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Published March 28, 2015 | Published + Supplemental Material
Journal Article Open

Ridge subduction sparked reorganization of the Pacific plate-mantle system 60-50 million years ago

Abstract

A reorganization centered on the Pacific plate occurred ~53–47 million years ago. A "top-down" 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 Ma to north-northeastward after 50 Ma. Our results agree with onshore geology, mantle tomography, and the inferred motion of the Hawaiian hot spot and are consistent with a plate tectonic process driving the rapid plate-mantle reorganization in the Pacific hemisphere between 60 and 50 Ma. This reorganization is reflected in tectonic changes in the Pacific and surrounding ocean basins.

Additional Information

© 2015 American Geophysical Union. Received 6 JAN 2015; Accepted 23 FEB 2015; Accepted article online 24 FEB 2015; Published online 24 MAR 2015. This study was supported by Australian Research Council grants DP0987713 (M.S.), FL0992245 (R.D.M.), and DE14100376 (J.W.); Statoil ASA industry research grants through ARC IH130200012; and partial support by the National Science Foundation EAR-1247022 and CMMI-1028978 (D.J.B. and M.G.). This research was undertaken with the assistance of resources provided at the NCI National Facility through the National Computational Merit Allocation Scheme supported by the Australian Government. We thank Thomas Landgrebe for his assistance with calculating intersection scores. The Editor thanks Lijun Liu and an anonymous reviewer for their assistance in evaluating this paper.

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Published - grl52688.pdf

Supplemental Material - grl52688-sup-0001-supinfo.pdf

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August 22, 2023
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