下庄中洞地区白垩纪基性脉岩地球化学特征及其源区性质  

Geochemical characteristics and the provenance of Cretaceous basic dikes in Zhongdong area of Xiazhuang uranium ore field

作　　者：王正其[1] 李子颖[2] 张国玉[1] 吴烈勤 孙晔[2] 

机构地区：[1]东华理工学院核资源与环境教育部重点实验室,江西南昌330013 [2]核工业北京地质研究院,北京100029 [3]核工业290研究所,广东韶关512026

出　　处：《铀矿地质》2007年第4期218-225,248,共9页Uranium Geology

基　　金：核工业铀矿地质调查项目(200553)资助

摘　　要：下庄铀矿田北西西向分布的白垩纪角闪辉绿岩构成区内基性脉岩的主体。研究表明,中洞地区角闪辉绿岩形成于大陆板内构造环境,地壳物质的混染作用不明显,基本代表了原始岩浆的成分。岩石富集LREE,无Eu亏损;富含大离子亲石元素和不相容元素(K、Rb、Ba、Th、Ta、Ce等);无Nb、Ta、Zr和Hf异常;特征微量元素比值及图解显示其与富集型地幔端元(EMI、EMII)值相似,岩石物质组成具有洋岛玄武岩(OIB)特征。因此,认为中洞地区角闪辉绿岩的源区属富集型地幔,其成因与下庄地区白垩纪大陆型热点活动相关。The NWW-extending Cretaceous amphibolic diabase dikes are developed in Xiazhuang uranium ore field, Northern Guangdong province. Geochemical characteristics and the provenance of Cretaceous amphibolic diabases from Xiazhuang area have been studied from the aspects of major and trace elemental geochemistry. It can be concluded that the amphibolic diabases formed at internal plate tectonic setting with less crustal rocks assimilation during their intrusion and evolution, which mostly represent the primary magma from the mantle. The rocks are enriched in LREE, LILE, incompatible elements （K. Rb. Ba. Th. Ta. Ce et al）, have no Nb, Ta, Zr and Hf anomalies and Eu depletion compared with that of OIB basalts. Trace elements ratios and discrimination diagrams indicate that the amphibolic diabases came from the enriched mantle （ EMI and EMIl） and related to activities of Cretaceous hotspots （mantle plume） in Xiazhuang district.

关 键 词：角闪辉绿岩 地球化学 富集型地幔 下庄中洞地区 

分 类 号：P597[天文地球—地球化学]