四川石棉县大水沟独立碲矿床地质特征

碲在地壳中的丰度极低,仅为0.0006ppm(黎彤,1976),主要作为伴生元素出现于斑岩铜铝)矿床、铜镍硫化物矿床、某些金矿床和块状硫化物犷床中。目前尚未见有独立成型碎矿床的报道。

GEOLOGICAL CHARACTERISTICS OF DASHUIGOU TELLURIUM ORE DEPOSIT IN SHIMIAN COUNTY,SICHUAN PROVINCE, CHINA

Dashuigou tellurium ore deposit is located in the connecting part between the geosycline and the Yangtze platform. It is limited in the leguminous tectonic microlithon, which is enclosed by the Luding-Mianning regional ductile shear zone. The microlithon is a xnetamorphic dome which is composed of middle-lower Triassic sirata. The core of the dome is a set of coarse-crystallized marble. The limbs are constituted by cafe-quartz shist, sericite-tremolite with marble interbed. It is 15000m thick.Twelve pyrrhotite veins have been found and four of them been mined. The strike of the ore veins are SN and NNE(0°-10°), the dip angle 60°～70°. Tellurium ore veins are closely associated with pyrrhotite ones and controlled by the lat ter. The former penetrates into the latter. The ore veins obviously bevel the strata around them. The single tellurium ore vein is 0.3-0.5m thick. All of them take the shape of lenticule and have the characteristics of thinning out and reproducibility in both strike and dip direction. The main ore vein is 150m long and extends 50m in the deep.Wall-rock,alterations are extensively developed in the mine. The main alterations are muscovitization, ankeritation, silication, sericitization, tourmalinization, chloritization and so on.Mineral assemblage of the ores are as follows: pyrite, pyrrhotite, tetradymite,chalcopyrite, sphalerite, joseite, tellurobismuthite, trigona, hessite, tellurium, etc. Its gangue minerals are dolomite, ankerite, calcite, quartz and muscovite, etc.As the first and the only independent tellurium ore deposit in the world at present, Dashuigou tellurium ore deposit is probably giant according to Laznicka P.(1989).