Re-Os geochronology and isotope systematics of the Tanami, Tennant Creek and Olympic Dam Cu-Au deposits
The 187Re-187Os system can determine directly the age of formation of ore deposits and can characterise the isotopic provenance of metals in ore systems. We report rhenium-osmium (Re-Os) isotope data from the Callie gold deposit of the Tanami district in the Northern Territory, the Gecko Cu-Au-Bi de...
| Main Authors: | , , , , |
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| Format: | Journal Article |
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Taylor & Francis Co Ltd
2008
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| Online Access: | http://hdl.handle.net/20.500.11937/21867 |
| _version_ | 1848750710681763840 |
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| author | McInnes, Brent Keays, R. Lambert, D. Hellstrom, J. Allwood, J. |
| author_facet | McInnes, Brent Keays, R. Lambert, D. Hellstrom, J. Allwood, J. |
| author_sort | McInnes, Brent |
| building | Curtin Institutional Repository |
| collection | Online Access |
| description | The 187Re-187Os system can determine directly the age of formation of ore deposits and can characterise the isotopic provenance of metals in ore systems. We report rhenium-osmium (Re-Os) isotope data from the Callie gold deposit of the Tanami district in the Northern Territory, the Gecko Cu-Au-Bi deposit of the Tennant Creek district in the Northern Territory and the giant Olympic Dam Cu-Au-U deposit in South Australia. Re-Os data for vein sulfides from the Callie deposit produce an isochron age of 1622 ± 120 Ma, indicating that gold mineralisation occurred after emplacement of adjacent granitoid plutons in the Tanami region. Sulfide minerals from the Callie gold-quartz vein system have initial Os isotope ratios that overlap mantle values, indicating that the Os in the Callie gold deposit was derived from a non-radiogenic source with a distinctly different isotopic composition than the surrounding crustal rocks. Cu-Au-Bi sulfide ores from the Gecko 44 Deposit in the Tennant Creek camp produced a Re-Os age of 1665 ± 66 Ma, confirming a post-Barramundi epigenetic formation age for the Cu-sulfide ores. The Re-Os age supports earlier hypotheses that late-stage granitoids (e.g. Warrego Granite) were a potential source of fluids and Cu, Au, Bi, U and S to the sulfide stage deposits of the Tennant Creek district. The initial Os isotope ratio of the Gecko Cu-sulfide deposit is non-radiogenic and suggests a mantle-like source for Os. Whole-rock ore samples and mineral separates from the chalcopyrite zone of the Olympic Dam Cu-Au-U deposit yielded a Re-Os age of 1258±;28 Ma. Because the ages of both the associated Roxby Downs Granite and felsic dykes that cross-cut mineralisation are much older (ca1590 Ma), the ca 1258 Ma age is interpreted as the time when the Re-Os isotope system at Olympic Dam was reset by a secondary process, possibly related to thermal metamorphism or supergene alteration. |
| first_indexed | 2025-11-14T07:41:10Z |
| format | Journal Article |
| id | curtin-20.500.11937-21867 |
| institution | Curtin University Malaysia |
| institution_category | Local University |
| last_indexed | 2025-11-14T07:41:10Z |
| publishDate | 2008 |
| publisher | Taylor & Francis Co Ltd |
| recordtype | eprints |
| repository_type | Digital Repository |
| spelling | curtin-20.500.11937-218672017-09-13T13:53:06Z Re-Os geochronology and isotope systematics of the Tanami, Tennant Creek and Olympic Dam Cu-Au deposits McInnes, Brent Keays, R. Lambert, D. Hellstrom, J. Allwood, J. The 187Re-187Os system can determine directly the age of formation of ore deposits and can characterise the isotopic provenance of metals in ore systems. We report rhenium-osmium (Re-Os) isotope data from the Callie gold deposit of the Tanami district in the Northern Territory, the Gecko Cu-Au-Bi deposit of the Tennant Creek district in the Northern Territory and the giant Olympic Dam Cu-Au-U deposit in South Australia. Re-Os data for vein sulfides from the Callie deposit produce an isochron age of 1622 ± 120 Ma, indicating that gold mineralisation occurred after emplacement of adjacent granitoid plutons in the Tanami region. Sulfide minerals from the Callie gold-quartz vein system have initial Os isotope ratios that overlap mantle values, indicating that the Os in the Callie gold deposit was derived from a non-radiogenic source with a distinctly different isotopic composition than the surrounding crustal rocks. Cu-Au-Bi sulfide ores from the Gecko 44 Deposit in the Tennant Creek camp produced a Re-Os age of 1665 ± 66 Ma, confirming a post-Barramundi epigenetic formation age for the Cu-sulfide ores. The Re-Os age supports earlier hypotheses that late-stage granitoids (e.g. Warrego Granite) were a potential source of fluids and Cu, Au, Bi, U and S to the sulfide stage deposits of the Tennant Creek district. The initial Os isotope ratio of the Gecko Cu-sulfide deposit is non-radiogenic and suggests a mantle-like source for Os. Whole-rock ore samples and mineral separates from the chalcopyrite zone of the Olympic Dam Cu-Au-U deposit yielded a Re-Os age of 1258±;28 Ma. Because the ages of both the associated Roxby Downs Granite and felsic dykes that cross-cut mineralisation are much older (ca1590 Ma), the ca 1258 Ma age is interpreted as the time when the Re-Os isotope system at Olympic Dam was reset by a secondary process, possibly related to thermal metamorphism or supergene alteration. 2008 Journal Article http://hdl.handle.net/20.500.11937/21867 10.1080/08120090802097443 Taylor & Francis Co Ltd restricted |
| spellingShingle | McInnes, Brent Keays, R. Lambert, D. Hellstrom, J. Allwood, J. Re-Os geochronology and isotope systematics of the Tanami, Tennant Creek and Olympic Dam Cu-Au deposits |
| title | Re-Os geochronology and isotope systematics of the Tanami, Tennant Creek and Olympic Dam Cu-Au deposits |
| title_full | Re-Os geochronology and isotope systematics of the Tanami, Tennant Creek and Olympic Dam Cu-Au deposits |
| title_fullStr | Re-Os geochronology and isotope systematics of the Tanami, Tennant Creek and Olympic Dam Cu-Au deposits |
| title_full_unstemmed | Re-Os geochronology and isotope systematics of the Tanami, Tennant Creek and Olympic Dam Cu-Au deposits |
| title_short | Re-Os geochronology and isotope systematics of the Tanami, Tennant Creek and Olympic Dam Cu-Au deposits |
| title_sort | re-os geochronology and isotope systematics of the tanami, tennant creek and olympic dam cu-au deposits |
| url | http://hdl.handle.net/20.500.11937/21867 |