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  • <div>A keynote talk talk given at Uncover Curnamona 2022 by Angela O'Rourke outlining the rationale, work program and new data acquisition for Geoscience Australia's Darling-Curnamona-Delamerian Project within Exploring for the Future</div> This presentation was given to the 2022 Uncover Curnamona 2022 Conference 31 May - 2 June:<br>(https://www.gsa.org.au/common/Uploaded%20files/Events/Uncover%20Curnamona%202021/UC2022_short_program_A4_web%20(003).pdf)

  • AusLAMP is a collaborative national project to cover Australia with long-period magnetotelluric (MT) data in an approximately 55 km spaced array. Signatures from past tectonothermal events can be retained in the lithosphere for hundreds of millions of years when these events deposit conductive mineralogy that is imaged by MT as electrically conductive pathways. MT also images regions of different bulk conductivity and can help to understand the continuation of crustal domains down into the mantle, and address questions on the tectonic evolution of Australia. The AusLAMP data presented here were collected as part of three separate collaborative projects involving several organisations. Geoscience Australia (GA), the Geological Survey of South Australia, the Geological Survey of New South Wales, the Geological Survey of Victoria, and the University of Adelaide all contributed staff and/or funding to collection of AusLAMP data; GA and AuScope contributed instrumentation. The data cover the Paleo-Mesoproterozoic Curnamona Province, the Neoproterozoic Flinders Ranges, and the Cambrian Delamerian Orogen, encompassing eastern South Australia and western New South Wales and western Victoria. This project represents the first electrical resistivity model to image the entire Curnamona Province and most of the onshore extent of the Delamerian Orogen, crossing the geographical state borders between South Australia, New South Wales and Victoria.

  • <div><strong>Output Type:</strong> Exploring for the Future Extended Abstract</div><div><br></div><div><strong>Short Abstract: </strong>An advanced understanding of regional-scale metallogenic characteristics and ore-formation controls is fundamental for mineral discovery, particularly in underexplored covered terranes, such as the Delamerian Orogen of southeastern Australia. The Delamerian Orogen is defined as the spatial extent of rocks first deformed by the Delamerian Orogeny, though the Orogen was also affected by younger geodynamic events. Petrology of the mineralised host rocks from over 20 mineral prospects and deposits has led to the recognition of four types of mineral systems related to the geodynamic history of the Delamerian Orogen on mainland Australia, including (1) porphyry-epithermal; (2) volcanic-hosted massive sulphide (VHMS); (3) orogenic gold; and (4) mafic-ultramafic magmatic Cu-Ni-PGE systems. Several other prospects are yet to be classified due to insufficient data, although there is strong evidence to suggest that these are magmatic-hydrothermal in origin. Direct dating of hydrothermal alteration and mineralisation at key mineral deposits and prospects (using U-Pb in titanite and apatite, and Sm-Nd in fluorite) identified four major metallogenic events in the Delamerian Orogen margin. The middle to late Cambrian (505–494 Ma) mineral systems, throughout the eastern margin of the Delamerian Orogen, are potentially the most significant. However, our new dating indicates other metallogenic events at 590–580 Ma, 480–460 Ma, and 412–399 Ma. Analysis of data related to mineral systems fertility reveals crustal controls on the location and type of mineralisation in the Delamerian Orogen. Integration of Hf and O isotopes in zircon, and S isotopes in sulphide minerals indicates that the geology of the Orogen may host multiple opportunities for mineral system development. An indicative map of ca.600–400 Ma mineral system potential was developed by integrating this new data, together with other geological, geochemical and geophysical datasets within the geodynamic context of the Delamerian Orogen. Importantly, this study demonstrates the metallogenic characteristics of multiple types and episodes of mineral system development, and the geological processes that have controlled their formation to aid exploration.</div><div><br></div><div><strong>Citation: </strong>Cheng, Y., Gilmore, P., Lewis, C., Roach, I., Clark, A., Mole, D., Pitt, L., Doublier, M., Sanchez, G., Schofield, A., O'Rourke, A., Budd, A., Huston, D., Czarnota, K., Meffre, S., Feig, S., Maas, R., Gilbert, S., Cairns, C., Cayley, R., Wise, T., Wade, C., Werner, M., Folkes, C. &amp; Hughes, K., 2024. Mineral systems and metallogeny of the Delamerian Orogen margin. In: Czarnota, K. (ed.) Exploring for the Future: Extended Abstracts. Geoscience Australia, Canberra. https://doi.org/10.26186/149657</div><div><br></div>

  • <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>

  • <div>This study is part of the Mineral Potential Assessment (MPA) module of Geoscience Australia's Darling-Curnamona-Delamerian (DCD) project, a deep-dive project within the Exploring for the Future Program (EFTF) 2020-2024. An objective of the DCD project is to further the understanding of the geological architecture of the Delamerian Orogen into a cohesive framework enable a regional mineral potential assessment of this under-explored and mostly under cover Orogen. The MPA module is one of eight modules under the umbrella of the DCD project. To facilitate assessment of the mineral potential of the project area, the mineral potential assessment study has 3 key scientific objectives: (1) Defining the characteristics of the mineral systems / prospects. (2)&nbsp;&nbsp;Evaluating the temporal framework of the formation of mineral systems / prospects; and (3) Understanding the regional magma fertility. This study delivers Objective 1, i.e., outlining the principle geological and metallogenic characteristics of reported mineral prospects in the project area.&nbsp;</div><div><br></div><div>Legacy drill cores best demonstrating metallogenic features of different mineral system types at key prospects across the project area were selected for viewing and sampling following review of historical exploration reports and assay results. Four sets of data are included in the appendices of this report: (1)&nbsp;&nbsp;HyLogger spectral images of 20 drill holes of 8 prospects in New South Wales. (2)&nbsp;&nbsp;143 high-resolution scan files of legacy drill core samples across the project area. (3)&nbsp;&nbsp;16 microscopic images of thin sections for 4 prospects of the Loch Lilly-Kars Belt, New South Wales. (4)&nbsp;&nbsp;53 Backscattered Electron (BSE) images and 53 Advanced Mineral Identification and Characterization System (AMICS) high-resolution mineral maps of 53 samples from 18 prospects across the whole Delamerian Margin.&nbsp;</div><div><br></div><div>Metallogenic characteristics of samples from four different mineral deposit types were studied, along deposits of uncertain affiliation (referred here as undefined systems), including (1) Porphyry-epithermal mineral systems. (2)&nbsp;&nbsp;Volcanic hosted massive sulfide (VHMS) mineral systems. (3)&nbsp;&nbsp;Orogenic gold mineral systems. (4)&nbsp;&nbsp;Mafic-ultramafic Cu-Ni-PGE mineral systems. (5)&nbsp;&nbsp;Metallogenetically undefined systems. Detailed metallogenic characteristics of the samples from 22 key prospects in Delamerian Orogen are documented in this report.&nbsp;&nbsp;</div><div><br></div><div>This is the first systemic study on the essential metallogenic characteristics of the mineral systems in Delamerian. The characterisations outlined in this report are foundational for understanding the regional metallogenesis and assessing the potential of multiple types of mineral systems in the Delamerian Belt, which should be useful in both academic and the mineral exploration sector.</div><div><br></div><div>The high-resolution BSE and AMICS mineral maps are available at Geoscience Australia. Please reach out to the senior author of this GA Record, Dr. Yanbo Cheng (Yanbo.cheng@ga.gov.au). </div>

  • A comprehensive compilation of rock, regolith and groundwater geochemistry across the Curnamona Province and overlying basins. This product is part of the Curnamona Geochemistry module of GA's Exploring for the Future program, which is seeking to understand geochemical baselines within the Curnamona Province to support mineral exploration under cover. Data is sourced from GA, CSIRO and state databases, and run through a quality control process to address common database issues (such as unit errors). The data has been separated by sample type and migrated into a standard data structure to make the data internally consistent. A central source for cleaned geochemical data in the same data format is a valuable resource for further research and exploration in the region.

  • <div>Magmatic arcs represent a critical source of modern civilisation’s mineral wealth, with their importance only enhanced by the ongoing global transition to a low-carbon society. The ~830-495 Ma Delamerian Orogen, formed at Australia’s eastern cratonic margin, represents rocks ascribed to rift/passive-margin, convergent margin arc, orogenic, and post-orogenic settings. However, poor exposure has limited exploration activity across much of the orogen, despite demonstrated potential for numerous mineral systems. To address this issue, an orogen-wide zircon Hf-O isotope and trace element survey was performed on 55 magmatic samples to constrain the crustal architecture, evolution, and fertility of the Delamerian Orogen, and in turn map parameters that can be used as a guide to mineral potential. These new data define two broad magmatic episodes at: (1) ~585-480 Ma, related to rift/passive margin, convergent arc, orogenic, and post-orogenic activity (Delamerian Cycle); and (2) magmatism associated with the ~490-320 Ma Lachlan Orogen, with peaks at ~420 Ma (onshore, Tabberabberan Cycle) and ~370 Ma (western Tasmania). Isotopic and geochemical mapping of these events show that the ~585-480 Ma Delamerian Cycle has significant orogen-wide variation in magmatic Hf-O isotopes and oxidation-state, suggesting a spatial variation in the occurrence and type of potential mineral systems. The ~420 Ma magmatic event involved predominantly mantle-like Hf-O and oxidised magmatism, whilst the ~370 Ma magmatism shows opposing features. In general, The potential to host Cu-Au porphyry and VMS mineralisation (e.g., Stavely, Koonenberry) is present, but restricted, whereas signatures favourable for Sn-W granite-hosted systems (e.g., Tasmania), are more common. These new data constrain time-space variations in magma composition that provide a valuable geological framework for mineral system fertility assessments across the Delamerian Orogen. Furthermore, these data and associated maps can used to assess time-space mineral potential and facilitate more effective exploration targeting in this covered region.</div> <b>Citation:</b> Mole, D., Bodorkos, S., Gilmore, P.J., Fraser, G., Jagodzinski, E.A., Cheng, Y., Clark, A.D., Doublier, M., Waltenberg, K., Stern, R.A., Evans, N.J., 2023. Architecture, evolution and fertility of the Delamerian Orogen: Insights from zircon. In: Czarnota, K. (ed.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, <a href+"https://dx.doi.org/10.26186/148981">https://dx.doi.org/10.26186/148981</a>

  • This report contains new whole-rock and isotope geochemical data, associated sample metadata, an assessment of the data’s quality assurance, for 742 samples collected in and around the Curnamona and Delamerian provinces, across numerous drillcore sampling campaigns through 2021-23. The data can be downloaded via the Geoscience Australia EFTF portal (https://portal.ga.gov.au/persona/eftf) or in the files attached with this record (http://pid.geoscience.gov.au/dataset/ga/148651). Geochemical sampling in the Curnamona region straddles both South Australia and New South Wales. The objective of sampling was to obtain representative coverage (both stratigraphically and spatially) to support developing regional geochemical baselines (in conjunction with existing geochemistry). Thus, this sampling included both the Curnamona Province and the overlying basins (Eromanga Basin, Lake Eyre Basin). Whole-rock geochemistry is reported for 562 samples, with a subset of 13 samples analysed for Pb and Sr isotopes, and another subset of 36 samples analysed by thin section petrography (all presented herein). Geochemical sampling in the Delamerian region has focussed on available legacy drill core in South Australia, New South Wales and Victoria. The objective of sampling was to (systematically) constrain the geochemical character of magmatic rocks across the mainland extent of the Delamerian Orogen, as well as younger volcanics within the Delamerian Orogen and/or overlying cover. This geochemical sampling was conducted in conjunction with geochronology, mineral systems sampling and stratigraphic drilling (all components of the DCD project) to reinterpret the timing, character and fertility of the Delamerian Orogen. Whole-rock geochemistry is reported for 180 samples. Version 2.0 (published 28 November 2023) has added whole rock geochemistry for 22 new samples in the Delamerian region. The data products and report have been updated accordingly.

  • <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).&nbsp;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.&nbsp;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>

  • 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. This Record presents new U-Pb zircon geochronology from the Loch-Lilly Kars and Lake Wintlow (as described by Clark et al. 2024) Belts of the central Delamerian Orogen (Foden et al., 2020; Gilmore et al., 2023; Mole et al., 2023), performed on Geoscience Australia’s (GA) sensitive high-resolution ion microprobe (SHRIMP). The eight samples presented here (three sedimentary and five igneous rocks; Table i) were collected during Geoscience Australia’s drilling campaign across the region, which consisted of 17 drill-holes (Pitt et al., 2023), using two drilling techniques (coiled-tube rotary and conventional diamond). This work was performed as part of the MinEx CRC National Drilling initiative (NDI) and Geoscience Australia’s Darling-Curnamona-Delamerian project of the Exploring for the Future program (EFTF; <a href="https://www.eftf.ga.gov.au/">https://www.eftf.ga.gov.au/</a>). The primary aims of this drilling were to (1) understand and constrain the geology of the southern Loch-Lilly Kars Belt; and (2) assess whether Cambrian magmatic rocks continued to the south-west in the Lake Wintlow Belt, marking a possible continuation of the Stavely Belt volcanic arc rocks observed in western Victoria (Bowman et al., 2019; Lewis et al., 2016; Lewis et al., 2015; Schofield, 2018; Figure i). As both these regions are covered, this new drilling and the geochronology they allow provide the first constraints on the age of these rock units. In addition, due to the lack of surface correlation and detailed geological mapping, these units currently have no officially-defined stratigraphic nomenclature and remain unnamed. For detailed information on all drill-holes completed as part of the survey, we direct readers to the summary report by Pitt et al. (2023): <a href="https://ecat.ga.gov.au/geonetwork/srv/eng/catalog.search#/metadata/148639">eCat 148639</a>.