吉林小红石砬子铅锌银矿区综合物探三维建模及矿体定位预测

3D modeling of integrated geophysical prospecting and orebody location prediction in Xiaohongshilazi Pb-Zn-Ag mining area,Jilin Province

小红石砬子铅锌银矿地处华北板块东北部与兴蒙—吉黑造山带交接部位,矿体呈层状或脉状赋存于层间破碎带内,成矿受断裂构造和岩浆岩作用的综合控制。通过对地面高精度磁测数据的化极、延拓、场位分离等精细处理,确定断裂构造和成矿岩体的分布;采用共轭梯度法反演三维物性特征并结合激电测量结果构建了矿区三维地质-地球物理模型;通过钻探验证了推断结果的可靠性。研究结果表明,控制Ⅱ号矿化蚀变带的NW向断裂构造延长延深稳定,在已发现矿体的南东延长方向存在较好找矿潜力,推断矿体赋存于300~800 m标高之间。经钻孔验证发现3.9 m低品位矿体和2.7 m的工业矿体,为后期勘查工程布置提供了科学依据。

The Xiaohongshilazi Pb-Zn-Ag deposit is located in the junction of northeastern North China plate and Xingmeng-Jihei orogenic belt.The ore bodies are layered or veined in the interlayer fracture zone,and the mineralization is controlled both by the fault system and magmatic event.The distributions of faults and ore-related plutons are inferred by processing the high-precision magnetic survey data on the ground with conventional methods such as pole reduction,continuation and field separation.The three-dimensional(3D)geological-geophysical model of the mining area is established by inversion of 3D physical properties using the conjugate gradient method,combined with the results of induced polarization measurement.The inferred results was verified by drilling.The results show that the NW-trending faults controlled No.Ⅱmineralization alteration zone,and are stable in extension and depth.There is good prospecting potential in the southeast extension of the discovered ore body,and the potential ore body might exist between 300~800 m elevation.The borehole outcroped 3.9 m low-grade ore body and 2.7 m industrial ore body,which provides scientific basis for the later exploration engineering layout.