Experimental Diffusional Crack Healing in Olivine

  1. Robert N. Schock
  1. B. J. Wanamaker and
  2. Brian Evans

Published Online: 18 MAR 2013

DOI: 10.1029/GM031p0194

Point Defects in Minerals

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

Author Information

  1. Department of Geological and Geophysical Sciences, Princeton University, Princeton, New Jersey 08544

Publication History

  1. Published Online: 18 MAR 2013
  2. Published Print: 1 JAN 1985

ISBN Information

Print ISBN: 9780875900568

Online ISBN: 9781118664070

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Keywords:

  • Mineralogical chemistry—Congresses;
  • Crystals—Defects—Congresses

Summary

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.