西准噶尔宝贝金矿地质与容矿火山岩的锆石SHRIMP年龄  

Geology of the Baobei Gold Deposit in Western Juggar and Zircon SHRIMP Age of Its Wall-Rocks, Western Junggar (Xinjiang, NW China)

作　　者：王瑞[1] 朱永峰[1] 

机构地区：[1]造山带与地壳演化教育部重点实验室北京大学地球与空间科学学院,北京100871

出　　处：《高校地质学报》2007年第3期590-602,共13页Geological Journal of China Universities

基　　金：国家科技支撑计划重点项目(2006BAB07B08)资助

摘　　要：位于西准噶尔的宝贝金矿主要由石英脉型矿石组成,主要含金矿物为银金矿,以裂隙金和包裹金的形式赋存在毒砂、黄铁矿和石英中。宝贝金矿的黄铁矿普遍含As(最高达3.88%,平均1.49%)。根据脉穿切和矿物共生组合可将宝贝金矿的成矿作用划分出四个成矿阶段:钠长石–石英阶段(Ⅰ)、银金矿–黄铁矿–毒砂–石英阶段(Ⅱ)、多金属硫化物浸染状矿化阶段(Ⅲ)和碳酸盐化阶段(IV),其中第Ⅱ和Ⅲ阶段为主要成矿期。利用锆石SHRIMP方法测定了赋矿围岩(酸性凝灰岩)的形成时代,其U–Pb谐和年龄为328.1±1.8Ma(MSWD=1.6,n=13)。该年龄代表宝贝金矿赋矿围岩的形成时间,即西准噶尔地区大规模中酸性火山岩的喷发时间。The Baobei gold deposit is located in the Early Carboniferous volcanic-sedimentary formation named as Tailegula group. The Baobei gold deposit is mainly composed of gold-bearing quartz veins. The major gold mineral is electrum, which mainly occurs as inclusions in arsenopyrite. Pyrite with electrum inclusions contains relatively higher As. The mineral paragenesis analysis suggests four stages of ore-formation including albite-quartz stage （Ⅰ）, electrum-pyrite-arsenopyrite-quartz stage （Ⅱ）, sulphide stage （Ⅲ）, and carbonatization stage （Ⅳ）. The stages Ⅱ and Ⅲ correspond to the major periods of gold mineralization. The zircon SHRIMP dating for the zircons separated from the altered felsic tuff （the wall-rock of the gold-bearing quartz vein） gives a concordant U-Pb age of 328.1 ± 1.8 Ma （MSWD=1.6, n = 13）.

关 键 词：宝贝金矿 西准噶尔 毒砂 银金矿 锆石SHRIMP 成矿阶段 

分 类 号：P611.3[天文地球—矿床学] P597.3[天文地球—地质学]