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Evaluation of Gossans in Relation to Lead-Zinc Mineralisation in the Mount Isa Inlier, Queensland

Created 17/10/2025

Updated 17/10/2025

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Structural, textural, mineralogical, and geochemical properties of gossans associated with lead-zinc mineralisation in the Carpentarian Mount Isa Inlier of northwest Queensland have been studied. Mineralisation at Mount Isa, Hilton, and Lady Loretta is associated with abundant stratiform pyrite, which, upon oxidation, has formed prominent gossanous ridges at each deposit. The gossans, which have a laminated structure and occasional boxworks and casts after pyrite, generally carry only minor to trace levels of target and pathfinder elements. Where orebodies were close to the surface, cerussite and other secondary lead minerals are abundant, but Zn and Ag have been substantially leached from surface gossans. Immature gossans are found on the Dugald River and Pegmont dposits, both of which have low iron sulphide contents and a partially truncated profile. At Dugald River, the normally mobile elements (e.g. K , S, Zn, Cu, Cd, Tl) have been retained because of reaction between acid solutions and carbonate-rich wall rocks. The Pegmont mineralisation occurs in a quartz-magnetite-garnet-apatite banded iron formation, which, on oxidation, has given rise to a Mn-, Pb-, and Zn-rich gossan with abundant plumbogummite, pyromorphite, and coronadite. Gossans and ironstones from elsewhere within the Paradise Creek Formation, Soldiers Cap Group, Mount Isa Group, and Answer Slate often have similar laminated structures and mineralogy, but their variable geochemical signatures make direct comparison with other deposits difficult. Various statistical techniques have been used to evaluate these geochemical data in relation to gossans and ironstones of known association from throughout the Mount Isa Inlier. Although reflecting some known mineralogical and elemental associations, neither correlation coefficients nor R-mode factor analysis are of use in assigning group membership, because of the diverse geochemical characteristics of the ferruginous outcrops. Stepwise discriminant analysis using Pb, P, Ba, As, Zn, Mn, Co, S, and Sb was found to classify all gossans and ironstones into six geologically distinct groups.

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Title Evaluation of Gossans in Relation to Lead-Zinc Mineralisation in the Mount Isa Inlier, Queensland
Language eng
Licence Not Specified
Landing Page https://data.gov.au/data/dataset/95ba64fb-777d-4a8c-93a6-a68f9e7ceec7
Contact Point
Geoscience Australia Data
clientservices@ga.gov.au
Reference Period 20/04/2018
Geospatial Coverage
Map data © OpenStreetMap contributors
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  "type": "Polygon"
}
Data Portal Geoscience Australia

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This dataset was originally found on Geoscience Australia "Evaluation of Gossans in Relation to Lead-Zinc Mineralisation in the Mount Isa Inlier, Queensland". Please visit the source to access the original metadata of the dataset:
https://ecat.ga.gov.au/geonetwork/srv/eng/csw/dataset/evaluation-of-gossans-in-relation-to-lead-zinc-mineralisation-in-the-mount-isa-inlier-queenslan