Grain-size reduction reduces the impact of viscous shear heating in lithospheric mantle shear zones
Ruh, Jonas B. (Instituto de Ciencias del Mar - CSIC)

Additional title:	Grain-size reduction undermines the importance of viscous shear heating in lithospheric mantle shear zones
Date:	2025
Abstract:	Active plate tectonics require weak boundaries that accommodate large strain over long time periods. Many studies argue that shear heating converted from dissipated mechanical energy may be responsible for the necessary weakening in the mantle lithosphere to initiate and sustain weak plate boundaries. Here, I present simple numerical simulations of pure olivine systems with a composite diffusion-dislocation creep rheology coupled to a self-consistent grain size evolution model to investigate the effect of grain size reduction on shear heating. Results demonstrate that the weakening related to grain size reduction and the activation of grain-size-sensitive diffusion creep undermines the importance of shear heating in mantle shear zones. Depending on shear zone width, shear velocity and apparent stresses, estimations on ideal shear zone widths and viscosities are presented.
Rights:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre i quan aquestes es distribueixin sota la mateixa llicència que regula l'obra original i es reconegui l'autoria.
Language:	Anglès
Document:	Article ; recerca ; Versió publicada
Subject:	Shear heating ; Grain-size evolution ; Shear zones ; Numerical modelling
Published in:	Geologica acta, Vol. 23 (2025) (Articles) , ISSN 1696-5728

Adreça original: https://revistes.ub.edu/index.php/GEOACTA/article/view/50412

11 p, 2.3 MB

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