Tectonic property and deformation history of Sangzhi-Shimen synclinorium corridor profile in western margin region of Hunan-Hubei Province

Abstract

The Sangzhi-Shimen synclinorium, which is in the western margin region of the Hunan-Hubei Province and as the southeast part of the middle Yangtze platform, is a second-level tectonics unit in the south of this region. Along the profile, it can be divided into 5 third-level structure belts. By the comprehensive interpretation of seismic data and magnetotelluric (MT) sounding data, it is found that the surface structure is not in accordance with that of the underground, and this un-coordination can be conducted by many decollement surfaces between the layers. There are three periods of deformation in its geo-history in this region: before the early Yanshan stage, during the early Yanshan stage and after the early Yanshan stage, while the main deformation period is during the early Yanshan stage. And the mechanism of deformation is the thrust faults in basement, which are controlled by many decollements, in addition to the decollement of the cap-rock.

Keywords

Sangzhi-Shimen synclinorium / tectonic property / structure decollement surface / deformation mechanism