Electrical structures in the central part of the North China Craton and their implications for the mechanism of Craton destruction

Abstract

The North China Craton is a stable cratonic block that emerged in the Paleozoic era. During the late Mesozoic era, lithospheric stretching and thinning, as well as volcanic activities, caused extensive destruction of the craton. In this study, we conducted a magnetotelluric profile within the North China Craton, covering the western (Ordos Block), middle (Taihangshan Uplift), and eastern (North China Plain) segments of the craton. The electrical structure along the profile was obtained. Our analysis revealed that the Huoshan fault and the piedmont fault of the Taihangshan are large-scale high- and low-resistivity boundaries, which traverse the entire crust. These two faults divide the three major secondary blocks within the North China Craton. The crust of the Taihangshan Uplift is characterized by a layered high-resistivity body, while the lower and middle crust exhibits widespread high conductivity layer. The crustal-scale structures of the North China Plain and the Ordos Block on both sides are dominated by stable layered resistivity structures. This indicates that the lithospheric destruction near the profile may have mainly concentrated beneath the central Taihangshan Uplift. The seismogenic environment of the 1303 Hongtong earthquake may have been controlled by multiple factors. The upwelling of mantle-derived materials in the lower and middle crust beneath the Taihangshan Uplift caused the extension of the Shanxi Graben fault system where the Linfen Graben is located. The main controlling factor of this earthquake is the southeastward sliding of the Huoshan fault. We speculate that the destruction process beneath the central Taihangshan Uplift of the North China Craton exhibited a bottom-up process, and the thermo-mechanical-chemical erosion mechanism may have dominated the destruction of craton.