Global Analysis of Experimental Data on the Rheology of Olivine Aggregates

Jain, Chinmay; Korenaga, Jun; Karato, Shun‐ichiro

doi:10.1029/2018jb016558

Cited by 29 publications

(50 citation statements)

References 42 publications

(110 reference statements)

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“…Correlation coefficients are reported in Tables S2 and S3. a The error in V 2 and V 4 for model OL-WB 2 listed here is double the value reported in Jain et al (2019). This is because the high-pressure experimental data used in their study are expected to have larger than reported error; consequently the uncertainty in these parameters reported by Jain et al 2019 For the prescribed surface velocity, the width of our domain encompasses seafloor ages from 0 at the ridge to ∼85 Myr at x = 6,000 km ( Figure S1).…”

Section: Our Ridge Flow Modelmentioning

confidence: 80%

“…For dislocation creep, probabilistic modeling yields values of 33 ± 5 (case S2d 10 ) and 29 ± 9 cm 3 mol −1 (case S2d eq ) for the activation volume under dry conditions, designated as V 3 . The a posteriori probability distributions of the successful models in our study ( Figures S4 and S5) indicate that both V 1 and V 3 are only loosely constrained, but these parameters were previously not constrained by the MCMC inversion of deformation data for lack of sufficient high-pressure experimental data under dry conditions (Jain et al, 2019).…”

Section: New Constraints On the Flow Law Parameters For Olivinementioning

confidence: 86%

“…We model upper mantle rheology in our geodynamic model using a composite flow law for olivine, which assumes the simultaneous operation of both diffusion and dislocation creep under mantle conditions. Dislocation‐accommodated grain boundary sliding is not included in the composite flow law because its contribution is likely to be trivial under upper mantle conditions (Jain et al, 2019). The following constitutive equations govern diffusion and dislocation creep in olivine (Karato, 2008):

{\overset{ϵ}{true}}_{d i f f, d r y} = \overset{ϵ_{1}}{true} = A_{1} d^{- p_{1}} σ \exp ((), - \frac{E_{1} + P V_{1}}{R T}),

{\overset{ϵ}{true}}_{d i f f, w e t} = \overset{ϵ_{2}}{true} = A_{2} d^{- p_{2}} C_{w}^{r_{2}} σ \exp ((), - \frac{E_{2} + P V_{2}}{R T}),

{\overset{ϵ}{true}}_{d i s l, d r y} = \overset{ϵ_{3}}{true} = A_{3} σ^{n_{3}} \exp ((), - \frac{E_{3} + P V_{3}}{R T}),

{\overset{ϵ}{true}}_{d i s l, w e t} = \overset{ϵ_{4}}{true} = A_{4} σ^{n_{}}

…”

Section: Methods and Datamentioning

confidence: 99%

“…Note that only the dry flow laws are used to predict viscosity under dry conditions, and only the wet flow laws model wet rheology. We use the composite rheological model [Equation 6] with the flow law parameters reported by Jain et al (2019) to estimate olivine rheology. In particular, the composite flow law for case OL‐DB 2 in Jain et al (2019) is used to model dry rheology and that for case OL‐WB 1 to model wet rheology in our study.…”

Section: Methods and Datamentioning

confidence: 99%

“…where m runs from 1 to M and k from 1 to K. Finally, in accordance with Jain et al (2019), the perturbed values of A i are normalized to 1,523 K and 0.3 GPa using the perturbed values of E i and V i .…”

Section: Perturbation Of Mean Flow Lawsmentioning

confidence: 99%

See 4 more Smart Citations

Synergy of Experimental Rock Mechanics, Seismology, and Geodynamics Reveals Still Elusive Upper Mantle Rheology

Jain

Korenaga

2020

JGR Solid Earth

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We present a novel geodynamic approach that can potentially tighten existing constraints on mantle rheology. This new approach, which we call probabilistic geodynamic modeling, is applied here to the rheology of the upper mantle. We combine the numerical modeling of plate-driven corner flow and the seismic observation of radial anisotropy, aiming to reduce substantial uncertainties associated with experimentally derived flow laws, but our results also highlight the complex competition among different deformation mechanisms under mantle conditions. Despite the remaining rheological uncertainty, our study suggests that significant background shear flow is required near the lithosphere-asthenosphere boundary to explain the strong radial anisotropy observed at 100-200 km depth underneath the Pacific plate, and the plausible nature of this background flow is characterized using our new probabilistic approach. Our analysis also provides a new insight into the asthenospheric water content and the grain size distribution in the upper mantle, but these results are also subject to nontrivial nonuniqueness. The merit of our probabilistic approach lies in its ability to assess the extent of such nonuniqueness, and we demonstrate this by quantifying the robustness of some of our results. Plain Language Summary A detailed understanding of how silicate minerals deform under various conditions is central to conducting realistic simulations of mantle dynamics, but the currently available experimental constraints on the flow laws of olivine, which is the dominant phase of the upper mantle, suffer from considerable uncertainties. We present a new kind of geodynamic modeling, which can reduce such uncertainties by assimilating geophysical observations. Unlike previous similar attempts, our approach properly handles parameter uncertainties such that the flow laws under consideration remain consistent with experimental deformation data. Most important, our new approach provides a unifying framework to combine experimental rock mechanics, observational geophysics, and theoretical geodynamics in a self-consistent manner.

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Section: Our Ridge Flow Modelmentioning

confidence: 80%

Section: New Constraints On the Flow Law Parameters For Olivinementioning

confidence: 86%