宁夏卫宁北山地区金场子金矿区找矿模型及成矿预测

Prospecting model and metallogenic prediction of the Jinchangzigold deposit in the Weiningbeishan area, Ningxia

卫宁北山地区位于北祁连造山带东段,是宁夏境内金多金属矿床成矿条件最好、成矿迹象最多的地区之一,其中金场子金矿是该地区已知最大的金矿床。在归纳该区近年来找矿成果基础上,对金场子金矿床控矿因素、找矿标志和深部矿化规律进行了总结,构建了基于地-物-化多要素的综合找矿模型,并对矿区及外围、深部找矿靶区进行了圈定。研究表明:金场子金矿控矿因素主要为构造和地层,其中控矿构造表现为东西向断裂、北东向断裂及其次生裂隙为主,控矿地层表现为特定的地层层位及岩性组合。赤铁矿-褐铁矿化、硅化、绢云母化、黄铁矿化、黄钾铁矾化等围岩蚀变,Au-Ag-As-Sb化探组合异常以及中电阻率、中-高极化率地球物理异常为该区主要找矿标志。综合控矿因素和找矿标志,构建了矿区金矿综合找矿模型,并以此圈定地表找矿靶区6处,并进一步根据矿化深部变化规律圈定深部找矿靶区3处。通过对矿区及外围靶区开展地球化学剖面测量以及深部靶区钻探工作,验证了此次靶区圈定的合理性,为今后该地区找矿工作起到了很好的示范作用。

The Weiningbeishan area in the eastern section of the North Qilian orogenic belt is one of the areas with the best metallogenic conditions and the most metallogenic signs of gold polymetallic deposits in Ningxia.In recent years,the Jinchangzi gold deposit is one of the breakthroughs in exploration work in this area.Based on the previous data,this paper summarizes the ore-controlling factors and prospecting indicators of the Jinchangzi gold deposit.A multielement comprehensive prospecting model based on geological-geophysical-geochemical prospecting was constructed,and the mining area and surrounding prospecting target areas were delineated.The research shows that the ore-controlling factors of the Jinchangzi gold deposit are mainly stratigraphic and structural.Stratigraphic factor is mainly manifested in specific strata and lithological combinations,and structural factor is mainly controlled by east-west regional faults and their secondary fissures.Hematitization-limonitization,silicification,sericitization,pyritization,jarosite alteration and other surrounding rock alterations,Au-Ag-As-Sb geochemical anomalies,and medium resistivity and medium-high polarizability anomalies are the main prospecting indicators in this area.Based on ore-controlling factors and prospecting indicators,a comprehensive gold prospecting model suitable is proposed for this area.6 prospecting target areas and 3 deep prospecting target areas are delineated based on this model.Through the geochemical profile and the deep drilling of the target area,the rationality of target area has been confirmed,providing a well tool for future prospecting work in this area.