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High temperature olivine creep: Evidence for control by edge dislocations
Author(s) -
Gueguen Yves
Publication year - 1979
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/gl006i005p00357
Subject(s) - creep , dislocation , olivine , nucleation , activation energy , condensed matter physics , materials science , climb , dislocation creep , enhanced data rates for gsm evolution , peridotite , microstructure , diffusion , geology , mineralogy , thermodynamics , mantle (geology) , composite material , chemistry , physics , geochemistry , telecommunications , computer science , organic chemistry
Dislocation microstructures in olivine grains from experimentally deformed specimens as well as from peridotite xenoliths in lavas indicate that (1) edge dislocations probably control the creep rate and (2) {110} planes exert a strong crystallographic control on b=[100] edge dislocations even at very high temperatures (0,9 Tm). This observation can be explained by a sessile splitting or by the existence of a deep Peierls valley in {110} planes. In either case, kink and jog nucleation are likely to be difficult so that creep can be controlled either by kink or jog formation. This interpretation implies that different activation energies should be associated with the different glide systems. It is in agreement with the fact that the activation energy for creep is not that for oxygen diffusion.