Folding with thermal mechanical feedback: Another reply

In response to Schmid et al. (2010): (i) The linear Biot theory assumes fold wavelengths grow independently of each other; this is the “Biot process”. (ii) The Biot theory predicts that only one wavelength grows to finite amplitudes; a spread of wavelengths at finite amplitudes indicates non-Biot processes operate. (iii) Boundary conditions control the wavelength that grows. (iv) Non-linear behaviour can result in non-Biot behaviour such as localised folding with no dominant wavelength. (v) Strain-rate softening is one form of non-linearity and leads to folding and boudinage at all scales; thermal–mechanical feedback leads to strain-rate softening producing folding and boudinage at the kilometre scale. (vi) The larger the viscosity ratio the larger the feedback effect. (vii) The Biot process may be important in some deformed rocks but others perhaps dominate.