AbstractsEarth & Environmental Science

The structural evolution of the Northern Carnarvon Basin, Northwest Australia

by Bulut Tortopoglu

Institution: Colorado School of Mines
Year: 2015
Keywords: Barrow; Exmouth Plateau; Argo and Cuvier Abyssal Plains; Northwest Shelf of Australia; Exmouth; Gascoynee; Rankin Platform; Northern Carnarvon Basin; Beagle and Dampier Sub-basin
Posted: 02/05/2017
Record ID: 2066098
Full text PDF: http://hdl.handle.net/11124/20135


3D and 2D seismic data from the Northern Carnarvon Basin provide an opportunity to analyze the structural evolution of the basin. This is a rift-dominated basin, formed by five phases of extension (Pre-Top Permian, Top Permian, Base Jurassic, Middle Jurassic, and Late Jurassic Extension, versus only the four previously identified) and the Base Cretaceous inversion across the Northwest Shelf of Australia. The first deformation by listric fault initiation in the basin resulted in a newly defined Pre-Top Permian Extension, generating the Exmouth, Dampier, Barrow and Beagle Sub-basins. The magnitude of the rift phases remained approximately the same during the earliest three phases of extensions, but increased during the Middle and Late Jurassic Extension. Additionally, four detachment surfaces are identified whereas only two were determined previously. Moreover, a simple shear “Wernicke” model best defines the style of deformation during the five phases of extension in the Northern Carnarvon Basin, with delamination under the region between the WNW edge of the Exmouth Plateau and the Gascoynee Abyssal Plain, opposing the symmetrical McKenzie Model previously assigned bu Mutter et al. Lastly, the amount of extension during the rift phases and the amount of shortening during the inversion are determined to be highly variable from the results of restorations throughout the basin. A transition from the rift-dominated margin to the passive margin is marked by the end of the Late Jurassic Extension. Results of this research are applicable to hydrocarbon exploration because this study is conducted across the entire Northwest Shelf of Australia, showing more precise relationships between structural features such as sub-basins, plateaus, shelves, platforms, synclines, arches, troughs, abyssal plains, depocenter evolution, faults, folds, harpoon structures etc. rather than limited to a smaller scale. Output of 3D surfaces with the modelled fault families in a structural framework demonstrates that rift initiation generated accommodation, and rift mini-basins formed coevally for deposition. Also, regional stretching models of the basin from restorations for each phase are another significant implication of this study for understanding the structural evolution of the entire basin. Advisors/Committee Members: Trudgill, Bruce, 1964- (advisor), Sonnenberg, Stephen A. (committee member), Kluth, Chuck (committee member).