Paleozoic deformational characteristics of the central Xuefeng Mt. and implication—A case study on the Suining-Jingzhou-Tianzhu-Xinhuang section, China

The Suining-Jingzhou (Huitong)-Tianzhu-Xinhuang section of the central Mt.Xuefeng shows that the deformation of the central Mt.Xuefeng gets weaker from the east to the west, i.e. from the west-vergencing tight folds in the east to the open folds in the west. The deformation has affected the Nanhuan System and Sinian System-Lower Paleozoic strata in the eastern section (Suining-Jingzhou), and the style of folds indicates that there is a regional decollement between the Nanhuan System and the Banxi Group in the east. The shortening of the eastern section is about 11km. The deformation has affected the Banxi Group, Nanhua System and Lower Paleozoic strata in the western section (Jingzhou-Tianzhu-Xinhuang), the regional decollement mainly occurred in the lower part of the Banxi Group or between the Banxi Group and Lengjiaxi Group. The shortening of the western section is about 46km. The boundary between the western and the eastern sections is the normal fault controlling the early depositing of the Banxi Group and the Nanhuan System. This study has obtained the minimum shortening distance across the central Mt.Xuefeng, which is similar to previous data. This means that no large scale thrusting had ever occurred in the Mt.Xuefeng during the Paleozoic.The facts of the overlap unconformity between the Carboniferous and penetratively deformed Nanhuan Systems in the central Mt.Xuefeng, the tectonic attribute of the Jingzhou basin, and deformational style along the section indicated that the deformation of the Proterozoic and Lower Paleozoic strata in the central Mt.Xuefeng took place in Early Paleozoic. The Paleozoic deformation in the Mt.Xuefeng was the result of the inversion of the early rift, which belongs to thin-skinned structure.