Craig Stone@nobulart
Wang and Mitchell (2023) argue that true polar wander is a mechanical inevitability of a rotating and convecting planet. When mantle mass redistributes, the Earth’s solid body reorients relative to its spin axis due to conservation of angular momentum. The paleomagnetic record shows episodes of coherent great-circle motion and rates exceeding tectonic limits, suggesting whole-Earth responses linked to supercontinent assembly, megacontinent inheritance, and deep mantle structure. If this interpretation holds, parts of the stratigraphic record, such as sea-level excursions, climate belt migrations, and biodiversity shifts, might encode planetary rebalancing rather than just lateral plate drift. This raises the question of how much of Earth’s history has been interpreted within a plate-only framework, when the planet itself was reorienting.
Abstract: "True polar wander (TPW), or planetary reorientation, is the rotation of solid Earth (crust and mantle) about the liquid outer core in order to stabilize Earth’s rotation due to mass redistribution. Although TPW is well-documented on Earth presently with satellites and for multiple planets and moons in the Solar System, the prevalence of TPW in Earth history remains contentious. Despite a history of controversy, both the physical plausibility of TPW on Earth and an empirical basis for it are now undisputed. Lingering resistance to the old idea likely stems from the fact that, like plate tectonics, TPW may influence much of the Earth system, thus acknowledging its existence requires rethinking how many different datasets are interpreted. This review summarizes the development of TPW as a concept and provides a framework for future research that no longer regards TPW like a ghost process that may or may not exist, but as an integral part of the Earth system that can relate shallow and deep processes that are otherwise only mysteriously linked. Specifically, we focus on the temporal regularity of large TPW, and discuss its relationship with the supercontinent–megacontinent cycle based on previous studies. We suggest the assembly of mega-continents has a close linkage to large TPW. Meanwhile, supercontinent tenure and breakup have a close linkage to fast TPW. The effects of TPW on sea level changes, paleoclimate, biological diversity, and other facets of the Earth system are presented and require interdisciplinary tests in the future."
True polar wander in the Earth system, Chong Wang & Ross N. Mitchell (2023), link.springer.com/article/10.100… >>
