内蒙古镶黄旗道郎和都格矿区钨多金属成矿地质背景与综合定位预测方法

Metallogenic Geological Background and Integrated Positioning Forecasting Method of Daolangheduge Tungsten-Polymetallic Deposit in Xianghuangqi,Inner Mongolia,China

道郎和都格矿区地表沙土和草原覆盖严重,直接寻找钨多金属矿的信息较少。地质地球化学研究结果表明,与钨多金属矿关系密切的是早白垩世钾长花岗岩,赋矿围岩主要是二叠纪辉石闪长岩。根据围岩与矿体之间的物性差异,完成了矿区1∶1万地质填图、磁法和重力测量,对数据进行重磁联合反演,识别出3条走向北东、长度800～3 000m、宽度50～100m的重要的构造蚀变带(分别对应于负磁异常带),均分布在矿区西北侧的辉石闪长岩中,且平行于辉石闪长岩和钾长花岗岩的接触带。预测了6个综合物探异常区,也位于矿区西北侧的辉石闪长岩分布区,单个异常面积为500 800m2,异常深度不超过1 000m。经钻探工程验证,在3个异常部位发现了隐伏的构造破碎带型钨多金属找矿靶区,钨多金属矿体埋藏深度为150～650m,单个矿体厚度为2～4m。表明成矿地质条件分析与重磁联合反演相结合的定位预测方法,在覆盖区寻找钨矿效果明显,值得进一步推广。

Due to much covering by sand and grass,there is less mineralization information on the ground in Daolangheduge tungsten-polymetallic mine.Geological and geochemical studies show that the Early Cretaceous K-feldspar granite closely correlates to tungsten mineralization,while the ore-hosting rock is chiefly the Permian augite diorite.According to the difference of physical property between host rock and ore body,the geological mapping,magnetic and gravity survey at scale of 1∶10 000 have been completed in the deposit.By integrated gravity-magnetic inversions of data,three NE-trending important structural alteration zones are identified in augite diorite occurring in the northwestern part of the deposit,which correspond to negative magnetic anomalies,respectively.Parallel to the boundary between augite diorite and K-feldspar granite,the three zones have the length of 800-3 000 m and the width of 50-100 m.As a result,six integrated geophysical anomalies are predicted in augite diorite.The depth of anomalies does not exceed 1 000 m and the area of a single anomaly is usually 500 800 m2.Through drilling,three blinded fractured-zone type tungsten-polymetallic exploration targets are discovered.Tungsten-polymetallic ore bodies are sited in the depth of 150-650 m.The thickness of the ore body is 2-4 m.The combination method of regional metallogenic condition analysis and integrated gravity-magnetic inversions is confirmed to be effective for forecasting tungsten deposit in covered area and worth to being applied in other region.