Basement constraints on offshore basin architecture as determined by new aeromagnetic data acquired over Bass Strait and western margin of Tasmania

Abstract

The geology and petroleum potential of the western Tasmanian offshore basins is poorly understood. As part of a strategy to improve the understanding of these basins, aeromagnetic data was acquired by Geoscience Australia and Mineral Resources Tasmania under a National Geoscience Agreement and partly funded by the Commonwealth Government?s Offshore Energy Security Program. The survey acquired 141,234 line km of high quality data with a line spacing of 800 m across the Bass, southern Otway and Sorell basins and Torquay Sub-basin (Figure 1). The aim of this survey was to acquire new aeromagnetic data to help delineate the structural architecture of the basins and underlying basement and the distribution of igneous rocks. The data fill a gap in the existing aeromagnetic coverage between Tasmania and mainland Australia and provide fresh insights into basement structure and its control on basin architecture and sedimentation patterns during the breakup of Gondwana and separation of Australia from Antarctica.