新疆阿尔泰巴特巴克布拉克铁矿床矽卡岩矿物特征及其地质意义

巴特巴克布拉克铁矿床为在新疆阿尔泰新发现的中型铁矿床,赋存于上志留统—下泥盆统康布铁堡组变质火山-沉积岩系中,近矿围岩为石榴子石矽卡岩、角闪斜长变粒岩和浅粒岩,矿体呈似层状、透镜状及不规则状,周围发育大量矽卡岩矿物。文章对矽卡岩矿物进行了研究,电子探针分析结果显示,石榴子石端员组分为钙铁榴石-钙铝榴石系列,辉石端员组分以透辉石-钙铁辉石为主,角闪石端员组分以铁镁钙闪石为主。研究表明,矿区矽卡岩为交代成因矽卡岩。通过矿床地质及矿物成因研究,认为该矽卡岩是由岩浆热液交代火山岩所形成,磁铁矿的富集成矿与矽卡岩的退化蚀变密切相关。

Skarn mineral characteristics of Batebakebulake iron deposit in Altay, Xinjiang, and their geological significance

The medium-sized Batebakebulake iron deposit in Altay of Xinjiang is hosted in the metamorphosed volcaniclastic-sedimentary sequence of the Upper Silurian-Lower Devonian Kangbutiebao Formation, with the host rocks being garnet skarn, hornblende-plagioclase leptynite and leptite. Orebodies occur as stratiform-like, lenticular and irregular shapes, surrounded by skarn minerals. Electron microprobe analyses show that the end member of garnet is mainly andradite, whereas the composition of pyroxene is mainly diopside-hedenbergite. The amphiboles are mostly ferrotschermakite. The composition of these skarn minerals suggests that skarn in the Batebakebulake iron deposit belongs to metasomatic skarn. An investigation of the genesis of minerals shows that the skarn might have resulted from hydrothermal interaction with volcanic rocks, whereas the formation of magnetite was related to the retrogressive metamorphism of the skarn.