Abstract: | The theory of folding in stratified media presented by Biot and Ramberg has been extended by considering a more general type of material response. The model consists of a viscous layer embedded in a less viscous medium, compressed parallel to the layering. A transition from Newtonian to non-Newtonian behavior is considered and an approximate solution to the governing equation is discussed. The results give the effect of local, stress-induced changes in the viscosity on the profile of the fold. The results indicate that as the transition to non-Newtonian behavior proceeds, the wavelength selection process described by Biot and Ramberg breaks down; the wavelength of the fold which develops probably will not be the “dominant” wavelength defined by Biot. |