Mineralogy and crystallography
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<div>The ubiquitous nature of dust, along with localised chemical and biological signatures, makes it an ideal medium for provenance determination in a forensic context. Metabarcoding of dust can yield biological communities unique to the site of interest, similarly, geochemical and mineralogical analyses can uncover elements and minerals within dust than can be matched to a geographic location. Combining these analyses presents multiple lines of evidence as to the origin of collected dust samples. In this work, we investigated whether the time an item spent at a site collecting dust influenced the ability to assign provenance. We then integrated dust metabarcoding of bacterial and fungal communities into a framework amenable to forensic casework, (i.e., using calibrated log-likelihood ratios to predict the origin of dust samples) and assessed whether current soil metabarcoding databases could be utilised to predict dust origin. Furthermore, we tested whether both metabarcoding and geochemical/mineralogical analyses could be conducted on a single sample for situations where sampling is limited. We found both analyses could generate results capable of separating sites from a single swabbed sample and that the duration of time to accumulate dust did not impact site separation. We did find significant variation within sites at different sampling time periods, showing that bacterial and fungal community profiles vary over time and space – but not to the extent that they are non-discriminatory. We successfully modelled soil and dust samples for both bacterial and fungal diversity, developing calibrated log-likelihood ratio plots and used these to predict provenance for dust samples. We found that the temporal variation in community composition influenced our ability to predict dust provenance and recommend reference samples be collected as close to the sampling time as possible. Thus, our framework showed soil metabarcoding databases are capable of being used to predict dust provenance but the temporal variation in metabarcoded communities will need to be addressed to improve provenance estimates. </div> <b>Citation:</b> Nicole R. Foster, Duncan Taylor, Jurian Hoogewerff, Michael G. Aberle, Patrice de Caritat, Paul Roffey, Robert Edwards, Arif Malik, Michelle Waycott and Jennifer M. Young, The secret hidden in dust: Uncovering the potential to use biological and chemical properties of the airborne soil fraction to assign provenance and integrating this into forensic casework, <i>Forensic Science International: Genetics,</i> (2023) doi:https://doi.org/10.1016/j.fsigen.2023.102931
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<div>Environmental DNA (eDNA), elemental and mineralogical analyses of soil have been shown to be specific to their source material, prompting consideration of the use of dust for forensic provenancing. Dust is ubiquitous in the environment and is easily transferred to items belonging to a person of interest, making dust analysis an ideal tool in forensic casework. The advent of Next Generation Sequencing technologies means that metabarcoding of eDNA can uncover microbial, fungal, and even plant genetic fingerprints in dust particles. Combining this with elemental and mineralogical compositions offers multiple, complementary lines of evidence for tracing the origin of an unknown dust sample. This is particularly pertinent when recovering dust from a person of interest to ascertain where they may have travelled. Prior to proposing dust as a forensic trace material, however, the optimum sampling protocols and detection limits need to be established to place parameters around its utility in this context. We tested several approaches to collecting dust from different materials and determined the lowest quantity of dust that could be analysed for eDNA, geochemistry and mineralogy, whilst still yielding results capable of distinguishing between sites. We found that fungal eDNA profiles could be obtained from multiple sample types and that tape lifts were the optimum collection method for discriminating between sites. We successfully recovered both fungal and bacterial eDNA profiles down to 3 mg of dust (the lowest tested quantity) and recovered elemental and mineralogical compositions for all tested sample quantities. We show that dust can be reliably recovered from different sample types, using different sampling techniques, and that fungal, bacterial, and elemental and mineralogical profiles, can be generated from small sample quantities, highlighting the utility of dust as a forensic provenance material.</div> <b>Citation:</b> Nicole R. Foster, Belinda Martin, Jurian Hoogewerff, Michael G. Aberle, Patrice de Caritat, Paul Roffey, Robert Edwards, Arif Malik, Priscilla Thwaites, Michelle Waycott, Jennifer Young, The utility of dust for forensic intelligence: Exploring collection methods and detection limits for environmental DNA, elemental and mineralogical analyses of dust samples, <i>Forensic Science International </i>, Volume 344, 2023, 111599, ISSN 0379-0738, https://doi.org/10.1016/j.forsciint.2023.111599. ISSN 0379-0738,
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<div>The National Geochemical Survey of Australia (NGSA) is Australia’s only internally consistent, continental-scale geochemical atlas and dataset. The present dataset contains additional mineralogical data obtained on NGSA samples selected from the Barkly-Isa-Georgetown (BIG) region of northeastern Australia for the second partial data release of the Heavy Mineral Map of Australia (HMMA) project. 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>One-hundred and eighty eight NGSA sediment samples were selected from the HMMA project within the EFTF’s BIG polygon plus an approximately one-degree buffer. The samples were taken on average from 60 to 80 cm depth in floodplain landforms, dried and sieved to a 75-430 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 151 different HMs in the BIG area. The dataset, consisting of over 18 million individual mineral grains, was quality controlled and validated by an expert team. The data released here can be visualised, explored and downloaded using an online, bespoke mineral network analysis (MNA) tool built on a cloud-based platform. Preliminary analysis suggests that copper minerals cuprite and chalcopyrite may be indicative of base-metal/copper mineralisation in the area. Accompanying this report are two data files of TIMA results, and a minerals vocabulary file. </div><div>When completed in 2023, it is hoped the HMMA project will positively impact mineral exploration and prospectivity modelling around Australia, as well as have other applications in earth and environmental sciences.</div>
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<div>This look-book was developed to accompany the specimen display in the office of the Hon Madeleine King MP, Minister for Resources and Northern Australia. It contains information about each of the specimens including their name, link to resource commodities and where they were from. </div><div><br></div><div>The collection was carefully curated to highlight some of Australia’s well known resources commodities as well as the emerging commodities that will further the Australian economy and contribute to the low energy transition. The collection has been sourced from Geoscience Australia’s National Mineral and Fossil Collection. </div><div><br></div><div>The collection focuses on critical minerals, ore minerals as well as some fuel minerals. These specimens align with some of Geoscience Australia major projects including the Exploring For the Future (EFTF) program, the Trusted Environmental and Geological Information program (TEGI) as well as the Repository and the public education and outreach program. </div>
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<div>The South Nicholson National Drilling Initiative (NDI) Carrara 1 stratigraphic drill hole was completed in late 2020, as a collaboration between Geoscience Australia, the Northern Territory Geological Survey (NTGS), and the MinEx CRC. The drilling aimed to gather new subsurface data on the potential mineral and energy resources in the newly identified Carrara Sub-basin. NDI Carrara 1 is located in the eastern Northern Territory, on the western flanks of the Carrara Sub-basin on the South Nicholson Seismic line, reaching a total depth of 1751 m, intersecting ca. 630 m of Cambrian Georgina Basin overlying ca. 1100 m of Proterozoic carbonates, black shales and minor siliciclastics (https://portal.ga.gov.au/bhcr/minerals/648482).</div><div> </div><div>Following a public data release of the borehole completion report, CSIRO was contracted by Geoscience Australia (GA) under the Exploring for the Future program to analyse samples from NDI Carrara 1 for quantitative bulk and clay fraction analysis. This report presents results for quantitative bulk and clay (<2 µm) fraction analysis by X-ray powder diffraction (XRD) on 32 bulk core samples from the NDI Carrara 1. Samples were prepared and analysed at the CSIRO’s Waite Laboratories in South Australia.</div><div><br></div>
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<div>The lookbook accompanies a loan of Australian critical mineral samples provided by Geoscience Australia for display at the Australian Embassy in Washington DC, United States. It contains information about each of the samples, including their provenance, mineral or rock name, and the critical mineral they contain.</div>
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<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 (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>
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<div>Bulk quantitative mineralogy of regolith is a useful indicator of lithological precursor (protolith), degree of weathering, and soil properties affecting various potential landuse decisions. To date, no empirical national-scale maps of regolith mineralogy are available in Australia. Satellite-derived mineralogical proxy products exist, however, they require on-the-ground validation. Catchment outlet sediments collected over 80% of the continent as part of the National Geochemical Survey of Australia (NGSA) afford a unique opportunity to rapidly and cost-effectively determine regolith mineralogy using the archived sample material. This report releases mineralogical data and metadata obtained as part of a study extending a previous pilot project for such a national regolith mineralogy database and atlas.</div><div>The area chosen for this study includes the part of South Australia not inside the pilot project, which focussed on the 2020-2024 Exploring for the Future (EFTF) Darling-Curnamona-Delamerian (DCD) region of southeastern Australia, as well as the EFTF Barkly-Isa-Georgetown (BIG) region of northern Australia. The South Australian part of the study was selected because the Geological Survey of South Australia indicated interest in expanding the pilot (DCD) project to the rest of the State. The BIG region was selected because it is a ‘deep-dive’ data acquisition and analysis area within the EFTF Australian Government initiative managed at Geoscience Australia. The whole study area essentially describes a continuous north-south trans-continental transect spanning South Australia (SA), Queensland (Qld) and the Northern Territory (NT), and is herein abbreviated as SA-Qld-NT.</div><div>Two hundred and sixty four NGSA sites from the SA-Qld-NT region were prepared for X-Ray Diffraction (XRD) analysis, which consisted of qualitative mineral identification of the bulk samples (i.e., ‘major’ minerals), qualitative clay mineral identification of the <2 µm grain-size fraction, and quantitative analysis of both major and clay minerals of the bulk sample. The identified mineral phases were quartz, kaolinite, plagioclase, K-feldspar, nosean (a sulfate bearing feldspathoid), calcite, dolomite, aragonite, ankerite, hornblende, gypsum, bassanite (a partially hydrated calcium sulfate), halite, hematite, goethite, magnetite, rutile, anatase, pyrite, interstratified or mixed-layer illite-smectite, smectite, muscovite, chlorite (group), talc, palygorskite, jarosite, alunite, and zeolite (group). Poorly diffracting material was also quantified and reported as ‘amorphous.’ Mineral identification relied on the EVA® software, whilst quantification was performed using Siroquant®. Resulting mineral abundances are reported with a Chi-squared goodness-of-fit between the actual diffractogram and a modelled diffractogram for each sample, as well as an estimated standard error (esd) measurement of uncertainty for each mineral phase quantified. Sensitivity down to 0.1 weight percent (wt%) was achieved, with any mineral detection below that threshold reported as ‘trace.’ </div><div>Although detailed interpretation of the mineralogical data is outside the remit of the present data release, preliminary observations of mineral abundance patterns suggest a strong link to geology, including proximity to fresh bedrock, weathering during sediment transport, and robust relationships between mineralogy and geochemistry. The mineralogical data generated by this study are downloadable as a .csv file from the Geoscience Australia website (https://dx.doi.org/10.26186/147990). </div>
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<div>This report presents the results of petrographic and X-ray Diffraction analysis undertaken by Microanalysis Australia under contract to Geoscience Australia, on rock samples collected from selected drill holes across the Proterozoic Birrindudu Basin and underlying metamorphic basement.</div><div><br></div>