桂北地区锡多金属矿床中锡石的成因矿物学研究

A GENETIC MINERALOGICAL STUDY OF CASSITERITES FROM TIN POLYMETALLIC DEPOSITS IN NORTHERN GUANGXI

本文系统地研究了桂北地区锡多金属矿床中锡石的产状、化学成分、微量元素及稀土元素、晶胞参数、物理性质、红外光谱、流体包裹体和氢氧同位素组成等特征。说明本区锡石在时空和成因上与基性-超基性岩有着密切联系，同时明显受雪峰期黑云母花岗岩和四堡群变质岩影响，具明显的多期多阶段、多物质来源、多成因特征。其锡石的化学成分、微量元素及稀土元素、物理性质和地球化学特征等方面不同于国内外其它锡矿中不同产状和成因类型的锡石，因而这种锡石具有重要的标型意义，并提供了矿床成因类型、成矿作用演化和成矿环境等方面的成因信息。

Systematically described in this paper is the genetic mineralogy of cassiterites from tinpolymetallic deposits in northern Guangxi, China,including their natural occurrence, chemicalcomposition, trace elements and REE, physical properties, unit-cell parameters, infrared spectrum, fluid inclusions, hydrogen-oxygen isotopic composition, etc. It is suggested that thecassiterites are closely related to the basic-ultrabasic rocks both in space-time and in genesis andare affected by the Xuefengian biotite granites and metamorphic rocks of the Sibao Group. Thecassiterites are characterized as being of multiperiod, multistage, and multisource andmultigenesis. Their chemical compositions, trace elements and REE, physical properties andgeochemical characteristics are different from those in other regions and hence are of typomorphicsignificance. Genetic mineralogic studies of these cassiterites may provide information about thegenesis, metallogenic evolution and metallogenic conditions of tin polymetallic deposits in northern Guangxi.