Carbon Capture and Storage (CCS) is a technique for mitigating anthropogenic climate change by separating CO2 from industrial flue gas, transporting it to and storing it in a subsurface geological storage reservoir. The low-salinity (TDS<3 000 mg/L) Jurassic sandstone formations in Australia's Surat Basin have been identified as a potential reservoir system for geological CO2 sequestration. However, given the prevailing use of saline reservoirs in CCS projects elsewhere, limited data are available on CO2-water-rock dynamics during geological sequestration in such low-salinity formations. Here, a combined batch experiment and numerical modelling approach is used to characterise potential CO2-water-rock reaction pathways, to assess potential impacts of CCS on groundwater chemistry, and to identify geochemical tracers of inter- and intra-formational CO2 migration during geological sequestration within the Jurassic sandstones. Mineralogy and physical properties of the prospective reservoir are characterized for 66 core samples from stratigraphic well GSQ Chinchilla 4. Representative samples are reacted with synthetic formation water and high-purity CO2 for up to 27 days at a range of pressures to simulate conditions during carbon sequestration in the Jurassic sandstones. Results show the low formation water salinity, temperature, and mineralization in the reservoirs yield high solubility trapping capacity (1.18 mol/L at 45°C, 100 bar), while the paucity of divalent cations in groundwater and the silicate reservoir matrix result in very low mineral trapping capacity within the footprint of the supercritical CO2 (scCO2) plume. Though alkalinity buffers formation water pH under elevated CO2 pressure, the acidic pH significantly enhances mineral dissolution in reactors with heterogeneous Hutton and Boxvale Sandstone samples. Smaller TDS changes are observed for samples of the mature Precipice Sandstone than for the other formations. Non-radiogenic, regional groundwater-like 87Sr/86Sr values (0.704845 - 0.706600) in batch reactors indicate carbonate and authigenic clay dissolution as the primary reaction pathways regulating solution composition in all formations during carbon sequestration. Slightly higher Sr isotope ratios in felsic samples than in calcitic samples, and dissolved Si concentrations in mature Precipice Sandstone reactors show detrital silicate dissolution to be an ancillary process. Batch reactor degassing at the end of the incubation period was simulated to assess geochemical changes in formation waters during transport away from a scCO2 plume. Model results suggest geological sequestration in the Jurassic sandstone formations would increase regional groundwater alkalinity and redistribute carbonate minerals outside the scCO2 footprint, but is unlikely to result in net mineral trapping of CO2. Several elements are mobilised in concentrations greater than found in regional groundwater, making them viable tracers of CO2 migration. Most notable is cobalt, concentrations of which are significantly elevated regardless of CO2 pressure or sample mineralogy. Experimental results indicate manganese and cadmium concentrations may locally exceed drinking water quality guidelines, but further modelling of intra aquifer mixing is required to quantify the potential risk to regional groundwaters from trace element mobilisation.

The stabilities of uranyl-carbonate and uranyl-hydroxide aqueous complexes were experimentally determined at temperatures ranging from 25 to 125 °C using in situ UV–vis and Raman spectroscopic techniques. Combined with earlier determinations of the stability of chloride, sulfate, and hydroxide complexes at temperatures up to 250 °C, these data permit to create a consolidated dataset suitable for modeling of U(VI) mobilization in natural systems. The parameters of the Modified Ryzhenko-Bryzgalin and the Helgeson-Kirkham-Flowers (HKF) Equations of State (EoS) were derived based on this dataset and used for thermodynamic modeling different scenarios of U(VI) mobilization. These models suggest that at conditions relevant to natural systems, carbonate-mediated transport of U(VI) is likely suppressed by the high stability of solid UO2(OH)2 and Na2U2O7. In contrast, sulfate-mediated mobilization mechanisms are highly efficient at acidic and near-neutral pH conditions and can lead to effective hydrothermal mobilization of U(VI). <b>Citation:</b> A. Migdisov, E. Bastrakov, C. Alcorn, M. Reece, H. Boukhalfa, F.A. Capporuscio, C. Jove-Colon, A spectroscopic study of the stability of uranyl-carbonate complexes at 25–150 °C and re-visiting the data available for uranyl-chloride, uranyl-sulfate, and uranyl-hydroxide species, <i>Geochimica et Cosmochimica Acta</i>, 2024, ISSN 0016-7037, https://doi.org/10.1016/j.gca.2024.04.023.

<div>Heavy rare earth elements are essential in renewable energy and high-tech products. Some natural rare earth element (REE) deposits exhibit heavy rare earth element (HREE) enrichment from &lt;&nbsp;10% to ~85% of the REE budget (Williams-Jones et al., 2015). </div><div><br></div><div>Controls on REE fractionation in hydrothermal systems are imposed by (1) changes in the relative stability of REE aqueous complexes with temperature (Migdisov et al., 2016) and (2) incorporation or rejection of REE by crystalline structures. Also, the REEs are invariably found as solid solutions but not as pure minerals. REE and yttrium (Y) sulphate complexes are some of the most stable REE and Y aqueous species in hydrothermal fluids (Migdisov and William-Jones, 2008, 2016; Guan et al., 2022) and may be responsible for REE transport and deposition in sediment-hosted deposits. Within the unconformity-related deposits, REEs are hosted mostly by xenotime ((Y,Dy,Er,Tb,Yb)PO4) and minor florencite ((La,Ce)Al3(PO4)2(OH)6) (Nazari-Dehkordi et al., 2019). Modelling the stability of xenotime in the H-O-Cl-(±F)-S-P aqueous system is critical for understanding HREE enrichment in this mineral system.</div><div><br></div><div>We use a newly derived thermodynamic dataset depos for REESO4+ and REE(SO4)2‑ aqueous complexes to generate stability diagrams illustrating mechanisms of REE transport and deposition in the above deposits. Sulphate REE complexes may dominate even in chloride-rich brines and facilitate REE mobilization in acid oxidizing environments. Previously Nazari-Dehkordi et al. (2019) proposed an ore genesis model involving the mixing of discrete hydrothermal fluids that separately carried REE + yttrium and phosphorus. The speciation model that includes sulphate complexes expands this scenario; a process resulting in fluid neutralization or reduction will also promote precipitation of xenotime enriched in HREEs.&nbsp;</div><div><br></div>This Abstract was submitted/presented to the 2022 Specialist Group in Geochemistry, Mineralogy and Petrology (SGGMP) Conference 7-11 November (https://gsasggmp.wixsite.com/home/biennial-conference-2021)

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>Levelling of geochemical data between surveys is a vital step in using datasets together. This code can apply a number of approaches to eliminate inter-laboratory differences from multi-generational and spatially isolated geochemical surveys. This codes allow the use of a variety of levelling methods: re-analysis, single standards, and multiple standards. The methodology and effectiveness of each of these methods are outlined in Main, P.T. and Champion, D.C., 2022. Levelling of multi-generational and spatially isolated geochemical surveys. Journal of Geochemical Exploration.</div>

A comprehensive geochemical program was carried out on rock samples collected in the NDI Carrara 1 drill hole, the first stratigraphic test of the newly discovered Carrara Sub-basin located in the South Nicholson region of northern Australia. The drill hole recovered continuous core from 284 m to total depth at 1750 m and intersected approximately 1120 m of Proterozoic sedimentary rocks, unconformably overlain by 630 m of Cambrian Georgina Basin carbonate-rich rocks. Total organic carbon (TOC) contents from Rock-Eval pyrolysis highlight the potential for several thick black shales to be a source of petroleum for conventional and unconventional plays. Cambrian rocks contain an organic-rich section with TOC contents of up to 4.7 wt.% and excellent oil-generating potential. The Proterozoic section is overmature for oil generation but mature for gas generation, with potential for generating gas in carbonaceous mudstones showing TOC contents up to 5.5 wt.% between 680 and 725 m depth. A sustained release of methane (up to 2%) recorded during drilling from 1150 to 1500 m suggests potential for an unconventional gas system in the Proterozoic rocks from 950 to 1415 m depth, which exhibit favourable organic richness and thermal maturity. The Proterozoic rocks, which are comparable in age to the sediment-hosted deposits of the Century Mine, contain local occurrences of lead, zinc and copper sulfide minerals providing hints of mineralisation. The combined geochemical results offer the promise of a potential new resource province in northern Australia. <b>Citation:</b> E. Grosjean, A.J.M. Jarrett, C.J. Boreham, L. Wang, L. Johnson, J.M. Hope, P. Ranasinghe, J.J. Brocks, A.H.E. Bailey, G.A. Butcher, C.J. Carson, Resource potential of the Proterozoic–Paleozoic Carrara depocentre, South Nicholson region, Australia: Insights from stratigraphic drilling, <i>Organic Geochemistry</i>, Volume 186, 2023, 104688, ISSN 0146-6380, DOI: https://doi.org/10.1016/j.orggeochem.2023.104688.

<b>Legacy service retired 29/11/2022</b> This is an Open Geospatial Consortium (OGC) web service providing access to Australian onshore and offshore borehole data conforming to the GeoSciML version 4.0 specification. The borehole data includes Mineral Drillholes, Petroleum Wells and Water Bores along with a variety of others types. The dataset has been restricted to onshore and offshore Australian boreholes, and bores that have the potential to support geological investigations and assessment of a variety of resources.

<div>Soil is a complex and spatially variable material that has a demonstrated potential to be a useful evidence class in forensic casework and intelligence operations. Here, the capability to spatially constrain searches and prioritise resources by triaging areas as low and high interest is advantageous. Conducted between 2017 and 2021, a forensically relevant topsoil survey (0-5 cm depth; 1 sample per 1 km2) has been carried out over Canberra, Australia, with the aims of documenting the distribution of chemical elements in an urban/suburban environment, and of acting as a testbed for investigating various aspects of forensic soil provenancing. Geochemical data from X-Ray Fluorescence (XRF; for total major oxides) and Inductively Coupled Plasma-Mass Spectrometry (ICP-MS; for trace elements) following a total digestion (HF + HNO3) were obtained from the survey’s 685 topsoil samples (plus 138 additional quality control samples and six “Blind” simulated evidentiary samples). Using those “Blind” samples, we document a likelihood ratio approach where for each grid cell the analytical similarity between the grid cell and evidentiary sample is attributed from a measure of overlap between both Cauchy distributions, including appropriate uncertainties. Unlike existing methods that base inclusion/exclusion on an arbitrary threshold (e.g., ± three standard deviations), our approach is free from strict binary or Boolean thresholds, providing an unconstrained gradual transition dictated by the analytical similarity. Using this provenancing model, we present and evaluate a new method for upscaling from a fine (25 m x 25 m) interpolated grid to a more appropriate coarser (500 m x 500 m) grid, in addition to an objective method using Random Match Probabilities for ranking individual variables to be used for provenancing prior to receiving evidentiary material. Our results show this collective procedure generates more consistent and robust provenance maps between two different interpolation algorithms (e.g., inverse distance weighting, and natural neighbour), grid placements (e.g., grid shifts to the north or east) and theoretical users (e.g., different computer systems, or forensic geoscientists).</div> <b>Citation:</b> Michael G. Aberle, Patrice de Caritat, James Robertson, Jurian A. Hoogewerff, A robust interpolation-based method for forensic soil provenancing: A Bayesian likelihood ratio approach,<i> Forensic Science International</i>, Volume 353, 2023, 111883, ISSN 0379-0738. https://doi.org/10.1016/j.forsciint.2023.111883.

<div>The Darling-Curnamona-Delamerian (DCD) project focused on the covered portion of the Delamerian orogen, situated in the south-eastern mainland states of Australia.&nbsp;The aims of the project were to develop a greater understanding of the geodynamic history of the Delamerian Orogen, characterise known magmatic-hydrothermal mineral systems, and assess mineral potential for a suite of minerals including copper (Cu), gold (Au), and nickel (Ni), and critical minerals like platinum-group elements (PGEs) and rare-earth elements (REEs). </div><div>Here, we collate whole rock geochemistry data from new and legacy samples of mafic to intermediate magmatic rocks of the Loch Lilly-Kars Belt in order to determine the likely source of these magmas and constrain the prevailing tectonic setting during their emplacement. We apply multi-elemental diagrams and various elemental discrimination diagrams to characterise various groups of magmatic rocks in these belts, taking into account their geographic affinity and new geochronological data (e.g. Mole et al., 2023; Mole et al., 2024). The geochemical characteristics of these groups and the implications for the tectonic setting into which they were emplaced are discussed. Comparisons are made with potentially similar magmatic rocks of the&nbsp;Koonenberry Belt and Grampians-Stavely Zone. Results from this study have significant implications for the tectonic setting in which the Loch Lilly-Kars Belt developed, and hence also the mineral potential of the Belt. </div><div> </div>

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.