9406208 Davis The Colorado Plateau is a large area of relatively undeformed rock that nevertheless was distal to a series of tectonic stress patterns during Sevier, Laramide and Tertiary time. The plateau stratigraphy is rich in porous sandstones in which deformation bands form with strains as small as 0.1%. Because these are work- hardening features, successive deformations are likely to form new sets of deformation bands rather than extensively reactivate old ones. This project will map deformation bands in suitable lithologies and related them to large features (faults) of known age. After spatial correlations, the stress orientations implied by the deformation bands will be inverted from band orientations and a set of paleostress patterns for the Colorado Plateau produced. Results should provide a much better understanding of the directions, magnitude and degree of localization of stress of these events in the Colorado Plateau.