基于重磁场特征的洛宁地区构造特征研究及矿产预测

Research on structural characteristics and mineral prediction of the Luoning area based on the characteristics of gravitational and magnetic fields

洛宁地区位于崤山隆起与洛宁盆地的结合处,属第四系浅覆盖区,已发现有老里湾、中河等大型银、铅、锌矿床,矿床形成与受断裂构造控制的酸性岩体关系密切。本文利用1∶5万重、磁资料,采用最小曲率位场分离技术、归一化总水平导数垂向导数技术、相关分析法、三维物性反演等方法进行处理,研究断裂构造及酸性岩体分布特征。通过研究表明:洛宁地区受NW向、NE向及EW向三期构造影响,以老里湾为中心,多组断裂呈现半径6.5 km的“环状”分布特征;发现多处隐伏岩体,重新厘定了老里湾岩体、中河岩体等边界,花岗岩体分布受环状构造控制,岩体埋深约3 km;“环状”构造与磁异常梯级带相关性较好的多处钻孔见矿,在该区开展找矿研究具有重要意义。

The Luoning area is located at the junction of the Xiaoshan Uplift and the Luoning Basin and falls into the Quaternary shallow overburden area.Large-scale silver-lead-zinc deposits such as Laoliwan and Zhonghe have been discovered in this area,and their formation is closely related to the acidic plutons controlled by fault structures.This study investigated the distribution of fault structures and acidic plutons based on the processing of 1:50000 gravity and magnetic data using the minimum curvature potential field separation technique,the normalized vertical derivative of the total horizontal derivative(NVDR-THDR)technique,the correlation analysis method,and the three-dimensional physical property inversion.The study results are as follows:(1)The Luoning area is affected by the NW-,NE-,and EW-trending structures;(2)Centering on the Laoliwan area,multiple sets of faults present a ring-shaped distribution with a radius of 6.5 km;(3)Multiple concealed plutons were discovered,and the boundaries of Laoliwan and Zhonghe plutons were re-determined;(4)The distribution of granites is controlled by ring-shaped structures and have a burial depth of about 3 km;(4)The ring-shaped structures are well correlated with magnetic anomaly gradient zones,where ores were found in many boreholes.Therefore,it is of great significance to carry out prospecting studies in these zones.