The first continuous global full-plate animation back to 2 Ga

Li, Zheng-Xiang1, Wu, Lei1,2, Liu, Yebo1, Pisarevsky, Sergei1,

1Earth Dynamics Research Group, TIGeR, School of Earth and Planetary Sciences, Curtin University, Perth WA 6845, Australia, 2Department of Earth & Planetary Sciences, McGill University, 3450 Rue University, Montréal, Québec, H3A 0E8, Canada

Creditable global plate reconstructions back to early Earth are crucial for understanding the evolution and driving mechanisms of the Earth system. Here we present the first continuous global full-plate reconstruction model back to 2 Ga, featuring the assembly and break-up of three successive supercontinents: Nuna (tenure ca. 1600–1300 Ga), Rodinia (900–700 Ma) and Pangaea (320–170 Ma). We revised the configuration of both Nuna and Rodinia based on the updated global palaeomagnetic database with correction applied to inclination shallowing, and calibrated our reconstruction using geological and tectonic databases and prior knowledge. We generally adopt an orthoversion longitudinal rule for supercontinent assembly (i.e., each supercontinent is longitudinally 90° away from the previous one), but provide an alternative for longitudinal evolution between Nuna and Rodinia. We also adopt an alternating introversion and extroversion mechanism for supercontinent assembly, with Rodinia being assembled through introversion, and Pangaea extroversion. For Rodinia reconstruction, we recognise the possible repeated true polar wander events during the tenure of the supercontinent and interpret the phenomenon as inertia interchange true polar wander (IITPW) due to an inherited degree-2 mantle structure from the Nuna cycle. We used the palaeomagnetic reference frame (i.e., a reference frame fixed to the spin axis) for our reconstruction instead of plume or LLSVP reference frames as increasing evidences suggest a dynamic nature of deep mantle structures that are linked to the supercontinent and superocean cycles and plate tectonics.


Biography

Zheng-Xiang Li is an ARC Laureate Fellow and a Co-Leader of IGCP 648. After PhD at Macquarie, he worked for UWA for >17 years before joining Curtin in 2007. The Earth Dynamics Research Group that he leads aims to explore Earth’s evolution since the Proterozoic and the dynamic driving mechanisms.

About the GSA

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