| The Yishan slope of the Ordos basin to the Xiaoshan Mountain area is located in the southern part of the North China Craton, and it’s an important hub connecting the Ordos block with the southern edge of North China, and its tectonic evolution reflects the deep dynamic influence of tectonic domains such as the ancient Tethys, the western Pacific, and the Himalayas, making it a natural laboratory for revealing the destruction of the craton and the formation of the rift basins at the southeastern margin of the Ordos block. Broadband magnetotelluric exploration, as an important method for studying lithospheric structures, can finely characterize the deep electrical properties of significant blocks and major geological boundaries, providing strong constraints for investigating the geodynamic mechanisms of basin-mountain coupling in the region. This study completed high-precision (ultra) wide-frequency magnetotelluric sounding over approximately 170 km from Hancheng to Lushi, and based on the characteristics of typical survey curves, data dimensionality, and conductivity principal axis analysis, profile static correction and 2D inversion were performed, constructing a lithospheric conductivity structure profile from the Yishan slope to the Xiaoshan area. The study focused on analyzing the electrical structural characteristics of each tectonic unit, identifying nearly vertical electrical interfaces on both the north and south sides of the Fenwei graben system that almost penetrate the top of the lithosphere, and based on this, divided the study area into the high-resistivity Yishan slope, the medium- to low-resistivity Fenwei graben system, and the primarily high-resistivity but locally renovated Xiaoshan region. Based on the analysis of the regional tectonic background, it is considered that under the influence of Pacific subduction during the Mesozoic and Cenozoic, the southern margin of the North China Craton experienced intense extension and thinning of the lithosphere, and the upward movement of deep mantle materials brings about a large amount of heart and fluids, forming vertically continuous, medium-to-low resistivity channels in the deep parts of the Fenwei graben system, resulting to the vertical uplift in the Emei terrace and Zhongtiao mountain tectonic belt, which in turn controlled the formation and evolution of the Yellow river valley fault depression, Yuncheng fault depression, and Sanmenxia basin. |