A Discussion on natural strain and geological structure - Some current aspects of experimental rock deformation

Abstract

This review considers first some general aspects of the relevance of laboratory rock deformation experiments to geological conditions and then, specifically, recent work on olivine and quartz. Improvements in temperature capability and reliability of apparatus now permit the exploration of regimes of flow characteristic of higher temperatures and lower stresses and strain rates than those used hitherto. These experimental advances, together with the availability now of transmission electron microscopy, open the way to a greater understanding of the major deformation mechanisms, an understanding, or at least recognition, that must form a vital link in validly extrapolating experimentally determined flow laws to natural conditions. Recent work on olivine crystals has considerably improved our understanding of its deformation mechanisms and likely geological behaviour, but in the case of quartz there are many aspects of behaviour, especially involving the role of water, that remain obscure.