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Chinkuashih, Jinguashi |
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Taiwan |
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Au Cu
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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 Chinkuashih (or Jinguashi) high sulphidation epithermal gold deposit is located in Cenozoic island arc rocks on the northern tip of eastern Taiwan (#Location: 25° 07'N, 121° 51'E).
Gold mineralisation is hosted in the late Pliocene-Pleistocene Penshan, Chiufen and Wutanshan sub-volcanic dacite domes and the intruded Miocene dacitic volcanics, sandstone and shale. These are members of a cluster of dacitic domes that range from a few hundred metres to 2 km across within the surrounding district. The orebodies are localised by large, north-south striking, normal fault and parallel secondary faults, which dip subvertically to the east, and continue to depths of at least 700 m.
The mineralisation is also reported to be controlled by fracturing related to a caldera and comprises an upper Au rich zone passing down into a Cu rich ores at depth.
Mineralisation was found in numerous large veins, breccia pipes, vein networks and replacement bodies. Lateral and vertical mineral zoning is present over several sq. km at surface and to depths of 1 km.
The central Penshan, Tsushihsan and Changen orebodies represent energite-gold zones in which copper increases with depth, while the peripheral Chuifen and Wutanshan veins are mainly gold-bearing.
The epithermal high-sulphidation mineralisation comprises quartz>alunite, barite, rhodochrosite, calcite, pyrite, enargite, luzonite, famatinite, electrum veins and breccia pipes, with lesser chalcopyrite, chalcocite, sphalerite and gold, and traces of marcasite and cinnabar, in silicified and advanced argillic altered wallrocks.
The dacite bodies exhibit broad alteration patterns adjacent to mineralisation, passing from fresh rock into a chlorite-carbonate zone and to sericite-silica (with dickite and nacrite), grading to a cherty silicified rock with pyrite, alunite (pyrophyllite) alteration, adjacent to mineralisation. An acid-sulphate assemblage composed of alunite-dickite-minor native sulphur is present in the upper portions of the larger orebodies.
Between 1894 and 1988, more than 92 tonnes of Au, 0.119 Mt of Cu metal and 183 t Ag were produced from 20 Mt of ore @ 0.6% Cu, 4.6 g/t Au, 9 g/t Ag (Chen, 1993).
The most recent source geological information used to prepare this decription was dated: 2002.
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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Chen C S, 1993 - Application of CSAMT Method for Gold-Copper Deposits, Chinkuashih Area, Northern Taiwan: in Terrestrial, Atmospheric and Oceanic Sciences v.4 pp. 339-350
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Henley R W and Berger B R, 2012 - Pyrite-sulfosalt reactions and semimetal fractionation in the Chinkuashih, Taiwan, copper–gold deposit: a 1 Ma paleo-fumarole: in Geofluids v.12 pp. 199–263
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Wang Y S, Sasakib M, Sasadab M and Chen C H, 1999 - Fluid inclusion studies of the Chinkuashih high-sulfidation gold-copper deposits in Taiwan: in Chemical Geology v.154 pp. 155–167
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