Experimental Diffusional Crack Healing in Olivine
- Robert N. Schock
Published Online: 18 MAR 2013
Copyright 1985 by the American Geophysical Union.
Point Defects in Minerals
How to Cite
Wanamaker, B. J. and Evans, B. (1985) Experimental Diffusional Crack Healing in Olivine, in Point Defects in Minerals (ed R. N. Schock), American Geophysical Union, Washington, D. C.. doi: 10.1029/GM031p0194
- Published Online: 18 MAR 2013
- Published Print: 1 JAN 1985
Print ISBN: 9780875900568
Online ISBN: 9781118664070
- Mineralogical chemistry—Congresses;
Both natural and laboratory produced cracks in San Carlos peridot heal by a two stage process involving the initial formation of cylindrical voids and the subsequent formation of spherical pores when subjected to heat treatments at 1250°C–1400°C; laboratory produced cracks also heal rapidly at 1000°C. In addition to being thermally activated, the kinetics of the healing process depend on the crack dimensions and apparently either the chemical speciation or the pressure of the fluid filling the crack. Interpretation of the results of these experiments using theories of diffusive crack healing developed for metals and ceramics indicates that surface diffusion is probably the dominant mechanism of crack healing. The effective activation energy of the break-up of the cylindrical voids is approximately 53 ± 22 kcal/mole and the time necessary to produce a spherical void from a cylinder is proportional to the fourth power of the radius of the cylinder. The region of healed crystal between the spherical pores contains dislocations which are apparently formed during the healing process as accommodation of strain between the free crack surfaces.