广西下巴铅锌矿床稀土元素地球化学特征研究

摘要

利用电感耦合等离子体质谱（ICP-MS）分析了广西下巴铅锌矿床中不同矿脉矿石以及围岩中的稀土元素地球化学特征，并对成矿流体的来源进行了探讨。结果表明：下巴铅锌矿床的稀土总量较低，为0.51×10-6～36.53×10-6， LREE/HREE比值相对稳定，介于3.06～6.05之间；在不同类型矿体中，稀土含量和配分模式变化较大，样品测试结果中出现Ce的负异常和Eu的正负两种异常。根据上述结果和矿床特征研究，推断矿床成因为含矿热卤水与深部循环地下热水汇合形成，在特定的物理化学条件下沉淀下来并富集成矿。%This paper used inductively coupled plasma mass spectrometry (ICP-MS)to determine the concen-tration of rare earth elements (REE)and the composition of ore and surrounding rocks of Pb-Zn deposit from Xiaba,Guangxi Province,and discussed the geochemical characteristics and the source of ore-forming fluid of the deposit. The results show that the total rare earth content is quite low,ranging from 0.5 1 ×10 -6 to 36.53 × 10 -6,while LREE/HREE is about 3.06 to 6.05.In different types of ore body,the content and distribution patterns of REE vary in a quite wide range,and negative anomaly for Ce and both positive and negative anomaly for Eu are presented in the samples. Combined with the REE parameters and geological features of the ore,it can be deduced that the metallogenic fluid source of Xiaba deposit is a hybrid of ore-bearing brine and deep cir-cling underground water under special physical-chemical condition.