Formation of ridges in a stable lithosphere in mantle convection models with a viscoplastic rheology

Numerical simulations of mantle convection with a viscoplastic rheology usually display mobile, episodic or stagnant lid regimes. In this study, we report a new convective regime in which a ridge can form without destabilizing the surrounding lithosphere or forming subduction zones. Using simulation...

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Bibliographic Details
Published in:Geophysical research letters 2015-06, Vol.42 (12), p.4770-4777
Main Authors: Rozel, A., Golabek, G. J., Näf, R., Tackley, P. J.
Format: Article
Language:English
Subjects:
Coefficients
Computer simulation
Convection
Convection models
Convection modes
convection regime
Depth
depth dependent
Dynamics of Lithosphere and Mantle: General
Earth's Interior: Dynamics
Forming
Friction
Geodesy and Gravity
Heating
Lithosphere
Mantle
Mantle convection
Mathematical models
Numerical simulations
Parameters
Planetary Sciences: Solid Surface Planets
Planetary Tectonics
Research Letter
Research Letters
Rheological properties
Rheology
ridge only
Ridges
Subduction
Subduction (geology)
Subduction zones
Tectonics
Tectonophysics
viscoplastic
Viscosity
Yield strength
Yield stress
Yields
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Summary:Numerical simulations of mantle convection with a viscoplastic rheology usually display mobile, episodic or stagnant lid regimes. In this study, we report a new convective regime in which a ridge can form without destabilizing the surrounding lithosphere or forming subduction zones. Using simulations in 2‐D spherical annulus geometry, we show that a depth‐dependent yield stress is sufficient to reach this ridge only regime. This regime occurs when the friction coefficient is close to the critical value between mobile lid and stagnant lid regimes. Maps of convective regime as a function of the parameters friction coefficients and depth dependence of viscosity are provided for both basal heating and mixed heating situations. The ridge only regime appears for both pure basal heating and mixed heating mode. For basal heating, this regime can occur for all vertical viscosity contrasts, while for mixed heating, a highly viscous deep mantle is required. Key Points Stable ridges can appear in the lithosphere without generating subduction zones A depth‐dependent yield stress is necessary to obtain stable ridges This “ridge only” regime can be found between stagnant and mobile lid regimes
ISSN:0094-8276
1944-8007
DOI:10.1002/2015GL063483