Figure 7
From: Effect of stress state on slow rupture propagation in synthetic fault gouges
Optical photomicrographs of experimentally deformed liz/ctl, antigorite, and olivine synthetic fault gouges. Optical photomicrographs of experimentally deformed liz/ctl, antigorite, and olivine synthetic fault gouges observed in (A and B) cross-polarized light and (C and D) plane-polarized light. The shear sense along each fault gouge in A and B is indicated by the large white arrows. (A) Liz/ctl gouge (P c  = 60 MPa), highlighting the development of regularly spaced R1 shears that curve in a listric fashion into the B shears present on either side of the gouge layer. (B) Liz/ctl gouge (P c  = 140 MPa), highlighting the development of a number of anastomosing Y and B shears, showing strong evidence of the preferred crystallographic orientation of serpentine (i.e., a distinctive shear-zone-parallel planar fabric). (C) Liz/ctl gouge (P c  = 120 MPa), highlighting well-developed, anastomosing Y and B shears that are interleaved with regions of intervening gouge where the mineral grains are more massive and less deformed. (D) Liz/ctl gouge (P c  = 170 MPa), highlighting the development of densely distributed Y shears that show a pronounced wavy appearance linked to the development of kink-bands oriented parallel to the X- and R2-shear directions.