Brumbys 1 was an appraisal well drilled and cored through Brumbys Fault at the CO2CRC Otway International Test Centre in 2018. The Otway Project is located in South West Victoria, on private farming property approximately 35 km southeast of Warrnambool and approximately 10 km northwest of the town of Peterborough. Total measured depth was 126.6 m (80 degrees). Sonic drilling enabled excellent core recovery and the borehole was completed as a groundwater monitoring well. Brumbys 1 cores through the upper Hesse Clay, Port Campbell Limestone and extends into the Gellibrand Marl. This dataset compiles the extensive analysis undertaken on the core. Analysis includes: Core log; Foram Analysis; Paleodepth; % Carbonate (CaCO3); X-Ray Fluorescence Spectrometry (XRF); Inductively Coupled Plasma Mass Spectrometry (ICP-MS); X-Ray Diffraction (XRD); Grain Size; Density; Surface Area Analysis (SAA); Gamma. Samples were taken at approximately 1-2 m intervals.

<div>Throughout geological history, marine organic-rich shales show variable but appreciable enrichment in uranium (U), < 5 to > 500 ppm. Here we report the results of high-energy resolution fluorescence detection (HERFD) x-ray absorption spectroscopy at U L3 and M4 edges to characterize U speciation in marine sediments.</div><div><br></div><div>We characterised U oxidation state in samples from the Cretaceous Toolebuc Formation of the Eromanga Basin, Australia. Nine samples were carbonaceous shales with high total organic carbon (TOC) content of 5.9 to 13.4 wt&nbsp;% and with low maturity organic matter. Two samples of coquinite were selected for comparison (TOC 0.3 and 2.4 wt %).</div><div><br></div><div>Our results suggest that a significant proportion of U in marine black shales (~20 to 30%) exists as U(VI) (Figures 1-2), despite the extremely reducing (anoxic to euxinic) conditions during sediment precipitation and diagenesis. Within individual samples, spot analyses indicate variation in the estimated oxidation state within a range of ~20% of U(VI). Uranium is unevenly distributed at mm to nanoscale. Nanoscale secondary ion mass spectrometry (NanoSIMS) reveals different associations that often coexist in single samples; nano-particulate uranium is associated with organic matter matrix or sulphide minerals, whereas phosphate minerals display diffuse uranium enrichment. The coquinite has a higher proportion of U(VI), consistent with the dysoxic depositional environment (Boreham and Powell, 1987).</div><div><br></div><div>The unexpectedly enhanced proportion of U(VI) relative to U(IV) within marine organic-rich shales implies that U might not be immediately fixed by reduction processes during sedimentation, but adsorbed by accumulating organic matter, at least in part as U(VI). This is consistent with the behaviour of uranium reported within the water column of the anoxic Black Sea (Anderson, 1989), experiments on U(VI) sorption by organic matter (e.g., Bhat et al., 2008), and previously documented redox state of U from continental organic-rich Eocene (56-34 Ma) sediments of paleochannel and lacustrine origin (Cumberland et al., 2018).</div><div><br></div><div>The results are significant for improving hydrocarbon exploration in known fields (covering the gap to a carbon-free economy without development of new greenfield oil provinces); economic geology (uranium, base-metal, and critical-metal deposits); and environmental management (evaluating potential mobilization of U by groundwaters).</div><div><br></div>This Abstract was submitted and presented to the 2023 Goldschmidt Conference Lyon, France (https://conf.goldschmidt.info/goldschmidt/2023/meetingapp.cgi)

<div>Geoscience Australia has a large holding of surface sediment samples, such as stream and overbank sediments, from geochemical surveys conducted over more than 50 years across the Australian continent. Geochemical data from these surface materials are of national importance as they can contribute significantly to establishing geochemical environmental baselines and their use in land management, as well as aiding in the discovery of new mineral deposits. Samples from these legacy surveys provide valuable insights into areas of Australia that are remote, difficult to access, or have since been developed. The age of a large number of these surveys, however, means that the original results included data for a&nbsp;smaller range of chemical elements, typically with poorer analytical precision and accuracy than those of modern surveys. This small range of chemical elements also typically doesn’t include important elements for modern use, such as critical minerals (i.e. Co, Bi, REEs), which are increasing in their importance. As part of Geoscience Australia’s Exploring for the Future program, a collection of over 9000 samples from these surveys was reanalysed using modern analytical techniques for a&nbsp;suite of 60 chemical elements. These samples cover several regions within Australia, including Kakadu, Cape York, the Mount Isa region, and near the Canberra region. The new analytical data maximise the value of the historical geochemical surveys and will provide new insights into the mineral potential of these regions and improve the quality of geochemical environmental baselines.&nbsp;</div><div><br></div><div>This data release includes: 1) information on the surveys and their samples; 2) quality assurance results; 3) a discussion of sample preparation and analytical methods used; 4) results for total content geochemistry (XRF and LA-ICP-MS); and 5) individual element maps for each of the regions for preliminary interpretation of the data.</div><div><br></div><div>Acquisition and release of this dataset forms part of a larger program aimed at creating a levelled geochemical baseline for the whole Australia (Main and Champion, 2020).</div>

This report presents the results of an elemental and carbon and oxygen isotope chemostratigraphy study on three historic wells; Kidson-1, Willara-1 and Samphire Marsh-1, from the southern Canning Basin, Western Australia. The objective of this study was to correlate the Early to Middle Ordovician sections of the three wells to each other and to wells with existing elemental and carbonate carbon isotope chemostratigraphy data from the Broome Platform, Kidson and Willara sub-basins, and the recently drilled and fully cored stratigraphic Waukarlycarly 1 well from the Waukarlycarly Embayment.

<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>

As part of the Exploring for the Future (EFTF) program, a chemostratigraphic framework for the Officer Basin was developed that correlates inorganic geochemical sequences between exploration wells. The Officer Basin spans 525,000 km² across Western Australia and South Australia, where it remains an unproven frontier basin which has seen little exploration. The objective of this study was to undertake a bulk rock elemental chemostratigraphy study on ten historic wells in order to better correlate the Neoproterozoic and Cambrian sections. Ten study wells, five from Western Australia and five from South Australia, were selected, and core (241) and cuttings (1,245) samples were acquired from their respective state core libraries. All samples were analysed using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS), resulting in quantitative data for 50 elements. The approximate proportions of dolomite, clastics, halite and anhydrite for the samples were derived using stoichiometric geochemical calculations. Halite was identified in some formations based on mud log and wireline data, but was not always preserved in the cuttings samples. This non-detection of halite resulted in poor matches between the wireline gamma ray (GR) and ChemGR profiles for halite-bearing units in some wells (e.g. Dragoon-1, Mulyawara-1, and Yowalga-3). Key element and ratios utilised to subdivide the strata were principally chosen to highlight changes in sediment provenance, climatic, and organic matter changes, as they typically have the best correlation potential over a greater distance. The stratigraphy within the study wells has been subdivided into eight chemostratigraphic mega-sequences referred to as MS1 to MS8, which are further subdivided into a total of twenty-four sequences. Mega-Sequences MS1 to MS4 broadly correspond to the published Neoproterozoic–Cambrian Centralian Supersequences (CS1 to CS4). While overall there is broad agreement between these two schemes, there are also sections where the stratigraphy has been reassigned. For example, within Kutjara-1, the section previously assigned to Centralian Supersequence CS2, and equivalent to the Cryogenian Tapley Hill Formation, is assigned to Mega-Sequence MS3 (not MS2). Within MS4, the lithostratigraphically defined members of the Observatory Hill Formation show some significant variation to the chemostratigraphy, with differences occurring within sequences MS4-S3, MS4-S4 and MS4-S5 (e.g. Birksgate-1; Trainor Echo-1). Mega-Sequence MS6 encompasses the Mount Chandler Sandstone in Trainor Echo-1 in the east and the lithological lateral equivalent Lennis Sandstone in Lungkarta-1/ST1 and Yowalga-1 in the west; however, these two argillaceous sandstones are chemically distinct. Carbonate-containing samples from three wells (Birksgate-1, Yowalga-3, and Giles-1) were analysed for their δ13Ccarb and δ18Ocarb isotope signature using Isotope-Ratio Mass Spectrometry (IRMS), with results from the least altered carbonates being of sufficient quality to attempt preliminary age dating. Comparison of the Officer Basin isotope data to global type sections enabled tentative correlation of the Yowalga-3 carbonates to the Tonian and late Ediacaran, and the Birksgate-1 carbonates to the early Cambrian. The geochemistry analyses from 10 basin-wide wells provide a robust dataset that has been used to confirm which sections correlate within the existing lithostratigraphic and sequence stratigraphic framework. This study also highlights where further work needs to be undertaken to elucidate the spatial and temporal relationships of some Cryogenian and early Cambrian sections across the entire basin, given that rocks of these ages contain both potential source and reservoir rocks for petroleum generation and accumulation.

Geoscience Australia and its predecessors have analysed hydrochemistry of water sampled from boreholes (both pore water and groundwater), surface features, and rainwater. Sampling was undertaken during drilling or monitoring projects, and this dataset represents a significant subset of stored analyses. Water chemistry including isotopic data is essential to better understand groundwater origins, ages and dynamics, processes such as recharge and inter-aquifer connectivity and for informing conceptual and numerical groundwater models. This GA dataset underpins a nationally consistent data delivery tool and web-based mapping to visualise, analyse and download groundwater chemistry and environmental isotope data. This dataset is a spatially-enabled groundwater hydrochemistry database based on hydrochemistry data from projects completed in Geoscience Australia. The database includes information on physical-chemical parameters (EC, pH, redox potential, dissolved oxygen), major and minor ions, trace elements, nutrients, pesticides, isotopes and organic chemicals. Basic calculations for piper plots colours are derived from Peeters, 2013 - A Background Color Scheme for Piper Plots to Spatially Visualize Hydrochemical Patterns - Groundwater, Volume 52(1) <https://doi.org/10.1111/gwat.12118>. Upon loading the data to the database, all hydrochemistry data are assessed for reliability using Quality Assurance/Quality Control procedures and all datasets were standardised. This data is made accessible with open geospatial consortium (OGC) web services and is discoverable via the Geoscience Australia Portal (<a href="https://portal.ga.gov.au/">https://portal.ga.gov.au/</a>). This dataset is published with the permission of the CEO, Geoscience Australia.

<div>The Exploring for the Future (EFTF) program is an Australian government initiative aimed at stimulating investment in resource exploration and development. It operates multiple interconnected projects, such as the Australia’s Resources Framework (ARF), a continental-scale endeavor to enhance understanding of Australia's geology and resource potential. A module of ARF, the Geochemistry for Basin Prospectivity (G4BP), studies Australian basins with prospective base metal mineral systems. </div><div><br></div><div>The current report focuses on the Neoproterozoic segment of the Stuart Shelf region in South Australia, a part of the Adelaide Rift Complex. This research is conducted collaboratively with the Geological Survey of South Australia, examining sediment-hosted copper potential in the rift complex.</div><div><br></div><div>The Adelaide Rift Complex is a geological formation that underwent extensive sedimentation from the Neoproterozoic to early Cambrian, particularly within the rift zone. Stuart Shelf sediments overlay Mesoproterozoic magmatic and Paleoproterozoic metasediment layers. The complex hosts multiple copper deposits, which are usually associated with movement of basinal brines that leach metals from lower basinal layers or rift-related volcanic rocks.</div><div><br></div><div>To improve understanding of the geology of the Stuart Shelf and related copper mineralisation, two primary objectives were set: </div><div><br></div><div>1. Geochemical fingerprinting and baseline data collection: This involves compilation and reanalysis of existing data, along with new data collection aimed at providing comprehensive geochemical data for stratigraphic units within the Stuart Shelf.</div><div><br></div><div>2. Identification of mineral system components: Utilising data from the first objective, this phase aims to identify potential metal and fluid sources and potential sites of metal deposition. </div><div>In conjunction with these efforts, a GA-GSSA geochemical sampling project is underway, tying geochemistry to lithostratigraphic units and facies. The newly acquired geochemical data will be integrated into the overall GSSA-CSIRO project to contribute to a more comprehensive understanding of the sediment-hosted stratabound mineral system.</div><div><br></div>

The Paleo- to Mesoproterozoic McArthur Basin and Mount Isa region of northern Australia (Figure 1) is richly-endowed with a range of deposit types (e.g., Ahmad et al., 2013; Geological Survey of Queensland, 2011). These include the basin-hosted base metal (Zn-Pb-Ag) deposits of the North Australian Zinc Belt, the richest zinc province in the world (Geological Survey of Queensland, 2011; Huston et al., 2006), as well as Cu (e.g., Mt Isa Copper) and IOCG (e.g., Ernest Henry) deposits (Geological Survey of Queensland, 2011). The giant size of the base metal deposits makes them attractive exploration targets and significant effort has been undertaken in understanding their genesis and setting and developing methodologies and data sets to aid in further discovery. As part of its Exploring for the Future program, Geoscience Australia is acquiring new, and reprocessing old, data sets to provide industry with new exploration tools for these basin-hosted Zn-Pb and Cu deposits, as well as iron-oxide copper-gold deposits. We have adopted a mineral systems approach (e.g., Huston et al., 2016) focussing on regional aspects such as source rocks, locations of mineral deposits, mineralisation haloes and footprints. Increased understanding of these aspects requires knowledge of the background variability of unaltered rocks within the basin. To assist in this we have undertaken a campaign of baseline geochemical studies, with over 800 new samples collected from sedimentary and igneous units of selected parts of the greater McArthur Basin–Mount Isa region. This has allowed us to document temporal and regional background geochemical (and mineralogical) variation within, and between sedimentary and igneous units. The main focus of this work was directed towards aspects of base metal mineralisation; a concurrent GA study (e.g., Jarrett et al., 2019) looking at aspects of hydrocarbon potential was undertaken in parallel. Appeared in Annual Geoscience Exploration Seminar (AGES) Proceedings, Alice Springs, Northern Territory 24-25 March 2020, p. 105

The Exploring for the Future (EFTF) program is an Australian government initiative to boost investment in resource exploration and development in Australia, and is committed to supporting a strong economy, resilient society and sustainable environment for the benefit of Australians. There are a number of interrelated projects within the EFTF, including the Australia’s Resources Framework (ARF) project. The latter is a continental-scale project aimed at laying the foundations for a national view of Australia’s surface and subsurface geology, to underpin our understanding of the continent’s mineral, energy and groundwater potential. The ARF project involves new, large-scale data acquisition, advances in big data analytics and tailored resource assessments, to support the resource sector, agriculture, remote communities and the environment, and contribute to community safety. As part of ARF, Geoscience Australia has been undertaking studies of Australian basins that are prospective for, or have potential for, basin-hosted base metal mineral systems (Pb-Zn, Co-Cu), as part of the basins module. The first component of this module (2016-2020) investigated the Paleoproterozoic to Mesoproterozoic greater McArthur Basin system, Northern Territory and western Queensland (Champion et al., 2020 a, b, c; Huston et al. 2020). The 2020-2024 module is focusing on the Neoproterozoic part of the Stuart Shelf region of the Adelaide Superbasin, South Australia. The Paleo- to Mesoproterozoic sedimentary and volcanic sequences of the Mount Isa–McArthur Basin region of Northern Territory and Queensland are host to a range of world class mineral deposits (Hutton et al., 2012) and include the basin-hosted base metal deposits of the North Australian Zinc Belt, the world’s richest belt of zinc deposits (Huston et al., 2006; Large et al., 2005). These syngenetic (and epigenetic) basin-hosted mineral deposits include McArthur River (formerly HYC) and Century lead-zinc (Pb-Zn) deposits, the Walford Creek Zn-Pb-Cu-Ag deposit (Rohrlach et al., 1998; Large et al., 2005; Hutton et al. 2012) and the Redbank Cu deposit (Knutson et al. 1979). The Neoproterozoic sedimentary sequences of the Stuart Shelf, and their continuation into the Torrens Hinge Zone and Adelaide Rift Complex (Adelaide Superbasin), South Australia, are host to, or form an integral part of, a number of, often historically important, deposits, including the first copper mining region in Australia. These include, amongst others, the Kapunda, Mt Gunson, Cattle Grid, MG14, Windabout, Myall Creek, and Emmie Bluff copper deposits (Lambert et al. 1980, 1984, 1985 1987; Knutson et al. 1983; Coda Minerals 2020, 2021). These deposits are hosted within the Neoproterozoic sediments or along the basal unconformity with older Mesoproterozoic clastic sedimentary rocks (Lambert et al. 1987). This report contains reanalysed geochemical data, and associated sample metadata, for legacy samples collected by the Baas Becking laboratories in the 1970’s from deposits and surrounds in the MacArthur Basin and Stuart Shelf region. This includes samples (mafic igneous rocks, mineralised samples and sedimentary rocks) from the Redbank Cu deposit and surrounds in the McArthur Basin, partly documented in Knutson et al. (1979); samples (sediments, mafic igneous rocks including basement volcanic units (Gawler Range Volcanics), and mineralised samples) from the Mt Gunson deposit and surrounds (Mt Gunson-Lake Dutton area) documented in Knutson et al. (1983, 1992); and a small subset of five samples (sediments, variably mineralised) from the Myall Creek prospect, documented in Lambert et al. (1984). The great majority of these samples are from drill core, with the full list of samples analyses and metadata listed in Appendix A and summarised in Table 1. This data release also includes 52 samples from the Killi Killi Hills regions and surrounds, Tanami, Northern Territory (jobno 9004424), collected by the NTGS and GA, and originally analysed, in the early 1990’s and early 2000’s. These samples included a subset of P2O5-Sr-HREE-enriched Gardiner Sandstone samples from the Killi Killi Hills prospect. These samples are not directly related to the basins project but have been included as they were analysed at the same time as the Stuart Shelf and Redbank samples, and they increase the number of samples and the range of rock types analysed, and so help with statistics for QA/QC purposes. All geochemical data are provided in the appendices, listed by batch. The data can be downloaded via the Geoscience Australia EFTF portal (https://portal.ga.gov.au/persona/eftf).