藏北羌塘中部难爬日铁矿地质特征及矿床成因

难爬日铁矿位于羌塘中央隆起区。对难爬日铁矿的地质特征、矿体及矿石特征进行初步调查,通过野外调研及室内岩相学与矿相学观察,将难爬日铁矿的形成划分为早期矽卡岩阶段、晚期矽卡岩阶段、氧化物阶段、石英—硫化物阶段及后期氧化作用阶段5个成矿阶段,同时对难爬日铁矿的围岩蚀变和矿化富集规律进行分析。根据矿体产出地质条件、矿石矿物组合及围岩蚀变特征,并结合前人资料认为,难爬日矿床属接触交代型铁矿床,晚三叠世中酸性侵入岩与碳酸盐岩接触部位为重点找矿地段。

Geological characteristics and ore genesis of the Nanpari iron deposit in Central Qiangtang, Tibet

The Nanpari iron deposit is located in Central Qiangtang Uplift Belt, in which the tectonics and magmatism are complicated and the ore-forming geological condition is favorable because of the influence of the regional structural evolution of Lungmu Co-Shuanghu-Lancang River Ocean. This paper firstly reports the geological characteristics of the Nanpari iron deposit. Based on field survey as well as petrographic and ore microscope studies, the authors divide the ore-forming process of the deposit into five stages, i.e., early skarn, late skarn, oxide minerals, quartz-sulfides and oxidation stage. Moreover, the wall rock alteration regularity and metallogenic elements of this deposit are analyzed. It can be concluded that the deposit belongs to the contact metasomatic iron deposit according to ore occurrence and ore mineral assemblages, and that the contact zone between late Triassic intermediate-acid intrusive rocks and carbonate is the favorable place for ore prospecting.