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TitreRheological modelling and deformation instability of lithosphere under extension - II. Depth - dependent rheology
AuteurBassi, G; Bonnin, J
SourceGeophysical Journal of the Royal Astronomical Society vol. 94, no. 3, 1988 p. 559-565, (Accès ouvert)
Séries alt.Commission géologique du Canada, Contributions aux publications extérieures 34587
ÉditeurOxford University Press (OUP)
Documentpublication en série
Mediapapier; en ligne; numérique
Sujetsrhéologie; déformation; lithosphère; croûte continentale; établissement de modèles; méthodes statistiques; géomathématique; tectonique
Résumé(Sommaire disponible en anglais seulement)
Bassi & Bonnin (1988) have recently discussed the stability of continental lithosphere in extension. They examine the hypothesis that thickness inhomogeneities can be amplified during extension and be responsible for lithospheric necking. We carry our analysis one step further by accounting for the increase of strength with depth in brittle layers, namely the upper crust and, in some cases, the upper part of the mantle. This variation had been neglected in the previous study to simplify the mathematical formulation. Rather than a constant, the equivalent viscosity is now a linear function of depth, as predicted by Byerlee's friction law which is postulated to control the mechanical behavior of brittle layers. This more realistic rheological model confirms the results of the original analysis, specifically that the interfaces between layers tend to flatten during extension unless they correspond to an inversion of density. Therefore, extension of continental lithosphere appears to be stable if there is no other initial defect susceptible of localizing the deformation.