Spatial variations in crustal structure and shear wave velocity across the Canning Basin, NW Australia

The Canning Basin Passive Seismic project is in collaboration with UWA, Macquarie University and the Institute of Geology and Geophysics at the Chinese Academy of Sciences (ICG-CAS). The Canning Basin of Western Australia is one of the largest Palaeozoic basins in the world with a total extent of > 640 000 km2 of which 530 000 km2 is onshore. Despite oil production offshore, it is one of the least explored Palaeozoic basins in the world. The Canning Basin covers the area between the Proterozoic Kimberley Basin, King Leopold Orogen and Halls Creek Orogen of the Northern Australian Craton and the Pilbara Craton of the Western Australian Craton. The suture between these two cratons is interpreted to underlie somewhere under the Canning Basin. Although a recent seismic reflection line 14GA-CC, shot in collaboration with Geoscience Australia, and many commercial seismic lines have imaged individual sub-basins well, the deeper structure including the Moho were poorly imaged. This project aims to look at the deep structure of the basin's bedrock and the history of Proterozoic craton amalgamation and Paleozoic rifting and basin development.

We processed initial waveforms in the first 9 months of the deployment, recorded by 19 land stations and seven ocean bottom seismometers. We applied receiver function stacking and ambient noise tomography to image the crustal architecture across the basin. Initial results show large crustal domains that correlate with the large-scale depth-to basement variations that include low-velocity sub-basins and intervening high velocity platforms. The structures are interpreted with potential field data and the active source reflection results to shed light on the complex regional tectonics during the assembly of the Australian continent and subsequent intracontinental reworking processes.