This is a sample of a type of metamorphic rock called a gniess. It has distinctive light and dark bands formed by different minerals. The folds visible in this sample formed as tectonic plates pushed together and built the mountain chains seen along the length of the West Coast. The rock could once have been layered sediments or an igneous intrusion, but the force of the tectonic plates converging was enough to metamorphose, or transform, it to a schist and cause folding. The folds in this sample form a complex pattern that tells us the rock has been squeezed in more than one direction over time.
Store: Pacific Museum of the Earth, University of British Columbia
Accession #: PME/IC 106
Primary Mineral: Gneiss
Secondary Mineral: –
Site Locality: –
Location: Unknown. British Columbia
Special Features: n/a