云南会泽大黑山铝土矿地球化学特征及其物源分析

Geochemistry and provenance analysis of the Daheishan bauxite deposit in Huize,Yunnan

大黑山铝土矿赋存于上二叠统宣威组底部,下伏地层为峨眉山玄武岩。矿石结构主要以泥晶结构为主,具有少量鲕状、粒屑结构。矿石构造以致密块状构造为主,局部呈层状、似层状。铝土矿石中Al2O3与Fe2O3、Si O2呈现较好的负相关关系,Ti O2与Zr、Hf、Nb、Ta相关性较好,Zr-Hf、Nb-Ta的相关性拟合度很高。铝土矿与峨眉山玄武岩样品具有相似的稀土元素配分模式。综合稳定元素相关性、微量元素及稀土元素标准化图解、lg Ni和lg Cr二元图解等分析方法对大黑山铝土矿的成矿物质来源进行探讨,研究结果表明铝土矿的成矿物质来源主要来自峨眉山玄武岩。

The Daheishan bauxite deposit in Huize,Yunnan resides in the basal part of the Upper Permian Xuanwei Formation underlain by the Emeishan basalts. The bauxite ores from the Daheishan deposit display micritic,oolitic and granular textures,and densely massive,stratified and stratoid structures. There are both negative correlations between Al2O3 and Fe2O3,and Al2O3 and Si O2 and good correlations between Ti O2 and Zr,Hf,Nb and Ta,Zr and Hf,Nb and Ta. The bauxite and basalt samples in this study exhibit similar normalized distribution patterns. The ore-forming matter may be derived from the underlying Emeishan basalts,as indicated by Log Ni and Log Cr diagram.