Kinematic indicators কী?

A kinematic indicator is a structure whose asymmetry records the sense of shear, the sense in which one wall of a shear zone moved relative to the other, read in the plane that contains the stretching lineation and is perpendicular to the foliation. An S–C fabric is a pair of foliations: S, the foliation of flattened grains, oblique to the zone and turned towards the direction of stretching, and C, shear bands parallel to the zone. A porphyroclast system is a strong grain with tails of recrystallised material: in a $\sigma$-type the tails step from one side of the clast’s centre line to the other without crossing it, in a $\delta$-type, dragged round by the clast’s rotation, they cross it. A mica fish is a lozenge-shaped mica grain inclined to the shear plane, with thin tails, stepping like those of a $\sigma$-type clast.