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How aseismic ridges modify the dynamics of free subduction: a 3-D numerical investigation

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Title: How aseismic ridges modify the dynamics of free subduction: a 3-D numerical investigation
Authors: Suchoy, L
Goes, S
Chen, F
Davies, R
Item Type: Journal Article
Abstract: The subduction of positively buoyant features has been implicated in the development of flat and shallow dipping slabs, the formation of cusps in trench geometry, and the cessation of associated arc magmatism. However, how such buoyant anomalies influence subduction dynamics to produce these different tectonic expressions remains debated. In this paper, using a series of multi-material 3-D simulations of free subduction, we investigate how linear buoyant ridges modify subduction dynamics, in particular downgoing plate velocities, trench motions and slab morphology. We examine the sensitivity of results to downgoing plate age (affecting buoyancy and strength), ridge buoyancy and ridge location along the trench, finding that buoyant ridges can locally change slab sinking and trench retreat rates, in turn modifying the evolution of slab morphology at depth and trench shape at the surface. In all cases examined, trench retreat is reduced, or switches to trench advance, where the ridge subducts. These effects depend strongly on downgoing plate age: on young, weak plates, the change in trench shape is more localised than on old, strong plates. Slab shallowing at the ridge only occurs for young plates, while the stronger and more negatively buoyant older plates pull down the ridge at a steeper angle than the rest of the slab. On old plates, ridges located near regions of trench stagnation or advance, which typically develop in wide slabs, have a stronger effect on trench and slab shape. The combined effects of buoyant feature location, subducting plate age and overriding plate properties can result in a range of responses: from mainly trench deformation, through local slab shallowing, to the formation of a flat slab, a variation in expressions also observed on Earth.
Issue Date: 5-May-2022
Date of Acceptance: 30-Mar-2022
URI: http://hdl.handle.net/10044/1/96352
DOI: 10.3389/feart.2022.852742
ISSN: 2296-6463
Publisher: Frontiers Media
Journal / Book Title: Frontiers in Earth Science
Volume: 10
Copyright Statement: © 2022 Suchoy, Goes, Chen and Davies. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) and the copyright owner(s) are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
Sponsor/Funder: Natural Environment Research Council (NERC)
Natural Environment Research Council (NERC)
Funder's Grant Number: NE/G004749/1
Keywords: Science & Technology
Physical Sciences
Geosciences, Multidisciplinary
flat slab
slab dip
numerical model
aseismic ridge
buoyant ridge
trench geometry
0403 Geology
0404 Geophysics
0406 Physical Geography and Environmental Geoscience
Publication Status: Published
Online Publication Date: 2022-05-05
Appears in Collections:Earth Science and Engineering
Faculty of Engineering

This item is licensed under a Creative Commons License Creative Commons