江西岩背斑岩锡矿蚀变分带及其主要蚀变岩的地球化学特征

ALTERATION ZONING OF THE YANBEI PORPHYRY TIN DEPOSIT IN JIANGXI PROVINCE AND GEOCHEMICAL CHARACTERSTICS OF ITS MAIN ALTERED ROCKS

通过对野外１１条勘探线剖面、７２个钻孔岩心的地质编录和室内５００多块薄片的系统观察，将岩背锡矿围岩蚀变自下而上划分为三个蚀变带，即黄玉石英化带、绿泥石黄玉石英化带和绢云母石英化带，并对各蚀变带主要蚀变岩进行了系统的岩石化学、微量元素和稀土元素的研究结果表明，蚀变岩氟含量很高，热液中氟的存在有利于Ｓｎ、ｗ、Ｃｕ及ＲＥＥ的迁移和富集，含氟流体是导致蚀变岩Ｓｎ、ｗ、Ｃｕ的富集和ＲＥＥ含量增加的主要因素。

The Yanbei porphyry tin deposit is situated in the Yanbei volcanic basinand within the Shicheng-Xunwu deep fault belt.Based on detailed field geo-logical work and systematic thin section observations,the authors have dividedthe wall rock alterations in the Yanbei tin deposit into three alteration zones,i.e. the topaz-quartzification zone,the chlorite-topaz-quartzification zone andthe sericite-quartzification zone,and have made systematic studies on majoraltered rocks in various alteration zones in the light of petrochemishy,traceelements and rare earth elements. The results show that the altered rockscontain very high F,that the existence of F in the hydrothermal solutionwas favorable for the migration and enrichment of Sn,W,Cu and REE,andthat tbe F-bearing fluids must have been the main factor resulting in theenrichment of Sn,W and Cu in the altered rocks and the increase in REE content.