Characteristics and Geological Significance of High-precision Aeromagnetic Data in LinFen-YunCheng

The study area is located in the south margin of the North China Block, the south end of the junction between the Ordos Block and the Hehuai Block, and is part of the Fenwei Graben System and the Shanxi Cenozoic fault basin in the central part of the North China Craton. The study area has a complex regional geological structure, intense tectonic movement, and frequent magmatic activities. Based on the latest high-precision aeromagnetic data, an integrated interpretation was completed by combining the regional geology, regional gravity, and magnetic susceptibility information. In this paper, the magnetic field characteristics and the relationship with the structure division are described in detail based on the block features in different zones of the reduction-to-the-pole aeromagnetic data. We showed that the different characteristics of the magnetic field depend on the concentrated reflection such as tectonic movement, magmatic activity, and stratigraphic distribution, and the fault structures were inferred and studied, especially the deep and large fault structures. The fault structures were distributed to the northeast (NE) and northwest (NW) directions. On the aeromagnetic map, faults are reflected as a boundary of different magnetic fields and aeromagnetic gradient belts. Under the interaction of NE and NW faults, an X-shaped fault structural system is formed. The NE faults control the magnetic field division, the sedimentary formation, magmatism, metamorphism, and mineral distribution, whereas the NW faults control the magmatism only. The NW faults are characterized by dislocation of NE faults, and the formation time of NE faults is earlier than that of NW trending faults. This study provides insight into the geophysical basis and reference for basic geological research and potential analysis for iron and other metal minerals in the study area in the future.