湘东南永兴地区上地壳电性结构及其地质意义

Electrical Structure of Upper Crust in Yongxing Region,Southeast Hunan Province

为了解湘东南永兴地区上地壳地质构造特征及圈定潜在的找矿靶区,对郴州永兴地区的5条大地电磁剖面数据进行了分析与处理,并应用非线性共轭梯度法进行二维反演,获得了该地区上地壳电性结构.结果显示该地区电性分布不均匀,横向上出现高低阻相间分布,纵向无明显电性分层特征.结合湘东南区域地质资料,详细分析了研究区电性结构的地质构造含义.研究表明茶郴断裂带为深大断裂带,控制着研究区内的地质构造及成矿流体上涌通道.根据南岭成矿带铅锌金属矿的成矿规律,结合区域电性结构特征,对研究区内两处铅锌矿体成矿机理与电性结构之间的关系进行了分析讨论.研究结果对认识湘东南永兴地区上地壳的结构特征及寻找潜在矿体具有很好的参考.

In order to understand the characteristics of the geological structure in the Yongxing region and delineate potential prospecting targets,it investigated the electrical structures of the upper crust in this region using magnetotelluric(MT)data.The electrical resistivity model was obtained by 2D nonlinear conjugate gradient inversion of MT data from five profiles deployed in the Yongxing region of Chenzhou District,Southeast Hunan Province.The results show that the electrical structures are laterally heterogeneous and reveal a subvertical moderate resistivity zone.Combined with the regional geological data of Southeast Hunan,the subvertical resistivity zone is interpreted as the manifestation of the Chaling-Chenzhou fault zone,which controls the geological structure and upwelling channel of ore-forming fluids in the study area.Finally,following structural characteristics of lead-zinc metal deposits in the Nanling metallogenic belt,it discusses the relationship between the metallogenic mechanism and the electrical structures for two existing lead-zinc deposits in the study area.