The Stony Mountain Formation is a

stratigraphical Stratigraphy is a branch of geology concerned with the study of rock layers (strata) and layering (stratification). It is primarily used in the study of sedimentary and layered volcanic rocks. Stratigraphy has three related subfields: lithostrati ...

unit of Ashgill

age Age or AGE may refer to: Time and its effects * Age, the amount of time someone or something has been alive or has existed ** East Asian age reckoning, an Asian system of marking age starting at 1 * Ageing or aging, the process of becoming older ...

in the Western Canadian Sedimentary Basin. It takes the name from the community Stony Mountain, Manitoba, and was first described in the town quarry by D.B. Dowling in 1900.Dowling, D.B., 1900. Report on the Geology of the West Shore and Islands of Lake Winnipeg; Geological Survey of Canada, Annual Report 1898, Volume XI, Part F, with Map 664.

Lithology

Subdivisions

The Stony Mountain Formation is divided in the following sub-units: ;South ( Williston Basin) * Penitentiary Member: argillaceous

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 ...

Gunn Member The Stony Mountain Formation is a stratigraphical unit of Ashgill age in the Western Canadian Sedimentary Basin. It takes the name from the community Stony Mountain, Manitoba, and was first described in the town quarry by D.B. Dowling in 1900 ...

: interbedded calcareous

shale Shale is a fine-grained, clastic sedimentary rock formed from mud that is a mix of flakes of clay minerals (hydrous aluminium phyllosilicates, e.g. kaolin, Al2 Si2 O5( OH)4) and tiny fragments (silt-sized particles) of other minerals, especial ...

and

fossil 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 ...

iferous

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

;North *

Gunton Member The Stony Mountain Formation is a stratigraphical unit of Ashgill age in the Western Canadian Sedimentary Basin. It takes the name from the community Stony Mountain, Manitoba, and was first described in the town quarry by D.B. Dowling in 1900 ...

: crystalline dolomite *Lower Stony Mountain: argillaceous dolomite

Distribution

The Stony Mountain Formation occurs throughout the Williston Basin. It reaches a maximum thickness of in the sub-surface at the

Canada Canada is a country in North America. Its ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

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border, and thins out towards the east, north and west. In

Manitoba Manitoba ( ) is a Provinces and territories of Canada, province of Canada at the Centre of Canada, longitudinal centre of the country. It is Canada's Population of Canada by province and territory, fifth-most populous province, with a population o ...

, where it is exposed at the surface in the erosion belt, it has a thickness of .

Relationship to other units

The Stony Mountain Formation is slightly

unconformably An unconformity is a buried erosional or non-depositional surface separating two rock masses or strata of different ages, indicating that sediment deposition was not continuous. In general, the older layer was exposed to erosion for an interval o ...

overlain by the Stonewall Formation and sharply overlays the

Red River Formation The Red River Formation is a stratigraphical unit of Late Ordovician age in the Williston Basin. It takes the name from the Red River of the North, and was first described in outcrop in the Tyndall Stone quarries and along the Red River Valley ...

or the

Herald Formation The Herald Formation is a stratigraphical unit of Late Ordovician age in the Western Canadian Sedimentary Basin. It was defined in well ''Imperial Herald 1-31-1-20W2M'' by the Lower Paleozoic Names and Correlations Committee of the Saskatchewan ...

References

{{Western Canadian Sedimentary Basin, Saskatchewan=yes Stratigraphy of Saskatchewan Stratigraphy of Manitoba Ordovician geology of North Dakota