TY - THES

T1 - Skarn and low-temperature mineralisation and alteration at the Yongping Copper Deposit, Jiangxi Province, China

AU - Papst, Irene

N1 - embargoed until null

PY - 2006

Y1 - 2006

N2 - The objectives of this study in the Yongping copper deposit (Jiangxi Province/China) were to describe the skarn and low-temperature alteration and mineralisation developed around a granitic porphyry intrusion in the central part of the open pit mine. Three alteration/mineralisation stages can be distinguished, but the boundaries appear transitional: An early skarn stage, a main stage of sulphide ore formation and a late stage of low-temperature alteration. Minerals of the skarn assemblage are only partly preserved. The main skarn mineral is andraditic garnet and seldom diopside and epidote. Calcite, quartz and pyrite were also stable in this stage. The main sulphides of the sulphide stage are pyrite and chalcopyrite. They occur disseminated to massive as well as in veinlets. The pervasive low-temperature alteration affecting the skarn rock often completely destroyed the previous higher-temperature mineral assemblage. The alteration minerals are very fine-grained and mostly consist of chlorite and calcite. The fluid inclusion study revealed homogenisation temperatures of 400°C for the fluid inclusions in skarn garnet (7w% NaCl eq and XCO2=0.02). Inclusions studied in the granitic porphyry rock yielded a wide range of homogenisation temperatures (180-350°C, 3.7-12.3w% NaCl eq, XCO2=0.01-0.02). They might represent fluids that were sucessively entrapped during cooling of the hydrothermal system. Inclusions in a fluorite vein gave Th of 140-190°C (0w% NaCl eq XCO2=0.02-0.03).

AB - The objectives of this study in the Yongping copper deposit (Jiangxi Province/China) were to describe the skarn and low-temperature alteration and mineralisation developed around a granitic porphyry intrusion in the central part of the open pit mine. Three alteration/mineralisation stages can be distinguished, but the boundaries appear transitional: An early skarn stage, a main stage of sulphide ore formation and a late stage of low-temperature alteration. Minerals of the skarn assemblage are only partly preserved. The main skarn mineral is andraditic garnet and seldom diopside and epidote. Calcite, quartz and pyrite were also stable in this stage. The main sulphides of the sulphide stage are pyrite and chalcopyrite. They occur disseminated to massive as well as in veinlets. The pervasive low-temperature alteration affecting the skarn rock often completely destroyed the previous higher-temperature mineral assemblage. The alteration minerals are very fine-grained and mostly consist of chlorite and calcite. The fluid inclusion study revealed homogenisation temperatures of 400°C for the fluid inclusions in skarn garnet (7w% NaCl eq and XCO2=0.02). Inclusions studied in the granitic porphyry rock yielded a wide range of homogenisation temperatures (180-350°C, 3.7-12.3w% NaCl eq, XCO2=0.01-0.02). They might represent fluids that were sucessively entrapped during cooling of the hydrothermal system. Inclusions in a fluorite vein gave Th of 140-190°C (0w% NaCl eq XCO2=0.02-0.03).

KW - skarn South China fluid inclusions porphyry systems copper deposits

KW - Skarn Südchina Flüssigkeitseinschlüsse Porphyrysysteme Kupferlagerstätte

M3 - Diploma Thesis

ER -