COAXIAL REFOLDING

The hinges of early folds are not deformed and lie parallel to those of later folds. The axial planes of early folds are folded. Many such structures are actually generated in a single phase of progressive deformation. For example if the early folds are formed by gravity gliding, then these folds get coaxially refolded under the influence of the same stress field by heterogeneous simple shear parallel to the enveloping surfaces of early folds. In fact the process is a very continuous one and it might be incorrect to call terms such as early or late. The early folds, very soon after their buckling begins, give rise to distinct asymmetry which suggests that HSS begins too early in the process.