Sulfur isotopic composition of the Bainiuchang super-large Ag polymetallic deposit, Yunnan Province, China: Implications
The Bainiuchang deposit in Yunnan Province, China, is located geographically between the Gejiu ore field and the Dulong ore field. In addition to >7000 t Ag reserves, the deposit possesses large-scale Pb, Zn, Sn reserves and a mass of dispersed elements (i.e., In, Cd, Ge, Ga, etc.). Based on systematic studies of sulfur isotopic composition, the authors conclude: The Bainiuchang deposit experienced two epochs of metallogenesis, i.e., the Middle-Cambrian sea-floor exhalative sedimentary metallogenic epoch and the Yanshanian magmatic hydrothermal superimposition metallogenic epoch. In the two metallogenic epochs, the δ34S values of sulfides were all near 0, showing a tendency of being enriched slightly in heavy sulfur. The δ34S values of sulfides in the early metallogenic epoch are within the range of 2‰-5‰ with a peak value range of 2‰-3‰ and an average of 3.0‰, and those of sulfides in the late metallogenic epoch are within the range of 2‰-6‰ with a peak value of 3‰-4‰ and an average of 3.9‰. For the single metallogenic epoch, sulfur in the ore-forming fluids in the early epoch already reached isotopic equilibrium and was derived mainly from underneath the magma chamber or basement metamorphic igneous rocks. Sulfur in the sulfides in the late epoch was derived mainly from magmatic hydrothermal fluids formed in the process of remelting of the basement metamorphic igneous rocks.
作 者： XIE Hongjing ZHU Chaohui ZHANG Qian WANG Dapeng FAN Liangwu 作者单位： XIE Hongjing,WANG Dapeng,FAN Liangwu(State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China;Graduate School o the Chinese Academy of Sciences, Beijing 100039, China)ZHU Chaohui(State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China;Scientific Research Institution of State Land Resources, Henan Province, Zhenzhou 450053, China)
ZHANG Qian(State Key Laboratory of Ore Deposit Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang 550002, China)
刊 名： 中国地球化学学报（英文版） 英文刊名： CHINESE JOURNAL OF GEOCHEMISTRY 年，卷(期)： 2009 28(3) 分类号： P5 关键词： Bainiuchang Ag-polymetallic deposit sulfur isotopic composition ore-forming fluid Yunnan Province,China