Solution Exercise 2
Shear fractures and faults can be identified by the presence of the offset of a marker bed on either side of the fracture that was continuous before the shearing motion. Faults often have nearly planar surfaces with a polished appearance and striations and grooves formed in the direction of slip. Although offset marker horizons can indicate that shearing has occurred, for defining the mechanism of faulting and kinematic vectors (fault slip direction), the planar fault surface and striations/grooves on the fault surface must be examined. If there is no evidence of these shear indicators, the discontinuity is likely a joint where the subparallel fracture walls moved away from one another without an offset (opening fracture).
The image below provides an example of offset marker horizons.
