赣南6722铀矿床方解石Sm-Nd等时线年龄及其地质意义  

Calcite Sm-Nd Isochron Age and Its Geological Significance of the 6722 Uranium Ore Deposit,Southern Jiangxi Province,China

作　　者：陈恒[1,2] 胡瑞忠[1] 毕献武[1] 朱经经[1,2] 石少华[1,2] 

机构地区：[1]中国科学院地球化学研究所矿床地球化学国家重点实验室,贵州贵阳550002 [2]中国科学院研究生院,北京100049

出　　处：《矿物学报》2012年第1期52-59,共8页Acta Mineralogica Sinica

基　　金：国家重点基础研究发展规划项目(批准号:2007CB411408);国家自然科学基金重大项目(批准号:40634020)

摘　　要：6722热液型铀矿床位于东西向南岭构造和北东向武夷隆起交汇部位的禾草坑铀矿田内。本文利用采集于该矿床花岗岩型矿石中的8件方解石进行Sm-Nd年龄测定,确定了成矿年龄为113.4±6.9 Ma。这期发生在花岗岩中的铀矿化早于隐爆角砾岩中的矿化。我们推测前期花岗岩中的矿化为后期隐爆角砾岩中富矿体的形成提供了预富集。白垩纪时6722矿床所在会昌地区处于岩石圈伸展的地段,伸展作用为铀成矿创造有力条件,岩石圈伸展与铀成矿之间具有良好的对应关系。The 6722 Vein-type Uranium Deposit, the largest deposit in Hecaokeng uranium ore fields, lies in the intersection of EW-trending Narding Mountains and NE-trending Wuyi uplift. In this study, eight samples of syngenic calcite from granite-type ore body were collected for Sm-Nd isochron age dating, and the result was 113.4 ± 6. 9 Ma. Early-stage mineralization happening in 113 Ma preceded main-stage mineralization in felsie eryptoexplosive breccia. It is inferred that early-stage mineralization （113 Ma） created preconcentration of uranium for the formation of later higher-grade ore in cryptoexplosive breccia. During Cretaceous period, the Huichang district had experienced strong crustal extension, which provided essential tectonic advantages for uranium mineralization. The period of crustal ex- tension is well consistent with uranium metallogenesis.

关 键 词：禾草坑 方解石 SM-ND定年 中生代 地壳伸展 

分 类 号：P597[天文地球—地球化学] P611[天文地球—地质学]