鄂西白果园银钒矿床地球化学特征与成矿作用

Geochemical Characteristics and Mineralization of Baiguoyuan Ag-V Deposit in Western Hubei Province

鄂西白果园银钒矿是典型的黑色岩系矿床。地球化学研究表明:矿化主要见于震旦系陡山沱组第4段下部黑色页岩中,银钒矿化具有较强正相关性;岩(矿)石的常量元素及氧化物分析结果表明,黑色岩系沉积环境处于大陆边缘,物源主要来自于陆源;稀土元素具有明显的Eu和Ce的负异常,分配模式及相关元素特征显示成岩成矿过程中以正常海水沉积作用为主,有轻微的海相热水沉积参与;微量元素特征同样指示成岩成矿的主要物质来自于陆源,但也有热水沉积的显示。综合研究认为白果园银钒矿为较典型的低温热水沉积成岩成矿的黑色页岩型矿床;最主要的成矿作用是沉积成岩作用,最有利的成矿部位是沉积古地理环境大陆边缘附近的浅海陆棚泻湖环境,成矿是在较为缺氧还原的条件下发生的,海相热水的参与以及生物(有机质)作用对矿化富集起到了重要作用。

This paper summarizes the geochemical characteristics and mineralization of Baiguoyuan Ag-V deposit,a large-scale black shale-type deposit in western Hubei Province,according to research on the major elements,rare earth elements and trace elements.Ag-V mineralization occurs in the Sinian Doushantuo Formation black shales and have obviously positive correlation.The major elements and oxides analysis of wall rocks and ores show that black shale sedimentary environment is at continental margin and its material source is terrigenous.The rare earth elements characteristics of wall rocks and ores,such as negative anomalies of δEu and δCe,REE distribution pattern and eigenvalues of related elements.It indicates that seawater sedimentation played a major role and accompanied with slight marine hydrothermal sedimentation during diagenesis and mineralization.Characteristics of trace elements also show these conclusions.In summary,Baiguoyuan Ag-V deposit is a typical low temperature hydrothermal sedimentary diagenesis and mineralization black shale-type deposit.The most major mineralization is sedimentary diagenesis under anoxic and reduced environment.Roles of marine hydrothermal sedimentation and biological or organic matter are promoted mineralization greatly.