The effect of energy feedbacks on continental strength

The classical strength profile of continents is derived from a quasi-static view of their rheological response to stress—one that does not consider dynamic interactions between brittle and ductile layers. Such interactions result in complexities of failure in the brittle–ductile transition and the n...

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Bibliographic Details
Published in:Nature (London) 2006-07, Vol.442 (7098), p.67-70
Main Authors: Regenauer-Lieb, Klaus, Weinberg, Roberto F, Rosenbaum, Gideon
Format: Article
Language:English
Subjects:
Continents
Earth sciences
Earth, ocean, space
Energy
Exact sciences and technology
Feedback
Geophysics
Humanities and Social Sciences
Internal geophysics
letter
multidisciplinary
Plate tectonics
Rheology
Science
Science (multidisciplinary)
Solid-earth geophysics, tectonophysics, gravimetry
Strain
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Summary:The classical strength profile of continents is derived from a quasi-static view of their rheological response to stress—one that does not consider dynamic interactions between brittle and ductile layers. Such interactions result in complexities of failure in the brittle–ductile transition and the need to couple energy to understand strain localization. Here we investigate continental deformation by solving the fully coupled energy, momentum and continuum equations. We show that this approach produces unexpected feedback processes, leading to a significantly weaker dynamic strength evolution. In our model, stress localization focused on the brittle–ductile transition leads to the spontaneous development of mid-crustal detachment faults immediately above the strongest crustal layer. We also find that an additional decoupling layer forms between the lower crust and mantle. Our results explain the development of decoupling layers that are observed to accommodate hundreds of kilometres of horizontal motions during continental deformation.
ISSN:0028-0836
1476-4687
DOI:10.1038/nature04868