Kinematic analysis is the art to figure out the relative sense of motion across faults and shear zones. To do this, structural geologists use "kinematic criteria" ie. structures and microstructures that develop during faulting and whose geometric characteristics depend on the sense of shear. The main kinematic criteria for brittle faults are:
1/ Riedel shear fractures (R and R'): R are synthetic at 10-15º to the fault plane; R' are antithetic (opposite sense of shear) and oriented at 70-80º to the fault plane. 2/ Tool marks: Cavities formed by the mecanical erosion of the fault plane by hard inclusions. 3/ Extensional fractures at ca. 30º angle to the fault plane.
4/ Mineralized steps: Step-shaped cavities filled with fibrous minerals (often quartz or calcite). 5/ Dry steps: same as above but with no crystallization. 6/ Rough surfaces (usually with stryloliths) form due to pressure solution, and smooth (or polished) surface .
