Basin-mountain system and tectonic coupling between Yangtze block and South Qinling orogen.
扬子地块与南秦岭造山带的盆山系统与构造耦合

In this paper, we studied the prototype of the Late Paleozoic-Early Mesozoic sedimentary basins in the northwestern margin of the Yangtze block systematically. Together with the synthetical analysis on the formation of the South Qinling orogen and the Mianlue suture, we discuss the collision history and basin-range coupling between the Yangtze block and the South Qinling orogen. Our result indicates that the initial contact between the two tectonic units occurred as early as the late period of Late Permian (upper member of Changxing Formation) and the early period of Early Triassic (lower member of the Feixianguan Formation). Several collision-related rift basins, including the Kaijiang-Liangping rift, the Chengkou-Exi rift and the Dangyang rift formed between the two tectonic units at that time from west to east. They lasted for ca. 5~6Ma and were characterized by the deposition of marine molasse sediments. During the period when the second member of the Jialingjiang Formation (Early Triassic) was deposited, the paleo-thrust belts related to the peripheral foreland basin formed near the Daba Shan and the Micang Shan due to the sustaining collision of the two blocks, which led to the formation of angular unconformity and the deposition of fluvial sediments near the suture. While far away from the suture, marine carbonate deposition remained dominating. During the Late Triassic, the South Qinling orogen and the Yangtze block collided completely and the ocean between them disappeared. Marine deposition ceased since then, and the foreland basin which was characterized by terrestrial molasse sediments started to develop in the front of the Daba Shan and the Micang Shan, the Shengnongjia-Huangling uplift and the Micang Shan uplift formed in the northern margin of the Yangtze block as well at the time. The Daba Shan and the Micang Shan areas were complicatedly altered by multi-stage contractional tectonic events since the Late Triassic, including the weak tectonic activity during the Late Jurassic and the early stage of the Early Cretaceous (J3-K1) marked by regional disconformities and low-angular unconformities, the late stage of the Early Cretaceous characterized by the thin-skinned thrusting, and the strong deformation during the Late Cenozoic that was dominated by arc thrusting in front of the Daba Shan and basement-involved thrusting in front of the Micang Shan.