Seismic wave fields and dynamical response for Qinling orogen and sedimentary basins and crystalline basement

The Qinling-Dabie orogenic belt traverses the central part of Chinese continent, dividing the eastern part of China into a north and a south part, that is, the North China craton and the Yangtze craton. Driven by the opposite movement force system, the orogen turns into an extremely complex composite superimposed tectonic belt, metallogenic belt and seismic active zone. Meanwhile, the force system also conduced the anomalies of sedimentary formation and strongly undulating crystalline basement in the region. However, it is not clear what is the geophysical boundary field response, abnormal changes of lithofacies and structure, in particular, the deep understanding of the dynamic processes on the response of basin-mountain coupling. The seismic detection and research have been done along the profile of Yulin-Tongchuan-Fuling which is about 1000 km long. And geological interpretation to these features is made. The result shows that the variation in thickness of sedimentary formation is 4-10 km and the crystalline basement is with the intense undulations by 4-6 km. The study area was cut into the southern Ordos Basin, Qinling north foreland basin, Qinling-Daba orogenic belt, south foreland basin and northeast Sichuan basin by a series of basement faults; in addition, the foreland basin including the Weihe river basin north of Qinling and the Tongjiang-Wanyuan basin south of Qinling. Qinling orogenic belt, an intracontinental rising mountain, was formed by the North China Craton pushing towards south while the Yangtze craton squeezing towards north. And the process formed the southern and the northern foreland basin. The south and north boundary of Qinling orogenic belt is not a boundary fault but a combination boundary belt including the foreland basin. Qinling and Daba arc-shaped mountain originated from the same deep crystalline basement, that is to say, they were born from the same root. The series of new knowledge has significant implications for deeply comprehending the deep dynamic process and evolution mechanism of Qinling-Daba orogenic belt and redefinition of the true north boundary of Yangtze craton.