Paleomagnetic constraints on the geodynamic history of the major blocks of China from the Permian to the present

Abstract

Paleomagnetic study of China and its environs has been the center of a major international effort for the last 10 years. In this paper, we critically review all available paleomagnetic poles of Upper Permian to Tertiary age from the main blocks of China with the goal of placing constraints on models of the formation and the subsequent deformation of the region. After selecting “reliable” poles by applying objective criteria, we divide our analysis into first‐order (motions of blocks) and second order (deformation within blocks). For first order analysis, apparent polar wander paths are constructed for the major blocks. We discuss the compatibilities and contradictions between the geological and paleomagnetic records. A sequence of paleogeographic configurations taking into account geological constraints but remaining within paleomagnetic uncertainties is presented. In general, the major blocks were probably in contact throughout the Permian and Triassic, but the Jurassic was the key age during which most of the movement toward China's present configuration took place. Our reconstructions include certain details which are suggested by the paleomagnetic record but whose geological signatures seem to have been hidden by subsequent events. During the Cretaceous, Chinese poles agree with poles from other continents transferred onto Eurasia. At the second order, we observe that for almost each period with sufficient data the paleomagnetic poles are streaked along a small circle centered on the sampling region, indicating that much of China has been affected by small (< 20°) differential rotations. This we interpret as deformation caused in part by the extrusion of the Chinese blocks away from the Indian collision. The complete annotated list of poles is given as an appendix.

Provenance and tectonic-paleogeographic evolution: Constraints from detrital zircon U–Pb ages of Late Triassic-Early Jurassic deposits in the northern Sichuan basin, central China

“…For example, the accretion of the SCB to NCB was suggested to occur along the Shangdan suture zone in Silurian-Devonian following the fact that the South Qinling belt (SQB) began to receive sediments from the North Qinling in middle Paleozoic (Gao et al, 1995;Kröener et al, 1993;Zhang et al, 1997). In contrast, paleomagnetic data (Enkin et al, 1992;Yang et al, 1992), together with ultrahigh-pressure metamorphism at 230 Ma in the easternmost Qinling-Dabie belt (Ames et al, 1996;Hacker et al, 1998;Okay et al, 1993) blocks. The discovery of the Mianlue suture zone between the South Qinling and SCB was invoked to reconcile the above inconsistence and draw a conclusion that it is the Late Triassic collision between the SCB and South Qinling that finally resulted in the accretion of the SCB to NCB Zhang, 1999, 2000;Ratschbacher et al, 2003).…”

“…On the basis of paleomagnetism (Enkin et al, 1992;Zhao and Coe, 1987;Zhu et al, 1998) and geochronology (Dong et al, 2011 and references therein;Yin and Nie, 1993), the first collision was considered to have occurred diachronously, starting from the east in Shandong and northern Korea in late Early Permian and progressing to the west in Qinling-Dabie in the latest Triassic to earliest Jurassic. However, the time when the amalgamation between the NCB and SCB began and ended along the Qinling-Dabie-Sulu orogen has been disputed for many years Liu et al, 2013;Ratschbacher et al, 2003).…”

The geological and geodynamic condition on the formation of the Dabashan thrust nappe structure: Based on FLAC numerical modelling

“…1a). It is at a key tectonic position, been considered as a composite orogenic belt, formed by the collision of the South China and North China blocks (Mattauer et al, 1985;Sengor, 1985;Zhang, 1985;Ren et al, 1986;Hsu et al, 1987;Zhang et al, 1987Zhang et al, , 1989Enkin et al, 1992;Kröner et al, 1993;Li et al, 1993;Okay and Sengor, 1993;Ames et al, 1996;Zhang et al, 1996a;Hacker et al, 1998;Meng and Zhang, 1999;Faure et al, 2001;Zhang et al, 2001;Ratschbacher et al, 2003Ratschbacher et al, , 2006Dong et al, 2011aDong et al, ,b,c, 2012aBader et al, 2013a,b;Dong et al, 2013;Li et al, 2015;Dong et al, 2016). Qinling orogenic belt has preserved a lot of kinematic evolution records of long-term multiple stages subduction and collision between the South China and North China blocks, as well as tectonic records of overthrust thrusting, strike-slip regulation, extensional collapse, been a good region for studying orogenic tectonic process.…”

A new mammal skull from the Lower Cretaceous of China with implications for the evolution of obtuse-angled molars and ‘amphilestid’ eutriconodonts

“…Intriguingly, its lower molar cusp pattern is similar to that of Juchilestes and Hakusanodon in having cusp b higher than c (Averianov et al 2005). Clearly, however, East Asia had a complex palaeogeographic history that included prolonged isolation and intermittent connections, of which the exact timing and pattern is still uncertain (Enkin et al 1992;Haggart et al 2006).…”