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Mt McClure - Cockburn, Lotus, Success, Parmelia, Challenger, Success |
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Western Australia, WA, Australia |
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Au
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Super Porphyry Cu and Au
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IOCG Deposits - 70 papers
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All papers now Open Access.
Available as Full Text for direct download or on request. |
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The Mt McClure Archaean gold deposits are distributed over a strike length of 25 km within the Yandal greenstone belt in the northern Yilgarn Craton, Western Australia. This string of deposits is around 10 km west of the major Bronzewing gold deposit. Individual deposits include, from north to south: Lotus, Cockburn, Success, Parmelia, Challenger and Dragon.
The Mt McClure group of deposits are located on the western margin of the Yandal greenstone belt in an Archaean volcano-sedimentary succession that dips near vertical and strikes NNW. The Mt McClure Fault, a major NNW trending shear zone, separates this sucession from a sequence of felsic and mafic gneiss to the west, while a large granitoid lies between the Mt McClure hosts and the Mt Keith greenstone belt to the south. The Yandal Belt is on the eastern margin of the craton wide Norseman-Wiluna greenstone belt which hosts much of the gold endowment of the Craton.
Within the mineralised zone the probably east facing greenstone sequence comprises, from west to east: i). felsic (andesite-dacite) pyroclastics, ii). komatiitic volcanics and tuffaceous graphitic sediments, iii). tholeiitic basalts and tuffs, iv). basaltic to andesitic volcanics, with intercalated sulphidic cherts, v). felsic (mainly dacitic) volcanics (tuffs and lavas), and vi). basaltic to felsic volcanics.
In addition to this stratigraphy the sequence is intruded by granodiorites and a series of generally conformable dolerite sills up to 200 m thick. In some areas such as the Lotus-Cockburn segment, there are swarms of intermediate dykes (calc-alkaline lamprophyres).
Lotus and Cockburn are part of a 3 km mineralised zone separated by a 600 m gap with only sporadic mineralisation. Gold occurs in dolerites as blebs and veinlets within a major NNW trending shear that cuts the sequence obliquely. The upper sections of the deposits have been deeply weathered and ore is mined from the laterite and saprolite. The lodes dip at 50 to 80° E, within the 25 to 40 m wide mineralised shear with hanginwall and footwall lodes.
The four southern gold deposits, Success, Parmelia, Challenger and Dragon are are all close to the western margin of the Yandal Belt and are essentially NNW trending tabular bodies dipping 50° E, conformable with the foliation and bedding of the enclosing rocks - mainly hosted by strongly foliated, weakly to moderatley graphitic felsic cherty tuff enclosed between an overlying chloritic tuffaceous sediment and an underlying sequence of strongly foliated dacitic tuffs. Gold is associated with quartz(-carbonate-chlorite) veins up to 10 cm thick with disseminated sulphide(pyrite-arsenopyrite).
Total proved+probale reserves in 1996 were: 12.566 Mt @ 2.0 g/t Au
Indicated resources at the same date were: 1.975 Mt @ 2.0 g/t Au.
Production from 1992 to 1996 was 3.083 Mt @ 3.4 g/t Au
For detail consult the reference(s) listed below.
The most recent source geological information used to prepare this decription was dated: 1998.
This description is a summary from published sources, the chief of which are listed below.
© Copyright Porter GeoConsultancy Pty Ltd. Unauthorised copying, reproduction, storage or dissemination prohibited.
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Harris J L 1998 - Mount McClure gold deposits: in Berkman D A, Mackenzie D H (Ed.s), 1998 Geology of Australian & Papua New Guinean Mineral Deposits The AusIMM, Melbourne Mono 22 pp 137-147
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Phillips G N, Vearncombe J R, Eshuys E 1998 - Yandal Greenstone Belt, Western Australia: 12 million ounces of gold in the 1990 s: in Mineralium Deposita v33 pp 310-316
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Porter GeoConsultancy Pty Ltd (PorterGeo) provides access to this database at no charge. It is largely based on scientific papers and reports in the public domain, and was current when the sources consulted were published. While PorterGeo endeavour to ensure the information was accurate at the time of compilation and subsequent updating, PorterGeo, its employees and servants: i). do not warrant, or make any representation regarding the use, or results of the use of the information contained herein as to its correctness, accuracy, currency, or otherwise; and ii). expressly disclaim all liability or responsibility to any person using the information or conclusions contained herein.
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