高精度磁测技术在西成铅锌矿勘探中的应用

近年来，甘肃西成铅锌矿的勘探向周边地区扩展，高精度磁法测量发挥了一定作用。利用化极磁异常垂向一阶导数和归一化总水平导数垂向导数，推断出5处地质体边界和4条断裂。根据该区地质和矿产分布特征，推测矿体主要分布于黑云母石英片岩向大理岩的接触或过渡地带，对应中泥盆统安家岔组厂坝层D2a1条带状大理岩。根据化极磁异常和该区构造，结合化探圈定出与成矿有关的4个靶区，这些靶区与Pb、Zn化探异常对应，可见若干矿化点。选取靶区内一磁测剖面进行反演，反演结果说明矿体向北西倾斜。经钻孔验证，已在不同深度见矿，证明了靶区的找矿潜力。

Application of the high-precision magnetic technique to exploration in the Xicheng lead-zinc deposit, Gansu Province

In recent years, exploration of the Xicheng lead-zinc ore field has been expanded toward surrounding areas, in which the high-precision magnetic survey played a certain role. Using vertical first-order derivates and normalized total horizontal derivates from reduced to the pole (RTP) magnetic anomalies, we delineated five geological boundaries and four faults. Then we inferred that ore bodies are mainly distributed in the contact or transition zones between quartz biotite schist and marble in the light of geological conditions and mineral distribution characteristics, corresponding to middle Devonian Anjiacha Group Changba Bed D2a1. According to the RTP magnetic anomalies and geological structure conditions, four target regions were forecasted combining with geochemical data. These target areas are consistent with Pb-Zn geochemical anomalies, bearing several mineralized spots seen. We chose a magnetic profile in the target regions to implement magnetic data inversion. The results show that the ore body inclines to NW. The borehole drilling verified the existence of ore at different depths, and proved the ore-search potential of the target regions.