吐鲁番中南部地区航磁异常特征及其地质意义

Features of aeromagnetic anomalies in central-south Turpan and their geologic significance

为了深入研究吐鲁番中南部地区航磁异常特征及其地质意义,本文基于1:50000航空磁力ΔT总场异常数据计算了航磁化极异常,并对航磁化极异常数据利用正则化滤波方法进行了异常的分解、利用罗森巴赫Ⅱ式进行了垂向二阶导数异常的换算,获取了吐鲁番中南部地区区域磁力异常、局部磁力异常及垂向二阶导数异常.结合已有的地质及地球物理研究成果,对航磁异常特征进行了深入分析,并就磁力异常与地表地质信息之间的关系进行了深入研究,探讨了本区断裂分布、岩浆岩分布及磁性特征.研究结果表明,研究区太古界总体表现为较强磁性,元古界、古生界、中生界及新生界总体表现为弱磁性.研究区构造复杂,断裂构造特征具有明显的分区性.研究区岩浆活动明显受构造控制,岩体长轴与构造走向一致.研究区中性岩表现为弱磁性,而酸性岩则大致以独峰山-梧桐沟一线为界表现为北弱南强的磁性特征.

In order to study the features of aeromagnetic anomalies and their geologic significance in central-south Turpan, the authors calculated the aeromagnetic anomaly by reduction to the pole based on the aeromagnetic total intensity anomaly(ΔT) at a 1:50000 scale, and then resolved the aeromagnetic anomaly by reduction to the pole using the regularization filtering method and converted the vertical second derivative anomaly by Rosenbach Ⅱ formula, and obtained the regional magnetic anomaly, the local magnetic anomaly, and the vertical second derivative anomaly in central-south Turpan. Combined with the existing geologic and geophysical researches, this paper analyses the features of these aeromagnetic anomalies, studies the correspondence between these magnetic anomalies and the surface geologic information, discusses the distribution of faults and igneous rocks and the magnetic characteristic of the igneous rocks in central-south Turpan. The results showed that the Archean strata displayed strong magnetic characteristics, and the Paleozoic strata, the Proterozoic strata, the Paleozoic strata, the Mesozoic strata, and the Cenozoic strata displayed weak magnetic characteristics in central-south Turpan. The study revealed that the structure is complex and the fault structure is characterized with clear zoning in the study area. The magmatic activity is obviously controlled by the fault structure in the study area, and the long axes of the rock masses are consistent with the structural tend. The intermediate rocks displayed weak magnetic characteristics, while the acidic rocks are characterized by the magnetic characteristics of weak in the north and strong in the south based on the boundary of Dufengshan-Wutonggou in central-south Turpan.