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Sulfur isotope characteristics of the Archean Cu-Zn Gossan Hill VHMS deposit, Western Australia


Sharpe, R and Gemmell, JB, Sulfur isotope characteristics of the Archean Cu-Zn Gossan Hill VHMS deposit, Western Australia, Mineralium Deposita, 35, (6) pp. 533-550. ISSN 0026-4598 (2000) [Refereed Article]

DOI: doi:10.1007/s001260050260


Gossan Hill is an Archean (~3.0 Ga) Cu-Zn-magnetite-rich volcanic-hosted massive sulfide (VHMS) deposit in the Yilgarn Craton of Western Australia. Massive sulfide and magnetite occur within a layered succession of tuffaceous, felsic volcaniclastic rocks of the Golden Grove Formation. The Gossan Hill deposit consists of two stratigraphically separate ore zones that are stratabound and interconnected by sulfide veins. Thickly developed massive sulfide and stockwork zones in the north of the deposit are interpreted to represent a feeder zone. The deposit is broadly zoned from a Cu-Fe-rich lower ore zone, upwards through Cu-Zn to Zn-Ag-Au-Pb enrichment in the upper ore zone. New sulfur isotope studies at the Gossan Hill deposit indicate that the variation is wider than previously reported, with sulfide δ34S values varying between -1.6 and 7.8‰ with an average of 2.1 ± 1.4‰ (1σ error). Sulfur isotope values have a broad systematic stratigraphic increase of approximately 1.2‰ from the base to the top of the deposit. This variation in sulfur isotope values is significant in view of typical narrow ranges for Archean VHMS deposits. Copper-rich sulfides in the lower ore zone have a narrower range (δ34S values of -1.6 to 3.4‰, average ~1.6 ± 0.9‰) than sulfides in the upper ore zone. The lower ore zone is interpreted to have formed from a relatively uniform reduced sulfur source dominated by leached igneous rock sulfur and minor magmatic sulfur. Towards the upper Zn-rich ore zone, an overall increase in δ34S values is accompanied by a wider range of δ34S values, with the greatest variation occurring in massive pyrite at the southern margin of the upper ore zone (-1.0 to 7.8‰). The higher average δ34S values (2.8 ± 2.1‰) and their wider range are explained by mixing of hydrothermal fluids containing leached igneous rock sulfur with Archean seawater (δ34S values of 2 to 3‰) near the paleoseafloor. The widest range of δ34S values at the southern margin of the deposit occurs away from the feeder zone and is attributed to greater seawater mixing away from the central upflow zone.

Item Details

Item Type:Refereed Article
Research Division:Earth Sciences
Research Group:Geochemistry
Research Field:Geochemistry not elsewhere classified
Objective Division:Mineral Resources (Excl. Energy Resources)
Objective Group:Other mineral resources (excl. energy resources)
Objective Field:Other mineral resources (excl. energy resources) not elsewhere classified
UTAS Author:Sharpe, R (Dr Robina Sharpe)
UTAS Author:Gemmell, JB (Professor Bruce Gemmell)
ID Code:20606
Year Published:2000
Web of Science® Times Cited:8
Deposited By:Centre for Ore Deposit Research - CODES CoE
Deposited On:2000-08-01
Last Modified:2001-03-21

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