祁连西段德勒诺尔-石板墩地区水系沉积物地球化学特征及找矿远景

Geochemical Characteristics of Stream Sediments and Ore-Search Prospect in the Dleno-Shibandun Area of Western Qilian Mountains,Gansu Province

1∶5万水系沉积物测量作为一种重要的地球化学普查手段,现已被广泛应用。此次在祁连西段德勒诺尔-石板墩地区开展1∶5万水系沉积物测量,旨在圈定异常,通过对异常的检查和评价,圈定找矿靶区,进而划分成矿远景区,并作出成矿预测。本次1∶5万水系沉积物测量,采样粒级选择-10~80目,分析项目为Au、Ag、As、Sb、Hg、Cu、Pb、Zn、W、Sn、Mo、Bi、Cr、Ni、Co、Ti、Mn、Ba等18种元素。根据样品分析测试结果,圈定了1115个单元素异常、3类组合异常、26处综合异常。笔者对圈定的单元素异常特征和组合异常特征进行了研究,对26处综合异常进行了检查评价,根据查证结果对异常进行了分类与排序。在综合分析异常特征和区域成矿地质条件的基础上,划分了7个成矿远景区,优选出以W、Pb、Ag、Cu、Ni为主的成矿远景区5处,初步评价了其成矿潜力,并对其找矿远景进行预测,指出了在德勒诺尔-石板墩地区寻找矽卡岩型钨矿床、岩浆型铜、镍硫化物矿床、沉积型铅锌银矿床的优势区域。

As an important geochemical survey method,the 1∶50000 stream sediment survey has been widely used.Such a tool was applied to the Dleno-Shibandun area of the western Qilian Mountains to delineate geochemical anomalies.Through the examination and evaluation of these anomalies,the prospecting target areas were delineated,the metallogenic prospect areas were divided,and the metallogenic prognosis was made.In this survey,the sampling grain size was-10~80 mesh,and the analysis items included 18 elements,i.e.,Au,Ag,As,Sb,Hg,Cu,Pb,Zn,W,Sn,Mo,Bi,Cr,Ni,Co,Ti,Mn,and Ba.According to the results of chemical analysis,1115 single element anomalies,3 types of composite anomalies and 28 comprehensive anomalies were delineated.We studied the characteristics of single element anomaly and composite anomaly,checked and evaluated 26 comprehensive anomalies,and classified and sorted the anomalies according to the evaluation results.On the basis of comprehensive analysis of anomaly characteristics and regional metallogenic geological background,seven metallogenic prospect areas were divided,and five metallogenic prospect areas were selected with W,Pb,Ag,Cu and Ni as the dominant ore species.After the metallogenic and the ore-searching prospects were evaluated and predicted respectively,the dominant areas for searching skarn type tungsten deposits,magmatic copper and nickel sulfide deposits,and sedimentary lead-zinc silver deposits were pointed out in Dleno-Shibandun area.