Exploring for the Future (EFTF) is an Australian Government program led by Geoscience Australia, in partnership with state and Northern Territory governments. This first phase of the EFTF program (2016–2020) aimed to assist industry investment in resource exploration in frontier regions of northern Australia by providing precompetitive data and information about energy, mineral and groundwater resource potential. As part of this initiative, this record presents whole-rock inorganic geochemistry data including X-ray fluorescence (XRF) and laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS) analyses and quantitative X-ray diffraction (qXRD) results for 67 drill core and cuttings samples of sedimentary rocks from Barnicarndy 1 drilled in the Barnicarndy Graben of the Canning Basin. The inorganic geochemistry analyses were undertaken by Geoscience Australia and Bureau Veritas (BV). This work complements other components of the EFTF program, including a comprehensive sampling program of the Barnicarndy 1 deep stratigraphic well, the Kidson Sub-basin seismic survey, and the Kidson Sub-basin petroleum systems model to better understand the geological evolution, basin architecture and petroleum prospectivity of the region.

<div>Geochemical and mineralogical analysis of surficial materials (streams, soils, catchment samples, etc) can provide valuable information about the potential for mineral systems, and the background mineralogical and geochemical variation for a region. However, collecting new samples can be time consuming and expensive, particularly for regional-scale studies. Fortunately, Geoscience Australia has a large holding of archived samples from regional- to continental-scale geochemical studies conducted over the last 50 years, the majority collected at high sampling densities that would be cost-prohibitive today. Although all these samples have already been analysed, their vintage can mean that analyses were obtained by a variety of analytical methods, are of variable quality, and often only available for a small number of elements. As part of the Australian government’s Exploring for the Future program, funding was dedicated to re-analyse ~9,000 samples from these legacy surveys. They were re-analysed for 63 elements (total content) at a single laboratory producing a seamless, internally consistent, high-quality dataset, providing valuable new insights.</div><div><br></div><div>A large number (7,700) of these legacy samples were collected from north Queensland, predominantly in the Cape York – Georgetown area (5,472) — an area with both a wide-range of existing deposit types and known potential for many critical minerals. The sample densities of these studies, up to 1 sample per ~2.5 km2 for Georgetown, makes them directly applicable for determining local- and regional-scale areas of interest for mineral potential. Early interpretation of the Cape York – Georgetown data has identified several locations with stream sediments enriched in both heavy and light rare earth elements (maximum 4000 and 31,800 ppm, respectively), demonstrating the potential of this dataset, particularly for critical minerals. The greater sampling density means that these samples can also provide much more granular geochemical background information and contribute to our understanding of the lower density data commonly used in regional- and national-scale geochemical background studies.</div><div><br></div><div>In addition to the geochemical re-analysis of legacy surface samples, Geoscience Australia has also been undertaking mineral analysis of legacy continental-scale geochemical samples. The National Geochemical Survey of Australia (NGSA) sample archive has been utilised to provide a valuable new dataset. By separating and identifying heavy minerals (i.e., those with a specific gravity >2.9 g/cm3) new information about the mineral potential and provenance of samples can be gained. The Heavy Mineral Map of Australia (HMMA) project, undertaken in collaboration with Curtin University, has analysed the NGSA sample archive, with~81% coverage of the continent. The project has identified over 145 million individual mineral grains belonging to 163 unique mineral species. Preliminary analysis of the data has indicated that zinc minerals and native elements may be useful for mineral prospectivity. Due to the large amount of data generated as part of this HMMA project, a mineral network analysis tool has been developed to help visualise the relationship between minerals and aid in the interpretation of the data. Abstract presented to the Australian Institute of Geoscientists – ALS Friday Seminar Series: Geophysical and Geochemical Signatures of Queensland Mineral Deposits October 2023 (https://www.aig.org.au/events/aig-als-friday-seminar-series-geophysical-and-geochemical-signatures-of-qld-mineral-deposits/)

<div>Geoscience Australia’s Exploring for the Future (EFTF) program aims to enhance decision-making on Australia's mineral, energy, and groundwater resources by providing comprehensive geoscience data. Launched in 2016 with a $225m investment, the program has spawned various national projects, including the Australia's Resources Framework (ARF). The ARF focuses on a national perspective of Australia's surface and subsurface geology, supporting economic and social benefits, including transition to net-zero emissions.</div><div><br></div><div>One key sub-project within EFTF is the Geochemistry for Basin Prospectivity (G4BP) module. It explores Australian basins for basin-hosted base metal systems. The current focus (2020-2024) is on the Stuart Shelf region in South Australia, in collaboration with the Geological Survey of South Australia (GSSA) and CSIRO. The efforts aim to refine our understanding of sediment-hosted copper-cobalt-silver (Cu-Co-Ag) potential in this area.</div><div><br></div><div>This work has two primary objectives:</div><div><br></div><div>Geochemical fingerprinting and baseline data collection: Comprehensive data collection and reanalysis of existing samples aim to establish baseline geochemistry for stratigraphic units.</div><div>Mineral system components: Identification of potential metal sources, fluid sources, and trap rocks using a mineral systems approach.</div><div><br></div><div>This data release forms the second stage release of new geochemical data for the Stuart Shelf region; the first stage release was detailed in Champion et al. (2023b). There is also an earlier data release (Champion et al., 2023a) featuring reanalysis, by modern analytical methods, of legacy mineralised and/or altered Stuart Shelf and underlying basement samples held at Geoscience Australia.</div>

<div>The Birrindudu Basin is a region of focus for the second phase of the Exploring for the Future program (EFTF; 2020–2024) as it contains strata of similar age to the prospective McArthur Basin, South Nicholson region and Mount Isa Province, but remains comparatively poorly understood.</div><div><br></div><div>In order to provide an improved understanding of the stratigraphy, basin architecture and resource potential of the Birrindudu Basin and surrounding region, Geoscience Australia, in collaboration with the Northern Territory Geological Survey and CSIRO is acquiring a range of datasets as part of phase two of EFTF. </div><div><br></div><div>This data release presents XRD results from 79 bulk core samples from the Birrindudu and McArthur basins. This report and the associated analyses were conducted by CSIRO, under contract to Geoscience Australia.</div>

<div>Lithospheric structure and composition have direct relevance for our understanding of mineral prospectivity. Aspects of the lithosphere can be imaged using geophysical inversion or analysed from exhumed samples at the surface of the Earth, but it is a challenge to ensure consistency between competing models and datasets. The LitMod platform provides a probabilistic inversion framework that uses geology as the fabric to unify multiple geophysical techniques and incorporates a priori geochemical information. Here, we present results from the application of LitMod to the Australian continent. The rasters summarise the results and performance of a Markov-chain Monte Carlo sampling from the posterior model space. Release KY22 is developed using the primary-mode Rayleigh phase velocity grids of Yoshizawa (2014).</div><div><br></div><div>Geoscience Australia's Exploring for the Future program provides precompetitive information to inform decision-making by government, community and industry on the sustainable development of Australia's mineral, energy and groundwater resources. By gathering, analysing and interpreting new and existing precompetitive geoscience data and knowledge, we are building a national picture of Australia's geology and resource potential. This leads to a strong economy, resilient society and sustainable environment for the benefit of all Australians. This includes supporting Australia's transition to a low emissions economy, strong resources and agriculture sectors, and economic opportunities and social benefits for Australia's regional and remote communities. The Exploring for the Future program, which commenced in 2016, is an eight year, $225m investment by the Australian Government.</div>

<div>Geochemistry of soils, stream sediments, and overbank sediments, plays an important part in informing geochemical environmental baselines, mineral prospectivity, and environmental management practices. Australia has a large number of such surveys, but they are spatially isolated and often used in isolation. First released in 2020, the Levelled Geochemical Baseline of Australia focused on levelling such surveys across the North Australian Craton, so that they could be used as a seamless dataset. This data release acts as an update to the Levelled Geochemical Baseline of Australia by changing the focus to national scale and incorporating recently reanalysed legacy samples.</div><div><br></div><div>This work was undertaken as part of the Exploring for the Future program, an eight-year program by the Australian government. The Exploring for the Future program provides precompetitive information to inform decision-making by government, community and industry on the sustainable development of Australia's mineral, energy and groundwater resources. By gathering, analysing and interpreting new and existing precompetitive geoscience data and knowledge, we are building a national picture of Australia’s geology and resource potential. This leads to a strong economy, resilient society and sustainable environment for the benefit of all Australians. This includes supporting Australia’s transition to net zero emissions, strong, sustainable resources and agriculture sectors, and economic opportunities and social benefits for Australia’s regional and remote communities. The Exploring for the Future program, which commenced in 2016, was an eight year, $225m investment by the Australian Government.</div><div><br></div><div><br></div><div><br></div><div><br></div>

<div>This dataset comprises hydrochemistry results for groundwater, surface water, and rainwater samples collected as part of the Upper Darling Floodplain groundwater study. Associated methods, interpretation, and integration with other datasets are found in the Upper Darling Floodplain geological and hydrogeological assessment (Geoscience Australia Ecat ID:149689). This project is part of the Exploring for the Future (EFTF) program, an eight-year, $225 million Australian Government funded geoscience data and precompetitive information acquisition program. The dataset contains 68 groundwater samples, 17 surface water samples, and four rainwater samples. Groundwater samples are from the Cenozoic formations within the alluvium of the Darling River, the Great Artesian Basin, and the Murray geological basin. Surface water samples are from the Darling River, and rainwater samples were taken within the study area. Subsets of the samples were analysed for major ions and trace metals, stable isotopes of water (δ2H and δ18O), radiocarbon (14C), stable carbon isotopes (δ13C), strontium isotopes (87Sr/86Sr), sulfur hexafluoride (SF6), chlorofluorocarbon (CFC) isotopes, chlorine-36 (36Cl), noble gases, and Radon-222. The results were used to inform a range of hydrogeological questions including aquifer distribution and quality, inter-aquifer connectivity, and groundwater-surface water connectivity.&nbsp;</div><div><br></div>

<div>This guide and template details data requirements for submission of mineral deposit geochemical data to the Critical Minerals in Ores (CMiO) database, hosted by Geoscience Australia, in partnership with the United States Geological Survey and the Geological Survey of Canada. The CMiO database is designed to capture multielement geochemical data from a wide variety of critical mineral-bearing deposits around the world. Samples included within this database must be well-characterized and come from localities that have been sufficiently studied to have a reasonable constraint on their deposit type and environment of formation. As such, only samples analysed by modern geochemical methods, and with certain minimum metadata attribution, can be accepted. Data that is submitted to the CMiO database will also be published via the Geoscience Australia Portal (portal.ga.gov.au) and Critical Minerals Mapping Initiative Portal (https://portal.ga.gov.au/persona/cmmi).&nbsp;</div><div><br></div>

<div>Lithospheric structure and composition have direct relevance for our understanding of mineral prospectivity. Aspects of the lithosphere can be imaged using geophysical inversion or analysed from exhumed samples at the surface of the Earth, but it is a challenge to ensure consistency between competing models and datasets. The LitMod platform provides a probabilistic inversion framework that uses geology as the fabric to unify multiple geophysical techniques and incorporates a priori geochemical information. Here, we present results from the application of LitMod to the Australian continent. The rasters summarise the results and performance of a Markov-chain Monte Carlo sampling from the posterior model space. Release FR23 is developed using primary-mode Rayleigh phase velocity grids adapted from Fishwick & Rawlinson (2012).</div><div><br></div><div>Geoscience Australia's Exploring for the Future program provides precompetitive information to inform decision-making by government, community and industry on the sustainable development of Australia's mineral, energy and groundwater resources. By gathering, analysing and interpreting new and existing precompetitive geoscience data and knowledge, we are building a national picture of Australia's geology and resource potential. This leads to a strong economy, resilient society and sustainable environment for the benefit of all Australians. This includes supporting Australia's transition to a low emissions economy, strong resources and agriculture sectors, and economic opportunities and social benefits for Australia's regional and remote communities. The Exploring for the Future program, which commenced in 2016, is an eight year, $225m investment by the Australian Government.</div>

<div>A novel method of estimating the silica (SiO2) and loss-on-ignition (LOI) concentrations for the North American Soil Geochemical Landscapes (NASGL) project datasets is proposed. Combining the precision of the geochemical determinations with the completeness of the mineralogical NASGL data, we suggest a ‘reverse normative’ or inversion approach to calculate first the minimum SiO2, water (H2O) and carbon dioxide (CO2) concentrations in weight percent (wt%) in these samples. These can be used in a first step to compute minimum and maximum estimates for SiO2. In a recursive step, a ‘consensus’ SiO2 is then established as the average between the two aforementioned estimates, trimmed as necessary to yield a total composition (major oxides converted from reported Al, Ca, Fe, K, Mg, Mn, Na, P, S, and Ti elemental concentrations + ‘consensus’ SiO2 + reported trace element concentrations converted to wt% + ‘normative’ H2O + ‘normative’ CO2) of no more than 100 wt%. Any remaining compositional gap between 100 wt% and this sum is considered ‘other’ LOI and likely includes H2O and CO2 from the reported ‘amorphous’ phase (of unknown geochemical or mineralogical composition) as well as other volatile components present in soil. We validate the technique against a separate dataset from Australia where geochemical (including all major oxides) and mineralogical data exist on the same samples. The correlation between predicted and observed SiO2 is linear, strong (R2 = 0.91) and homoscedastic. We also compare the estimated NASGL SiO2 concentrations with another publicly available continental-scale survey over the conterminous USA, the ‘Shacklette and Boerngen’ dataset. This comparison shows the new data to be a reasonable representation of SiO2 values measured on the ground over the same study area. We recommend the approach of combining geochemical and mineralogical information to estimate missing SiO2 and LOI by the recursive inversion approach in datasets elsewhere, with the caveat to validate results.</div><div><br></div><div>The major oxide concentrations, including those for the estimated SiO2 and LOI, for the NASGL A and C horizons are available for download, as CSV files. A worked example for five selected NASGL C horizon samples is also available for download, as an XLSX file.</div> <b>Citation:</b> P. de Caritat, E. Grunsky, D.B. Smith; Estimating the silica content and loss-on-ignition in the North American Soil Geochemical Landscapes datasets: a recursive inversion approach. <i>Geochemistry: Exploration, Environment, Analysis</i> 2023; 23 (3): 2023-039 doi: https://doi.org/10.1144/geochem2023-039 This article appears in multiple journals (Lyell Collection & GeoScienceWorld)