Early Mesozoic intracontinental deformation in the eastern North China Block: Implication for an indentation model of North China to South China blocks

Abstract

The Qinling‐Dabie‐Sulu Orogen was formed by the collision of the North and South China blocks during the Indosinian Period. The intracontinental deformation was subsequently developed during the Late Triassic to Early Jurassic in the northeastern, eastern, and southeastern parts of eastern North China Block with different structural patterns. In this paper, we present structural analysis of the Indosinian deformation in the western Shandong and southern Liaoning provinces and synthesized the previous studies of the Triassic‐Early Jurassic deformation in different areas of the eastern North China Block, from the northeastern, central to southeastern parts. Integrating the previous studies of petrology, geochronology, and geophysics, we suggested that (1) a series of top‐to‐the‐northwest thrust‐nappes were formed in the Sulu Orogen, and the southeastward antithetic faults developed in the South China Block. In the eastern North China Block, the Indosinian intracontinental deformation is intensely developed near the orogenic belt as thrust‐nappes and away from the belt developed open folds. (2) The present‐day structural lines in the northeastern, central, and southeastern parts of eastern North China Block show the S‐N‐, E‐W‐, and NE‐trending lines, respectively. It could be the structural response to the dynamics of an orocline or indentation induced by Triassic collision of the North and South China blocks; (3) the eastern margin of the North China Block subducted southeastward beneath the South China Block along the Wulian‐Qingdao‐Yantai Fault during the Indosinian Period.

Formation environments and mechanisms of multistage paleokarst of Ordovician carbonates in Southern North China Basin

“…The Z values range from 108.66 to 115.84, with an average of 111.98 (Table 2), indicating the formation of paleoweathering crust karst primarily being affected by freshwater (e.g. meteoric water, surface water, and groundwater) 53,54 . The T values in Group B range from 30.54 to 44.84 °C, with an average of 37.38 °C (Table 2), and the H values range from 214.74 to 691.31 m, with an average of 442.78 m ( Table 2).…”

“…Paleoweathering crust karst. Paleoweathering crust karst was commonly developed within 0-100 m below the Ordovician unconformities in Northern China 53,54 . It was characterized by the development of dissolution vugs, high-angle fractures, channels, and caves, and the channels and caves were generally filled with karst breccias and gray-green argillaceous muds.…”

“…Affected by the Caledonian movement, uplifts generally occurred in Northern China after the Late Ordovician 38 , resulting in the Ordovician carbonates completely exposed to weathering and erosion environments of the surface or near-surface (Z = 108.66 to 115.84, T = 30.54 to 44.84 °C, see Table 2). Therefore, a large number of dissolution pores, vugs, and fractures, especially high-angle fractures were first developed at the top of the Ordovician strata 53 . Over time, dissolution was strengthened with increasing water flow.…”

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, ).…”

Central China Orogen along the Silk Road (Part I): Tectono‐thermal evolution and its links

“…In Volume I, 34 papers (Figure ) are included under four main regions: Sulu‐Dabie Orogen, Qinling Orogen, Qilian Orogen, and Kunlun Orogen and Tibet. In the Sulu‐Dabie Orogen (comprising six papers), the paper by Lan et al () assesses the evidence in East China for Early Mesozoic indentation of the North China and South China blocks. The paper by Guo et al () proposes a new exhumation model for HP‐UHP rocks in recognizing the late Triassic Dabie‐Sulu Orocline.…”