| The Dachang gold deposit is located in the North Bayan Har orogenic belt,the administrative division is located in Maduo Township,Qumalai County,Yushu Prefecture,Qinghai Province.The metallogenic conditions in this area are good and belong to the most important metallogenic area in Qinghai Province.There are several gold deposits in the area,such as Dachang gold deposit,zhajiatongna gold deposit and shaorie gold deposit.Dachang gold deposit has the largest scale,according to the distribution characteristics of the ore body,the deposit can be divided into three ore-forming zones: North Zone,main zone and south zone,with the trend of NW-SE.Among the three belts,main ore-forming belt of Dachang has the largest scale,the highest degree of exploration and the best continuity of ore body.This paper takes Dachang gold deposit as the research object.Through the analysis of the ore-forming geological background,the geological characteristics of the mining area and deposit,and the geochemical characteristics of the primary halo,the ore prospecting index of the deposit is summarized and a prospecting model is established.It provides a theoretical basis for further searching for deep ore bodies.The ore types of Dachang gold deposit are cataclastic sulfide altered rock type and quartz vein type.The useful minerals are natural gold,the metal minerals are mainly pyrite and arsenopyrite,and the gangue minerals are mostly quartz.The ore structure mainly includes granular structure,fragmentation structure and palimpsest texture.The ore structure is mainly massive structure,slightly directional structure,tabular structure and phyllitic structure.The wall rock alteration is mainly pyritization,arsenopyrite mineralization,silicification and sericitization,among which pyritization and arsenopyrite mineralization are most closely related to mineralization.The ore bodies of the main main belt show various irregular veins in spatial distribution and have the characteristics of branching and compound,pinching and reappearing,etc.The vertical zoning sequence of the primary halo is more prominent in the single ore body.The superposition phenomenon often exists between the upper orebody's tail halo and the lower orebody's front halo.The As,Sb,Pb,Cu,Zn and other elements in the deposit reflect the strong superposition of polymetallic sulfide phases.Based on the analysis of the geochemical characteristics of the primary halos in the mining area,this paper concludes that the denudation degree of the ore body in the dazhuang area is relatively shallow,and the lower part has great prospecting potential.The preliminary evaluation of deep metallogenic prospect is made in order to provide service for further prospecting work. |
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