RHEOLOGY AND DEFORMATION MECHANISMS OF AN ISOTROPIC MICA SCHIST Academic Article uri icon

abstract

  • We have investigated the transitional, semibrittle deformation of a mica schist (~75% biotite) by shortening cylinders cored at 0, 45, and 90 to foliation to varying strains, at confining pressures Pcto 500 MPa, constant strain rates from 1.5 x 10-7to 1.6 x 10-4s-1, and temperatures T from 25 to 400C. Deformation is concentrated within one or two more throughgoing, millimeter-wide shear zones at all conditions; these localize at low strains (<2%) through the nucleation and coalescence of dense sets of intragranular microkink bands (MKBs). Application of the results to crustal deformation suggests that mica-rich aggregates are weaker than other common rock types throughout a broad midcrustal depth range, supporting the inference that retrograde reaction to phyllosilicates may be important in localizing crustal deformations within large faults and shear zones. -from Authors

published proceedings

  • JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH

author list (cited authors)

  • SHEA, W. T., & KRONENBERG, A. K.

citation count

  • 115

complete list of authors

  • SHEA, WT||KRONENBERG, AK

publication date

  • January 1, 1992 11:11 AM