ANISOTROPY, ANOMALOUS THICK LAYER

Just as the anomalous thick competent layer affects the chevron fold model stability, so does that of the development of conjugate kink-bands if the anisotropy becomes lower because of the presence of an anomalous thick layer. At this place is shown four experiments carried out by Summers. In the first stage, the anomalous layer is too thick and the structures produced are sinusoidal folds of type 1 instability when the interlayer slip is hampered. But as the thickness of the central layer is reduced, we start getting first the type 3 structures of intermediate anisotropy until finally high anisotropy conjugate kink-bands are produced when the layer thickness is same as that of the other layers in the same complex. These last depict high anisotropy and easy interlayer slip on account of compressive and shear modulii being at great variance.