The Centralian Superbasin (Canning, Amadeus, Georgina and Officer basins) Stratigraphic Review and Well Correlations

Geoscience Australia is leading the regional evaluation of potential subsurface mineral, energy and groundwater resources, through the Exploring for the Future (EFTF) program. Understanding the subsurface stratigraphy and depositional systems is fundamental for any exploration activities. The major challenge for exploration in northern and southern Australian onshore basins is the limited seismic data coverage; however, maximising the use of data in existing wells is a valuable source of information from which to gain insights into prospectivity. Data from 142 wells from the Canning, Amadeus, Georgina and Officer basins in the Centralian Superbasin have been used to evaluate the subsurface geology, stratigraphy and depositional environments in order to generate two-dimensional well correlations within and between basins. Primary objectives of the study are to: • establish a methodology to integrate the well data with Geoscience Australia’s many other datasets (i.e., Australian Stratigraphic Unit, Time Scale, Geochronology, STRATDAT, RESFACS) and publicly available (published and unpublished) research data and information • determine the lithostratigraphic unit tops, log and lithology characterisations, depositional facies, boundary criteria, spatial and temporal distribution and regional correlation • identify key biostratigraphic zones and markers, and geochronological absolute age dates to generate a chronostratigraphic Time-Space Diagram for each basin. This report improves the understanding of the tectonostratigraphic relationships across the Centralian Superbasin. The age of the sedimentary successions of the Centralian Superbasin have been refined using geochronology, biostratigraphy and lithostratigraphic correlation. The key results of the study are: • the Centralian Superbasin started to form at about 840 Ma with a series of extension, rifting and crustal sagging events that preceded the breakup of the Neoproterozoic Rodinia Supercontinent in the mid-Tonian • sedimentary sections deposited through parts of the global Sturtian and Marinoan glaciations are recognised in the Centralian Superbasin representing time spans of 717–668 Ma and 640–635.5 Ma, respectively • the intra-basin connection between the Canning and the Amadeus basins with the Proto-Pacific Ocean in the east, known as the Larapintine Seaway, was formed during the 480–460 Ma extensional and subsidence of the Larapinta Event. This has been determined from the integration of the recently interpreted seismic data from the Kidson Sub-basin (Kidson Sub-basin 2D Seismic Survey, EFTF) and conodont biostratigraphy in the Amadeus Basin.