GEOCHEMISTRY
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A regional hydrocarbon prospectivity study was undertaken in the onshore Canning Basin in Western Australia as part of the Exploring for the Future (EFTF) program, an Australian Government initiative dedicated to driving investment in resource exploration. As part of this program, significant work has been carried out to deliver new pre-competitive data including new seismic acquisition, drilling of a stratigraphic well, and the geochemical analysis of geological samples recovered from exploration wells. A regional, 872 km long 2D seismic line (18GA-KB1) acquired in 2018 by Geoscience Australia (GA) and the Geological Survey of Western Australia (GSWA), images the Kidson Sub-basin of the Canning Basin. In order to provide a test of geological interpretations made from the Kidson seismic survey, a deep stratigraphic well, Barnicarndy 1, was drilled in 2019 in a partnership between Geoscience Australia (GA) and the Geological Survey of Western Australia (GSWA) in the Barnicarndy Graben, 67 km west of Telfer, in the southwest Canning Basin. Drilling recovered about 2100 m of continuous core from 580 mRT to the driller’s total depth (TD) of 2680.53 mRT. An extensive analytical program was carried out to characterise the lithology, age and depositional environment of these sediments. This data release presents organic geochemical analyses undertaken on rock extracts obtained from cores selected from the Barnicarndy 1 well. The molecular and stable isotope data carbon and hydrogen will be used to understand the type of organic matter being preserved, the depositional facies and thermal maturity of the Lower Ordovician sedimentary rocks penetrated in this well. This information provides complementary information to other datasets including organic petrological and palynological studies.
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Australia has been, and continues to be, a leader in isotope geochronology and geochemistry. While new isotopic data is being produced with ever increasing pace and diversity, there is also a rich legacy of existing high-quality age and isotopic data, most of which have been dispersed across a multitude of journal papers, reports and theses. Where compilations of isotopic data exist, they tend to have been undertaken at variable geographic scale, with variable purpose, format, styles, levels of detail and completeness. Consequently, it has been difficult to visualise or interrogate the collective value of age and isotopic data at continental-scale. Age and isotopic patterns at continental scale can provide intriguing insights into the temporal and chemical evolution of the continent (Fraser et al, 2020). As national custodian of geoscience data, Geoscience Australia has addressed this challenge by developing an Isotopic Atlas of Australia, which currently (as of November 2020) consists of national-scale coverages of four widely-used age and isotopic data-types: 4008 U-Pb mineral ages from magmatic, metamorphic and sedimentary rocks 2651 Sm-Nd whole-rock analyses, primarily of granites and felsic volcanics 5696 Lu-Hf (136 samples) and 553 O-isotope (24 samples) analyses of zircon 1522 Pb-Pb analyses of ores and ore-related minerals These isotopic coverages are now freely available as web-services for use and download from the GA Portal. While there is more legacy data to be added, and a never-ending stream of new data constantly emerging, the provision of these national coverages with consistent classification and attribution provides a range of benefits: vastly reduces duplication of effort in compiling bespoke datasets for specific regions or use-cases data density is sufficient to reveal meaningful temporal and spatial patterns a guide to the existence and source of data in areas of interest, and of major data gaps to be addressed in future work facilitates production of thematic maps from subsets of data. For example, a magmatic age map, or K-Ar mica cooling age map sample metadata such as lithology and stratigraphic unit is associated with each isotopic result, allowing for further filtering, subsetting and interpretation. The Isotopic Atlas of Australia will continue to develop via the addition of both new and legacy data to existing coverages, and by the addition of new data coverages from a wider range of isotopic systems and a wider range of geological sample media (e.g. soil, regolith and groundwater).
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The importance of critical minerals and the need to expand and diversify critical mineral supply chains has been endorsed by the Federal governments of Australia, Canada, and the United States. The geoscience organizations of Geoscience Australia, the Geological Survey of Canada and the U.S. Geological Survey have created the Critical Minerals Mapping Initiative to build a diversified critical minerals industry in Australia, Canada, and the United States by developing a better understanding of known critical mineral resources, determining geologic controls on critical mineral distribution for deposits currently producing byproducts, identifying new sources of supply through critical mineral potential mapping and quantitative mineral assessments, and promoting critical mineral discovery in all three countries.
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Soil geochemistry has been used to discover many mineral deposits in Australia. Further, it places first-order controls on soil fertility in agriculture and can be used to monitor the environment. With this utility in mind, an extensive soil sampling survey was undertaken as part of the Exploring for the Future program across the vast prospective exploration frontier between Tennant Creek and Mount Isa, dubbed the Northern Australia Geochemical Survey (NAGS). In all, 776 stream sediment outlet samples were collected at a depth of 0–10 cm, improving the density of the National Geochemical Survey of Australia by an order of magnitude, to one sample per ~500 km2. Two size fractions from each sample were analysed for a comprehensive suite of chemical elements after total digestion, Mobile Metal Ion™ (MMI) and aqua regia extractions, and fire assay. Here, we highlight the applicability of these results to base metal exploration, evaluation of soil fertility for agriculture and establishment of geochemical baselines. Our results reveal an association between elevated concentrations of commodity or pathfinder elements in the same or downstream catchments as known mineral deposits. Similar features elsewhere suggest new areas with potential for base metal discovery. <b>Citation:</b> Bastrakov, E.N. and Main, P.T., 2020. Northern Australia Geochemical Survey: a review of regional soil geochemical patterns. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.
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Small-angle neutron scattering (SANS) measurements were performed on 32 rock samples from the southern Georgina Basin, central Australia to assess nanopore anisotropy. Anisotropy can only be determined from oriented core material, hence the samples were cut perpendicular to bedding in cores selected from three wells that intersect the base of the hydrocarbon-bearing, organic-rich middle Cambrian Arthur Creek Formation; the latter is the source rock for both unconventional and conventional plays in the basin. The evolution of anisotropy of two-dimensional SANS intensity profiles with depth (for pore diameters ranging from 10 nm to 100 nm) was quantified and correlated with SANS intensity and total organic carbon (TOC) content. Our results confirm hydrocarbon generation at the base of the Arthur Creek Formation. The nanopore anisotropy in the basal Arthur Creek Formation at the well locations CKAD0001 (oil generation window) and MacIntyre 1 (late oil generation window) varies roughly according to normal compaction. When the Arthur Creek Formation is in the gas window, as sampled at Baldwin 1, there is a strong (negative) correlation between the average vertical-to-horizontal pore shape anisotropy and SANS intensity. The results indicate that unconventional gas production from organic-rich regions of over mature shale may be adversely affected by abnormal pore compaction.
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This collection of documents detail various field techniques and processes that GA conduct. They are in conjunction with a series of Field Activity Technique Engagement Animations. The target audience are the communities that are impacted by our data acquisition activities. Field techniques in this collection include; • AEM fixed wing • AEM Helicopter • Borehole Geophysics • Goundwater sampling • Magnetotelluric (MT) surveys • Passive seismic surveys • Rapid Deployment Kits (RDKs) • Reflection seismic surveys • Surface Magnetic Resonance (SMR) surveys • Stratigraphic drilling
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Heavy minerals (HMs) have been used successfully around the world in energy and mineral exploration, yet in Australia no public domain database or maps exist that document the background HM assemblages or distributions. Here, we describe a project that delivers the world’s first continental-scale HM maps. We applied automated mineralogical identification and quantification of the HMs contained in floodplain sediments from large catchments covering most of Australia. The composition of the sediments reflects the dominant rock types in each catchment, with the generally resistant HMs largely preserving the mineralogical fingerprint of their host protoliths through the weathering–transport–deposition cycle. Underpinning this vision was a pilot project, based on 10 samples from the national sediment sample archive, which in 2020 demonstrated the feasibility of a larger, national-scale project. Two tranches of the subsequent national HM dataset, one focusing on a 965,000 km2 region centred on Broken Hill in southeastern Australia, the other focusing on a 950,000 km2 area in northern Queensland and Northern Territory, were released in 2022. In those releases, over 47 million mineral grains were analysed in 411 samples, identifying over 150 HM species. We created a bespoke, cloud-based mineral network analysis (MNA) tool to visualize, explore and discover relationships between HMs as well as between them and geological settings or mineral deposits. We envisage that the Heavy Mineral Map of Australia and MNA tool, when released publicly by the end of 2023, will contribute significantly to mineral prospectivity analysis and modelling, particularly for technology critical elements and their host minerals <b>Citation:</b> Caritat P. de, Walker A.T., Bastrakov E. & McInnes B.I.A., 2023. From The Heavy Mineral Map of Australia: vision, implementation and progress. In: Czarnota, K. (ed.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, https://dx.doi.org/10.26186/148678
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The 2.1─1.79 Ga Trans-Australian and Canadian Trans-Hudson orogens preserve a common record of Himalayan-scale orogenesis and voluminous Cordilleran-style magmatism behind which turbidite-dominated sedimentary sequences evolved in a back-arc or retro-arc foreland setting. Successive cycles of subduction retreat and advance drove the orogenic process, culminating in continent-continent collision and closure of a shared and formerly contiguous ocean basin – the Paleoproterozoic Diamantina and Manikewan oceans. Cordilleran-style arc magmatism in proto-Australia commenced along the southern reaches of the Diamantina Ocean with emplacement of the 2005-1975 Ma Dalgaringa batholith along the leading edge of the Pilbara Craton (Gascoyne Province) before both it and its host craton docked against the Yilgarn Craton, resulting in the Glenburgh Orogeny. After a brief episode of post-kinematic granite magmatism from 1965─1945 Ma, tectonic activity switched to the opposing margin of the Diamantina Ocean in what is now northern Australia where a further three cycles of upper plate orogenesis and Cordilleran-style magmatism occurred from 1890─1850 Ma, 1840─1810 Ma and 1810─1760 Ma along a convergent continental margin extending from the Kimberley and Pine Creek regions southward through the Mount Isa domain into the eastern Gawler Craton. Batholiths developed along this margin include granites of both low and high Sr/Y composition with the more adakitic varieties interpreted to have been intruded during periods of enhanced asthenospheric upwelling accompanying the opening of one or more slab windows following slab breakoff, tearing and/or subduction of an actively spreading oceanic ridge. Terminal collision between the North and South Australian (Mawson) cratons at ca. 1790 Ma brought this succession of subduction-related events to a close, although neither this event nor the corresponding Trans-Hudson orogen need equate to final assembly of the Nuna supercontinent. Instead, the 1870 Ma peak in global compilations of magmatic and detrital zircon ages may be more simply interpreted as the result of elevated tectonism and magmatism along a Paleoproterozoic Cordilleran-style continental plate margin that was trans-continental in scale and continued uninterrupted from proto-Australia into northern Canada and beyond. <b>Citation:</b> G.M. Gibson, D.C. Champion, M.P. Doublier; The Paleoproterozoic Trans-Australian Orogen: Its magmatic and tectonothermal record, links to northern Laurentia, and implications for supercontinent assembly. GSA Bulletin 2024; doi: https://doi.org/10.1130/B36255.1
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<div>This record one in a series of reports detailing the geochemical and mineralogical results of sampling collected at mine waste sites across Australia as part of Geoscience Australia's Exploring for the Future program. It presents new data and information on nickel, cobalt and rare earth elements at the Eloise copper mine located in the North West Minerals Province, Queensland. </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 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, is an eight year, $225m investment by the Australian Government.</div>
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<div>This record one in a series of reports detailing the geochemical and mineralogical results of sampling collected at mine waste sites across Australia as part of Geoscience Australia's Exploring for the Future program. It presents new data and information regarding the tenor and deportment of indium, gallium, germanium, cadmium, antimony, and bismuth, as well as silver, lead, zinc, and copper at the Zeehan tailings site in western Tasmania.</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 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, is an eight year, $225m investment by the Australian Government.</div><div><br></div>