Please use this identifier to cite or link to this item: https://hdl.handle.net/10356/162772
Title: MCMC inversion of the transient and steady-state creep flow law parameters of dunite under dry and wet conditions
Authors: Masuti, Sagar
Barbot, Sylvain
Keywords: Science::Geology
Issue Date: 2021
Source: Masuti, S. & Barbot, S. (2021). MCMC inversion of the transient and steady-state creep flow law parameters of dunite under dry and wet conditions. Earth, Planets and Space, 73(1). https://dx.doi.org/10.1186/s40623-021-01543-9
Project: NRF-NRFF2013-04 
Journal: Earth, Planets and Space 
Abstract: The rheology of the upper mantle impacts a variety of geodynamic processes, including postseismic deformation following great earthquakes and post-glacial rebound. The deformation of upper mantle rocks is controlled by the rheology of olivine, the most abundant upper mantle mineral. The mechanical properties of olivine at steady state are well constrained. However, the physical mechanism underlying transient creep, an evolutionary, hardening phase converging to steady state asymptotically, is still poorly understood. Here, we constrain a constitutive framework that captures transient creep and steady state creep consistently using the mechanical data from laboratory experiments on natural dunites containing at least 94% olivine under both hydrous and anhydrous conditions. The constitutive framework represents a Burgers assembly with a thermally activated nonlinear stress-versus-strain-rate relationship for the dashpots. Work hardening is obtained by the evolution of a state variable that represents internal stress. We determine the flow law parameters for dunites using a Markov chain Monte Carlo method. We find the activation energy 430 ± 20 and 250 ± 10 kJ/mol for dry and wet conditions, respectively, and the stress exponent 2.0 ± 0.1 for both the dry and wet cases for transient creep, consistently lower than those of steady-state creep, suggesting a separate physical mechanism. For wet dunites in the grain-boundary sliding regime, the grain-size dependence is similar for transient creep and steady-state creep. The lower activation energy of transient creep could be due to a higher jog density of the corresponding soft-slip system. More experimental data are required to estimate the activation volume and water content exponent of transient creep. The constitutive relation used and its associated flow law parameters provide useful constraints for geodynamics applications.
URI: https://hdl.handle.net/10356/162772
ISSN: 1880-5981
DOI: 10.1186/s40623-021-01543-9
Rights: © The Author(s) 2021. Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
Fulltext Permission: open
Fulltext Availability: With Fulltext
Appears in Collections:ASE Journal Articles
EOS Journal Articles

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