Stress induced grain boundary migration in very soluble brittle salt

Citation
B. Den Brok et al., Stress induced grain boundary migration in very soluble brittle salt, J STRUC GEO, 21(2), 1999, pp. 147-151
Citations number
12
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Earth Sciences
Journal title
JOURNAL OF STRUCTURAL GEOLOGY
ISSN journal
0191-8141 → ACNP
Volume
21
Issue
2
Year of publication
1999
Pages
147 - 151
Database
ISI
SICI code
0191-8141(199902)21:2<147:SIGBMI>2.0.ZU;2-2
Abstract
Grain boundary migration (GBM) was studied in-situ at room temperature, atm ospheric pressure and an applied differential stress of similar to 9.5 MPa under the optical microscope, in a wet aggregate of an elastic-brittle salt (sodium chlorate). The aggregate was previously deformed predominantly by a combination of grain boundary sliding, pressure solution and cataclastic solution creep. After deformation, but when the sample was still under diff erential stress, undeformed, fracture-free grains were observed to grow at the cost of deformed, intensely fractured grains. GMB rates typically fell in the range 2-10 mu m/day. GBM took place only as long as the ample was un der stress. Boundaries stopped to migrate as soon as stress was taken off a nd started to migrate again as soon as the sample was stressed again. Our o bservations suggest that GBM in this material and under the prevailing expe rimental conditions is a stress-induced process, i.e. driven by differences in elastic strain between fractured and unfractured grains. (C) 1999 Elsev ier Science Ltd. All rights reserved.