<div>High purity quartz (HPQ) is the only naturally occurring and economically viable source for the production of silicon. Silicon is a critical mineral, and a key component in modern technologies such as semiconductors and photovoltaic cells. Critical minerals support the move towards a greater reliance on electrification, renewable energy sources and economic security. The global transition to net zero carbon emissions means there is a growing need for new discoveries of HPQ to supply the silicon production chain. High purity quartz deposits are identified in a multitude of geological settings, including pegmatites, hydrothermal veins, sedimentary accumulations and quartzite; however, deposits of sufficient volume and quality are rare. Quartz is abundant throughout Australia, but the exploration and discovery of HPQ occurrences is notably under-reported, making assessment of the HPQ potential in Australia extremely difficult. This paper presents a much-needed summary of the state of the HPQ industry, exploration and deposit styles in Australia. <b>Citation:</b> Jennings, A., Senior, A., Guerin, K., Main, P., & Walsh, J. (2024). A review of high-purity quartz for silicon production in Australia. <i>Australian Journal of Earth Sciences</i>, 1–13. https://doi.org/10.1080/08120099.2024.2362296

<div>Geoscience Australia's geoscientific relational databases use look-up tables to describe the data stored within. These look-ups contain, but are not limited to, information about boreholes, field geology, inorganic and organic geochemistry, hydrochemistry, geophysics, rock properties, samples and other general geological terms. These terms have then been compiled into a vocabulary of terms for publication via GA's vocabulary service. Within this vocabulary, GA references where sourced terms are published in external vocabularies with a source vocabulary URI (Uniform Resource Identifier). </div><div><br></div><div>All vocabularies, collections of concepts within vocabularies and individual concepts are identified with URI persistent identifiers of the form:</div><div>http://pid.geoscience.gov.au/def/voc/ga/{VOCABULARY-KEY}/{COLLECTION-OR-CONCEPT-NAME}</div>

<div>GeoInsight was an 18-month pilot project developed in the latter part of Geoscience Australia’s Exploring for the Future Program (2016–2024). The aim of this pilot was to develop a new approach to communicating geological information to non-technical audiences, that is, non-geoscience professionals. The pilot was developed using a human-centred design approach in which user needs were forefront considerations. Interviews and testing found that users wanted a simple and fast, plain-language experience which provided basic information and provided pathways for further research. GeoInsight’s vision is to be an accessible experience that curates information and data from across the Geoscience Australia ecosystem, helping users make decisions and refine their research approach, quickly and confidently.</div><div><br></div><div>Geoscience Australia hosts a wealth of geoscientific data, and the quantity of data available in the geosciences is expanding rapidly. This requires newly developed applications such as the GeoInsight pilot to be adaptable and malleable to changes and updates within this data. As such, utilising the existing Oracle databases, web service publication and platform development workflows currently employed within Geoscience Australia (GA) were optimal choices for data delivery for the GeoInsight pilot.&nbsp;This record is intended to give an overview of the how and why of the technical infrastructure of this project. It aims to summarise how the underlying databases were used for both existing and new data, as well as development of web services to supply the data to the pilot application.&nbsp;</div>

<div>The National Geochemical Survey of Australia (NGSA) is Australia’s only internally consistent, continental-scale geochemical atlas and dataset. The present report presents additional mineralogical data acquired as part of the Heavy Mineral Map of Australia (HMMA) project on the NGSA samples, covering ~81% of Australia. The HMMA project, a collaborative project between Geoscience Australia and Curtin University underpinned by a pilot project establishing its feasibility, is part of the Australian Government-funded Exploring for the Future (EFTF) program.</div><div>All of the 1315 NGSA bottom catchment outlet sediment samples, taken on average from 60 to 80 cm depth in floodplain landforms, were used in the HMMA project. The samples were dried and sieved to a 75-425 µm grainsize fraction, and the contained heavy minerals (HMs; i.e., those with a specific gravity > 2.9 g/cm3) were separated by dense fluids and mounted on cylindrical epoxy mounts. After polishing and carbon-coating, the mounts were subjected to automated mineralogical analysis on a TESCAN® Integrated Mineral Analyzer (TIMA). Using scanning electron microscopy and backscatter electron imaging integrated with energy dispersive X-ray analysis, the TIMA identified 163 unique phases (including ‘Unclassified”) in the NGSA sample set. The dataset, consisting of over 145 million individual mineral grains, was quality controlled and validated by an expert team. The data released here can be visualised, explored and downloaded using a free online, bespoke mineral network analysis (MNA) tool built on a cloud-based platform. Preliminary analysis suggests that zinc minerals and native elements&nbsp;(e.g., native gold and platinum) may be useful in mineral exploration applications. Detailed interpretations of the HMMA dataset will be provided elsewhere. Accompanying this report are data files of TIMA results, a minerals property file, and an atlas of HM distribution maps. </div><div>It is hoped the comprehensive dataset generated by the HMMA project will be of use to mineral exploration and prospectivity modelling around Australia, as well as have other applications in earth and environmental sciences.</div>

<div>The mineral potential toolkit (aka minpot-toolkit) provides tools to facilitate mineral potential analysis, from spatial associations to feature engineering and fully integrated mineral potential mapping.</div>

<div>In Australia, wide-spread sedimentary basin and regolith cover presents a key challenge to explorers, environmental managers and decision-makers, as it obscures underlying rocks of interest. To address this, a national coverage of airborne electromagnetics (AEM) with a 20&nbsp;km line-spacing is being acquired. This survey is acquired as part of the Exploring for the Future program and in collaboration with state and territory geological surveys. This survey presents an opportunity for regional geological interpretations on the modelled AEM data, helping constrain the characteristics of the near-surface geology beneath the abundant cover, to a depth of up to ~500&nbsp;m.</div><div> The AEM conductivity sections were used to delineate key chronostratigraphic boundaries, e.g. the bases of geological eras, and provide a first-pass interpretation of the subsurface geology. The interpretation was conducted with a high level of data integration with boreholes, potential fields geophysics, seismic, surface geology maps and solid geology maps. This approach led to the construction of well-informed geological interpretations and provided a platform for ongoing quality assurance and quality control of the interpretations and supporting datasets. These interpretations are delivered across various platforms in multidimensional non-proprietary open formats, and have been formatted for direct upload to Geoscience Australia’s (GA) Estimates of Geological and Geophysical Surfaces (EGGS) database, the national repository of multidisciplinary subsurface depth estimates.</div><div> These interpretations have resulted in significant advancements in our understanding of Australia’s near-surface geoscience, by revealing valuable information about the thickness and composition of the extensive cover, as well as the composition, structure and distribution of underlying rocks. Current interpretation coverage is ~110,000 line kilometres of AEM conductivity sections, or an area &gt;2,000,000&nbsp;km2, similar to the area of Greenland or Saudi Arabia. This ongoing work has led to the production of almost 600,000 depth estimate points, each attributed with interpretation-specific metadata. Three-dimensional line work and over 300,000 points are currently available for visualisation, integration and download through the GA Portal, or for download through GA’s eCat electronic catalogue. </div><div> These interpretations demonstrate the benefits of acquiring broadly-spaced AEM surveys. Interpretations derived from these surveys are important in supporting regional environmental management, resource exploration, hazard mapping, and stratigraphic unit certainty quantification. Delivered as precompetitive data, these interpretations provide users in academia, government and industry with a multidisciplinary tool for a wide range of investigations, and as a basis for further geoscientific studies.</div> Abstract submitted and presented at 2023 Australian Earth Science Convention (AESC), Perth WA (https://2023.aegc.com.au/)

<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>

<div>The Gas Chromatography-Mass Spectrometry (GC-MS) biomarker database table contains publicly available results from Geoscience Australia's organic geochemistry (ORGCHEM) schema and supporting oracle databases for the molecular (biomarker) compositions of source rock extracts and petroleum liquids (e.g., condensate, crude oil, bitumen) sampled from boreholes and field sites. These analyses are undertaken by various laboratories in service and exploration companies, Australian government institutions and universities using either gas chromatography-mass spectrometry (GC-MS) or gas chromatography-mass spectrometry-mass spectrometry (GC-MS-MS). Data includes the borehole or field site location, sample depth, shows and tests, stratigraphy, analytical methods, other relevant metadata, and the molecular composition of aliphatic hydrocarbons, aromatic hydrocarbons and heterocyclic compounds, which contain either nitrogen, oxygen or sulfur.</div><div><br></div><div>These data provide information about the molecular composition of the source rock and its generated petroleum, enabling the determination of the type of organic matter and depositional environment of the source rock and its thermal maturity. Interpretation of these data enable the determination of oil-source and oil-oil correlations, migration pathways, and any secondary alteration of the generated fluids. This information is useful for mapping total petroleum systems, and the assessment of sediment-hosted resources. Some data are generated in Geoscience Australia’s laboratory and released in Geoscience Australia records. Data are also collated from destructive analysis reports (DARs), well completion reports (WCRs), and literature. The biomarker data for crude oils and source rocks are delivered in the Petroleum and Rock Composition – Biomarker web services on the Geoscience Australia Data Discovery Portal at https://portal.ga.gov.au which will be periodically updated.</div>

<div>Geoscience Australia’s Onshore Basin Inventories project delivers a single point of reference and creates a standardised national basin inventory that provides a whole-of-basin catalogue of geology, petroleum systems, exploration status and data coverage of hydrocarbon-prone onshore Australian sedimentary basins. In addition to summarising the current state of knowledge within each basin, the onshore basin inventory reports identify critical science questions and key exploration uncertainties that may help inform future work program planning and decision making for both government and industry. Volume 1 of the inventory covers the McArthur, South Nicholson, Georgina, Wiso, Amadeus, Warburton, Cooper and Galilee basins and Volume 2 expands this list to include the Officer, Perth and onshore Canning basins. Under Geoscience Australia’s Exploring for the Future (EFTF) program, several new onshore basin inventory reports are being delivered. Upcoming releases include the Adavale Basin of southern Queensland, and a compilation report addressing Australia’s poorly understood Mesoproterozoic basins. These are supported by value-add products that address identified data gaps and evolve regional understanding of basin evolution and prospectivity, including petroleum systems modelling, seismic reprocessing and regional geochemical studies. The Onshore Basin Inventories project continues to provide scientific and strategic direction for pre-competitive data acquisition under the EFTF work program, guiding program planning and shaping post-acquisition analysis programs.</div>

<div>The interpretation of AusAEM airborne electromagnetic (AEM) survey conductivity sections in the Canning Basin region delineates the geo-electrical features that correspond to major chronostratigraphic boundaries, and captures detailed stratigraphic information associated with these boundaries. This interpretation forms part of an assessment of the underground hydrogen storage potential of salt features in the Canning Basin region based on integration and interpretation of AEM and other geological and geophysical datasets. A main aim of this work was to interpret the AEM to develop a regional understanding of the near-surface stratigraphy and structural geology. This regional geological framework was complimented by the identification and assessment of possible near-surface salt-related structures, as underground salt bodies have been identified as potential underground hydrogen storage sites. This study interpreted over 20,000 line kilometres of 20&nbsp;km nominally line-spaced AusAEM conductivity sections, covering an area approximately 450,000 km2 to a depth of approximately 500&nbsp;m in northwest Western Australia. These conductivity sections were integrated and interpreted with other geological and geophysical datasets, such as boreholes, potential fields, surface and basement geology maps, and seismic interpretations. This interpretation produced approximately 110,000 depth estimate points or 4,000 3D line segments, each attributed with high-quality geometric, stratigraphic, and ancillary data. The depth estimate points are formatted for Geoscience Australia’s Estimates of Geological and Geophysical Surfaces database, the national repository for formatted depth estimate points. Despite these interpretations being collected to support exploration of salt features for hydrogen storage, they are also intended for use in a wide range of other disciplines, such as mineral, energy and groundwater resource exploration, environmental management, subsurface mapping, tectonic evolution studies, and cover thickness, prospectivity, and economic modelling. Therefore, these interpretations will benefit government, industry and academia interested in the geology of the Canning Basin region.</div>