内蒙古吉林宝力格银多金属矿床地质特征及矿床成因探讨

PRELIMINARY STUDY ON THE GEOLOGY AND GENESIS OF THE JILINBAOLIGE SILVER POLYMETALLIC DEPOSIT IN INNER MONGOLIA

吉林宝力格多金属矿床位于内蒙古东乌珠穆沁旗地区,大地构造位置位于西伯利亚板块东南缘查干敖包-奥尤特-朝不楞早古生代构造-岩浆岩带东段.上泥盆统安格尔音乌拉组是矿区主要的赋矿地层,与银多金属成矿关系密切.矿区出露的吉林宝力格岩株,岩性主要为斑状二长花岗岩,其提供了成矿物质.矿区断裂构造发育,NE向张扭性和E-W向压性断裂是主要控矿构造,控制了大多数银多金属矿体的分布.对吉林宝力格银多金属矿床的硫、铅同位素特征研究表明,银多金属矿石中的硫可能来自沉积岩与岩浆硫或地幔硫的混合、平衡作用.铅主要来源于地幔,与矿区出露的二长花岗岩具有密切联系,伴随岩浆及其热液作用的进行,不可避免地混入了部分富放射成因铅的地壳物质.综合分析吉林宝力格银多金属矿床的地质和矿床地球化学特征,结合区域大地构造演化,认为吉林宝力格银多金属矿床是与华力西期中酸性岩浆活动有关的岩浆热液型银多金属矿床.

The Jilinbaolige silver polymetallic deposit in Dong Ujimqin Qi, Inner Mongolia, is tectonically located in the east of Early Paleozoic Chaganaobao-Aoyoute-Chaobuleng tectonic-magmatic belt on the southeastern margin of Siberian plate. The Upper Devonian Angeryinwula Formation is the main host stratum closely related to the silver polymetallic mineralization. The Jilinbaolige stock outcropping in the orefield, mainly composed of porphyritic monzogranite, is the supplier of ore-forming minerals. Fault structures are developed in the area, with NE striking tensional and E-W striking compressive fractures controlling the distribution of most silver polymetallic orebodies. With study on sulfur and lead isotope characteristics in Jilinbaolige silver polymetallic deposit, it is found that the sulfur in the silver polymetallic ores might come from the mixing and balancing effect of sediment sulfur and mantle or magma sulfur. The lead is mainly derived from the mantle and closely connected with the monzogranite outcropped in the orefield. Based on the comprehensive analysis on the geological and geochemical characteristics of the deposit, combined with study on regional tectonic evolution, it is concluded that the Jilinbaolige silver polymetallic deposit is related to the Variscan acidic-intermediate magmatic hydrothermal activities.