Abstract:

 Although the folding of the Paleozoic and Mesozoic in South China has hitherto ascribed to the results of Yanshanian tectonic stage in the Late Mesozoic, we argue that there were three stages of deformation, an early and a late compression, and an extension  between them, based on the observations of outcrops of the Huangling anticline, the analysis of the specific geology map, the seismic crosssection and stratigraphic column of Jianghan Basin and Qianjiang depression, and the summarization of the existing data. The Huangling anticline was formed primarily due to the tectonic deformation before the Early Cretaceous in the Early Indosinian and Late Yanshanian tectonic stage. Extensional uplifting and exhumation of metamorphic core complexes dominated the deformation in the Late Cretaceous. There was a final compressive folding at about 24.6 Ma, in the middle stage of Himalayan movement. The “Sichuan movement” that eventually formed the NNE trending compressive fold and nappethrust tectonics in South China was the results of the Himalayan tectonic event between the Oligocene and the Miocene, rather than the Sichuan movement in the Late Yanshanian of the Late Cretaceous proposed by Tan Xichou and Li Chunyu based on evidences recognized at that time. In that period, the Pacific Plate changed its direction of subduction between the middle Eocene and the Oligocene, from NWN before 4336 Ma to NWW. A NWWSEE oriented compressive stress field was formed in Eastern China including the Yangtze and South China plates, which resulted in the occurrence of NEN trending fold and nappethruststructures and the homologous basinmountain landforms in a vast area in eastern China from South to Northeast China. Correspondingly, the tectonic movement resulted in the basinrange landforms and coincided with the outline of Neocathaysian tectonic system raised by Lee Siguang in early days. In the Miocene, the ridge of Indian Ocean spread very fast, and then led the IndianAustralian Plate subducting to NNE, which formed the initial QingzangMinyue Plateau with NWW trending. The Huangling anticline was a tectonic knot of the initial QingzangMinyue Plateau and those basins and mountains belong to Neocathaysian tectonic system, so it has the features of two sides. It went through the uplift and denudation during the Miocene and the Pliocene, and the tectonic landforms of basinmountain nowadays were caused by intensive uplifting during the Late Pliocene and the Early Pleistocene (360.8 Ma).

Key words: Huangling anticline, period and tectonic setting of Sichuan movement, rotation of the Pacific Plate, first uplift of Qingzang Plateau, initial QingzangMinyue Plateau