In order to study mineralogical characteristics of skarns in the Jiama copper polymetallic deposit and further identify genetic type of this ore deposit, this paper has studied such skarn minerals as garnet, augite and wollastonite by means of electron microprobe analysis and microscopic examination. The results show that garnets in the ore deposit are mainly andradite-grossularite and augites are mainly diopside. The skarns in the Jiama ore deposit belong to typical calcic skams. Based on previous researches on the geochemistry of skams, wall rocks,granite and on geochronology, this paper has revealed the genetic mechanism of the Jiama copper polymetallic deposit. Mineralization was closely related to the granites and the ore deposit resulted from the replacement of the marble by granitoid magma. The Jiama ore deposit is a typical skam deposit.%为研究西藏甲玛铜多金属矿床中矽卡岩的矿物学特征,进一步确定矿床成因类型,利用电子探针测试和镜下鉴定手段对矽卡岩矿物中的石榴子石、辉石、硅灰石等矿物成分进行了分析.测试结果表明,矽卡岩中石榴子石以钙铁榴石一钙铝榴石为主,辉石以透辉石为主,甲玛矿床矽卡岩属于交代矽卡岩中典型的钙矽卡岩.结合前人对矿区矽卡岩、围岩和花岗岩类的岩石地球化学、矿床成矿年代学等的研究,进一步证实甲玛铜多金属矿床系矿区花岗岩类岩浆交代大理岩形成的典型矽卡岩型矿床.
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