Late Triassic Dabie–Sulu Orocline: New exhumation model of the HP–UHP rocks

Abstract

The Dabie–Sulu orogen is located in the eastern segment of the Central China Orogen between the North China Block (NCB) and the South China Block (SCB). The complex processes of break‐up and assemblage among the continental blocks of East Asia caused them to undergo multiple‐stage continental collisions. It is extremely important for the final kinematics and dynamics of convergence and collision among continental blocks to explore the exhumation mechanism of the HP (high pressure)‐UHP (ultra‐high pressure) metamorphic rocks. Therefore, this paper focuses on the final collisional process and tries to find a reasonable exhumation mechanism of the HP–UHP rocks. On the basis of the structural geology, petrology, seismic tomography, palaeomagnetism, and mathematical calculation, we propose a south‐eastward subduction of the NCB under the SCB in the Indosinian, and the Sulu Orogen actually became an orocline. This was caused by continuous south‐eastward subduction and the subsequent westward‐retreating delamination of the NCB slab. Coevally, it produced a two‐stage exhumation process, a vertical extrusion during the first stage (240–220 Ma) and an eastward extrusion controlled by an oroclinal contraction at the second stage (220–200 Ma).

Permian tectonic evolution of the southwestern Ordos Basin, North China: Integrating constraints from sandstone petrology and detrital zircon geochronology

“…The consumption of the residual ocean intervening the SCB and the NCC is constrained to have been completed by the Middle Triassic (Dong & Santosh, 2016; Guo et al, 2017; Li, Kusky, et al, 2011; Zhao et al, 2018; Zhou et al, 2017, 2019), recorded by the widespread syn‐ and post‐collisional granites of ~245–200 Ma, and the accompanied metamorphism (Dong & Santosh, 2016). The ongoing collision also gave the birth to a foreland along the southern margin of the Mianlue Suture during the Triassic (Liu et al, 2015; Liu, Su, & Zhang, 2013; Qian, 2015; Qian, Liu, Li, et al, 2015; Qian, Liu, Wang, et al, 2015).…”

Collisional processes between the Qiangtang Block and the Lhasa Block: Insights from structural analysis of the Bangong–Nujiang Suture Zone, central Tibet

“…Oroclines were originally defined by Carey () as bending around a vertical axis which initially were straight, or at least straighter than their present‐day orientation (Eldredge, Bachtadse, & Van der Voo, ; Guo et al, ). Yi et al () restricted the shape of the southern Asian Margin prior to the India–Asia collision as an approximately 315°E‐trending quasilinear orientation based on geochronologic and palaeomagnetic data of volcanic rocks from the westernmost Lhasa Block.…”

“…Field photographs of D 2 deformation along the BNSZ [Colour figure can be viewed at wileyonlinelibrary.com]present-day orientation(Eldredge, Bachtadse, & Van der Voo, 1985;Guo et al, 2017) Yi et al (2015). restricted the shape of the southern Asian Margin prior to the India-Asia collision as an approximately 315°E-trending quasilinear orientation based on geochronologic and palaeomagnetic data of volcanic rocks from the westernmost Lhasa Block.…”

Yanshanian deformation in Western Shandong, eastern North China Craton: Response to a transition from paleo‐Pacific to Pacific Plate subduction

“…This magmatism mainly developed in the northern NCC, for example, the northern and eastern Hebei Province, western and eastern Liaoning Province, as well as in the eastern NCC, that is, the Shandong Province; and in the southern NCC, that is, the Bengbu area. During the Early–Middle Triassic, the NCC collided in a scissor‐like manner with the South China Block (SCB) (Xu et al, ; Zhao et al, ), and even the eastern NCC southwardly indented into the SCB (Guo, Li, Suo, Wang, et al, ; Guo, Li, Suo, Li, et al, ; Lan, Li, Li, Guo, et al, ; Lan, Li, Li, Wang, et al, ; Li et al, ). Consequently, the NCC was totally uplifted, accompanied by intensive erosion as the main geological process (Wu, Li, Ren, & Lin, ).…”