Go to Login page
Logging at Blairmore, Alberta.
Miss Lily Elsie
Calgary Exhibition and Stampede, 1925, Fort Calgary, City of Calgary exhibit
Thickness of the ice near the margin.
Saddling up, wild horse race, Calgary Stampede
Railway porters presentation to Violet King, Calgary, Alberta.
[Steer roping], Calgary Stampede
Two Indians and their horses crossing a stream
Union Bank building, Pincher Creek, Alberta.
Index to Sheets of the Topographical Survey of the Rocky Mountains
View from first topographic station below camp June 5, looking up stream.
Calgary Stampede parade
Coldstream Guards Band, Calgary Stampede Parade, 1926
Hog tieing a steer, the Stampede, Calgary, Alta., 1912
Indians in the Stampede Parade
Sundre Cowboy Band in the Stampede Parade
View images with similar tones
Gneiss is a high-grade metapelite formed by regional metamorphism characterized by the foliation of alternating light and dark bands of medium- to coarse-grained crystals. Increasing temperature and pressure increases the intensity and grade of metamorphism. Regional metamorphism is explained using the Barrovian sequence which states that increasing metamorphic grade begins by transforming a shale parent rock into slate then phyllite then schist, and finally gneiss. When schist undergoes the heat and pressure to transform into gneiss, the platy micas increase in size and begin to recrystallize into granular minerals and lose vitreous lustre. The foliation loses parallel alignment in orientation and becomes an interlocking texture of the different coloured bands varying in thickness and continuity. The lighter bands are composed of felsic grains, such as feldspar and quartz, while the darker bands are composed of platy mafic minerals, like biotite. Some metamorphic rocks may also comprise of index minerals, such as chlorite, biotite, garnet, staurolite, kyanite, and sillimanite. They typically occur as porphyroblasts and characterize specific metamorphic zones and grade. These samples are classified as garnet gneisses, indicating intermediate to high-grade metamorphism because garnet is the highest-grade index mineral present. These samples vary in metamorphic intensity as there are slight differences in grain size and foliation orientation. It can be inferred that Sample A has undergone higher metamorphic intensity than Samples B and C due to its coarser garnet porphyroblasts, more granular texture, and less aligned foliation from stress in multiple directions. When compared to Sample C, the textural difference is visible, and the foliation is in a more preferred orientation from the influence of micaceous minerals and dominant one-directional stress.
Add to Lightbox
Calgary : University of Calgary
5184px × 3456px 87MB
Do you have more information or a correction for this item? Please suggest a metadata edit.
Suggest a metadata edit
How can you use this image?
Permitted uses are outlined in License and Usage Rights. Usage Restrictions can only be waived by the copyright holder. Add to cart and make a request if you have any questions.
Remix and adapt
"Gneiss samples", 2018, (CU124129) by , is used under . Courtesy of Collection, Libraries and Cultural Resources Digital Collections, University of Calgary.