Following the successful outcomes of the Tennant Creek-Mt Isa (TISA) mineral potential assessment (Murr et al., 2019; Skirrow et al., 2019), the methodology has been expanded to encompass the entire North Australian Craton (NAC). Like its predecessor, this assessment uses a knowledge-based, data-rich mineral systems approach to predict the potential for iron oxide-copper-gold (IOCG) mineralisation. With their high metal yield and large alteration footprint, IOCG mineral systems remain an attractive target in directing exploration efforts towards undercover regions. This mineral potential assessment uses a 2D GIS-based workflow to map four key mineral system components: (1) Sources of metals, fluids and ligands, (2) Energy to drive fluid flow, (3) Fluid flow pathways and architecture, and (4) Deposition mechanisms, such as redox or chemical gradients. For each of these key mineral system components, theoretical criteria representing important ore-forming processes were identified and translated into mappable proxies using a wide range of input datasets. Each of these criterion are weighted and combined using an established workflow to produce a models of IOCG potential. Metadata and selection rational are documented in the accompanying NAC IOCG Assessment Criteria Table. Two scenarios were modelled for this assessment. The first is a comprehensive assessment, targeting pre-Neoproterozoic mineral systems (>1500 Ma), using a combination of interpreted, geological and geophysical datasets. As geological interpretations are subjective to the geological knowledge of the interpreter, well-documented areas, such as shallow pre-Neoproterozoic basement, have a greater density of data. This increase in data density can create an inherent bias in the modelled result towards previously explored shallow terrains. The second assessment utilises only datasets which can be mapped consistently across the assessment area. As such, these are predominately based on geophysical data and are more consistent in assessing exposed and covered areas. However, far fewer criteria are included in this assessment, and observations are reflective of only the modern geological environment. Both assessments highlight existing mineral fields in WA, NT and QLD, and suggest that these regions extend under cover. Furthermore, regions not previously known for IOCG mineralisation display a high modelled potential, offering exploration prospects in previously unknown or discounted areas.

<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>

This web service provides access to datasets generated by the North Australian Craton (NAC) Iron Oxide Copper Gold (IOCG) Mineral Potential Assessment. Two outputs were created: a comprehensive assessment, using all available spatial data, limiting data where possible to capture mineral systems older than 1500 ma, and; a coverage assessment, which is constrained to data that have no reliance on outcrop or age of mineralisation.

This web service provides access to datasets generated by the North Australian Craton (NAC) Iron Oxide Copper Gold (IOCG) Mineral Potential Assessment. Two outputs were created: a comprehensive assessment, using all available spatial data, limiting data where possible to capture mineral systems older than 1500 ma, and; a coverage assessment, which is constrained to data that have no reliance on outcrop or age of mineralisation.

<div>Mineral prospectivity studies seek to map evidence of mineral system activity, with the aim of informing mineral exploration decisions and guiding exploration in the face of uncertainty. These studies leverage the growing volumes of information that are available to characterise the lithosphere by compiling covariate (or feature) grids that represent key mineral system ingredients. Previous studies have been categorised as either “knowledge-driven” or “data-driven” approaches depending on whether these grids are integrated via expert elicitation or by the empirical relationship to known mineralisation, respectively. However, to our knowledge, the underlying modelling framework and assumptions have not been systematically reviewed to understand how choices in the approach to the problem influence modelling outcomes. Here we show the broad mathematical equivalence in these approaches and highlight the limitations inherent when optimising to minimise misfit in potentially under-determined problems. We argue that advances in mineral prospectivity are more likely to be driven by careful consideration of the model selection problem. Focusing effort on model selection will not only drive more robust mineral prospectivity predictions but may also simultaneously refine our understanding of key mineral system processes. To build on these results, we present the Mineral Potential Toolkit; a software repository to facilitate feature engineering, statistical appraisal, and quantitative prospectivity modelling. The toolkit enables a novel approach that combines the best aspects of previous methods. Abstract presented to the 26th World Mining Congress 2023 (https://wmc2023.org/)

<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>

This web service provides access to datasets produced by the mineral potential assement of iron oxide-copper-gold (IOCG) mineral systems in the Tennant Creek – Mt Isa region. The mineral potential assessment uses a 2D, GIS-based workflow to qualitatively map four key mineral system components: (1) Sources of metals, fluids and ligands, (2) Energy to drive fluid flow, (3) Fluid flow pathways and architecture, and (4) Deposition mechanisms, such as redox or chemical gradients. For each of these key mineral system components theoretical criteria, representing important ore-forming processes, were identified and translated into mappable proxies using a wide range of input datasets. Each of these criteria are weighted and combined using an established workflow to produce the final map of IOCG potential.

One of the aims of the Exploring for the Future program is to promote the discovery of new mineral deposits in undercover frontiers. Iron oxide–copper–gold mineral systems are a desirable candidate for undercover exploration, because of their potential to generate large deposits with extensive alteration footprints. This mineral potential assessment uses the mineral systems concept: developing mappable proxies of required theoretical criteria, combined to demonstrate where conditions favourable for mineral deposit formation are spatially coincident. This assessment uses a 2D geographical information system workflow to map the favourability of the key mineral system components. Two outputs were created: a comprehensive assessment, using all available spatial data; and a coverage assessment, which is constrained to data that have no reliance on outcrop. The results of these assessment outputs were validated with spatial statistics, demonstrating how the assessment can predict the presence of known ore deposits. Both assessment outputs present new areas of interest with prospectivity in under-explored regions of undercover northern Australia. The intended aims are already being realised, as this tool has aided area selection for pre-competitive stratigraphic drilling as part of the MinEx CRC National Drilling Initiative. <b>Citation:</b> Murr, J., Skirrow, R.G., Schofield, A., Goodwin, J., Coghlan, R., Highet, L., Doublier, M.P., Duan, J. and Czarnota, K., 2020. Tennant Creek – Mount Isa IOCG mineral potential assessment. In: Czarnota, K., Roach, I., Abbott, S., Haynes, M., Kositcin, N., Ray, A. and Slatter, E. (eds.) Exploring for the Future: Extended Abstracts, Geoscience Australia, Canberra, 1–4.

<div>Building on the national-scale thermochemical tomographic inversions of Haynes & Afonso (2023), we infer regions of subduction-driven metasomatic alteration within the Australia sub-continental lithospheric mantle. Such regions are inferred on the basis of age-corrected magnesium number anomalies for bulk composition of the lithospheric mantle, and the spatial correlation of these features with electrical conductors. This defines a mappable criteria for mineral system conceptual models focused on the transport of melts from re-enriched upper mantle sources. Mapping this feature through stochastic uncertainty propogation of inferred mantle compositions enables us to quantify the level of agreement in the spatial constraints on the feature. Here, we present a voting map that quantifies the relative presence or absence of such features across Australia under any arbitrary model realisation.</div><div><br></div><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, $225m investment by the Australian Government.</div>

This web service provides access to datasets produced by the mineral potential assement of iron oxide-copper-gold (IOCG) mineral systems in the Tennant Creek – Mt Isa region. The mineral potential assessment uses a 2D, GIS-based workflow to qualitatively map four key mineral system components: (1) Sources of metals, fluids and ligands, (2) Energy to drive fluid flow, (3) Fluid flow pathways and architecture, and (4) Deposition mechanisms, such as redox or chemical gradients. For each of these key mineral system components theoretical criteria, representing important ore-forming processes, were identified and translated into mappable proxies using a wide range of input datasets. Each of these criteria are weighted and combined using an established workflow to produce the final map of IOCG potential.