Three-dimensional seismic geomorphology and sedimentology of heterozoan and photozoan carbonate systems, Browse Basin, NW Australia

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The Browse Basin on the North West Shelf, Australia, provides a rare insight into the Eocene to recent history of a carbonate shelf that developed from a cool-water ramp to a tropical rimmed-platform. Subsurface signatures of this variable carbonate system are recorded on high-resolution 3D reflection-seismic surveys covering > 1000 km2, 24.000 km regional 2D reflection-seismic lines, as well as on wireline logs and cores of 8 exploration wells. A detailed analysis of this comprehensive dataset will be used to address three key aspects of carbonate-platform development that are currently under discussion: Aspect 1 - It is an open question whether slope erosion in cool-water carbonates is dominantly controlled by slope inclination or sea-level fluctuations. Full 3D spatial control provided by the 3D seismic volume acquired for this study allows the analysis of the relationship between sea-level change, shelf morphology and slope erosion. Aspect 2 - The transition from an unrimmed cool-water ramp to a rimmed tropical carbonate platform has not yet been documented in 3D seismic data, and examples from regional 2D studies are rare. High-resolution 3D analysis in combination with detailed wireline and core studies will support the development of a generally applicable model for such transitions. Aspect 3 – The combined analysis of cores, wireline logs and 3D-seismic properties will contribute to resolve the internal architecture of the tropical carbonate shelf during drowning. 3D stratigraphic forward modelling will be used for a quantitative evaluation of the subsurface interpretation results, ultimately supporting the prediction of carbonate facies in similar but less explored settings. Results of this research project are expected to contribute to a better understanding of the internal architecture and external form of cool-water and tropical carbonate platforms, and to shed light on the key processes shaping these contrasting systems.