This document discusses field criteria for identifying faults and shear zones. Some key criteria include lateral or vertical displacement of markers along fault planes, fault scarps in topography, and offset beds. Faults are also characterized by damage zones, fault rocks like breccia and gouge, and slickensides on the fault plane. Shear zones form at depth and show deflection of markers or foliation on both sides, as well as mylonitic foliation that may be oblique to the regional foliation. Kinematic indicators can also help determine the sense of shear. Shear zones in igneous rocks cut randomly oriented rocks and may contain stretched pebbles oblique to shear bands.

1. Fault criteria in the field
Lateral or vertical displacement of markers
Fault scarps that appear as topographic scarp along the
fault plane
Drag of beds on both sides of the fault

2. Fault scarp

3. Lateral offset along the fault trace

4. Fault damage zone
Fracture zone and fault core

5. Fault rocks; fault breccia and gouge

6. Fault rocks; fault breccia and gouge
Coarse red clasts and white powder

7. Fault plane slickensideslickneside and steps

10. Shear is a ductile deformation that forms at great depths
Deflection of markers or foliation on both sides of the
shear zone.
Shear zone is characterized by mylonitic rock and
mylonitic foliation.
Orientation of mylonitic foliation is usually oblique or
normal to the regional foliation

11. Sense of shear:
Kinematic indicators

15. Shear zone cut across
randomly oriented rocks
(igneous rocks)

16. Stretched pebbles Stretched pebbles oblique to
shear bands