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Age constraints on the hydrothermal history of the Prominent Hill iron oxide copper-gold deposit, South Australia

Citation

Bowden, B and Fraser, G and Davidson, GJ and Meffre, S and Skirrow, R and Bull, S and Thompson, J, Age constraints on the hydrothermal history of the Prominent Hill iron oxide copper-gold deposit, South Australia, Mineralium Deposita, 52, (6) pp. 863-881. ISSN 0026-4598 (2017) [Refereed Article]

Copyright Statement

Copyright2016 Springer-Verlag Berlin Heidelberg

DOI: doi:10.1007/s00126-016-0689-1

Abstract

The Mesoproterozoic Prominent Hill iron-oxide copper–gold deposit lies on the fault-bound southern edge of the Mt Woods Domain, Gawler Craton, South Australia. Chalcocite–bornite–chalcopyrite ores occur in a hematitic breccia complex that has similarities to the Olympic Dam deposit, but were emplaced in a shallow water clastic–carbonate package overlying a thick andesite–dacite pile. The sequence has been overturned against the major, steep, east–west, Hangingwall Fault, beyond which lies the clastic to potentially evaporitic Blue Duck Metasediments. Immediately north of the deposit, these metasediments have been intruded by dacite porphyry and granitoid and metasomatised to form magnetite–calc–silicate skarn ± pyrite–chalcopyrite. The hematitic breccia complex is strongly sericitised and silicified, has a large sericite ± chlorite halo, and was intruded by dykes during and after sericitisation. This paper evaluates the age of sericite formation in the mineralised breccias and provides constraints on the timing of granitoid intrusion and skarn formation in the terrain adjoining the mineralisation. The breccia complex contains fragments of granitoid and porphyry that are found here to be part of the Gawler Range Volcanics/Hiltaba Suite magmatic event at 1600–1570 Ma. This indicates that some breccia formation post-dated granitoid intrusion. Monazite and apatite in Fe-P-REE-albite metasomatised granitoid, paragenetically linked with magnetite skarn formation north of the Hangingwall Fault, grew soon after granitoid intrusion, although the apatite experienced U–Pb–LREE loss during later fluid–mineral interaction; this accounts for its calculated age of 1544 ± 39 Ma. To the south of the fault, within the breccia, 40Ar–39Ar ages yield a minimum age of sericitisation (+Cu+Fe+REE) of dykes and volcanics of ∼1575 Ma, firmly placing Prominent Hill ore formation as part of the Gawler Range Volcanics/Hiltaba Suite magmatic event within the Olympic Cu–Au province of the Gawler Craton.

Item Details

Item Type:Refereed Article
Keywords:IOCG, U-Pb geochronology
Research Division:Earth Sciences
Research Group:Geology
Research Field:Geochronology
Objective Division:Expanding Knowledge
Objective Group:Expanding Knowledge
Objective Field:Expanding Knowledge in the Earth Sciences
Author:Bowden, B (Mr Bryan Bowden)
Author:Davidson, GJ (Dr Garry Davidson)
Author:Meffre, S (Dr Sebastien Meffre)
Author:Bull, S (Dr Stuart Bull)
Author:Thompson, J (Mr Jay Thompson)
ID Code:116869
Year Published:2017 (online first 2016)
Funding Support:Australian Research Council (CE0561595)
Deposited By:CODES ARC
Deposited On:2017-05-24
Last Modified:2017-11-03
Downloads:0

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