Models of hydrolytic weakening in quartz

Abstract
Three models of the weakening of quartz by small amounts of water are described and analysed. Attention is confined to the glide of dislocations caused by a double-kink nucleation process. The structure of a double kink on a basal 60° dislocation is described and its formation energy estimated using a short-range interaction potential. The same potential was used to give a lower bound to its migration energy. The energies of Griggs-Black-Frank and (4H)si models of water bound to kinks are also calculated. The results strongly support these models of hydrolytic weakening.