会泽超大型铅锌矿田方解石Sm-Nd等时线年龄及其地质意义  

Age of the Giant Huize Zn-Pb Deposits Determined by Sm-Nd Datingof Hydrothermal Calcite

作　　者：李文博[1] 黄智龙[1] 王银喜[2] 陈进[3] 韩润生[1] 许成[1] 管涛[1] 尹牡丹[1] 

机构地区：[1]中国科学院地球化学研究所 [2]南京大学现代分析中心,210093 [3]云南会泽铅锌矿,654211

出　　处：《地质论评》2004年第2期189-195,共7页Geological Review

基　　金：国家自然科学基金(编号40172038);云南省省院省校科技合作项目(编号2000YK-04)的成果

摘　　要：云南会泽超大型铅锌矿田由麟麒厂和矿山厂两个独立的铅锌矿床组成,方解石是两个矿床矿石中唯一的脉石矿物。本文利用方解石 Sm-Nd 等时线测定了麒麟厂6号矿体和矿山厂1号矿体的成矿时代。结果表明,会泽超大型铅锌矿田两个矿床的成矿时代一致,麒麟厂矿床为 226±15 Ma,矿山厂矿床为 225±38 Ma,如果把来自两个矿体的所有13个样品的数据作为一条等时线计算,在等时线图上仍然表现良好的线性关系,等时线年龄为222±14 Ma;结合地质、地球化学资料,认为两个矿床为同期同源成矿作用的产物。本文获得的会泽超大型铅锌矿床成矿时代与西南大面积峨眉山玄武岩成岩时代(250 Ma左右)在误差范围内接近,为“峨眉山玄武岩浆活动与铅锌成矿存在成因联系”提供了年代学证据。The giant Huize zinc-lead ore deposits comprise the Kuangshanchang deposit and the Qilinchang deposit separated by a distance of 3 km. The ages of the No. 1 ore body of the Kuangshanchang deposit and the No. 6 ore body of the Qilinchang deposit were determined by the samarium-neodymium isochron method for hydrothermal calcite. The ages are 225 ± 38 Ma and 226 ±15 Ma for the No. 1 ore body and the No. 6 ore body, respectively. If all calcite samples are plotted on one line an average age can be calculated. All the calcite samples fall on one line and yield a Sm-Nd isochron age of 222± 14 Ma. Combined with geological and geochemical data, it is concluded that the Kuangshanchang and the Qilinchang deposit formed during the same geological event and the metals have the same source. The ages of the two ore bodies in the Huize deposits are close to the age of the Emeishan Basalt, which is about 250 Ma. It implies that mineralization of the Huize Zn-Pb deposits maybe related to the event of the Emeishan Basalt.

关 键 词：铅锌矿田 方解石 SM-ND等时线年龄 成矿时代 云南 

分 类 号：P618.4[天文地球—矿床学]