasian Exploration Geoscience Conference (AEGC) 13-18 March, Brisbane (https://2023.aegc.com.au/)

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Field Value
Title Towards a regional understanding of Sherbrook Supersequence Gross Depositional Environments, offshore Otway Basin
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/en/dataset/2caf9ec3-bd2a-4ae8-bf27-24a1b29bd68e
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 24/03/2023
Geospatial Coverage
Map data © OpenStreetMap contributors
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Data Portal Geoscience Australia

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This dataset was originally found on Geoscience Australia "Towards a regional understanding of Sherbrook Supersequence Gross Depositional Environments, offshore Otway Basin". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/towards-a-regional-understanding-of-sherbrook-supersequence-gross-depositional-environments-off