西藏甲玛铜多金属矿床中白钨矿的产出特征及其找矿意义

西藏甲玛铜多金属矿床位于冈底斯成矿带中段,矿区内显示钨元素异常,局部矿化富集,但前人尚未对钨元素及钨矿物进行研究.为弥补该空缺,文章通过分析钨含量随孔深变化的关系、钨矿物显微镜下鉴定和电子探针分析,发现甲玛矿床矽卡岩型矿体的深部易于富集钨,且出现波峰,钨含量明显高于中浅部矿体;甲玛矿床中的钨矿物为白钨矿,主要赋存于矽卡...

Occurrence feature of scheelite from Jiama copper polymetallic deposit in Tibet and its ore-prospecting significance

The Jiama copper polymetallic deposit, located in the middle part of the Gangdese metallogenic belt, has tungsten anomalies and local enrichment. However, very insufficient research work has been devoted to tungsten and tungsten minerals. In order to make remedy in this aspect, the authors probed into the variation of tungsten content with the depth, and made microscope dentification and electron microprobe analysis. The results show that tungsten in Jiama is concentrated in the deep skarn type ore body rather than in the middle and shallow ore body. Scheelite is the only tungsten mineral found in Jiama and occurs as very fine grains in the skarn, which have to be identified by microscope. Mineral assemblages related to scheelite are such skarn minerals as andradite, wollastonite and diopside. WO3 and CaO contents in scheelite from Jiama are a little lower than their theoretical values because scheelite in Jiama contains very small amounts of P2O5, K2O, FeO, MnO, Cr2O3 and NiO. Therefore, the authors hold that there is only scheelite in Jiama, with no wolframite existent. Tungsten prospecting is promising in Gangdise, as evidenced by the continuous discovery of tungsten anomalies/ore spots in the skarn-type Cu_Mo polymetallic deposits.