贵州五指山纳雍枝铅锌矿床微量和稀土元素地球化学特征及其地质意义

摘要

Nayongzhi lead-zinc deposit is located in the southeastern limb of Wuzhishan anticline.The ore body is mainly hosted in the dolomite layer of Qingxudong Formation of the lower Cambrian system.The ore mineral is mainly sphalerite.The trace elements and rare earth elements of ores,mineralization rock and surrounding rock are analyzed with ICP-MS method.The result indicates that the ore is enriched of As,Cd,Sb,Bi,Ge,Mo,Sn,Cs,Tl and lost of V,Cr,Co,Cu,Rb,Sr,Nb,Ba,Ta.Dispersed elements of Ga,Ge,Cd,are positively correlated with Zn and As.It shows that the fluid is rich of these elements.The Ga/In value and ore occurrence status indicates that the deposit is hydrothermal genesis in middle-low temperature.The REE distribution patterns of ore,mineralization rock and surrounding rock are similar to each other,which are characterized by negative Eu anomaly.The enrichment types and enrichment degree are different among different ore types.It is considered that the source of metallogenic material of Nayongzhi lead-zinc deposit might be from the ore formation,the underlying strata of Dengying Formation and the deep base.%纳雍枝铅锌矿床位于五指山背斜南东翼,矿体产于下寒武统清虚洞组白云岩中,矿石矿物以闪锌矿为主.利用ICP-MS对矿床矿石、矿化岩石及围岩的微量及稀土元素进行测试,结果显示,矿石中以富集As、Cd、Sb、Bi、Ge、Mo、Sn、Cs、T1等微量元素,亏损V、Cr、Co、Cu、Rb、Sr、Nb、Ba、Ta等元素.分散元素Ga、Ge、Cd富集与Zn、As呈正相关,说明流体本身富含该类元素.Ga/In值及矿石产出状态指矿床是中低温热液成因.矿石、矿化白云岩及围岩的稀土配分模式相似,均以Eu负异常为特征,不同矿石类型之间富集元素类型及富集程度差别较大,认为该矿床成矿物质可能来源于含矿地层本身和下伏的灯影组地层及深部基底.