Verification of ultra-low strain rate effect on olivine rheology

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In this research, we observed the microstructures of both alpine-type peridotites and peridotite xenoliths in basalt, and analyzed the microchemistry around the dislocations developed in the olivine grains of the studied samples, using optical microscopy, EPMA, EBSD, TEM and ATEM techniques to clarify if the ultra-low strain rate has any effect on the olivine plasticity. We detected Fe-concentration along dislocation line in all observed samples, which was probably caused by Cottrell atmosphere. This result strongly suggests that the effect of ultra-low strain rate on olivine plasticity is very important to understand the dynamics of the upper mantle, which has not been studied so far. In addition, we tried to do the deformation experiments of olivine to support the above conclusion, which has yet to produce any confirming results.