The Laurelvale 1 borehole was drilled approximately 78 km SSW of Wanaaring, New South Wales, adjacent to the through-road between Tongo and Tilpa. The borehole was designed to test the geology of indistinct, linear aeromagnetic anomalies in the basement rocks, test the electrical conductivity properties of cover and basement rocks to validate airborne electromagnetic (AEM) data, and to test pre-drilling geophysical cover thickness estimates.

The National Geochemical Survey of Australia (NGSA) provides an internally consistent, state-of-the-art, continental-scale geochemical dataset that can be used to assess areas of Australia more elevated in commodity metals and/or pathfinder elements than others. But do regions elevated in such elements correspond to known mineralized provinces, and what is the best method for detecting and thus potentially predicting those? Here, using base metal associations as an example, I compare a trivariate rank-based index and a multivariate-based Principal Component Analysis method. The analysis suggests that the simpler rank-based index better discriminates catchments endowed with known base metal mineralization from barren ones and could be used as a first-pass prospectivity tool. <b>Citation:</b> Patrice de Caritat, Continental-scale geochemical surveys and mineral prospectivity: Comparison of a trivariate and a multivariate approach, <i>Journal of Geochemical Exploration</i>, Volume 188, 2018, Pages 87-94, ISSN 0375-6742, https://doi.org/10.1016/j.gexplo.2018.01.014

The Congararra 1 borehole was drilled approximately 70 km NNW of Bourke, NSW. The borehole was designed to test aeromagnetic anomalies in the basement rocks, test the electrical conductivity properties of cover and basement rocks to validate airborne electromagnetic (AEM) data, and to test pre-drilling geophysical cover thickness estimates.

<div>The Heavy Mineral Map of Australia (HMMA) project1, part of Geoscience Australia’s Exploring for the Future program, determined the abundance and distribution of heavy minerals (HMs; specific gravity >2.9 g/cm3) in 1315 floodplain sediment samples obtained from Geoscience Australia’s National Geochemical Survey of Australia (NGSA) project2. Archived NGSA samples from floodplain landforms were sub-sampled with the 75-430 µm fraction subjected to dense media separation and automated mineralogy assay using a TESCAN Integrated Mineral Analysis (TIMA) instrument at Curtin University.</div><div><br></div><div>Interpretation of the massive number of mineral observations generated during the project (~150&nbsp;million mineral observations; 166 unique mineral species) required the development of a novel workflow to allow end users to discover, visualise and interpret mineral co-occurrence and spatial relationships. Mineral Network Analysis (MNA) has been shown to be a dynamic and quantitative tool capable of revealing and visualizing complex patterns of abundance, diversity and distribution in large mineralogical data sets3. To facilitate the application of MNA for the interpretation of the HMMA dataset and efficient communication of the project results, we have developed a Mineral Network Analysis for Heavy Minerals (MNA4HM) web application utilising the ‘Shiny’ platform and R package. The MNA4HM application is used to reveal (1) the abundance and co-occurrences of heavy minerals, (2) their spatial distributions, and (3) their relations to first-order geological and geomorphological features. The latter include geological provinces, mineral deposits, topography and major river basins. Visualisation of the mineral network guides parsimonious yet meaningful mapping of minerals typomorphic of particular geological environments or mineral systems. The mineralogical dataset can be filtered or styled based on mineral attributes (e.g., simplified mineralogical classes) and properties (e.g., chemical composition).</div><div><br></div><div>In this talk we will demonstrate an optimised MNA4HM workflow (identification à mapping à interpretation) for exploration targeting selected critical minerals important for the transition to a lower carbon global economy. </div><div><br></div><div>The MNA4HM application is hosted at https://geoscienceaustralia.shinyapps.io/mna4hm and is available for use by the geological community and general public.</div> This Abstract was submitted and presented to the 2023 Goldschmidt Conference Lyon, France (https://conf.goldschmidt.info/goldschmidt/2023/meetingapp.cgi)

The GSQ Eulo 3 borehole was drilled approximately 50 km SW of Eulo, Queensland. The borehole was designed to test aeromagnetic anomalies in the basement rocks and to test the electrical conductivity properties of cover and basement rocks.

<div>Tin and tungsten have good potentials for increased demand applications particularly in the electrical and energy storage areas. Similar to other critical metals like Li and Co, Sn and W are essential ingredients for many applications and technologies that are important for a sustainable future. </div><div>&nbsp;</div><div>Granite related hydrothermal mineral systems are the predominant source for Sn and W deposits.Cassiterite, wolframite and scheelite are primary Sn and W ore minerals in nature. The distribution of Sn rich areas around the world is uneven, which may reflects that geochemical heritage is fundamental to form Sn and W deposits. Besides, magmatic differentiation has been considered as another efficient way to enrich Sn in various geological reservoirs. The tectonic setting of Sn and W mineralisation is well understood, with most Sn and W deposits having formed at active margin settings. A comparison between the Tethyan and Andean Sn-W mineral systems confirmed that Sn and W mineral systems can form under thickened continental crust associated with an oceanic crust subduction. The importance of granitoids for the formation of Sn and W mineral systems is well understood. The genetic affinity of causative intrusions can be either S-type, I-type or A-type, but a common feature is that they are reduced (or ilmenite series) and highly evolved (high SiO2 content and high Rb/Sr ratio). Another prominent feature for Sn and W mineral systems is their high concentration of critical metals, including Li, Ce, Ta and In etc. Therefore, Sn and W mineralisation has a close association with other critical metal mineralisation. Overall, the precipitation mechanisms of W (wolframite and scheelite) and Sn (cassiterite) ore minerals from the hydrothermal fluid include (1) fluids mixing, (2) boiling and, (3) water-rock interaction.&nbsp;</div><div><br></div><div>Recent studies have highlighted discrepancies in Sn mineralisation and W mineralisation conditions. Although Sn- and W-associated granites have substantial overlapping characteristics, many of their physico-chemical natures (e.g., aluminum-saturation index (ASI) values, zirconium saturation temperatures and crystal fractionation degrees) are distinctive, suggesting Sn- and W-granites may form under different geological conditions. The difference between Sn mineralisation and W mineralisation is also evident by their contrasting fluid-melt partitioning coefficients. Tungsten strongly partitions into the aqueous fluid and can be transported farther away from the intrusion, but Sn slightly partitions into the silicate melt and can precipitate as magmatic cassiterite or be incorporated into crystallizing micas (which can have >100 ppm Sn). Another area warranting more study is understanding the elemental associations observed in Sn and W mineral systems. It is common to have many other metals in Sn-dominant mineral systems, for example W, Li, Nb, Ta. For W-dominant mineral systems, apart from with Sn, other common associated metals include Mo, Au-Bi and Cu. Nevertheless, the relationship between Sn-W and Cu-Au mineral systems at both the regional/provincial-scale and deposit-scale is an intriguing puzzle, because Sn-W and Cu-Au deposits are generally formed under different geological conditions, though their tectonic setting are similar, i.e., arc-related subduction and continental collision. An emerging field for understanding Sn and W mineral systems is made possible with the development of micro-analytical techniques, e.g., in-situ U-Pb geochronology and O-isotopic analyses on cassiterite and wolframite enable a greater understanding of Sn and W mineralising systems. Since both are the primary ore minerals, U-Pb dating on them can deliver direct age information - an advantage compared with many other commodities types like Cu, Au and Ag. However, unlike those commodities, impactful advances on Sn and W exploration models, techniques, and tools have been deficient in recent years; therefore, more attention and effort is needed to boost Sn and W mineral exploration in the future.</div><div><br></div>This paper was presented to the 2022 Asian Current Research on Fluid Inclusions IX (ACROFI IX) Conference 12-13 December (http://www.csmpg.org.cn/tzgg2017/202210/t20221011_6522628.html)

Exploring for the Future (EFTF) is a multiyear (2016–2024) initiative of the Australian Government, conducted by Geoscience Australia. This program aims to improve Australia’s desirability for industry investment in resource exploration of frontier regions across Australia. This paper will focus on the science impacts from the EFTF program in northern Australia derived from the acquisition and interpretation of seismic surveys, the drilling of the NDI Carrara 1 and also complementary scientific analysis and interpretation to determine the resource potential of the region. This work was undertaken in collaboration with the Northern Territory Geological Survey, the Queensland Geological Survey, AuScope and the MinEx CRC. These new data link the highly prospective resource rich areas of the McArthur Basin and Mt Isa Province via a continuous seismic traverse across central northern Australia. The Exploring for the Future program aims to further de-risk exploration within greenfield regions and position northern Australia for future exploration investment. [Carr] The Sherbrook Supersequence is the youngest of four Cretaceous supersequences in the Otway Basin and was deposited during a phase of crustal extension. This presentation shows how a basin-scale gross depositional environment (GDE) map for the Sherbrook SS was constructed, the significance of the map for the Austral 3 petroleum system, and why GDE mapping is important for pre-competitive basin studies at Geoscience Australia. [Abbott]

The Euroli 1 borehole was drilled approximately 23 km SSW of Hungerford, Queensland (which is located on the New South Wales-Queensland border). The borehole was designed to test aeromagnetic anomalies in the basement rocks, test the electrical conductivity properties of cover and basement rocks to validate airborne electromagnetic (AEM) data, and to test pre-drilling geophysical cover thickness estimates. The Euroli 1 borehole was commenced as a vertical mud rotary borehole and was completed with a deviated diamond drilled tail using a wedge.

The National Geochemical Survey of Australia (NGSA) is Australia’s only internally consistent, continental-scale geochemical atlas and dataset (<a href="http://dx.doi.org/10.11636/Record.2011.020">http://dx.doi.org/10.11636/Record.2011.020</a>). The present dataset provides additional geochemical data for Li, Be, Cs, and Rb acquired as part of the Australian Government-funded Exploring for the Future (EFTF) program and in support of the Australian Government’s 2023-2030 Critical Minerals Strategy. The dataset fills a knowledge gap about Li distribution in Australia over areas dominated by transported regolith. The main ‘total’ element analysis method deployed for NGSA was based on making a fused bead using lithium-borate flux for XRF then ICP-MS analysis. Consequently, the samples could not be meaningfully analysed for Li. All 1315 NGSA milled coarse-fraction (<2 mm) top (“TOS”) catchment outlet sediment samples, taken from 0 to 10 cm depth in floodplain landforms, were analysed in the current project following the digestion method that provides near-total concentrations of Li, Be, Cs, and Rb. The samples were analysed by the commercial laboratory analysis service provider Bureau Veritas in Perth using low-level mixed acid (a mixture of nitric, perchloric and hydrofluoric acids) digestion with elements determined by ICP-MS (Bureau Veritas methods MA110 and MA112). The data are reported in the same format as the NGSA dataset, allowing for seamless integration with previously released NGSA data. Further details on the QA/QC procedures as well as data interpretation will be reported elsewhere. This data release also includes four continental-scale geochemical maps for Li, Be, Cs, and Rb built from these analytical data. This dataset, in conjunction with previous data published by NGSA, will be of use to mineral exploration and prospectivity modelling around Australia by providing geochemical baselines for Li, Be, Cs, and Rb, as well as identifying regions of anomalism. Additionally, these data also have relevance to other applications in earth and environmental sciences.

The GSQ Eulo 4 borehole was drilled approximately 35.5 km SW of Eulo, Queensland. The borehole was designed to test aeromagnetic anomalies in the basement rocks, and to test the electrical conductivity properties of cover and basement rocks to validate airborne electromagnetic (AEM) data.