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Thermal softening induced subduction initiation at a passive margin

Thermal softening induced subduction initiation at a passive margin

Authors :
Dániel Kiss
Thibault Duretz
Lorenzo G. Candioti
Stefan M. Schmalholz
Université de Lausanne (UNIL)
Géosciences Rennes (GR)
Université de Rennes 1 (UR1)
Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Centre National de la Recherche Scientifique (CNRS)
200020-149380, Stavros Niarchos Foundation
Université de Lausanne
Université de Lausanne = University of Lausanne (UNIL)
Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)
Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)
Source :
Geophysical Journal International, Geophysical Journal International, Oxford University Press (OUP), 2020, 220 (3), pp.2068-2073. ⟨10.1093/gji/ggz572⟩, Geophysical Journal International, 2020, 220 (3), pp.2068-2073. ⟨10.1093/gji/ggz572⟩
Publication Year :
2020
Publisher :
HAL CCSD, 2020.

Abstract

SUMMARY We present 2-D numerical simulations of convergence at a hyperextended passive margin with exhumed subcontinental mantle. We consider viscoelasto-plastic deformation, heat transfer and thermomechanical coupling by shear heating and associated thermal softening due to temperature dependent viscosity. The simulations show subduction initiation for convergence velocities of 2 cm yr−1, initial Moho temperatures of 525 °C and maximal deviatoric stresses of ca. 800 MPa, around the Moho, prior to localization. Subduction initiates in the region with thinned continental crust and is controlled by a thermally activated ductile shear zone in the mantle lithosphere. The shear zone temperature can be predicted with a recently published analytical expression. The criterion for subduction initiation is a temperature difference of at least 225 °C between predicted temperature and initial Moho temperature. The modelled forced subduction broadly agrees with geological data and reconstructions of subduction during closure of the Piemont-Liguria basin, caused by convergence of the European and Adriatic plates during the Alpine orogeny.

Details

Language :
English
ISSN :
0956540X and 1365246X
Database :
OpenAIRE
Journal :
Geophysical Journal International, Geophysical Journal International, Oxford University Press (OUP), 2020, 220 (3), pp.2068-2073. ⟨10.1093/gji/ggz572⟩, Geophysical Journal International, 2020, 220 (3), pp.2068-2073. ⟨10.1093/gji/ggz572⟩
Accession number :
edsair.doi.dedup.....b58893eecfef9d2002aa474f4e4da6d8
Full Text :
https://doi.org/10.1093/gji/ggz572⟩