A regional strike-slip fault under the Canning Basin
Yijie Zhan A * and Peter W. Haines AA Geological Survey of Western Australia, Perth, WA, Australia.
The APPEA Journal 62 S514-S518 https://doi.org/10.1071/AJ21169
Accepted: 10 March 2022 Published: 13 May 2022
© 2022 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of APPEA.
Abstract
Gravity data in the Canning Basin exhibit a northeast-trending linear feature that offsets a gravity ridge in the vicinity of the Jurgurra–Mowla Terraces with a displacement of about 30 km. The sharp displacement is aligned with similar disruptions on the Lennard Shelf to the northeast and Broome Platform to the southwest. The northeast part of the lineament also shows an anomalous offset on aeromagnetic images. However, the lineament does not correspond to fault displacement within the sedimentary succession of the Canning Basin based on seismic profiles. The geophysical responses to the linear feature vary in different areas, possibly caused by the different thickness of overlying sedimentary rocks across the basin. The lineament is interpreted as a left-lateral strike-slip fault that pre-dates the Canning Basin to account for the lack of seismic responses in the sedimentary section. This northeast-trending fault lies in the basement and might have originated during one of the younger Proterozoic to earliest Paleozoic orogenies pre-dating the Canning Basin. The northeast-oriented fault in the basement was orthogonal to the strike of the basin, thus was less likely to have significant impact on the basin deposition compared to the northwest-oriented faults, such as the Pinnacle and Fenton Fault system. However, these perpendicular features probably created a deeply seated crustal weakness near the intersection where the cluster of lamproite pipes of the Ellendale field intruded during the Miocene.
Keywords: Canning Basin, gravity, lamproite pipes, magnetic, Proterozoic, seismic data, sinistral offset, strike-slip fault.
Yijie (Alex) Zhan graduated from the China University of Geoscience (Beijing) with a BSc in 2005. He has worked on structural interpretation, fracture detection and reservoir modelling in various basins. He published in English and Chinese on seismic interpretation, azimuthal anisotropy, forward modelling and characterisation of gas-bearing volcanoclastic and conventional reservoirs. He joined the Geological Survey of Western Australia’s Basin and Energy Geoscience group as Senior Geophysicist in 2011, and is a member of PESA. |
Peter W. Haines holds Honours and PhD degrees in Geology from the University of Adelaide. He has previously held positions at the Northern Territory Geological Survey and Universities of South Australia, Adelaide and Tasmania. He joined GSWA in 2003 and currently holds the title of Basins Custodian within the Energy Geoscience and Carbon Strategy Branch. He is a member of PESA and the Geological Society of Australia (GSA). |
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