MinEx CRC – Mineral Exploration Cooperative Research Centre
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<div>NDI Carrara 1 is a deep stratigraphic borehole that was drilled in 2020 under the MinEx CRC’s National Drilling Initiative (NDI) program in collaboration with Geoscience Australia and the Northern Territory Geological Survey. NDI Carrara 1 is the first stratigraphic test of the recently described Carrara Sub-basin, a Proterozoic aged depocentre located in the South Nicholson region of northwest Queensland and the Northern Territory. The borehole was drilled to a total depth of 1751 m and penetrated a succession of Cambrian aged Georgina Basin carbonate and siliciclastic rocks that unconformably overly a thick succession of Proterozoic age siliciclastic and carbonate-rich sediments. Although drilled on the western flank of the Carrara Sub-basin, NDI Carrara 1 did not penetrate to basement. Interpretation of the L210 deep-crustal seismic survey suggests that further Proterozoic sedimentary packages known from the northern Lawn Hill Platform in northwest Queensland are likely to be found underlying the succession intersected in NDI Carrara 1. The borehole was continuously cored from 283 m to total depth, and an extensive suite of wireline logs was acquired. Geoscience Australia and partners have undertaken an extensive analytical program to understand the depositional, structural, and diagenetic history of the sediments intersected in NDI Carrara 1. This program includes a targeted geomechanical study that aims to characterise the physical properties of these Proterozoic rocks through laboratory analysis of core samples, the results of which are summarised in this data release.</div><div><br></div><div>This data release provides data from new unconfined compressive strength (UCS), single-stage triaxial testing, and laboratory ultrasonic testing for 36 sample plugs from NDI Carrara 1. These tests were performed at the CSIRO Geomechanics and Geophysics Laboratory in Perth, during January to June 2022. The full results as provided by CSIRO to Geoscience Australia are provided as an attachment to this document. </div>
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<div>The Carrara Sub-basin, discovered in 2017 based on interpretation of 2D deep seismic surveys acquired by Geoscience Australia, is a large sedimentary depocentre in the South Nicholson region straddling the Northern Territory and Queensland. It was interpreted to contain up to 8 km of Paleoproterozoic to Cambrian rocks including stratigraphic equivalents to the Isa Superbasin, South Nicholson Group and Georgina Basin. In order to validate these stratigraphic interpretations and assess the resource prospectivity of the Carrara Sub-basin, the South Nicholson National Drilling Initiative (NDI) Carrara 1 stratigraphic drill hole was completed in late 2020 as a collaboration between the MinEx Cooperative Research Centre, Geoscience Australia and the Northern Territory Geological Survey. NDI Carrara 1 was drilled on the western flanks of the Carrara Sub-basin and reached a total depth of 1751 m, intersecting ca. 630 m of Cambrian Georgina Basin overlying ca. 1100 m of Proterozoic carbonates, black shales and minor siliciclastics. More than 400 NDI Carrara 1 physical samples were analysed as part of an extensive geochemical program, including Rock-Eval pyrolysis and compositional analyses of hydrocarbon shows, whose results and implications for energy prospectivity are summarised here.</div> This Abstract was submitted/presented to the 2022 Australian Organic Geochemistry Conference 27-29 November (https://events.csiro.au/Events/2022/October/5/Australian-Organic-Geochemistry-Conference)
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<div>This study was commissioned by Geoscience Australia (GA) to produce a report on seal capacity of select samples from the deep stratigraphic hole NDI Carrara 1, located in the Proterozoic Carrara Sub-basin in the Northern Territory. Plugs were taken from depths of interest and analysed via mercury injection capillary pressure testing. Results were provided as two reports, Part A and Part B and demonstrate that the analysed samples are capable of sealing very large columns of both methane and carbon dioxide.</div>
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<div>NDI Carrara 1 is a 1751 m stratigraphic drill hole completed in 2020 as part of the MinEx CRC National Drilling Initiative (NDI). This campaign was a collaboration between Geoscience Australia under the Exploring for the Future program, together with MinEx CRC and the Northern Territory Geological Survey. It is the first drillhole to intersect Proterozoic rocks of the Carrara Sub-basin, a recently discovered depocentre in the South Nicholson region. The drill hole intersected ~625 m of the Paleozoic Georgina Basin, which overlies ~1120 m of Proterozoic carbonates, black shales and siliciclastic rocks, with hydrocarbon shows encountered in both the Paleozoic and Proterozoic sections. Following the completion of the drillhole, a comprehensive analytical program was carried out by Geoscience Australia to better understand the geology of the Carrara Sub-basin and its resource potential.</div><div><br></div><div>Here we present new high-resolution strontium (87Sr/86Sr), carbon (δ13C) and oxygen (δ18O) isotope data from carbonate bearing samples of the Paleozoic Georgina Basin and the Proterozoic Lawn Hill Formation intersected in NDI Carrara 1. The aim of this data acquisition was to provide an improved understanding of the paleo-depositional environments and local/global chemostratigraphy trends recorded in the Carrara Sub-basin. </div><div><br></div><div>The majority of samples show significant alteration and thus caution should be exercised when using this data for assessing primary depositional conditions and contemporary sea-water chemistry. Despite the altered nature of most samples, samples belonging to undifferentiated Georgina Basin preserve 87Sr/86Sr ratios close to that of mid-Cambrian seawater, indicating the sampled intervals of Georgina Basin were likely connected to the global Cambrian ocean. Two small positive δ13C excursions (with positive shift in δ18O) within Georgina Basin samples may coincide with reported mid-Cambrian positive δ13C global marine excursions. </div><div><br></div><div>The least altered samples from the Proterozoic Lawn Hill Formation show more radiogenic 87Sr/86Sr values than the expected value of coeval mid-Proterozoic ocean at ~1600 Ma. These radiogenic 87Sr/86Sr values may reflect (i) influx of terrigenous material into a restricted basin with reduced interaction with the global ocean, or (ii) secondary overprinting by more radiogenic diagenetic fluids.</div> Abstract/Poster submitted and presented at 2023 Australian Earth Science Convention (AESC), Perth WA (https://2023.aegc.com.au/)
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<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.</div><div><br></div><div>In order to gain insights into the resource potential of the South Nicholson region, a key region of focus for EFTF, National Drilling Initiative (NDI) Carrara 1 stratigraphic drill hole was completed in late 2020, as a collaboration between Geoscience Australia, the Northern Territory Geological Survey (NTGS), and the MinEx CRC. NDI Carrara 1 is the first drill hole to intersect the, as yet, undifferentiated Proterozoic rocks of the newly defined Carrara Sub-Basin within the South Nicholson region. NDI Carrara 1 is located on the western flank of the Carrara Sub-basin, reaching a total depth of 1751 m, intersecting ca. 630 m of Cambrian Georgina Basin overlying ca. 1100 m of Proterozoic carbonates, black shales and minor siliciclastics.</div><div><br></div><div>Geoscience Australia is undertaking a range of investigations on the lithology, stratigraphy and geotechnical properties of NDI Carrara 1 based on wireline data, as well as undertaking a range of analyses of over 400 physical samples recovered through the entire core. These analyses include geochronology, isotopic studies, mineralogy, inorganic and organic geochemistry, petrophysics, geomechanics, thermal maturity, and petroleum systems investigations. Hylogger™ data is available at the NTGS Geoscience Exploration and Mining Information System (GEMIS) webpage.</div><div><br></div><div>This data release presents results for analyses on selected rock samples from NDI Carrara 1, conducted by the Mawson Analytical Spectrometry Services, University of Adelaide, under contract to Geoscience Australia. These results include:</div><div><br></div><div>1. Carbon (δ13C), oxygen (δ18O) and strontium (87Sr/86Sr) isotopes on carbonate bearing samples, and</div><div>2. Trace element data on the leachates prepared for 87Sr/86Sr ratio analyses.</div><div><br></div>
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<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. 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 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>
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<div>NDI Carrara 1 is a deep stratigraphic drill hole completed in 2020 as part of the MinEx CRC National Drilling Initiative (NDI) in collaboration with Geoscience Australia and the Northern Territory Geological Survey. It is the first test of the Carrara Sub-Basin, a depocentre newly discovered in the South Nicholson region based on interpretation from seismic surveys (L210 in 2017 and L212 in 2019) recently acquired as part of the Exploring for the Future program. The drill hole intersected approximately 1100 m of Proterozoic sedimentary rocks uncomformably overlain by 630 m of Cambrian Georgina Basin carbonates. A comprehensive geochemical program designed to provide information about the region’s resource potential was carried out on samples collected at up to 4 meter intervals. This report presents data from Rock-Eval pyrolysis analyses undertaken by Geoscience Australia on selected rock samples to establish their total organic carbon content, hydrocarbon-generating potential and thermal maturity.</div>
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<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, $225 m investment by the Australian Government. </div><div>As part of this program, Geoscience Australia led two deep crustal reflection seismic surveys in the South Nicholson region, revealing the existence of the Carrara Sub-basin, a large sedimentary depocentre up to 8 km deep, beneath the Georgina Basin (Carr et al., 2019; 2020). The depocentre is believed to contain thick sequences of highly prospective Proterozoic rocks for base metals and unconventional hydrocarbons. To confirm geological interpretations and assess resource potential, the National Drilling Initiative, NDI Carrara 1 stratigraphic drill hole was completed in late 2020, as a collaboration between Geoscience Australia, the Northern Territory Geological Survey (NTGS) and the MinEx CRC (Geoscience Australia, 2021). NDI Carrara 1 is located on the western flank of the Carrara Sub-basin on the South Nicholson seismic line (17GA-SN1) (Figure 1.1; Figure 1.2), reaching a total depth of 1751 m, intersecting sedimentary rocks comprising ca. 630 m of Cambrian calcareous shales of the Georgina Basin and ca. 1100 m of Proterozoic carbonates and siliciclastics that include black shales of the Carrara Sub-basin.</div><div>This report presents data on selected rock samples from NDI Carrara 1, conducted by the Mawson Analytical Spectrometry Services, University of Adelaide, under contract to Geoscience Australia. These results include bulk carbon isotope ratios (δ13C) of bitumens and isolated kerogens. In addition, a selection of 10 samples was analysed at Geoscience Australia for comparison purposes.</div><div><br></div>
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<div>This Record presents new zircon U-Pb geochronological data, obtained via Sensitive High Resolution Ion Microprobe (SHRIMP), for 12 samples of igneous rocks from central and southern New South Wales, as part of an ongoing Geochronology Project conducted by the Geological Survey of New South Wales (GSNSW) and Geoscience Australia (GA) under a National Collaborative Framework agreement. Eight samples were selected to better understand the geological evolution and mineralisation history of areas prioritised for investigation by the MinEx Co-operative Research Centre (MinEx CRC) under its National Drilling Initiative (NDI) program. Three samples are from the northern Molong Volcanic Belt east of Dubbo (‘MXDU’), and five are from the eastern Lachlan Orogen near Forbes (‘MXFO’). The remaining four samples are from the central Lachlan Orogen in southern NSW, in support of GSNSW’s East Riverina mapping program (‘ERIV’). The results herein correspond to U-Pb SHRIMP zircon analyses undertaken by the GSNSW-GA Geochronology Project during the July 2020–June 2021 reporting period. All quoted uncertainties are 95% confidence intervals.</div> <b>Bibliographic reference: </b> Jones, S.L., Bodorkos, S., Eastlake, M.A.S., Campbell, L.M., Hughes, K.S., Blevin, P.L. and Fitzherbert, J.A., 2023. <i>New SHRIMP U-Pb zircon ages from the Lachlan Orogen, NSW: Dubbo, Forbes and East Riverina areas, July 2020–June 2021. </i>Record 2023/36, Geoscience Australia, Canberra. Report GS2023/0017, Geological Survey of New South Wales, Maitland. https://doi.org/10.26186/147971
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<div>A multi-disciplinary program of geological and geophysical data collection and integration, focussed on the Delamerian Orogen, was undertaken as part of Geoscience Australia’s Exploring for the Future (EFTF) program and the Mineral Exploration Cooperative Research Centres (MinEx CRC) National Drilling Initiative (NDI). In this study, we integrate learnings from these data with existing geological and geophysical data to refine the basement geology of the Loch Lilly-Kars Belt, Lake Wintlow Belt and Wilcannia High. Our interpretation provides a revised geological framework for a frontier exploration region in the Delamerian Orogen. This product includes ESRI shape files and layer files, accompanying notes, and several appendices containing new detrital zircon U-Pb geochronology data from the map area as well as the broader Delamerian Orogen.</div>