Abstract
Single crystalline San Carlos olivine (1 mm cube) was transformed to (Mg,Fe)2SiO4 β-phase at 13.5-15 GPa, 1030-1330 °C for 0-600 min using a multi-anvil high pressure apparatus. The α-β transformation occurred by incoherent surface nucleation and interface-controlled growth and recovered partially transformed samples showed sharply defined reaction rim. The growth rate of the β-phase rim significantly decreased with time and the growth eventually ceased. TEM observations revealed that many dislocations were created in both the relict olivine just near the α-β interface and the β-phase in the rim, which show evidence for deformation caused by interfacial stresses associated with the misfit elastic strain of the transformation. The observed tangled dislocation texture in β-phase suggested that the β-phase rim was hardened and relaxation of the interfacial stress was retarded. This probably caused a localized pressure drop in the relict olivine and decreased the growth rate. Time-dependent growth rates of β-phase is possibly controlled by the rheology of β-phase, which must be considered for the prediction of the olivine metastability in the subducting slabs.
Original language | English |
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Pages (from-to) | 1-6 |
Number of pages | 6 |
Journal | Physics and Chemistry of Minerals |
Volume | 26 |
Issue number | 1 |
DOIs | |
Publication status | Published - 1998 Dec 1 |
Keywords
- High pressure experiment
- San Carlos olivine
- Transformation kinetics
- Transformation mechanisms
- α-β transformation
ASJC Scopus subject areas
- Materials Science(all)
- Geochemistry and Petrology