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Abstract
Volcanic-hosted massive sulfide (VMS) occurrences in the Quinns district are hosted predominantly by ca. 2814-2800 Ma banded iron formation (BIF) within a sequence of rhyolite, basalt, and minor siltstone. The VMS occurrences and their surrounding rocks are folded, metamorphosed, and deeply weathered and variably covered by transported regolith. This study uses an integrated petrological and geochemical approach to map gradients in synvolcanic mineral and element abundances, with the aim of understanding the effects of postvolcanic processes on Archean VMS ore. Rhyolite-dominant footwall rocks and the BIF record kilometer-scale gradients in alteration mineral patterns and geochemistry. Rhyolite exposed throughout the district and intersected by drill holes records distal alteration assemblages of quartz-white mica ± chlorite. At the Austin deposit in the western part of the district, abundant talc and anthophyllite with minor cummingtonite and hornblende are associated with mineralization in the BIF, indicating intense magnesium metasomatism. Further away from mineralization, chlorite is the dominant alteration mineral. Adjacent rhyolite is altered to chlorite in proximal zones and white micas in more distal areas. Approaching known VMS prospects in the eastern half of the district, the rhyolite grades into a 2 × 1 km zone of schistose rhyolite with generally dispersed, but locally abundant, coarse-grained andalusite ± kyanite ± garnet rhyolitic schist. This broad Al-rich silicate alteration zone envelops two discrete 1 km × 500 m proximal alteration zones in rhyolite, defined by chlorite ± talc, with minor disseminated magnetite, pyrite, and chalcopyrite. The northernmost proximal alteration zone lies stratigraphically below the BIF-hosted Cu-Zn-rich gossan exposed near the Tasman prospect. The proximal zones are interpreted to be the result of the interaction between synvolcanic, Mg-rich fluids and rhyolite footwall at the time of VMS mineralization and BIF deposition.
Original language | English |
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Pages (from-to) | 1411-1438 |
Number of pages | 28 |
Journal | Economic Geology |
Volume | 111 |
Issue number | 6 |
Early online date | 17 Jun 2016 |
DOIs | |
Publication status | Published - 1 Sept 2016 |
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Dive into the research topics of 'Geochemical and spectral footprint of metamorphosed and deformed VMS-style mineralization in the Quinns district, Yilgarn craton, Western Australia'. Together they form a unique fingerprint.Projects
- 1 Finished
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Multiscale Dynamics of Ore Body Formation
APAI, N. N. (Investigator 01), McCuaig, C. (Investigator 02), Gessner, K. (Investigator 03), APAI, U. (Investigator 04), Hobbs, B. (Investigator 05), Cawood, P. (Investigator 06), Ord, A. (Investigator 07), Gorczyk, W. (Investigator 08), Gerya, T. (Investigator 09), Liu, J. (Investigator 10) & Lester, D. (Investigator 11)
ARC Australian Research Council , CSIRO, Eidgenössische Technische Hochschule Zürich, Geocrust Pty Ltd, Geological Survey of Western Australia, Golden Phoenix International Pty Ltd, Mineral Mapping Pty Ltd, Department of Primary Industries and Regions (South Australia), Silver Swan Group Ltd, Vearncombe & Associates Pty Ltd, Western Mining Services Australia Pty Ltd
1/01/10 → 31/12/15
Project: Research