Abrupt tectonics and rapid slab detachment with grain damage

Bercovici, David; Schubert, G.; Ricard, Yanick

doi:10.1073/pnas.1415473112

Cited by 54 publications

(40 citation statements)

References 40 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The simple ODE in Eq. (40) was elaborated into a system of ODE's to study the impact of coupling between grain-sensitive rheology and grain-size evolution with damage on slab detachment (Bercovici et al, 2015). The more elaborated system of ODE's had to be solved numerically.…”

Section: Lithospheric Neckingmentioning

confidence: 99%

“…The more elaborated system of ODE's had to be solved numerically. Bercovici et al (2015) showed that weakening due to grain size reduction and damage in polycrystalline rock can significantly accelerate necking and hence slab detachment, so that detachment can occur in about 1 My.…”

Section: Lithospheric Neckingmentioning

confidence: 99%

“…Lithospheric necking can also generate a crustal-scale pinch-andswell structure (Fletcher and Hallet, 1983;Gueguen et al, 1997;Fig. 7b) and is a first-order process during slab detachment (Lister et al, 2008;Schmalholz, 2011;Duretz et al, 2012;Bercovici et al, 2015).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Folding and necking across the scales: a review of theoretical and experimental results and their applications

Schmalholz

Mancktelow

2016

Solid Earth

View full text Add to dashboard Cite

Abstract. The shortening and extension of mechanically layered ductile rock generates folds and pinch-and-swell structures (also referred to as necks or continuous boudins), which result from mechanical instabilities termed folding and necking, respectively. Folding and necking are the preferred deformation modes in layered rock because the corresponding mechanical work involved is less than that associated with a homogeneous deformation. The effective viscosity of a layered rock decreases during folding and necking, even when all material parameters remain constant. This mechanical softening due to viscosity decrease is solely the result of fold and pinch-and-swell structure development and is hence termed structural softening (or geometric weakening). Folding and necking occur over the whole range of geological scales, from microscopic up to the size of lithospheric plates. Lithospheric folding and necking are evidence for significant deformation of continental plates, which contradicts the rigid-plate paradigm of plate tectonics. We review here some theoretical and experimental results on folding and necking, including the lithospheric scale, together with a short historical overview of research on folding and necking. We focus on theoretical studies and analytical solutions that provide the best insight into the fundamental parameters controlling folding and necking, although they invariably involve simplifications. To first order, the two essential parameters to quantify folding and necking are the dominant wavelength and the corresponding maximal amplification rate. This review also includes a short overview of experimental studies, a discussion of recent developments involving mainly numerical models, a presentation of some practical applications of theoretical results, and a summary of similarities and differences between folding and necking.

show abstract

Section: Lithospheric Neckingmentioning

confidence: 99%

Section: Lithospheric Neckingmentioning

confidence: 99%

See 1 more Smart Citation

Folding and necking across the scales: a review of theoretical and experimental results and their applications

Schmalholz

Mancktelow

2016

Solid Earth

View full text Add to dashboard Cite

show abstract

“…Due to its simplicity, relative to the full set of equations and , the pinned state limit is frequently used in geodynamic applications of grain damage theory (Bellas et al, ; Bercovici et al, , ; Mulyukova & Bercovici, , ).…”

Section: Grain Damage Physicsmentioning

confidence: 99%

The Generation of Plate Tectonics From Grains to Global Scales: A Brief Review

Mulyukova

Bercovici

2019

Tectonics

Self Cite

View full text Add to dashboard Cite

The physics of rock deformation in the lithosphere governs the formation of tectonic plates, which are characterized by strong, broad plate interiors, separated by weak, localized plate boundaries. The size of mineral grains in particular controls rock strength and grain reduction can lead to shear localization and weakening in the strong ductile portion of the lithosphere. Grain damage theory describes the competition between grain growth and grain size reduction as a result of deformation, and the effect of grain size evolution on the rheology of lithospheric rocks. The self-weakening feedback predicted by grain damage theory can explain the formation of mylonites, typically found in deep ductile lithospheric shear zones, which are characteristic of localized tectonic plate boundaries. The amplification of damage is most effective when minerallic phases, like olivine and pyroxene, are well mixed on the grain scale. Grain mixing theory predicts two coexisting deformation states of unmixed materials undergoing slow strain rate, and well-mixed materials with large strain rate; this is in agreement with recent laboratory experiments, and is analogous to Earth's plate-like state. A new theory for the role of dislocations in grain size evolution resolves the rapid timescale of dynamic recrystallization. In particular, a toy model for the competition between normal grain growth and dynamic recrystallization predicts oscillations in grain size with periods comparable to earthquake cycles and postseismic recovery, thus connecting plate boundary formation processes to the human timescale.

show abstract

“…Here we explore an alternative view that material strength might not be instantaneously restored to its full pre-yielded value and acknowledge that the geological material may have been weakened as a result. We use a computationally efficient way of parameterizing the effective viscosity that may result due to any number of mechanisms that may be active subsequent to leaving the high stress bending region, including the development of weakened tectonic fabrics or subgrid faults in the lithosphere, in addition to the possible activation of Peierls creep, damage rheology, or other non-Newtonian rheologies (Kameyama et al, 1999;Bercovici, 2003;Garel et al, 2014;Bercovici et al, 2015;Holt et al, 2015a).…”

Section: Rheologymentioning

confidence: 99%

The subduction dichotomy of strong plates and weak slabs

2017

View full text Add to dashboard Cite

Abstract. A key element of plate tectonics on Earth is that the lithosphere is subducting into the mantle. Subduction results from forces that bend and pull the lithosphere into the interior of the Earth. Once subducted, lithospheric slabs are further modified by dynamic forces in the mantle, and their sinking is inhibited by the increase in viscosity of the lower mantle. These forces are resisted by the material strength of the lithosphere. Using geodynamic models, we investigate several subduction models, wherein we control material strength by setting a maximum viscosity for the surface plates and the subducted slabs independently. We find that models characterized by a dichotomy of lithosphere strengths produce a spectrum of results that are comparable to interpretations of observations of subduction on Earth. These models have strong lithospheric plates at the surface, which promotes Earth-like single-sided subduction. At the same time, these models have weakened lithospheric subducted slabs which can more easily bend to either lie flat or fold into a slab pile atop the lower mantle, reproducing the spectrum of slab morphologies that have been interpreted from images of seismic tomography.

show abstract

Abrupt tectonics and rapid slab detachment with grain damage

Cited by 54 publications

References 40 publications

Folding and necking across the scales: a review of theoretical and experimental results and their applications

Folding and necking across the scales: a review of theoretical and experimental results and their applications

The Generation of Plate Tectonics From Grains to Global Scales: A Brief Review

The subduction dichotomy of strong plates and weak slabs

Contact Info

Product

Resources

About