陕西陈耳金矿床不同构造-岩相带微量元素地球化学特征及构造控矿机理

Trace elements geochemistry of different structural-lithofacies zones of the Chen'er gold deposit in Shaanxi Province and structural ore-control mechanism

通过对陈耳金矿床两类不同构造-岩相带微量元素分布特征分析,发现元素特别是成矿元素Au的含量从片理化带→破碎蚀变带→石英脉逐渐增强。构造-岩相带内变形岩石的石英Rf/φ法有限应变测量表明,片理化带应变强度最大,破碎蚀变带应变强度小,应变集中在韧性剪切带边部的片理化带内。R型聚类分析表明Au与Ag、Cu、Pb及Zn的相关系数远大于Au与Ni、Co元素的相关系数,甚至接近于1。研究认为:破碎蚀变带内由于应变软化导致脆性裂隙大量发育,易于成矿流体的迁入与淀积而强富集;片理化带由于应变集中,造成成矿流体的迁出而弱富集。韧性剪切带脆-韧性变形转换不仅控制了矿体就位空间,同时也决定着元素迁移的方向。

The content of trace elements,especially the content of Au,becomes higher from the schistosity zone through the cataclastic alteration zone to quartz vein zone,as evidenced by an analysis of features of trace elements in different structure-lithofacies zones of the Chen＇er gold deposit.Strain measurement of quartz in different structural-lithofacies zones shows that the strain intensity in the schistosity zone is higher than that in the cataclastic alteration zone,and the strain intensities are concentrated in the schistosity zone.The R Cluster Analysis indicates that Au is closely related to Ag,Cu,Pb and Zn and slightly related to Ni and Co.The authors have found that the cataclastic alteration zone had a lot of structures and made ore fluid concentration easy,and the schistosity zone had weak capability for concentrating the ore fluid.The transition of ductile and brittle deformation not only controlled the space of the ore deposit but also determined the direction of elements transportation.