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The strength of large-scale plate boundaries: Constraints from the dynamics of the Philippine Sea plate since ~5Ma

Iaffaldano, Giampiero

Description

Friction controls most of the strength of tectonic plate boundaries, and thus the force mutually exchanged between plates. Estimates of the plate-boundary friction-coefficient are therefore of paramount importance to our understanding of the lithosphere torque balance. However, several lines of evidence indicate that the friction-coefficient of plate margins is significantly lower than is measured in laboratory experiments on fractured rocks. This poses a significant limit to extrapolation from...[Show more]

dc.contributor.authorIaffaldano, Giampiero
dc.date.accessioned2015-12-10T23:36:07Z
dc.identifier.issn0012-821X
dc.identifier.urihttp://hdl.handle.net/1885/70012
dc.description.abstractFriction controls most of the strength of tectonic plate boundaries, and thus the force mutually exchanged between plates. Estimates of the plate-boundary friction-coefficient are therefore of paramount importance to our understanding of the lithosphere torque balance. However, several lines of evidence indicate that the friction-coefficient of plate margins is significantly lower than is measured in laboratory experiments on fractured rocks. This poses a significant limit to extrapolation from the laboratory scale to the large-scale of Earth's lithosphere. The record of past and present-day plate motions represents an efficient probe into the torque balance of plate tectonics, because plate-motions readjust virtually instantaneously to temporal changes in driving and resisting forces. Here I derive inferences on the strength of large-scale plate boundaries by focusing on the convergence of the fast-moving Philippine Sea plate towards Eurasia, since subduction initiation ~5. Myr ago. Because at the present-day the Philippine slab reaches depths shallower than the 410-km transition zone in the upper mantle, its weight is unlikely to provide sufficient driving force to shear the trailing plate over the viscous mantle at the observed rates. Using global models of the coupled mantle/lithosphere system, I argue that frictional coupling with the Pacific and Eurasia plates is the main driver for the dynamics of the Philippine Sea plate. This allows me to infer that the friction-coefficient of large-scale plate boundaries is in range 0.01-0.07, and that the amount of sediments entering plate margins efficiently modulates the friction-coefficient, contributing significantly to its lateral variations. Importantly, I corroborate my conclusions by looking at the present-day vertical deformation of the Philippine Sea/Eurasia margin, evident from observed trench-parallel gravity anomalies.
dc.publisherElsevier
dc.sourceEarth and Planetary Science Letters
dc.subjectKeywords: Driving forces; Eurasia; Eurasia plate; Fractured rock; Friction coefficients; Friction control; Global models; Gravity anomalies; Laboratory experiments; Lateral variations; Mechanical coupling; Philippine Sea plate dynamics since ~5Ma; Plate boundaries; Mechanical coupling; Philippine Sea plate dynamics since ~5Ma; Plate-boundary friction coefficients; Trench-parallel gravity anomalies
dc.titleThe strength of large-scale plate boundaries: Constraints from the dynamics of the Philippine Sea plate since ~5Ma
dc.typeJournal article
local.description.notesImported from ARIES
local.identifier.citationvolume357-358
dc.date.issued2012
local.identifier.absfor040305 - Marine Geoscience
local.identifier.absfor040313 - Tectonics
local.identifier.absfor040402 - Geodynamics
local.identifier.ariespublicationf5625xPUB2193
local.type.statusPublished Version
local.contributor.affiliationIaffaldano, Giampiero, College of Physical and Mathematical Sciences, ANU
local.description.embargo2037-12-31
local.bibliographicCitation.startpage21
local.bibliographicCitation.lastpage30
local.identifier.doi10.1016/j.epsl.2012.09.018
local.identifier.absseo970104 - Expanding Knowledge in the Earth Sciences
dc.date.updated2016-02-24T08:55:37Z
local.identifier.scopusID2-s2.0-84867596074
local.identifier.thomsonID000312621600003
CollectionsANU Research Publications

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