Jianchaling, Jian-Cha-Ling |
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Shanxi, China |
Main commodities:
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 Jianchaling gold deposit is located in the southwestern part of Shaanxi Province in central China, approximately 260 km west-southwest of the provincial capital of Xian.
The gold deposit falls within a geologically complex area of the Qinling Fold Belt, and is hosted by folded and faulted Palaeoproterozoic rocks, along the northern margin of the South China craton. It is Mesozoic in age, fault controlled, and occurs within the uplifted Mian-Lue-Yang block, adjacent to the Mianlue suture zone, within the West Qinling mineral province.
Gold mineralisation is localised within the F145 fault, which has been defined over a strike length of at least 4km, with further extensions likely. It is one of a number of large, generally NW-SE oriented faults that cut through the region. The F145 fault is generally steeply N-dipping and WNW trending and is a deformation zone that resulted from dislocation along bedding planes, early foliation and axial planar surfaces of regional folds. Brittle-ductile deformation, partitioning of strain along pre-existing zones of weakness, and the formation of intra-shear zone lozenges contributed to the development of a complex fault zone geometry.
Variations in both dip and strike of discrete dislocation surfaces related to oblique, sinistral-reverse movement along the F145 fault zone focussed gold bearing hydrothermal fluids along three dominant structural orientations. Gold was preferentially deposited along shallowly NNE-dipping and shallowly to moderately NNW-dipping fault segments, and is also associated with shallowly WSW-dipping, dolomite dominated vein sets and as disseminated, economic gold grades (>4 g/t Au) over a 5 to 10 m thick zone below the contact with the hanging wall. The bulk of the ore is hosted by the altered ultramafic rocks, which also host significant nickel sulphide mineralisation 1.4km to the south.
Gold is very fine grained and intimately associated with finely disseminated pyrite and arsenopyrite. Gold is also related to laminated, realgar- and orpiment-bearing sheeted veins and hydrothermal breccias, as well as slickensides and fault gouge. Gold-bearing vein sets are located within the relatively undeformed, ultramafic intrashear zone lozenges. Gold-related alteration is dominated by extremely fine-grained, arsenic-bearing sulphide minerals and dolomite, with additional white mica and clay minerals.
The pre-mining geological resource was around 16.5 tonnes (0.536 Moz), with the better sections having a grade of 7.5 g/t Au.
For detail consult the references listed below.
The most recent source geological information used to prepare this decription was dated: 2003.
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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Erceg M, Kaiqiang F and Leach T 2004 - The Jianchaling mine, Shaanxi Province, Peoples Republic of China - A Carlin type gold deposit ?: in Hi Tech and World Competitive Mineral Success Stories Around the Pacific Rim, Proc. Pacrim 2004 Conference, Adelaide, 19-22 September, 2004, AusIMM, Melbourne, pp 143-151
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Vielreicher R M, Vielreicher N M, Hagemann S G, Jones G 2003 - Fault zone evolution and its controls on ore-grade distribution at the Jian Cha Ling gold deposit, western Qinling region, central China: in Mineralium Deposita v38 pp 538-554
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