相山铀矿田钾玄质岩石与铀成矿  

SHOSHONITIC ROCK AND URANIUM MINERALIZATION IN XIANGSHAN URANIUM ORE-FIELD IN JIANGXI

作　　者：张树明[1] 余达淦[2] 吴仁贵[2] 张丽芬[2] 

机构地区：[1]中国地质大学,湖北武汉430074 [2]东华理工学院核资源与环境工程技术中心,江西抚州344000

出　　处：《大地构造与成矿学》2005年第4期527-536,共10页Geotectonica et Metallogenia

基　　金：国家自然科学基金(编号:40133020);核工业科学基金(编号:Y5630718)项目资助.

摘　　要：岩石学、元素地球化学研究表明,相山铀矿田的英安斑岩属于板内型钾玄质岩类,为钾玄质英安斑岩。其主要地球化学特征是:SiO2含量变化小(66.73%～69.88%),高碱(K2O+Na2O=6.06%～8.41%),高K2O/Na2O比值(1.53～3.49),高Al2O3(13.24%～15.96%),强烈富集大离子亲石元素(LILE)和轻稀土元素(LREE),P、Sr、Ti显著负异常,无明显的Nb和Ta负异常,Th/Yb>5,U和Th异常偏高。相山钾玄质英安斑岩的形成是源于地幔玄武岩浆的底侵作用,其中较基性的包体应为地幔岩浆残留产物。相山铀矿化在时空上与钾玄质英安斑岩关系密切,其形成应该与钾玄质岩有关,幔源流体在铀成矿过程中扮演了重要角色。Studies of petrology and elemental geochemistry indicate that the Xiangshan uranium ore -field dacite porphyry belongs to intra - plate shoshonitic rock type and is a kind of shoshonitic dacite porphyry. The main geochemical characters of the shoshonitic dacite include： SiO2 = 66.73% -69.88% ; high alkali （K2O＋ Na2O = 6.06% - 8.41% ） ; high K2O/Na2O ratio （1.53 - 3.49） ; high Al2O3 （13.24% - 15.96% ） ; being intensively enriched in LILE and LREE; remarkable P, Sr and Ti negative abnomalies; weak Nb and Ta negative abnomalies; Th/Yb 〉 5; high U and Th content. Xiangshan shoshonitic dacite porphyry was originated from mantle basaltic magma underplated. The enclave in shoshonitic dacite porphyry was the atexite of mantle - derived magma. Xiangshan uranium mineralization was related to the shoshonitic dacite porphyry in both time and space, and the uranium deposit should be related to the shoshonitic dacite. Mantle - derived fluids had played an important role in uranium mineralization.

关 键 词：钾玄质岩 铀成矿 幔源流体 相山铀矿田 

分 类 号：P588.1[天文地球—岩石学] P611.1[天文地球—地质学]