内蒙古阿拉善盟西尼乌苏金钨矿地质特征及成因浅析

Geological Characters and Genesis of Xiniwusu Gold-Tungsten Deposit in Alashan,Inner Mongolia

西尼乌苏金钨矿为2015年矿调工作过程中新发现矿点,位于珠斯楞-乌拉尚德铜、金、铅锌成矿亚带中部。金矿化产于石炭系白山组糜棱岩化石英片岩中,部分产于片岩中充填的微细石英脉中;钨矿化主要产于沿脆性断层充填的石英脉及两侧硅化蚀变岩中。1∶1万土壤测量显示,Au、W、Mo等异常规模大,强度高,其中Au、W均达三级浓度带;激电中梯测量显示矿区中部有一面型低阻高极化体,与Mo、W异常高度吻合,激电测深显示在-220m处出现面型高极化体,推测深部有斑岩(云英岩)型钼钨矿床存在,与盘陀山钨矿等同类矿床(点)相似。华力西期及期后形成的S型花岗岩体具有较明显地壳浅部物质重熔特征,轻稀土弱富集,负Eu、Yi异常明显,为金、钨矿化提供了重要的物源及热源,其中金元素初始矿源层经深部韧性变形、后期构造叠加及水循环作用,成矿元素不断的活化、迁移、富集,最终形成西尼乌苏西金钨矿。

Xiniwusu gold-tungsten deposit was discovered during the geologic survey in 2015. It＇s in the middle of Zhusileng-Wulashangde copper-gold-lead-zinc metallogenic subzone. Gold mineralization is hosted in carboniferous baishan group silicated-mylonitized quartz-schist, partly in the quartz veinlets of the schist. Tungsten mineralization is mainly hosted in the quartz veins filled in the brittle faults, and also in the silicated rocks surrounding the quartz. Soil geochemical survey（1：10000） shows that anomalies of gold, tungsten, and molybdenum are large and intensive,Au and W have reached the level 3 concentration belt. IP survey shows that there＇s a anomaly of low resistivity and high chargeability. The geophysical anomaly is anastomotic with the soil anomaly. The sounding shows that there＇s a anomaly of high chargeability at the depth of -220m, which is inferred to be the position of contact of intrusive rocks. The tungsten mineralization is related with S granite of orogenic period and afterwards, similar with the local tungsten mines of Pantuoshan.The S type granite rock formed in Variscan stage and after,which has obvious characteristics of shalom crust substance remeltling,weak light rare earth concentration,negative Eu Yi anomalies is obvious.For gold-tungsten deposit provides an important source and heat source.Initial source bed for gold element by deep ductile deformation,and the late tectonic superposition and water cirlulation,the activation,migration and enrichment of ore-forming elements constantly. Eventually formed the Xiniwusu gold-tungsten deposit.