贵州赫章铜厂沟铜矿稀土元素地球化学特征及成矿物源示踪

REE Geochemistry and Sources of Metallogenetic Materials Tracing of Copper Ore in Tongchanggou,Hezhang,Guizhou

通过对赫章铜矿化带的野外地质调查、采样、室内显微镜下分析、化学分析、扫描电镜、X衍射成分分析,研究了铜矿的矿物组成、矿石类型特征(初步划分为砂岩型铜矿石和蚀变构造角砾岩型铜矿石),矿石铜品位为3.26%～3.88%。采用ICP-MS方法测定了赫章铜矿两类型矿石、赋矿围岩及峨眉山玄武岩的稀土元素及微量元素组成,并进行了稀土特征值等的对比研究;LREE/HREE比值为9.43～11.12,La/Yb比值为11.86～14.6,显示出各样品轻稀土明显富集;δCe值为0.75～0.84,显示出负异常。除HTC-3的δEu=1.11、显示出很弱正异常外,其余样品的δEu=0.94～1.06,Eu仅显示非常微弱的异常。铜厂沟铜矿岩矿样品微量元素分布模式图表明其分布特征具有同源性。通过研究各样品的稀土元素、微量元素地球化学特征、铜矿化蚀变过程中稀土元素的迁移规律及呈现继承性的特点,结合飞仙关组砂岩的形成环境,得出峨眉山玄武岩为铜矿成矿(矿化)的物质来源结论。

Field geological investigation,sampling,indoor microscope analysis,SEM and X-ray diffraction component analysis for copper mineralized zone in Hezhang were conducted.The results show that the characteristics of the ore types is initially divided into sandstone-type copper ore and alteration tectonic breccia copper ore,and the grade of copper is 3.26%~3.88%.ICP-MS method was used to determine the composition of REE and trace elements in two types of ore of Hezhang copper,ore-hosting rock and Emeishan basalts,and rare earth characteristic values were contrasted.LREE/HREE ratio of 9.43~11.12 and La/Yb ratio of 11.86~14.6 show that the light rare earth in samples is significantly enriched.δCe value of 0.75-0.84 shows negative anomaly.In addition to HTC-3 with δEu1.11 showing a weak positive anomaly,the remaining samples with δEu0.94~1.06 show that Eu displays very weak anomalies.The diagram of trace element distribution patterns of Tongchanggou copper ore samples shows that its distribution characteristics have homology.By studying the rare earth and trace element geochemical characteristics and the rare earth elements migration in copper mineralization alteration process and presentation of the nature of succession,combined with the formation environment of Feixianguan sandstone,conclusions are obtained that Emeishan basalts provide material sources for copper metallogenic and copper mineralization.