Authors / CoAuthors
de Caritat, P. | Petts, A. | Kelaart, C.
Abstract
<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>
Product Type
document
eCat Id
147990
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Cnr Jerrabomberra Ave and Hindmarsh Dr GPO Box 378
Canberra
ACT
2601
Australia
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Keywords
- ( Project )
-
- EFTF – Exploring for the Future
- ( Project )
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- Australia’s Resources Framework
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- Regolith
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- Mineralogy
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- X-ray diffraction
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- mapping
- theme.ANZRC Fields of Research.rdf
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- Mineralogy and crystallography
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- Published_External
Publication Date
2023-07-25T05:23:56
Creation Date
2023-05-28T12:00:00
Security Constraints
Legal Constraints
Status
completed
Purpose
Present results of recent mineralogical investigation on NGSA samples, as part of the EFTF program
Maintenance Information
asNeeded
Topic Category
geoscientificInformation
Series Information
GA Record GA Record 2023/15
Lineage
<div>National Geochemical Survey of Australia http://dx.doi.org/10.11636/Record.2011.020 </div><div>Towards a Regolith Mineralogy Map of the Australian Continent - A Feasibility Study http://dx.doi.org/10.11636/Record.2021.035</div>
Parent Information
Extents
[-38, -15, 129, 145]
Reference System
Spatial Resolution
Service Information
Associations
Association Type - wasInformedBy
Towards a Regolith Mineralogy Map of the Australian Continent - A Feasibility Study in the Darling-Curnamona-Delamerian Region
eCat Identifier - 145916,
UUID - 295df5ac-902e-40a2-8818-28d81102be5c
Association Type - wasDerivedFrom
National Geochemical Survey of Australia: The Geochemical Atlas of Australia
eCat Identifier - 71973,
UUID - a4a1ac2e-0a2c-653b-e044-00144fdd4fa6
Source Information