青海查查香卡铀矿地质特征及控矿因素分析

Geological Characteristic and Control Factors in Chachaxiangka Uranium Deposit,Qinghai

查查香卡铀矿产于岩体外接触带滩间山群绿片岩相强烈变形岩石中,受北西西向韧-脆性剪切带控制,矿化岩石中穿插大量肉红色钾长石脉,赤铁矿化、黄铁矿化、碳酸盐化、硅化等近矿蚀变发育。岩、矿石主量元素分析表明铀矿化过程中Mg O,K2O,Fe2O3含量增高,Si O2含量减少。轻、重稀土元素强烈分馏,轻稀土富集,负铕异常明显。结合该矿地球化学分析结果,详细阐述了铀成矿地质特征,指出韧-脆性剪切带、滩间山群变质岩系、中酸性岩(脉)体"三位一体"成矿机制,构成该铀矿的三大主控矿因素。

Chachaxiangka uranium deposit is found in Tanjianshan Group which have been highly metamorphosed into the green schist facies. The uranium deposits is located in outer contact zone of rock, controlled by NWW ductile-brittle shear zone. Wallrock alterations such as hematite, pyritization, carbonation and silicide are well developed. Mineralized rocks interspersed with a lot of feldspar veins. The main elements of rock and ore analysis show that mineralization process with the content of MgO, K2O and Fe2O3 increase, but SiO2 decrease. The rare earth elements show a distribution of fractionated strongly and LREE enrichment, with a obviously negative Eu a- nomaly. With the geochemical data, the geological characteristic of uranium mineralization are described in details,and points out that NW ductile-brittle shear zone, Tanjianshan metamorphosed rock series and acid magma are the three major ore-controlling factors.