Features of Deep Crustal Structure Beneath the Wutai Mountain Area of Shanxi Province

Abstract

AbstractIn this paper, the deep crustal structures in Wutai mountain area are studied by using deep seismic sounding (DSS) data obtained from wide‐angle reflection/refraction profiles which pass through Shanxi down‐faulted zone and Wutai mountain area. The results show that the crust in this area presents obviously layered structures. The boundary interface between upper and lower crust is determined by means of reliable intra‐crust reflected waves P3 that can be traced continuously. The thickness of upper crust is 23~28km, and the depth of Moho discontinuity is 39~43 km. The Moho discontinuity in Wutai mountain area is the deepest in this region. In Wutai mountain and its adjacent areas, the crust structures have strong inhomogeneous characteristics. The large‐scale low velocity bodies in upper crust and strong intra‐crust reflected wave groups can be regarded as a sign of magma activity in deep crust. The breaking of intra‐crust interfaces and the local discontinuation of seismic wave group Pm as well as existence of deep crustal faults and so on indicate that the crust in this region suffered violent squeeze, deformation, and tectonic activities. Therefore the complex topography and anomalous structural characteristics in deep and shallow crust have been formed in this region.