青海西部祁漫塔格地区矽卡岩型铁铜多金属矿床的矽卡岩类型和矿物学特征

摘要

青海西部祁漫塔格地区矽卡岩型铁铜多金属矿床分布广泛,主要发育两类矽卡岩,即钙矽卡岩和锰质矽卡岩,少数矿区还有镁矽卡岩.钙矽卡岩的组成矿物主要有透辉石、钙铁辉石、钙铝-钙铁系列石榴石、绿帘石、阳起石和方柱石,常伴随Fe、Cu、Mo矿化,构成钙矽卡岩型铁多金属矿床或铜(钼)矿床,而锰质矽卡岩主要由锰钙铁辉石组成,含少量锰三斜辉石,常伴随Pb、Zn(Ag)矿化,构成锰质矽卡岩型铅锌(银)矿床；镁矽卡岩主要组成矿物有透辉石、镁橄榄石、钙镁橄榄石和金云母,仅伴随磁铁矿化.因此,矽卡岩类型是判别矿化类型的重要标志之一.%Fe-Cu-polymetallic skarn deposits are widely distributed in the Qimantage area of western Qinghai Province. Two main skarn deposits are recognized; calcic skarn and manganoan skarn, with magnesian skarn occurring in a few deposits. Calcic skarn consists mainly of diopside, hedenbergite grossular, andradite, epidote, actinolite and scapolite, and often acompanys Fe, Cu and Mo mineralization, forming calcic skarn-type iron metallic deposit or Cu (Mo) deposits. The manganoan skarn are chiefly Mn-hedenbergite with minor pyroxmangite, associated with Pb, Zn and Ag mineralizations. Their associated mineralizations are Fe, Cu, and Mo, while for manganoan skarn are chiefly Mn-hedenbergite with minor pyroxmangite, associated with Pb, Zn and Ag mineralizations. The magnesian skarn is made up of diopside, forsterite, monticellite, and phlogopite, associated only magnetite and ludwigite. Therefore, the type of skarns is one of the important indicators to identify mineralization.