<div>The soil gas database table contains publicly available results from Geoscience Australia's organic geochemistry (ORGCHEM) schema and supporting oracle databases for gas analyses undertaken by Geoscience Australia's laboratory on soil samples taken from shallow (down to 1 m below the surface) percussion holes. Data includes the percussion hole field site location, sample depth, analytical methods and other relevant metadata, as well as the molecular and isotopic compositions of the soil gas with air included in the reported results. Acquisition of the molecular compounds are by gas chromatography (GC) and the isotopic ratios by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). The concentrations of argon (Ar), carbon dioxide (CO₂), nitrogen (N₂) and oxygen (O₂) are given in mole percent (mol%). The concentrations of carbon monoxide (CO), helium (He), hydrogen (H₂) and methane (C₁, CH₄) are given in parts per million (ppm). Compound concentrations that are below detection limit (BDL) are reported as the value -99999. The stable carbon (¹³C/¹²C) and nitrogen (¹⁵N/¹⁴N) isotopic ratios are presented in parts per mil (‰) and in delta notation as δ¹³C and δ¹⁵N, respectively.</div><div><br></div><div>Determining the individual sources and migration pathways of the components of natural gases found in the near surface are useful in basin analysis with derived information being used to support exploration for energy resources (petroleum and hydrogen) and helium in Australian provinces. These data are collated from Geoscience Australia records with the results being delivered in the Soil Gas web services on the Geoscience Australia Data Discovery portal at https://portal.ga.gov.au which will be periodically updated.</div>

<div>Exploring for the Future (EFTF) is an Australian Government program led by Geoscience Australia, in partnership with state and Northern Territory governments. EFTF program (2016-2024) aims to drive industry investment in resource exploration in frontier regions of northern Australia by providing new precompetitive data and information about energy, mineral and groundwater resource potential. In order to address this overarching objective of EFTF program, Geoscience Australia led a key element of the Australian Government’s commitment to achieve net zero by 2050 is the adoption of hydrogen (H2) energy. The key benefit of using H2 is that it is a clean fuel, emitting only water vapour and heat when combusted. The recent discovery of a 98% pure geologic H2 gas field in Mali has captured the imagination of explorers and the search is now on for new natural H2 gas accumulations across the world. Australia is considered one of the most prospective locations for sub-surface natural H2 due to our ancient geology and presence of potentially suitable H2 traps. A review of occurrences of natural (or geologic) H2 found high concentrations of H2 gas present in central western, New South Wales (NSW). This project, in collaboration with the Geological Survey of NSW, builds on that early work and presents the results identifying new occurrences of natural H2 through soil gas surveys in various locations across central and far west, NSW. Funded through the EFTF Strategic Innovation Reserve Fund (SIRF), FrontierSI was commissioned to identify circular to sub-circular morphologies, sometimes called Fairy Circles, across parts of far west, NSW as potential locations for naturally occurring hydrogen gas deposits. This report briefly introduces hydrogen gas exploration, and its importance to Australia's future energy mix, outlines the methods used to identify circular morphologies, the results, discussion, and recommendations for future work. Specifically, currently available literature was reviewed that describes the observable features believed to be related to natural hydrogen seeps, the previous methods used as well as the variety of datasets previously explored. The aim was to utilise open-source data and earth observation datasets where possible, and work towards an automated detection method. The Digital Earth Australia (DEA) Water Observation dataset was found to include many of the known hydrogen related features in Western Australia and was used as a foundation for creating an identification methodology. A modified version of the water observation layer was used along with other datasets including vegetation cover, which was applied to help refine and remove features that did not meet the set criteria for naturally occurring hydrogen deposits. This resulted in the production of two datasets over the two areas of interest, identified by Geoscience Australia at the beginning of the project, and used by their teams for site selection.