Horizontal mantle flow controls subduction dynamics

Abstract It is generally accepted that subduction is driven by downgoing-plate negative buoyancy. Yet plate age –the main control on buoyancy– exhibits little correlation with most of the present-day subduction velocities and slab dips. “West”-directed subduction zones are on average steeper (~65°)...

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Autores principales:	E. Ficini, L. Dal Zilio, C. Doglioni, T. V. Gerya
Formato:	article
Lenguaje:	EN
Publicado:	Nature Portfolio 2017
Materias:	Medicine R Science Q
Acceso en línea:	https://doaj.org/article/bf00244753e241d3a912505ca1effc6c
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spelling	oai:doaj.org-article:bf00244753e241d3a912505ca1effc6c2021-12-02T11:52:24ZHorizontal mantle flow controls subduction dynamics10.1038/s41598-017-06551-y2045-2322https://doaj.org/article/bf00244753e241d3a912505ca1effc6c2017-08-01T00:00:00Zhttps://doi.org/10.1038/s41598-017-06551-yhttps://doaj.org/toc/2045-2322Abstract It is generally accepted that subduction is driven by downgoing-plate negative buoyancy. Yet plate age –the main control on buoyancy– exhibits little correlation with most of the present-day subduction velocities and slab dips. “West”-directed subduction zones are on average steeper (~65°) than “East”-directed (~27°). Also, a “westerly”-directed net rotation of the lithosphere relative to the mantle has been detected in the hotspot reference frame. Thus, the existence of an “easterly”-directed horizontal mantle wind could explain this subduction asymmetry, favouring steepening or lifting of slab dip angles. Here we test this hypothesis using high-resolution two-dimensional numerical thermomechanical models of oceanic plate subduction interacting with a mantle flow. Results show that when subduction polarity is opposite to that of the mantle flow, the descending slab dips subvertically and the hinge retreats, thus leading to the development of a back-arc basin. In contrast, concordance between mantle flow and subduction polarity results in shallow dipping subduction, hinge advance and pronounced topography of the overriding plate, regardless of their age-dependent negative buoyancy. Our results are consistent with seismicity data and tomographic images of subduction zones. Thus, our models may explain why subduction asymmetry is a common feature of convergent margins on Earth.E. FiciniL. Dal ZilioC. DoglioniT. V. GeryaNature PortfolioarticleMedicineRScienceQENScientific Reports, Vol 7, Iss 1, Pp 1-7 (2017)
institution	DOAJ
collection	DOAJ
language	EN
topic	Medicine R Science Q
spellingShingle	Medicine R Science Q E. Ficini L. Dal Zilio C. Doglioni T. V. Gerya Horizontal mantle flow controls subduction dynamics
description	Abstract It is generally accepted that subduction is driven by downgoing-plate negative buoyancy. Yet plate age –the main control on buoyancy– exhibits little correlation with most of the present-day subduction velocities and slab dips. “West”-directed subduction zones are on average steeper (~65°) than “East”-directed (~27°). Also, a “westerly”-directed net rotation of the lithosphere relative to the mantle has been detected in the hotspot reference frame. Thus, the existence of an “easterly”-directed horizontal mantle wind could explain this subduction asymmetry, favouring steepening or lifting of slab dip angles. Here we test this hypothesis using high-resolution two-dimensional numerical thermomechanical models of oceanic plate subduction interacting with a mantle flow. Results show that when subduction polarity is opposite to that of the mantle flow, the descending slab dips subvertically and the hinge retreats, thus leading to the development of a back-arc basin. In contrast, concordance between mantle flow and subduction polarity results in shallow dipping subduction, hinge advance and pronounced topography of the overriding plate, regardless of their age-dependent negative buoyancy. Our results are consistent with seismicity data and tomographic images of subduction zones. Thus, our models may explain why subduction asymmetry is a common feature of convergent margins on Earth.
format	article
author	E. Ficini L. Dal Zilio C. Doglioni T. V. Gerya
author_facet	E. Ficini L. Dal Zilio C. Doglioni T. V. Gerya
author_sort	E. Ficini
title	Horizontal mantle flow controls subduction dynamics
title_short	Horizontal mantle flow controls subduction dynamics
title_full	Horizontal mantle flow controls subduction dynamics
title_fullStr	Horizontal mantle flow controls subduction dynamics
title_full_unstemmed	Horizontal mantle flow controls subduction dynamics
title_sort	horizontal mantle flow controls subduction dynamics
publisher	Nature Portfolio
publishDate	2017
url	https://doaj.org/article/bf00244753e241d3a912505ca1effc6c
work_keys_str_mv	AT eficini horizontalmantleflowcontrolssubductiondynamics AT ldalzilio horizontalmantleflowcontrolssubductiondynamics AT cdoglioni horizontalmantleflowcontrolssubductiondynamics AT tvgerya horizontalmantleflowcontrolssubductiondynamics
_version_	1718395067119435776

Horizontal mantle flow controls subduction dynamics

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