青海多尔娘地区地层和岩体含矿性研究

Study on the ore-bearing properties of strata and rock masses in Dorniang area,Qinghai Province

为研究多尔娘地区地层和岩体含矿性,以1∶50000水系沉积物测量为基础,分析元素在各地质单元的特征参数和分布演化规律。结果表明:研究区Au,As,Sb为强分异(变异系数C_(v)>1.5),Hg显示分异,Bi呈相对均匀分布,其余元素均呈均匀分布;甘德组、清水河组二段、三段及花岗闪长岩中,元素多呈低背景-贫乏分布,清水河组一段以强富集As,Sb,Au,富集Bi为特征,富集序列由高到低依次为Au(2.39)→As(2.31)→Sb(2.15)→Bi(1.24),As(4.01),Au(2.00)强分异;二长花岗斑岩中As,Sb呈强富集、强分异,Bi,Au富集分布,显示分异特征,具寻找构造热液型金、锑矿潜力;第四系地层中Sb呈富集分布,显示强分异,Au,As分异,具寻找砂金、砂锑矿潜力;金、锑为区内主攻矿种,最佳富集时代为晚三叠纪,含矿地质单元为清水河组一段和二长花岗斑岩。

In order to study the ore-bearing properties of strata and rock masses in Dorniang area,the characteristic parameters,distribution and evolution of elements in each geological unit were analyzed based on 1∶50000 stream sediment survey.In the study area,Au,As and Sb were strongly differentiated(C_(v)>1.5),Hg showed differentiation,Bi showed relatively uniform distribution,and other elements showed uniform distribution.In second and third members of Gande formation,Qingshuihe formation and granodiorite,the elements were mostly distributed in low background and poor.The first member of Qingshuihe formation was characterized by strong enrichment of As,Sb,Au and Bi;The enrichment sequence from high to low was Au(2.39)→As(2.31)→Sb(2.15)→Bi(1.24);As(4.01)and Au(2.00)were strongly differentiated.As and Sb in monzonitic granite porphyry were strongly enriched and differentiated,Bi and Au were enriched and distributed,showing characteristics of differentiation,having the potential to search for structural hydrothermal gold and antimony deposits.In the Quaternary strata,Sb was enriched and distributed,showing strong differentiation,Au and As were differentiated.It had the potential to search for placer gold and placer antimony deposits.Gold and antimony were the main ore types in the area,and the best enrichment age was the Late Triassic.The ore-bearing geological units were the first member of Qingshuihe formation and the monzonite granite porphyry.