Numerical models of mantle lithosphere weakening, erosion and delamination induced by melt extraction and emplacement

Wallner, Herbert; Schmeling, Harro

doi:10.1007/s00531-016-1343-y

Cited by 15 publications

(24 citation statements)

References 66 publications

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“…However, numerical model results might be biased by the approach chosen to introduce the melt-enhanced weakening (Jamieson and Beaumont, 2011;Labrousse et al, 2015;Butler et al, 2015;Maierová et al, 2016). Furthermore, low resolution of these models (~1 km grid spacing) does not allow simulation of mesoscale to microscale deformation mechanisms coupled with porous melt flow and melt segregation (see Wallner and Schmeling, 2016).…”

Section: Introductionmentioning

confidence: 99%

Role of strain localization and melt flow on exhumation of deeply subducted continental crust

et al. 2018

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A section of anatectic felsic rocks from a high-pressure (>13 kbar) continental crust (Variscan Bohemian Massif) preserves unique evidence for coupled melt flow and heterogeneous deformation during continental subduction. The section reveals layers of migmatitic granofels interlayered with anatectic banded orthogneiss and other rock types within a single deformation fabric related to the prograde metamorphism. Granofels layers represent high strain zones and have traces of localized porous melt flow that infiltrated the host banded orthogneiss and crystallized granitic melt in the grain interstices. This process is inferred from: (1) gradational contacts between orthogneiss and granofels layers; (2) grain size decrease and crystallographic preferred orientation of major phases, compatible with oriented growth of crystals from interstitial melt during granular flow, accommodated by melt-assisted grain boundary diffusion creep mechanisms; and (3) pressuretemperature equilibria modeling showing that the melts were not generated in situ. We further argue that this porous melt flow, focused along the deformation layering, significantly decreases the strength of the crustal section of the subducting continental lithosphere. As a result, detachment folds develop that decouple the shallower parts of the layered anatectic sequence from the underlying and continuously subducting continental plate, which triggers exhumation of this anatectic sequence.

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Section: Introductionmentioning

confidence: 99%

Role of strain localization and melt flow on exhumation of deeply subducted continental crust

et al. 2018

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“…The solid and liquid pressures P s and P l are different (and different from the average pressure of the melt‐solid mixture

\bar{P}

) and a micromechanical model [see Šrámek et al ., ] suggests that they are related by

ϕ Δ P = - K μ_{s} \nabla \cdot v_{s},

where K of order 1 is related to the topology of the melt‐matrix interface and we take K = 1 in the following. The quantity

K μ_{s} / ϕ

takes the same role as the bulk viscosity introduced by McKenzie [] and see also Bercovici and Ricard [] and Wallner and Schmeling [].…”

Section: A Multiphase Modelmentioning

confidence: 99%

“…where K of order 1 is related to the topology of the melt-matrix interface and we take K 5 1 in the following. The quantity Kl s =/ takes the same role as the bulk viscosity introduced by McKenzie [1984] and see also Bercovici and Ricard [2003] and Wallner and Schmeling [2016].…”

Section: Two-phase Equations For a Silicate Mantle: Melt And Solidmentioning

confidence: 99%

“…[], Bercovici and Ricard [], and Šrámek []. Other multiphase numerical codes sharing a similar approach have been used by Schmeling [] and Wallner and Schmeling []. The equations are described in the next section.…”

Section: Introductionmentioning

confidence: 99%

“…The mathematical basis of the code is inspired from the work of Bercovici et al [2001], Bercovici and Ricard [2003], and Sr amek [2007]. Other multiphase numerical codes sharing a similar approach have been used by Schmeling [2000] and Wallner and Schmeling [2016]. The equations are described in the next section.…”

Section: Introductionmentioning

confidence: 99%

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Modeling phase separation and phase change for magma ocean solidification dynamics

Boukaré

Ricard

2017

Geochem Geophys Geosyst

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Just after accretion, the Earth's mantle was significantly molten by the heat dissipation due to large impacts and to the segregation of the core. The mineralogical observations and thermodynamics models of solid‐liquid equilibrium of silicates show that several types of crystallization may have happened at different depths in the mantle. Solids were probably formed first at the bottom of the lower mantle or at midmantle leaving two possible magma oceans, a shallow one and an abyssal one. Near the bottom of the mantle, the liquid phase might become denser than solids due to iron enrichment. In the shallow magma ocean, the crystallizing solid phase was denser and sank through the magma to settle and compact at depth. To understand these complex dynamics, we develop a two‐phase numerical code that can handle simultaneously convection in each phase and in the slurry, and the compaction or decompaction of the two phases. Although our code can only run in a parameter range (Rayleigh number, viscosity contrast between phases, Prandlt number) far from what would be realistic, we think it already provides a rich dynamics that illustrates what could have happened. We show situations in which the crystallization front is gravitationally stable and situations where the newly formed solids are gravitationally unstable and can snow across the magma. Our study suggests that the location of a density contrast between solid and magma must be considered of equal importance with that of the intersection between liquidus and isentrope for what concerns mantle solidification.

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The Getxo crustal-scale cross-section: Testing tectonic models in the Bay of Biscay-Pyrenean rift system

Pedrera

García-Senz

Peropadre

et al. 2021

Earth-Science Reviews

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Numerical models of mantle lithosphere weakening, erosion and delamination induced by melt extraction and emplacement

Cited by 15 publications

References 66 publications

Role of strain localization and melt flow on exhumation of deeply subducted continental crust

Role of strain localization and melt flow on exhumation of deeply subducted continental crust

Modeling phase separation and phase change for magma ocean solidification dynamics

The Getxo crustal-scale cross-section: Testing tectonic models in the Bay of Biscay-Pyrenean rift system

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