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A reorganization centered on the Pacific plate occurred ~53-47 million years ago. A ‘topdown’ plate tectonic mechanism, complete subduction of the Izanagi plate, as opposed to a ‘bottom-up’ mantle flow mechanism, has been proposed as the main driver. Verification based on marine geophysical observations is impossible as most ocean crust recording this event has been subducted. Using a forward modeling approach, which assimilates surface plate velocities and shallow thermal structure of slabs into mantle flow models, we show that complete Izanagi plate subduction and margin-wide slab detachment induced a major change in sub-Pacific mantle flow, from dominantly southward before 60 M to north-northeastward after 50 Ma. Our results agree with onshore geology, mantle tomography, and the inferred motion of the Hawaiian hotspot and are consistent with a plate-tectonic process driving the rapid plate-mantle reorganization in the Pacific hemisphere between 60 and 50 Ma, as reflected in tectonic changes in the Pacific and surrounding ocean basins.

Item Type:	Refereed Article
Keywords:	Izangi, Pacific, geodynamics, plate tectonics, subduction, mid-ocean ridge
Research Division:	Earth Sciences
Research Group:	Geophysics
Research Field:	Geodynamics
Objective Division:	Expanding Knowledge
Objective Group:	Expanding Knowledge
Objective Field:	Expanding Knowledge in the Earth Sciences
UTAS Author:	Whittaker, J (Associate Professor Jo Whittaker)
ID Code:	99194
Year Published:	2015
Funding Support:	Australian Research Council (DE140100376)
Web of Science® Times Cited:	64
Deposited By:	IMAS Research and Education Centre
Deposited On:	2015-03-17
Last Modified:	2017-10-25
Downloads:	210 View Download Statistics