青海索拉沟铜多金属矿含矿围岩主要特征

Characteristics of Ore-Bearing Wall Rocks from the Suolagou Copper Polymetallic Deposit,Qinghai Province

青海索拉沟大型铜多金属矿位于鄂拉山叠覆造山带。索拉沟铜多金属矿含矿围岩为杂色非晶质致密块状均质、具条带状构造的不纯硅质岩,其中夹有火山岩及火山碎屑岩。根据岩石化学特征,其中火山岩属中性火山岩类。从火山岩原岩恢复图解看,在TiO2-SiO2图解中6个点全部落入火成岩区,而(al+fm)-(c+alk)-Si图中6个点有3个落入火山岩区,另外3个落入钙质沉积岩区,火山岩属于安山质岩类。综合研究认为,索拉沟含矿地层宜归属为鄂拉山组,矿床类型属于与弧火山作用有关的沉积-热液复合型矿床。

The large-size Suolagou copper polymetallic deposit is located in the Elashan ore belt of Qinghai Province. This work is based on field investigations,detailed rock geochemistry,isotope geochemistry,petrography feature and protolith recovery analysis,and the result shows that the ore-bearing wall rocks of the Suolagou deposit are compact massive impured siliceous rocks with banded structure,intercalated with volcanic rocks and volcaniclastic rocks. Petrochemical characteristics suggest that the volcanic rocks are of intermediate type. The six samples of impured siliceous rocks belong to volcanic rocks in the TiO2- SiO2 diagram,while in the( al + fm)-( c + alk)- Si diagram,three of them fall into area of volcanic rocks and the others fall into area of calcareous sedimentary rocks. The volcanic rocks in the impured siliceous rocks are andesitic rocks. An integrated analysis indicates that,the ore-bearing stratum belongs to the Elashan Formation,and this deposit is of sedimentary-hydrothermal superimposition type.