四川石棉碲矿床地球化学特征研究

GEOCHEMICAL FEATURE STUDY OF TELLURIUM DEPOSIT IN SHIMIAN COUNTY, SICHUAN PROVINCE, CHINA

研究了世界首例碲矿床的地球化学特征，特别是微量分散元素碲富集成矿的地球化学条件。此矿床属Ｔｅ－Ｂｉ－Ａｕ－Ａｇ组合型中温热液矿床，矿体为碳酸盐脉和磁黄铁矿脉，矿石平均品位：Ｔｅ５．９８％、Ｂｉ８．０２％、Ａｕ９．７３×１０－６、Ａｇ３７．４５×１０－６。成矿元素Ｔｅ、Ａｕ、Ａｇ主要来源于深部富含ＣＯ２、Ｓ的热流体。此热流体沿深大断裂上升至地壳浅部时，从围岩中浸取了大量的成矿元素Ｂｉ、Ｆｅ等。热液中的硫优先与铁结合生成磁黄铁矿析出，降低了热液中的硫浓度，从而促使分散元素碲与其沉淀剂Ｂｉ、Ａｇ、Ａｕ相结合呈碲铋矿物、碲银矿和碲金矿等独立矿物形式沉淀，并富集成矿。

The geochemical features of the first tellurium deposit in the world are studied in this paper. The key point is placed on the geochemical condition of trace-dispersed element Te concentrating in the deposit. This deposit is a hydrothermal deposit which belong to the Te-Bi-Au-Ag association type. The ore bodies are the carbonate veins and pyrrhotite veins with the average grades of 5.98% Te, 8.02% Bi, 9.73 10-6 Au and 37.45 x 10-6 Ag.The ore-forming elements (Te, Au and Ag) mainly come from the deep hydrothermal fluid rich in CO2 and S. When the hydrothermal fluid raised along the abyssal fault to shallow crust,the ore-forming elements Bi and Fe were extracted from the surrounding rocks. The Sexsited in the fluid combined firstly with Fe, forming the pyrrhotite.As a result,the S concentration in the fluid was reduced. This made the trece-dispersed element Te combining with the precipitating agents such as Bi, Ag and Au and forming the tetradymite, tsumoite, joseite-B, hessile and calaverite. At last the deposit was formed.