Ductile shear zones as counterflow boundaries in pseudoplastic fluids: Discussion and theory

A model presented by Talbot (1999) attempts to use the shapes of S- or J-shaped structures in ductile shear zones experiencing simple shear to infer information about rock rheology, specifically the value of the stress exponent n in a power-law rheology. The model is incorrect, so cannot yield any insight into the deformation or rheology of shear zones. The shape of S- or J-shaped structures is more likely a function of variation across the shear zone of water fugacity, grain size, or other weakening mechanisms.