Deformation of Rocks of the Mahakaushal Super Group around Barman, the Narmada Valley, Narsinghpur District, M. P.

The rocks of Mahakaushal Super group exposed around Barman along the Narmada Valley has suffered the two phases of the deformation in the early proterozoic period, phase one accounts for shearing movement (E1), followed by phase two (E2 and E3) which caused folding episodes (F1 and F2) in the rocks. The first fold structures (F1, related to E2) caused by a combination of tangential longitudinal strain and oblique flexural slip, suggesting initial unsymmetrical disposition of rocks layers in relation to principal stresses which produced numerous slicken sided fibres which are unrelated to any recognisable faulting activity in the rocks. Cleavage contemporaneous with F1 folds shows slight transection in a few minor folds. In submacroscopic fold chains, the geometry of single or paired folds suggests their initiations in the north and gradual propagation to the south along the layering, newer folds probably appearing with the advancing stress front. The youngest structures (F2, related to E2) are broad flexural slip warps, lying at high angle to early folds. The shearing movement (E1) also caused intrusion of basic dikes and quartz veins. Intrusion of a second set of basic dikes was the youngest event in the area which is unrelated to any deformation or metamorphism.