Exploring for the Future- Source rock geochemistry of Northern Australia Data Release 2: Total organic carbon (TOC) and Rock-Eval pyrolysis of samples from the McArthur Basin, South Nicholson Basin and Isa Superbasin, Northern Territory

The Exploring for the Future program is an initiative by the Australian Government dedicated to boosting investment in resource exploration in Australia. The four-year program led by Geoscience Australia focusses on northern Australia and parts of South Australia to gather new data and information about the potential mineral, energy and groundwater resources concealed beneath the surface. As part of the Exploring for the Future program, this study aims to improve our understanding of the petroleum resource potential of northern Australia. As a component of this project, collaboration between the Onshore Energy Systems Branch, Geoscience Australia and the Northern Territory Geological Survey (NTGS) is designed to produce pre-competitive information to assist with the evaluation of the petroleum prospectivity of onshore Northern Territory basins. Proterozoic basins of northern Australia including the McArthur Basin, the Isa Superbasin and the Isa Superbasin have the potential to host conventional oil and gas, in addition to unconventional shale gas and oil plays (Muir et al., 1980; Munson, 2014; Revie, 2016; Revie, 2017; Gorton & Troup, 2018). To date, work on the prospective petroleum systems in the McArthur Basin has focused principally on source rocks within the McArthur and Roper groups in the southern parts of the basin. However due to limited data availability, the spatial variability in source rock quality, type and thermal maturity remains poorly constrained across the region. In the South Nicholson region of Queensland and the Northern Territory, data from the Paleoproterozoic Isa Superbasin and the Mesoproterozoic South Nicholson Basin is extremely limited and a large proportion of the available data is old and of poor quality. To more comprehensively characterise these organic rich source rocks, higher resolution coverages of pre-competitive geochemical data is required (Gorton & Troup, 2018; Jarrett et al. 2018). This data release contains the total organic carbon (TOC) content and Rock-Eval pyrolysis data of 314 samples selected from nine drill cores from the McArthur Basin, South Nicholson Basin and Isa Superbasin that are housed in the Northern Territory Geological Survey’s Darwin core repository. The wells include Glyde 1, Lamont Pass 3 (McArthur Basin), Brunette Downs 1, CRDD001, NTGS 00/1, NTGS 01/1, NTGS 02/1 (South Nicholson Basin), in addition to ND1 and ND2 (Isa Superbasin). This data was generated at the Isotope and Organic Geochemistry Laboratory at Geoscience Australia as part of the Exploring for the Future program. The results show that the McArthur Basin samples analysed contain source rocks with poor to fair oil and gas generative potential with variable thermal maturity from immature to early oil mature. The Isa Superbasin samples analysed have poor to good gas generative potential and the South Nicholson samples analysed have poor to excellent gas generative potential. Samples from the Walford Dolostone and the Mullera Formation are overmature and petroleum potential cannot be assessed from the results of this study. This data release provides additional information that can be used to characterise the organic richness, kerogen type and thermal maturity of source rocks in the Teena Dolostone, Barney Creek Formation and Lynott Formation of the McArthur Basin, the Walford Dolostone and Mount Les Siltstone of the Isa Superbasin, in addition to the Constance Sandstone and Mullera Formation of the South Nicholson Basin. This data is provided in preparation for future work to generate statistics quantifying the spatial distribution, quantity and quality of source rocks, providing important insights into the hydrocarbon prospectivity of northern Australian basins