Steady state flow of rocks

Abstract

Experimentally determined steady state flow properties and processes of important rock‐forming materials are reviewed in reference to those of metals and ceramics and to physical conditions in the earth's crust and upper mantle. Dislocation motion controls the creep rate over a wide range of steady state conditions in the experiments, and the observation that the same processes have operated during natural deformations permits extrapolations of the mechanical data. Under these conditions, strain rate is related to stress raised to the power 2–9, depending on the material and conditions, and the resulting flow stresses and equivalent viscosities are compared at a representative geological strain rate of 10−14/s. The results are applied in brief discussions of diapirism, growth of folds, and flow in the upper mantle.