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A series of regional pilot geochemical survey projects have been carried out in Australia over recent years. These pilot projects targeted a number of landscape and climate settings that are challenging for geochemical mapping, and applied increasingly lower sampling densities, from c . 1 site/300 km 2 to c . 1 site/ 2100 km 2 . Selected results are presented from pilot geochemical surveys in the Riverina, Gawler and Thomson regions, as well as results from modelling aimed at testing the robustness of ultra-low sampling densities in Australia. The salient conclusions are that: (1) geochemical surveys sampling surface and near-surface transported regolith are capable of identifying major lithologies and mineralization below the cover; and (2) a sampling strategy targeting outlet sediments of large catchments allows the application of ultra-low sampling densities in Australia. These findings overcome the main hurdles met by earlier attempts at designing a nation-wide geochemical survey. The strategy for the resulting National Geochemical Survey of Australia (NGSA) project, recently approved for funding under the Australian Government's Onshore Energy Security Initiative, is outlined. By 2011, the NGSA will produce a publicly available multi-element, internally consistent and state-of-the-art regolith geochemical database and atlas to support decision-makers.

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The Geological and Bioregional Assessment Program is a series of independent scientific studies undertaken by Geoscience Australia and the CSIRO, supported by the Bureau of Meteorology, and managed by the Department of Agriculture, Water and the Environment. The program consists of three stages across three regions with potential to deliver gas to the East Coast Gas Market. Stage 1 was a rapid regional prioritisation conducted by Geoscience Australia, to identify those sedimentary basins with the greatest potential to deliver shale and/or tight gas to the East Coast Gas Market within the next 5–10 years. This prioritisation process assessed 27 onshore eastern and northern Australian basins with shale and/or tight gas potential. Further screening reduced this to a shortlist of nine basins where exploration was underway. The shortlisted basins were ranked on a number of criteria. The Cooper Basin, the Beetaloo Subbasin and the Isa Superbasin were selected for more detailed assessment. Stage 2 of the program involved establishing a baseline understanding of the identified regions. Geoscience Australia produced regional geological evaluations and conceptualisations that informed the assessment of shale and/or tight gas prospectivity, ground- and surface-water impacts and hydraulic fracturing models. Geoscience Australia’s relative prospectivity assessments provide an indication of where viable petroleum plays are most likely to be present. These data indicate areal and stratigraphic constraints that support the program’s further work in Stage 3, on understanding likely development scenarios, impact assessments and causal pathways.