内蒙古白云鄂博北部金矿成矿特征及找矿方向

Mineralization characteristics and prospecting direction of gold deposit in north Baiyun'ebo, Inner Mongolia

白云鄂博位于华北地台与内蒙地槽接合部,其北部位于华北地台北缘狼山—白云鄂博台缘白云鄂博褶断束,已发现有赛乌素和干斯陶勒盖2个浅成中低温热液型金矿床,主成矿期的成矿温度为200～280℃,成矿压力为3 0×108～5 0×108Pa。微量元素、稀土元素和H、O同位素特征表明,白云鄂博群浅变质岩为矿源岩。区内轴向近EW,轴面N倾,向W侧伏的同斜背斜是控矿构造,由其派生的纵张断裂是主要的容矿构造。近年来,构造蚀变破碎带型、糜棱岩型等新类型金矿体及其深部盲矿体的发现,揭示了该区具有较大的找矿潜力。依据成矿控制条件,结合物化探测量成果,圈定了干斯陶勒盖—敖勒呼地区和赛乌素 号脉群西部及深部2处找矿靶区。

The Baiyun'ebo area is located the association part of the North China platform and Inner Mongolia geosyncline, and two gold deposits,the Saiwusu and Gansitaolegai, have been found in the north of Baiyun'ebo, the Langshan-Baiyun'ebo folded fault belt.The two deposits belong to shallow,low-to-moderate-temperature hydrothermal gold deposits,and ore-forming temperatures and pressures of the main ore-forming stage vary from 200 to 280 ℃ and 3.0×10~8 to 5.0×10~8 Pa,respectively.The combination characteristics of microelements,REE, H,O isotopes support that metallogenic materials came from the epimetamorphic rocks of Baiyun'ebo Group.The homocline anticline,of which the axis is EW-trending,axial plane N-dipping and W-plunging,is ore-control structures.And,its derivative structures,longitudinal extensive faults,are main host structures. Recently,new kinds of gold deposits,such as structure-alteration-fragmentation-belt-and mylonite-type gold deposits and buried orebodies in depths have been found,showing a great prospecting potential in the area.Based on the ore-control conditions combined with the results of geophysical-geochemical survey, two target areas,the Ganshitaolegai-Aolehu region and the west of No.B32 vein swarm and its depth,have been delineated.