Cretaceous–Tertiary inversion history of the Dampier Sub-basin, northwest Australia: Insights from quantitative basin modelling

Seismic sequence analysis has been combined with a kinematic and flexural model for the deformation of the lithosphere to define the history, distribution and magnitude of inversion within the Dampier Sub-basin, northwest Australia, during the Cretaceous and Tertiary. Inversion tends to be focused along the trend of pre-existing border fault systems and/or internal to the basin across the roll-over anticlines of collapsed hangingwall blocks. The spatial distribution of inversion varied with different faults involved in the inversion process at different times. Whereas Cretaceous inversion concentrated along major boundary faults of the northeast–southwest oriented Rankin, Madeleine, and Rosemary–Legendre trends, the locus of Miocene inversion was located adjacent to the northwest limits of the Rosemary–Legendre Trend. Total shortening of the lithosphere during the Santonian and Tertiary was modelled to be ∼2.6 and 0.16 km, respectively, with northeast–southwest trends being preferentially reactivated. The amplitudes of inversion structures range from ∼1000 m over the eastern Rankin Trend to hundreds of metres for inversion structures comprising the Rosemary–Legendre Trend. Although responsible for the development of relatively subtle features, inversion has critically controlled the major structures for trapping hydrocarbons within the Dampier Sub-basin.