漠河盆地中侏罗统砂岩地球化学特征及物源属性分析

Geochemistry and provenance analysis of the Middle Jurassic sandstones in the Mohe Basin,Heilongjiang

关键词:  地球化学  中侏罗统砂岩  物源分析  漠河盆地

Key words:  geochemistry  Middle Jurassic sandstone  provenance analysis  Mohe Basin

摘要:

漠河盆地的中侏罗统。砂岩具有高SiO₂、低Fe₂O₃、FeO、MgO和轻稀土元素富集,重稀土相对亏损,显示弱的负Eu异常的特征。综合分析砂岩的常量元素、微量元素和稀土元素的地球化学特征,经构造判别图解,笔者认为漠河盆地中侏罗统沉积时物源区具有大陆岛弧和活动大陆边缘的构造环境。盆地南侧的额尔古纳地块北缘古生代杂岩可能是盆地的主要物源。

Abstract:

The Middle Jurassic sandstones in the Mohe Basin,Heilongjiang are characterized by high contents of SiO₂ and low contents of Fe₂O₃,FeO and MgO,LREE enrichment,HREE depletion and slightly negative Eu anomaly.The geochemical signatures of major and trace elements and REEs,in integration with the discrimination diagrams for tectonic settings have mirrored that the Middle Jurassic deposits were derived from the continental island arcs and active continental margins.The Palaeozoic complexes on the northern margin of the Ergun block may be regarded as the main provenance of the basin.