The Spray River Group is a stratigraphic unit of Triassic age. It is present on the western edge of the

Western Canada Sedimentary Basin The Western Canadian Sedimentary Basin (WCSB) underlies of Western Canada including southwestern Manitoba, southern Saskatchewan, Alberta, northeastern British Columbia and the southwest corner of the Northwest Territories. This vast sedimentary ...

in the foothills and Rocky Mountains of western Alberta. It was originally described as the Spray River Formation by E.M. Kindle in 1924 and was later raised to group status.Gibson, D.W. 1974. Triassic rocks of the southern Canadian Rocky Mountains. Geological Survey of Canada, Bulletin 230, 65 p. Its type section is located in the Spray River gorge at the southern end of Sulphur Mountain. The Spray River Group includes marine

fossils A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserved in ...

from the Triassic period.

Stratigraphy and lithology

The Spray River Group was deposited on the

continental shelf A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...

along the western margin of the North American craton. It is subdivided into two formations: the Sulphur Mountain Formation at the base and the

Whitehorse Formation The Whitehorse Formation is a geologic formation in Nebraska and Oklahoma. It preserves fossils dating back to the Permian period. See also * List of fossiliferous stratigraphic units in Nebraska * Paleontology in Nebraska The location of th ...

at the top. The Sulphur Mountain Formation consists of

dolomitic Dolomite () is an anhydrous carbonate mineral composed of calcium magnesium carbonate, ideally The term is also used for a sedimentary carbonate rock composed mostly of the mineral dolomite. An alternative name sometimes used for the dolomiti ...

and calcitic

siltstone Siltstone, also known as aleurolite, is a clastic sedimentary rock that is composed mostly of silt. It is a form of mudrock with a low clay mineral content, which can be distinguished from shale by its lack of fissility.Blatt ''et al.'' 1980, p ...

s, silty

dolomite Dolomite may refer to: *Dolomite (mineral), a carbonate mineral *Dolomite (rock), also known as dolostone, a sedimentary carbonate rock *Dolomite, Alabama, United States, an unincorporated community *Dolomite, California, United States, an unincor ...

s, dolomitic limestones, and very fine-grained dolomitic quartz sandstones. The Whitehorse Formation consists of dolomites, dolomitic siltstones and limestones, and dolomitic and calcitic quartzites.Glass, D.J. (editor) 1997. Lexicon of Canadian Stratigraphy, vol. 4, Western Canada including eastern British Columbia, Alberta, Saskatchewan and southern Manitoba. Canadian Society of Petroleum Geologists, Calgary, 1423 p. on CD-ROM. .

References

{{Western Canadian Sedimentary Basin, Canadian Rockies=yes Stratigraphy of Alberta Triassic Alberta