The Magnitude of Exhumation in the Kidson Sub-basin, Western Australia, using Thermal and Compaction Techniques

The Kidson Sub-basin which forms the largest tectonic province of the Canning Basin has high potential for Uranium, sediment-hosted base metals, conventional and unconventional hydrocarbons. The basin has undergone major tectonic events since its formation in the Early Ordovician involving several inversion episodes resulting in extensive exhumation in the basin. The magnitude, timing and distribution of exhumation associated with these inversion episodes are poorly studied due to sparse data in the area. In this study, we integrate recently acquired seismic and well data with existing well data, combining for the first time thermal and compaction techniques to constrain the magnitude and distribution of exhumation associated with these major inversion episodes.Our results from vitrinite reflectance indicate that at least 300 to 500 m of exhumation occurred during the middle Silurian to Early Devonian inversion episode (Prices Creek Compression), 500 to 750 m of exhumation occurred during the middle Carboniferous inversion episode or Meda Transpression and 800 to 1200 m of exhumation occurred during the Late Triassic to Early Jurassic inversion episode, or Fitzroy Transpression. Data from apatite fission track analysis put temporal constraints on the timing of this exhumation and indicate that a paleo-thermal maximum was reached within the Kidson Sub-basin during the Late Triassic extensional event. During this period, we also detect that the sediments were affected by a slight increase in basal heat flow associated with the rifting event.The results from this study also demonstrate that the magnitude of exhumation generally increased with each exhumation period progressively. We suggest that this may have occurred due to the progressive weakening of inherited basement units during each phase. Results also illustrate that each of these inversion events had a much higher impact on the exhumation of the Kidson Sub-basin than previously thought.