title: Activation volume for creep in the upper mantle.
abstract: The activation volume for creep, V*, of olivine-rich rocks has been determined in pressure-differential creep experiments on dunite at temperatures from 1100 degrees to 1350 degrees C and confining pressures from 5 to 15 kilobars. Values of V* range from 10.6 to 15.4 cubic centimeters per mole with a mean value of 13.4 cubic centimeters per mole, near that expected for oxygen ion self-diffusion. The quantity V* is incorporated into existing flow equations; in combination with observations on naturally deformed mantle xenoliths, estimates are given of the variation with depth of stress, strain rate, and viscosity.
authors.forename: J V
authors.initials: JV
authors.lastname: Ross
authors.forename: H G
authors.initials: HG
authors.lastname: Ave'lallemant
authors.forename: N L
authors.initials: NL
authors.lastname: Carter