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Hetai Goldfield, Gaocun |
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Guangdong, China |
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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 Gaocun gold deposit is located within the Hetai Goldfield, in central Guandong, approximately 100 km NW of Guangzhou, and is the largest gold producing district in southern China.
The Hetai Goldfield, which contains at least six gold deposits (the largest of which is Gaocan), is within the Yunkai metamorphic terrane which covers large areas of western Guandong and south-eastern Guangxi provinces.
Gold mineralisation in the field is almost entirely confined to steeply dipping, ENE Hercynian-Indosinian ductile shear zones overprinting metamorphosed Sinian host rocks and is in the north-eastern part of the NE-SW trending Wuchuan-Sihua fracture zone, one of a series of crustal scale structures in southern China.
The Sinian hosts comprise mica schists, feldspar-mica schist and mica gneisses. These rocks are in structural contact with lower Palaeozoic sediments to the south, and with amphibolite facies to migmatites to the north intruded by Hercynian (392 Ma) and Indosinian (233 Ma) granitoids. These are overlain by Mesozoic tuffs and sediments.
At least 70 ductile shear zones (mylonite belts) are mapped in the Hetai Goldfield, ranging from several tens of centimetres to several tens of metres in width, and from tens of metres to more than 1 km in length.
The Gaocun deposit is hosted by a mylonite zone 40 m wide and 450 m in length which strikes at 70° and dips at 60 to 80° NNW. Ore occurs in almost equal proportions as strongly brecciated mesoscopic quartz veins (cemented by sulphides - 85% pyrite and 10% chalcopyrite) and as disseminations of sulphide (very fine grians to aggregares of 95% chalcopyrite and 5% pyrite) through sections of the mylonite, never occupying more than 50% of the shear at any one interval. The gold grade within un-mineralised mylonite is indistinuishable from the content of the gneisses and schists outside of the shear zone, namely around 3 ppb. This un-mineralised mylonite is weakly silicified, chloritised and carbonatised, but is not evidently sulphidised. Where pyritised the gold grades range from 1 to 70 ppm Au.
Historical production at Gaocun, prior to the commencement of mining in 1989, amounted to 30.7 tonnes of gold. The Hetai Goldfield is reported to contain resources of 50 t of contained Au at grades averaging 10 g/t Au.
For more detail consult the reference(s) listed below.
The most recent source geological information used to prepare this decription was dated: 2001.
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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Guilin Zhang, Boulter C A, Jincheng Liang 2001 - Brittle origins for disseminated Gold mineralization in Mylonite: Gaocun Gold deposit, Hetai Goldfield, Guangdong Province, South China: in Econ. Geol. v96 pp 49-59
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Li Miao, Ruisong Xu, Yueliang Ma, Jinhong Xu, Jie Wang, Rui Cai and Yu Chen 2008 - Biogeochemical characteristics of the Hetai goldfield, Guangdong Province, China: in J. of Geochemical Exploration v96 pp 43-52
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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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