锡铁山北西矿区岩石地球化学特征及找矿方向

Geochemical Characteristics and Prospecting Direction in the NW Mining Area of Xitieshan Deposit

锡铁山北西铅锌矿区位于柴达木地块北缘古生代裂谷带的中基性火山-沉积岩系中,成矿和改造的地质过程与柴达木地块周边地质演化有密切关系。全区地层(Pt1dk-O3tn-D-C)总体富集Cu、Pb、Zn、Ag、Au、As、Sn、Bi、Mn,反映该区是一个Cu、Pb、Zn、Ag、Au高背景区。通过岩石地球化学测量,显示出本区Au、Ba元素贫化,As、Hg强富集,Cu、Ag富集,为高背景区。Zn、Pb、Mn、Sb略富集,Pb、As元素变化数系大,Ba、Sb、Ag变化较大,存在较强分异性,矿化活动较强烈。元素组合异常自北东依次可划分为六个组合异常,显示出该区紧邻锡铁山主矿区较好的找矿前景,远离主矿带的西部区域,成矿环境和异常显示较弱。

Xitieshan lead-zinc deposit locates at the mafic-in termediate volcanic sedimentary rocks of the paleozoic rift zone in the north margin of the Qaidam block. The process of mineralization and geological transformation closely re- lates to the geological evolution of the Qaidam basin. The stratum（Ph dk--O3tn--D--C） in the area is rich in Cu, Pb, Zn, Ag, Au, As, Sn, Bi and Mn, which reflects that the area is a rich background region with Cu, Pb, Zn, Ag and Au. The results of geochemical survey indicates the area, with depletion of Au and Ba, strong enrichment of As and Hg, and enrichment of Cu and Ag, is a rich background re gion. The Zn, Pb, Mn and Sb have slight enrichment. Fur-thermore, the changes of Pb and As are greater than Ba, Sb and Ag, which indicates high differentiation and mineraliza- tion. Abnormal combination of elements from the NE to SW can be divided into six parts, showing the advantage of pros- pecting potential in the area closed to Xitieshan main mining area. The metallogenic environments and anomaly are weak in western region, which is far from the main belt.