Analytical results and associated sample and analysis metadata from the analysis of minerals in earth material samples.

Analytical results and associated sample and analysis metadata from the analysis of minerals in earth material samples.

Analytical results and associated sample and analysis metadata from the analysis of minerals in earth material samples.

During the last 10-20 years, Geological Surveys around the world have undertaken a major effort towards delivering fully harmonized and tightly quality controlled low-density multi-element soil geochemical maps and datasets of vast regions including up to whole continents. Concentrations of between 45 and 60 elements commonly have been determined in a variety of different regolith types (e.g., sediment, soil). The multi-element datasets are published as complete geochemical atlases and made available to the general public. Several other geochemical datasets covering smaller areas but generally at a higher spatial density are also available. These datasets may, however, not be found by superficial internet-based searches because the elements are not mentioned individually either in the title or in the keyword lists of the original references. This publication attempts to increase the visibility and discoverability of these fundamental background datasets covering large areas up to whole continents. <b>Citation:</b> P. de Caritat, C. Reimann, D.B. Smith, X. Wang, Chemical elements in the environment: Multi-element geochemical datasets from continental- to national-scale surveys on four continents, <i>Applied Geochemistry</i>, Volume 89, 2018, Pages 150-159, ISSN 0883-2927, https://doi.org/10.1016/j.apgeochem.2017.11.010

<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>&nbsp;</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>

<div>Indicator minerals are those minerals that indicate the presence of a specific mineral deposit, alteration or lithology[1]. Their utility to the exploration industry has been demonstrated in a range of environments and across multiple deposit types including Cu-Au porphyry[2], Cu-Zn-Pb-Ag VMS[3] and Ni-Cu-PGE[4]. Recent developments in the field of SEM-EDS analysis have enabled the rapid quantitative identification of indicator minerals during regional sampling campaigns[4,5].</div><div>Despite the demonstrated utility of indicator minerals for diamond and base metal exploration in Canada, Russia and Africa, there are relatively few case studies published from Australian deposits. We present the results of an indicator mineral case study over the Julimar exploration project located 90 km NE of Perth. The Gonneville Ni-Cu-PGE deposit, discovered by Chalice Mining in 2020, is hosted within a ~30 km long belt of 2670 Ma ultramafic intrusions within the western margin of the Yilgarn Craton[6].</div><div>Stream sediments collected from drainage channels around the Gonneville deposit were analysed by quantitative mineralogy techniques to determine if a unique indicator mineral footprint exists there. Samples were processed and analysed for heavy minerals using a workflow developed for the Curtin University-Geoscience Australia Heavy Mineral Map of Australia project[7]. Results indicate elevated abundances of indicator minerals associated with ultramafic/mafic magmatism and Ni-sulfide mineralisation in the drainages within the Julimar project area, including pyrrhotite, pentlandite, pyrite and chromite. We conclude that indicator mineral studies using automated mineralogy are powerful, yet currently underutilised, tools for mineral exploration in Australian environments.</div><div>[1]McClenaghan, 2005. https://doi.org/10.1144/1467-7873/03-066 </div><div>[2]Hashmi et al., 2015. https://doi.org/10.1144/geochem2014-310 </div><div>[3]Lougheed et al., 2020. https://doi.org/10.3390/min10040310 </div><div>[4]McClenaghan &amp; Cabri, 2011. https://doi.org/10.1144/1467-7873/10-IM-026 </div><div>[5]Porter et al., 2020. https://doi.org/10.1016/j.oregeorev.2020.103406 </div><div>[6]Lu et al., 2021. http://dx.doi.org/10.13140/RG.2.2.35768.47367 </div><div>[7]Caritat et al., 2022. https://doi.org/10.3390/min12080961 </div> This Abstract was submitted/presented to the 2023 Australian Exploration Geoscience Conference 13-18 Mar (https://2023.aegc.com.au/)

<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).&nbsp;</div>

<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.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</div>

<div>A novel method of estimating the silica (SiO2) and loss-on-ignition (LOI) concentrations for the North American Soil Geochemical Landscapes (NASGL) project datasets is proposed. Combining the precision of the geochemical determinations with the completeness of the mineralogical NASGL data, we suggest a ‘reverse normative’ or inversion approach to calculate first the minimum SiO2, water (H2O) and carbon dioxide (CO2) concentrations in weight percent (wt%) in these samples. These can be used in a first step to compute minimum and maximum estimates for SiO2. In a recursive step, a ‘consensus’ SiO2 is then established as the average between the two aforementioned estimates, trimmed as necessary to yield a total composition (major oxides converted from reported Al, Ca, Fe, K, Mg, Mn, Na, P, S, and Ti elemental concentrations + ‘consensus’ SiO2 + reported trace element concentrations converted to wt% + ‘normative’ H2O + ‘normative’ CO2) of no more than 100 wt%. Any remaining compositional gap between 100 wt% and this sum is considered ‘other’ LOI and likely includes H2O and CO2 from the reported ‘amorphous’ phase (of unknown geochemical or mineralogical composition) as well as other volatile components present in soil. We validate the technique against a separate dataset from Australia where geochemical (including all major oxides) and mineralogical data exist on the same samples. The correlation between predicted and observed SiO2 is linear, strong (R2 = 0.91) and homoscedastic. We also compare the estimated NASGL SiO2 concentrations with another publicly available continental-scale survey over the conterminous USA, the ‘Shacklette and Boerngen’ dataset. This comparison shows the new data to be a reasonable representation of SiO2 values measured on the ground over the same study area. We recommend the approach of combining geochemical and mineralogical information to estimate missing SiO2 and LOI by the recursive inversion approach in datasets elsewhere, with the caveat to validate results.</div><div><br></div><div>The major oxide concentrations, including those for the estimated SiO2 and LOI, for the NASGL A and C horizons are available for download, as CSV files. A worked example for five selected NASGL C horizon samples is also available for download, as an XLSX file.</div> <b>Citation:</b> P. de Caritat, E. Grunsky, D.B. Smith; Estimating the silica content and loss-on-ignition in the North American Soil Geochemical Landscapes datasets: a recursive inversion approach. <i>Geochemistry: Exploration, Environment, Analysis</i> 2023; 23 (3): 2023-039 doi: https://doi.org/10.1144/geochem2023-039 This article appears in multiple journals (Lyell Collection & GeoScienceWorld)

Geoscience Australia, in collaboration with the Geological Survey of New South Wales and the Geological Survey of Queensland, have been collecting precompetitive geoscience data in the southern Thomson Orogen as part of the Southern Thomson project. This Project is designed to encourage industry investment in this poorly understood area, and spark interest by explorers to potentially discover a new minerals province. A stratigraphic drilling program was established to: 1. Develop baseline geologic constraints 2. Improve the understanding of basement geology 3. Better understand the potential for mineralisation. In the frame of this project, hyperspectral data have been collected from mud rotary drill chips and diamond drill cores penetrating the Mesozoic Eromanga Basin into basement felsic igneous, clastic sedimentary and metasedimentary rocks of the southern Thomson Orogen. Geoscience Australia requested assistance from CSIRO in performing quality assurance (QA) by reprocessing and reinterpreting hyperspectral data collected from 14 boreholes to inform the components of the stratigraphic drilling program. This report outlines the results of CSIRO’s reprocessing of the hyperspectral drill core data, which consisted of the following: 1. Quality Assurance (QA) on the data 2. Identification of visible to near infrared, shortwave-infrared and thermal infrared active mineral species 3. Identification of mineral assemblages 4. Comparison of mineralogy with other available geoscience data, such as geochemistry, where available.