<div><strong>Output type: </strong>Exploring for the Future Extended Abstract </div><div><br></div><div><strong>Short Abstract: </strong>The Delamerian Orogen, with a length of ~1000 km on mainland Australia and a proven potential to host mineralisation, represents an evolving exploration opportunity. However, uncertainty surrounding the age and tectonic setting of the orogen is a barrier to confident exploration in frontier covered regions, such as the Loch Lilly-Kars Belt in western New South Wales and South Australia. A major area of uncertainty is the configuration and extent of the Cambrian convergent-margin system and lateral variations thereof. In this study, we highlight multidisciplinary data from new and legacy sources, including lithology, geochronology, geochemistry, potential-field geophysics, deep-crustal seismic, and magnetotelluric data that permit a revised interpretation of the geological framework for the Delamerian Orogen in mainland Australia, with an emphasis on the covered, central part of the system. These data indicate that a largely continuous, east-facing volcanic arc developed in the Delamerian Orogen in the Cambrian. The arc transitions from exhibiting a strong continental affinity in the Koonenberry Belt to having less continental affinity in the Grampians-Stavely Zone of Victoria. The Loch Lilly-Kars Belt is interpreted to have occupied a volcanic arc to incipient back-arc position in the middle Cambrian.&nbsp;</div><div><br></div><div><strong>Citation: </strong>Clark A.D., et al., 2024. Cambrian convergent margin configuration in the Delamerian Orogen of mainland Australia. In: Czarnota, K. (ed.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, https://doi.org/10.26186/149647 </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>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>.