|
1 Earth and Ocean Sciences, The University of British Columbia, 6339 Stores Road, Vancouver, BC, V6T 1Z4, Canada
2 Department of Geological Sciences, The University of Oregon, Eugene, OR, 97411
3 Earth, Atmospheric, and Planetary Sciences, The Massachusetts Institute of Technology, 77 Massachusetts Avenue, 54-710, Cambridge, MA, 02139-4307, USA naustin{at}mit.edu
To investigate the role of texture on the brittle deformation of dolomite, 23 triaxial deformation experiments were performed at confining pressures of 25, 50, and 100 MPa, dry, at room temperature, on dolomite from three texturally distinct sample suites. The variations in the mechanical response of these mineralogically and chemically similar dolomites, and the ensuing microstructures, indicate that grain boundary textures promote or inhibit the ability of grains to shear and rotate with respect to one another, whereas the presence of intragranular flaws, such as cleavage, that act as weaknesses, promote intragranular deformation. In samples with porosities greater than c. 7%, inelastic pore collapse controls the transition from brittle faulting to extensive intragranular deformation and cataclastic flow. This porosity is much higher than has been observed at the onset of pore collapse in calcite, as a consequence of the inability of dolomite to deform by crystal plastic processes at room temperature. Combined, these textural features may dictate the transition from brittle faulting to cataclastic flow in brittle rocks in the upper crust.
This article has been cited by other articles:
 |
|
 |
|
  N. J. Austin and L. A. Kennedy Textural controls on the brittle deformation of dolomite: variations in peak strength Geological Society, London, Special Publications, 2005; 243: 37 - 49. [Abstract] [PDF]
|
|
