Apparent polar wander paths of the major Chinese blocks since the Late Paleozoic: Toward restoring the amalgamation history of east Eurasia

Abstract

High quality paleomagnetic poles (a.k.a. paleopoles) are essential for quantitative lithospheric plate reconstruction. However, the current paleomagnetic database of the major Chinese blocks, including the North China Block (NCB), the South China Block (SCB), and the Tarim Block (TB), since the Late Paleozoic Era contain outdated and low quality data. Here, we update the database by adding recently published high quality paleopoles and rejecting low quality outdated ones. The database includes 288 paleopoles published 1980–2014, 90 of them published after 2000. Following the Van der Voo selection criteria, 75 paleopoles, each with a quality factor Q smaller than 4, were rejected in the first round of selection. We then removed another 59 paleopoles that have been locally rotated or shallowed since the acquisition of stable remanence. Eventually, 154 paleopoles were selected and adopted to calculate the new apparent polar wander paths (APWPs) for the major Chinese blocks. We found comparable clastic and igneous paleopoles at intervals when a quantitative comparison was available. As such comparison was not possible during most periods/epochs, our conclusions reflect an unclear extent of inclination errors in Chinese clastic paleopoles. New models of the Chinese APWPs, with and without inclination error corrections, were computed from carefully selected paleopoles: version 1 running mean (V1RM) paths were calculated at the period/epoch level; version 2 running mean (V2RM) paths were computed in a set sliding time window of 20 or 30Myr; spline paths were calculated with the same time windows along with a smoothing parameter of 50.Using a recent global reconstruction model and up-to-date geological observations, new models of the Chinese APWPs allowed us to re-evaluate the coalescence history of East Eurasia since the Late Paleozoic Era. Four major tectonic events were confirmed: (1) the TB accreted with the Kazakhstan orocline during amalgamation of the West Altaids during the Middle–Late Permian Period (ca. 265–250Ma); (2) the suturing of the NCB and the SCB likely occurred in a scissor-like pattern and had been accomplished no later than the Middle Jurassic Period (ca. 180–160Ma); (3) the amalgamation between the NCB and the TB along with the microblocks between the two might have been achieved during the Late Jurassic–Early Cretaceous Periods (ca. 160–140Ma); (4) the Mongol-Okhotsk Ocean should have been closed no later than the Early Cretaceous Period (ca. 140–120Ma).