PESA WA: October Technical Evening Presentation: Professor Chris Elders

Deep seismic profiles collected from continental margins around the world over the past 20 years have shown that there is no such thing as a “typical” passive continental margin. The role of structural inheritance (the influence of older structural fabrics on subsequent events) and multiple, distinct phases of rifting are some of the factors that contribute to variety and complexity. Recently completed PhD projects at Curtin University allow us to investigate this further in the context of the northern and western margins of Australia. These show that Paleozoic rifts that propagated east across the Northern Carnarvon and Roebuck basins and south along the western margin of Australia exerted a significant control on subsequent structural architecture and stratigraphy. The differences in the intensity of deformation may account for some of the contrasting features of these margins and in particular, set up the conditions for the accumulation of thick sequences of Triassic sediments in the Northern Carnarvon Basin depocentre. Being better able to quantify the extent of Permian rifts raises some interesting questions for tectonic reconstructions and the distribution of subsequent Mesozoic rift episodes but helps to explain the morphology of the resulting passive margin and the sedimentary processes that operated on it.