GRAVITY INDUCED KINK-BANDS
Folds, quite open and kink-bands can be formed by gravitational settling and these folds have subhorizontal axial planes. Such kink-bands were first described by Roberts from Trondheim region of Norway and by many workers later. Naha and Halyburton described these from Aravalli rocks. These folds and kink-bands are very common in Aravalli and Delhi fold belts and record last stages of the orogenic movement. The computation of principal stresses from conjugate kink bands or mere observation in the field leaves no doubt that these suggest vertical shortening.