Parameters controlling dynamically self‐consistent plate tectonics and single‐sided subduction in global models of mantle convection

Crameri, Fabio; Tackley, P. J.

doi:10.1002/2014jb011664

Cited by 52 publications

(64 citation statements)

References 126 publications

(173 reference statements)

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“…The large normal stresses that result from free-slip models are most likely used to build dynamic topography, which balances the convective stress and thus maintains a stress-free surface [e.g., Moresi and Parsons, 1995]. This is in line with Crameri and Tackley [2015] who find that a free surface is more appropriate to model plate tectonics. It is therefore a crucial question whether for real planets normal stresses become even less important for the initiation of plate tectonics than what we found here.…”

Section: Hints At Shear Stress Initiation But Open Questions Remainmentioning

confidence: 54%

The importance of temporal stress variation and dynamic disequilibrium for the initiation of plate tectonics

2016

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We use 1‐D thermal history models and 3‐D numerical experiments to study the impact of dynamic thermal disequilibrium and large temporal variations of normal and shear stresses on the initiation of plate tectonics. Previous models that explored plate tectonics initiation from a steady state, single plate mode of convection concluded that normal stresses govern the initiation of plate tectonics, which based on our 1‐D model leads to plate yielding being more likely with increasing interior heat and planet mass for a depth‐dependent Byerlee yield stress. Using 3‐D spherical shell mantle convection models in an episodic regime allows us to explore larger temporal stress variations than can be addressed by considering plate failure from a steady state stagnant lid configuration. The episodic models show that an increase in convective mantle shear stress at the lithospheric base initiates plate failure, which leads with our 1‐D model to plate yielding being less likely with increasing interior heat and planet mass. In this out‐of‐equilibrium and strongly time‐dependent stress scenario, the onset of lithospheric overturn events cannot be explained by boundary layer thickening and normal stresses alone. Our results indicate that in order to understand the initiation of plate tectonics, one should consider the temporal variation of stresses and dynamic disequilibrium.

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Section: Hints At Shear Stress Initiation But Open Questions Remainmentioning

confidence: 54%

The importance of temporal stress variation and dynamic disequilibrium for the initiation of plate tectonics

2016

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“…However, compared to the global models presented here, they all lack realistic single-sided subduction-a key feature of global mantle convection observed on Earth. The global model presented in this study, in contrast, develops nature-like subduction and is able to produce an episodic lid self-consistently even with a realistically high viscosity contrast (see Crameri and Tackley 2015).…”

Section: Discussionmentioning

confidence: 96%

“…In the case of a fixed, free-slip top boundary, a traction-derived surface topography is calculated, which is, however, only a valid approximation, if the resulting topography fulfils several criteria (see Crameri et al 2012a). Finally, our sticky-air models have been tested rigorously earlier in terms of both surface topography (Crameri et al 2012a) and plate tectonic characteristics (Crameri and Tackley 2015).…”

Section: Numerical Modelmentioning

confidence: 99%

Subduction initiation from a stagnant lid and global overturn: new insights from numerical models with a free surface

Crameri

Tackley

2016

Prog. in Earth and Planet. Sci.

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Subduction initiation is a key in understanding the dynamic evolution of the Earth and its fundamental difference to all other rocky planetary bodies in our solar system. Despite recent progress, the question about how a stiff, mostly stagnant planetary lid can break and become part in the global overturn of the mantle is still unresolved. Many mechanisms, externally or internally driven, are proposed in previous studies. Here, we present the results on subduction initiation obtained by dynamically self-consistent, time-dependent numerical modelling of mantle convection. We show that the stress distribution and resulting deformation of the lithosphere are strongly controlled by the top boundary formulation: A free surface enables surface topography and plate bending, increases gravitational sliding of the plates and leads to more realistic, lithosphere-scale shear zones. As a consequence, subduction initiation induced by regional mantle flow is demonstrably favoured by a free surface compared to the commonly applied, vertically fixed (i.e. free-slip) surface. In addition, we present global, three-dimensional mantle convection experiments that employ basal heating that leads to narrow mantle plumes. Narrow mantle plumes impinging on the base of the plate cause locally weak plate segments and a large topography at the lithosphere-asthenosphere boundary. Both are shown to be key to induce subduction initiation. Finally, our model self-consistently reproduces an episodic lid with a fast global overturn due to the hotter mantle developed below a former stagnant lid. We conclude that once in a stagnant-lid mode, a planet (like Venus) might preferentially evolve by temporally discrete, global overturn events rather than by a continuous recycling of lid and that this is something worth testing more rigorously in future studies.

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“…Similarly, low values of friction coefficient have been suggested for the San Andreas Fault systems and the Andean subduction zone (Bird & Kong, ; Carena & Moder, ; Humphreys & Coblentz, ; Iaffaldano et al, ; Mount & Suppe, ; Townend & Zoback, ; Zoback et al, ). Previous numerical models (Crameri & Tackley, ; Moresi & Solomatov, ; Richards et al, ; Tackley, ) have shown as well that the use of smaller coefficients of friction

μ < 0.1

(yield stress 100 MPa) would lead to plate tectonics in models of mantle convection.…”

Section: Introductionmentioning

confidence: 98%

Evaluating the Influence of Plate Boundary Friction and Mantle Viscosity on Plate Velocities

Tutu

Sobolev

Steinberger

et al. 2018

Geochem Geophys Geosyst

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Lithospheric plates move over the low‐viscosity asthenosphere balancing several forces, which generate plate motions. We use a global 3‐D lithosphere‐asthenosphere model (SLIM3D) with visco‐elasto‐plastic rheology coupled to a spectral model of mantle flow at 300 km depth to quantify the influence of intra‐plate friction and asthenospheric viscosity on plate velocities. We account for the brittle‐ductile deformation at plate boundaries (yield stress) using a plate boundary friction coefficient to predict the present‐day plate motion and net rotation of the lithospheric plates. Previous modeling studies have suggested that small friction coefficients ( μ<0.1, yield stress ∼ 100 MPa) can lead to plate tectonics in models of mantle convection. Here we show that in order to match the observed present‐day plate motion and net rotation, the frictional parameter must be less than 0.05. We obtain a good fit with the magnitude and orientation of the observed plate velocities (NUVEL‐1A) in a no‐net‐rotation (NNR) reference frame with μ<0.05 and a minimum asthenosphere viscosity of ∼ 5·1019 Pas to 1020 Pas. Our estimates of net rotation (NR) of the lithosphere suggest that amplitudes ∼ 0.1−0.2 ( °/Ma), similar to most observation‐based estimates, can be obtained with asthenosphere viscosity cutoff values of ∼ 1019 Pas to 5·1019 Pas and friction coefficients μ<0.05.

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Parameters controlling dynamically self‐consistent plate tectonics and single‐sided subduction in global models of mantle convection

Cited by 52 publications

References 126 publications

The importance of temporal stress variation and dynamic disequilibrium for the initiation of plate tectonics

The importance of temporal stress variation and dynamic disequilibrium for the initiation of plate tectonics

Subduction initiation from a stagnant lid and global overturn: new insights from numerical models with a free surface

Evaluating the Influence of Plate Boundary Friction and Mantle Viscosity on Plate Velocities

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