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Multivariate compositional analysis of groundwater geochemistry in the Georgina Basin. New insights for sediment-hosted mineral systems

Created 17/10/2025

Updated 17/10/2025

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The Georgina Basin in northern Australia holds significant potential for strategic minerals, particularly zinc and phosphate, which are crucial for Australia’s economy and transition to net-zero. This study applied multivariate statistical tools to groundwater geochemistry from the basin’s regional Cambrian Limestone Aquifer to investigate the prospectivity of sediment-hosted phosphate and Zn-Pb mineral systems in the northern half of the Georgina Basin. Robust principal component analysis (rPCA) identified Mo and I- (as well as Rb and Al) as key elements associated with the variation of P in groundwater. K-means cluster analysis then mapped a subset of spatial clusters where these P relationships were evident. This investigation culminated in the creation of a new geochemical index (Phos#) for identifying hydrogeochemical anomalies likely sourced from phosphate mineralisation. Five areas were most prospective using Phos#: three near Elliott, and one in each of the Central Georgina and Undilla Sub-basins. The hydrogeochemistry was also valuable in detecting regional sediment-hosted Zn-Pb mineralisation. Radiogenic Pb-isotope outliers (206Pb/204Pb of 22.00 to 24.00) in the Alexandria-Wonarah Basement High and Undilla Sub-basin (which were supported by elevated Pb or Zn in groundwater), were spatially correlated with observed sulfides at the surface or in drillholes and consistent with the radiogenic Pb-isotope signature of Georgina Basin’s Joplin-type, Mississippi Valley Type Zn-Pb mineralisation. This regional in-depth assessment of the groundwater chemistry provides an efficient scale-reduction tool with clear targets for follow-up, and is supported by a discussion on how this multivariate, index-based approach can be translated to other sedimentary basins and/or mineralisation assemblages.

Citation: Schroder, I.F., de Caritat, P., Huston, D. & Champion, D., 2025. Multivariate compositional analysis of groundwater geochemistry in the Georgina Basin: New insights for sediment-hosted mineral systems. Journal of Geochemical Exploration, 278, 107857. doi: https://doi.org/10.1016/j.gexplo.2025.107857

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Title Multivariate compositional analysis of groundwater geochemistry in the Georgina Basin. New insights for sediment-hosted mineral systems
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/en/dataset/454a827b-f245-48b2-a711-96ccdb94c2e0
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Geoscience Australia Data
clientservices@ga.gov.au
Reference Period
Geospatial Coverage
Map data © OpenStreetMap contributors
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This dataset was originally found on Geoscience Australia "Multivariate compositional analysis of groundwater geochemistry in the Georgina Basin. New insights for sediment-hosted mineral systems". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/multivariate-compositional-analysis-of-groundwater-geochemistry-in-the-georgina-basin-new-insig