Okanagan gneiss: layering in highly deformed metamorphic rock
The lower part of a bedrock cliff in the south part of the Okanagan valley, in south-central British Columbia, western Canada.
Scale: this cross-section of low-angle, sub-horizontal metamorphic layers is about 2.5 to 3 m thick (base to top of view). The thicker discrete layers are approx. 10 to 30 cm thick; the thinnest layers are about 1 cm thick.
This is a high-grade metamorphic rock, a 'basement' gneiss that has been intensely sheared (layer-parallel deformation) during regional tectonism; the layers and their lateral discontinuities (incl. thinning and truncation) are the result of this shearing (not sedimentary layering).
Copyright J.R. Devaney
Okanagan gneiss: layering in highly deformed metamorphic rock
The lower part of a bedrock cliff in the south part of the Okanagan valley, in south-central British Columbia, western Canada.
Scale: this cross-section of low-angle, sub-horizontal metamorphic layers is about 2.5 to 3 m thick (base to top of view). The thicker discrete layers are approx. 10 to 30 cm thick; the thinnest layers are about 1 cm thick.
This is a high-grade metamorphic rock, a 'basement' gneiss that has been intensely sheared (layer-parallel deformation) during regional tectonism; the layers and their lateral discontinuities (incl. thinning and truncation) are the result of this shearing (not sedimentary layering).
Copyright J.R. Devaney