贵州省遵义铝土矿矿物学及地球化学特征

Mineralogical and Geochemistry Feature of Zunyi Bauxite Deposit, Guizhou Province, China

遵义铝土矿成矿区是贵州省的主要成矿区之一,其铝土矿层大多赋存于下石炭统九架炉组。文章运用薄片鉴定、X射线粉晶衍射及扫描电子显微镜等多种分析测试方法,研究了铝土矿的矿物组成、含量及晶体形态,认为铝土矿成矿过程中不同层位一水硬铝石的晶体形态有所差异,且一水硬铝石含量与粘土矿物及石英含量均呈此消彼长的关系。同时,分析含矿岩系组构和元素地球化学特征得出,遵义仙人岩、后槽和新站3个矿区铝土矿的成矿物质来源极有可能同源且与其基底有关,成矿过程中成矿母岩在氧化还原条件交替的沉积环境下经历了较为充分的均一化,反映了成矿过程与古风化壳作用的一致性。上述的矿物学及地球化学特征标志对铝土矿的找矿和选矿具有一定的指示意义。

Zunyi metallogenic area is one of the main metallogenic areas of bauxite in Guizhou deposit occurred within the Lower Carboniferous Jiujialu Formation mostly. Researches on bauxite of mineralogical characteristics such as mineral composition, content and crystal morphology were carried out, by means of thin section analysis, X-ray diffraction(XRD) analysis and scanning electron microscope(SEM) analysis. Result shows that there is difference between the crystal morphology of diaspore in different horizon in the process of bauxite mineralization. In addition, the content of diaspore increases with decreasing contents of clay mineral and quartz. At the same time, systematical study on fabric and element geochemistry of ore-bearing rock series shows that the source of Zunyi bauxite deposit is homologous and relates to the basement. In the process of bauxite mineralization, the parent rock has full homogenization in the alternation of oxidation-reduction of sedimentary environment, showing that the mineralization process is consistent with ancient weathering crust. Therefore, the mineralogical and geochemical features indicate prospecting and mineral processing indication meaning for bauxite deposit.