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Si and O diffusion in olivine and implications for characterizing plastic flow in the mantle
Author(s) -
Dohmen Ralf,
Chakraborty Sumit,
Becker HansWerner
Publication year - 2002
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2002gl015480
Subject(s) - olivine , creep , climb , diffusion , activation energy , geology , mantle (geology) , diffusion creep , materials science , plasticity , thermodynamics , mineralogy , geophysics , chemical physics , microstructure , physics , chemistry , metallurgy , grain boundary
The relationship between diffusion of individual species and creep of silicates is unclear and has long been debated, factually anchored by the central observation that the activation energies for creep are higher than the activation energy for diffusion of any species. There have been numerous attempts to explain this difference. New advances in experimental technology enable us to demonstrate that this difference does not exist and was an artefact of the limited experimental resolution of earlier studies – the activation energies of creep and diffusion of Si in olivine are identical, 530 kJ/mol. This allows the creep mechanism in olivine to be understood as one of simple climb (consistent with microstructural observations) and opens possibilities of estimating, understanding and predicting the (much simplified) creep behavior of diverse silicates under a wide range of P‐T‐X conditions through the use of diffusion data–measured or computed.