Tectonic development of the Eastern Officer Basin, Central Australia

Abstract

Interactive interpretation of some 3000 km of seismic section, combined with the integration of well, potential field, subcrop and surface geological data with satellite imagery have shown that the structure of this prospective basin is controlled by compressive tectonics. Four stages of basin development between the late Proterozic and Carboniferous can be identified on calibrated seismic sections from the eastern Officer Basin. Recent work suggests that the Officer Basin was originally part of an extensional Centralian Superbasin which included the present Amadeus, Ngalia, Savory and Georgina Basins. Justification for this hypothesis comes from the broadly similar stratigraphy in each of these basins. A model is proposed which explains the deformation of the Centralian Superbasin into those basins recognised today, separated by basement uplifted to shallow depth and exposure by compression. The main deformation is believed to have commenced at or around the Proterozoic-Cambrian boundary, with a substantial pulse at the end of the Cambrian. As a result, the original broad platform depositional system was deformed into a series of foreland-style basins. Stacked thrust sheets of late Proterozic to Cambrian sediments, containing the best known source rocks in the basin, illustrate the intensity of the compressive deformation. lnterbedded reservoir units have been folded to form traps suitable for hydrocarbon retention. This model will enhance the probability of prospect generation and the search for commercial hydrocarbons.