Ore-forming Characters And Prospecting Orientation Of Copper-polymetal Deposits In The Middle And South Sections Of DaHinggan Mountains

The middle and south sections of Da Hinggan Mountains are mainly refer to the area located in the south of 47°N of southeast of Innermogolia, north of Xilamulun Rever deep fault and west of Nengjing deep fault. The west margin of the area can reach to Mandulatu town. The area is an important ore-forming centralized area of rare elements and polymetallic, where there are 6 large deposits,13 middle type deposit,30 small ones and hundreds of copper-polymetallic ore occurrences.Based on the geologic background of the middle and south sections of Da Hinggan Mountains and the ore-forming characteristics of copper-polymetal, the author took the 1:1000000 geology and ore deposits map as the base map,digitalized it by MapGis and built the database. Based on all of these,the author combined qualitative analysis with quantitative analysis by GIS technique, discussed the correlation of ore-formation and structures,strata and igneous rocks and primarily predicted and assessed the exploration targets.The main results are as following:(1) This area can be classified into 3 metallogenic belts: the Pb-Zn-Ag rich belt on the west slope of Da Hinggan Mountains,the Sn-Pb-Zn-Fe-Cu belt on the highest peak of Da Hinggan Mountains and the belt mainly rich in copper on the east slope of Da Hinggan Mountains.(2) The main ore-forming periods are Yanshanian and Hercynian.The Sedex type Pb-Zn-Ag-Cu-Sn-Fe deposits related to Permian volcanic-sedimentation were formed in Hercynian. The epithermal–porphyry–skarn type Pb-Zn-Cu-Mo-Sn-Ag-Au deposits related to continental volcano-intrusive complex were mainly formed in Yanshanian.(3) The Cu-Sn-Pb-Zn-Ag polymetallic belt in this area was formed by the overprinting of Mesozoic volcanic-magmatic activities on the ancient basemental structure strata which is rich in ore-forming materials and the Variscan geosyncline folds belt.(4) The copper-polymetal and precious metal deposits were rich in Permian strata. The main basemental strata of the middle and south sections of Da Hinggan Mountains are Permian marine volcanic-sedimental strata series, which are main host rock of copper-polymetal deposit and in which the ore-forming elements such as Cu,Pb,Zn,Sn,Ag were abundant and which formed an important material source of deposits.(5) Through the qualitative analysis on the ore forming ore-forming intensity and extensityof every geologic unit, the author delineated 5 preferable prospecting targets.