Ulrich Faul

Associate Professor

Rock Physics Group

Department of Earth Sciences - Boston University - ufaul@bu.edu

Deformation Experiments

Deformation experiments with high resolution of stress and strain rate are typically conducted with Paterson Gas-Medium apparatuses at pressures of 300MPa. This relatively low pressure necessitates careful control of the sample chemistry to suppress melting at temperatures above ~1150°C. The samples in our experiments are therefore made by a solution-gelation method. Comparison of the strength of genuinely melt-free sol-gel samples (dots) with nominally melt-free San Carlos olivine-derived samples indicates that melt contents up to 1% increase the the strain rates for a given stress by two orders of magnitude (from Faul and Jackson, 2007).

Comparison of the strength of nominally melt-free olivine with sol-gel. olivine.

FESEM orientation contrast image of a sol-gel sample deformed at 1300°C. A rare subgrain boundary is visible in the grain near the top-left.