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The Australian North West Shelf (NWS) has a complex geological history that has been affected by several phases of extension and rifting, creating features like the failed rift system in the Northern Carnarvon Basin (NCB). The NWS has been impacted by several regional tectonic events, most notably Gondwana’s dispersal and Australia’s collision with Southeast Asia. Such events created the various sub-basins of the Shelf and impacted the vertical and lateral – or kinematic – motions of these basins. To date, no studies have fully quantified the spatial and temporal distribution of these motions and their impacts on the region’s resource systems. This thesis proposes that accurate basin kinematic evolution models can reveal the time-dependent evolution of basins and how such evolution affects the development of resource systems in those basins. The NWS has a rich coverage of geological and geophysical datasets, hence an excellent location for building such models. I have built detailed kinematic evolution models of the Shelf basins using backstripping, decompaction and thermochronology techniques. The models extend vertical motion analysis from the traditional single-well analysis to accurate regional analysis by combining datasets from multiple wells and seismic sections. They also extend lateral motion analysis from traditional inter-plate analyses into intraplate settings to precisely reconstruct the pre-rift deformation of intracontinental rifts using novel methods. The thesis has modelled the spatial and temporal distribution of subsidence, rift-related lateral motions and exhumation in the NWS basins. The results reveal a northeast propagating rift in the NCB with rapid subsidence and sedimentation rates (up to 80 m/Ma) from the Jurassic to the Cretaceous. Based on this data, I developed a reconstruction model of this NCB rift system, which reveals multiphase anomalous rifting rates (8 mm/yr), correlating Gondwana dispersal events. The exhumation models reveal a complex multiphase Mesozoic-present exhumation of up to ~2.5 km across the NWS, likely caused by magmatic underplating, compression and depth-dependent extension. The exhumation impeded the development of various Jurassic-Cretaceous petroleum systems in the central Bonaparte Basin and the Exmouth Plateau, NCB. This thesis improves the understanding of the NWS basins’ evolution, considers the implications for CO2 and H2 storage locations, and has significant applications in resource exploration. |
