Late Ediacaran inertial-interchange true polar wander (IITPW) event: a new road to reconcile the enigmatic paleogeography prior to the final assembly of Gondwana

Authors: BIN WEN, CAIRONG LUO, YONG-XIANG LI, YANTING LIN

Abstract: The Ediacaran to Early Cambrian plate tectonics was dominated by a full dispersal of the supercontinent Rodinia and the subsequent amalgamation of Gondwana. There is a consensus that the final assembly of Gondwana was not completed until the Early Cambrian. Prior to the final assembly, however, one major uncertainty remains on the quantitative paleogeography: the mainland of Gondwana was plausibly positioned at either a high or low latitude at a single time instant to meet the dual-latitude ('high-latitude' and 'low-latitude') options of Laurentia and the requirement of <600 Ma Iapetus Ocean opening between Amazonia and Laurentia. This uncertainty mainly arises from the equivocal selections on the ca. 590-560 Ma paleopoles from Laurentia and very few paleomagnetic data from Gondwana continents. In this paper, we expanded the dataset of high-quality paleomagnetic poles on the basis of Robert et al. (2017, 2018) and Wen et al. (2020), and confirmed an inertial interchange true polar wander (IITPW) event from ca. 590-580 to 560 Ma. We then provide a continuously kinematic reconstruction in the TPW-based ('absolute') framework and thus reconcile the two enigmatic paleogeographic models in this interval. The occurrence of IITPW in late Ediacaran has important implications for understanding the coevolution of Earth's system, and multidisciplinary investigations of the IITPW associated processes are needed in future work.

Keywords: Inertial-interchange true polar wander (IITPW), paleomagnetism, paleogeography, late Ediacaran

Full Text: PDF