四川若尔盖阿西金矿床地质特征及成因探讨

通过对阿西金矿床地质特征、成矿条件和矿床成因的研究,认为阿西金矿床产于中三叠统扎尕山组第三、四段的碎屑岩和碳酸盐岩中,赋存于闪长岩体的内、外接触带,受NW向断裂带控制。金矿(化)带的形成与闪长岩体有密切关系,产于岩体外接触带围岩构造破碎带中的金矿体是阿西金矿床最重要的矿体。矿体形态为脉状、似层状及透镜状,矿体厚度及品位变化不大,矿化相对均匀。金矿化与硅化、碳酸盐化、黄铜矿化、黄铁矿化关系密切。中酸性岩浆活动与断裂构造是矿床形成的先决条件。该矿床成因为岩浆及(期后)热液改造型矿床。

Geological characteristics and genesis of A'xi gold deposit in Ruo'ergai county,Sichuan province

Based on the geological characteristics,formation conditions and genesis,it is believed that A＇xi gold deposit locates in the third and fourth sections of clastic and carbonate rocks of Zhagashan group of middle Triassic series and the inside and outside contact belts of diorite rock mass,and it is controlled by the NW fault belt.The formation of gold mineralization zone is closely related to the diorite rock mass.The orebodies occurred in the outer contact zone of the tectonic fracture zones of wall rock are the most important orebodies of A＇xi gold deposit.Orebody shapes are vein,stratiform-like and lentoid.Their thickness and grade have few changes,and the mineralization is relatively uniform.The gold mineralization is closely associated with silicification,carbonation,chalcopyrition and pyritization.Intermediate-acid magma activities and fault structures are the prerequisite for the deposit formation.The genesis of the deposit is magma and post-magma hydrothermal alteration.