schistosity

views updated

schistosity The planar alignment of platy micas and elongate amphiboles in a regional metamorphic rock. The alignment of these minerals into a planar fabric is caused by (a) the physical rotation of the mineral grains under the influence of a shear stress, or (b) the syntectonic, metamorphic growth of new minerals with their long axes perpendicular to the principal compressive stress direction.

More From encyclopedia.com