| 新疆坡北基性-超基性岩带Ⅰ号岩体Sm-Nd和SHRIMP U-Pb同位素年龄及其地质意义 |
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| 引用本文：李华芹，陈富文，梅玉萍，吴 华，程松林，杨甲全，代玉财.2006.Isotopic ages of No.1 intrusive body in Pobei mafic_ultramafic belt of Xinjiang and their geological significance[J].Mineral Deposits,25(4):463~469 |
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| 基金项目:国家重点基础研究发展规划项目（2001CB409810） |
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| 中文摘要:坡北基性-超基性岩带Ⅰ号岩体位于塔里木板块东北部北山裂谷带内，侵位于下石炭统红柳园组。该岩体规模较大、分异良好，是坡北岩带中寻找铜镍硫化物矿床最具代表性岩体之一。前人根据侵位地层的时代，间接推断该岩体形成于中、晚石炭世。笔者首次对该岩体不同岩相进行了同位素年代学研究，获得岩体Sm_Nd等时线年龄为(307±32) Ma（95%可信度，MSWD=0.12），辉长岩锆石SHRIMP U_Pb年龄为(278 ±2) Ma（95%可信度，MSWD=1.17）。鉴于铜镍矿化无论从时间上和空间上都与岩体的侵位密切相关，矿床成因类型为岩浆熔离型，说明坡北Ⅰ号铜镍矿区的成岩成矿作用发生于晚石炭世—早二叠世，是后碰撞构造背景下幔源岩浆上侵的产物。 |
| 中文关键词:地球化学 基性_超基性岩 坡北Ⅰ号岩体 Sm_Nd年龄 锆石SHRIMP U-Pb年龄 新疆 |
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| Isotopic ages of No.1 intrusive body in Pobei mafic_ultramafic belt of Xinjiang and their geological significance |
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| Abstract:Located in Beishan rift in the northeastern part of Tarim plate, the Pobei No.1 mafic_ultramafic body intruded into Early Carboniferous Hongliuyuan Formation. It is large in size and well differentiated，being one of the most important intrusive bodies in search for copper_nickel_sulfide orebodies. According to its emplacement strata, it was previously thought that this intrusive body was formed in Middle_Late Carboniferous. The authors dated for the first time different lithofacies of the Pobei No.1 mafic_ultramafic intrusive body, obtained a whole_rock Sm_Nd isochron age of (307±32) Ma（95% confidence，MSWD=0.12） and a zircon SHRIMP U_Pb age of (278 ±2) Ma（95% confidence，MSWD=1.17）. Cu_Ni mineralization shows a close time_space relationship with the mafic_ultramafic intrusive body, being a product of magmatic liquation. It is therefore concluded that the intrusion of the Pobei No.1 mafic_ultramafic rock body and the related mineralization occurred in a post_orogenic dynamic setting in Late Carboniferous_Early Permian. |
| keywords:geochemistry, mafic_ultramafic rock, Pobei No.1 intrusive body, Sm_Nd age, zircon SHRIMP |
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