The Herald 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: lithostrat ...

unit of

Late Ordovician The Ordovician ( ) is a geologic period and system, the second of six periods of the Paleozoic Era. The Ordovician spans 41.6 million years from the end of the Cambrian Period million years ago (Mya) to the start of the Silurian Period Mya. T ...

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 olde ...

in the

Western Canadian 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 ...

. It was defined in well ''Imperial Herald 1-31-1-20W2M'' by the Lower Paleozoic Names and Correlations Committee of the Saskatchewan Geological Society in 1958.Saskatchewan Geological Society, 1958. Report of the Lower Paleozoic Names and Correlation Committee, Regina.

Lithology

The Herald Formation is composed 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 dol ...

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 wh ...

and

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 ...

, which can be microcrystalline, argillaceous or microlaminated. In the centre of the basin, it is represented by

anhydrite Anhydrite, or anhydrous calcium sulfate, is a mineral with the chemical formula CaSO4. It is in the orthorhombic crystal system, with three directions of perfect cleavage parallel to the three planes of symmetry. It is not isomorphous with t ...

Distribution

The Herald Formation reaches a maximum thickness of in the

Lake Alma Lake Alma is a special service area within the Rural Municipality of Lake Alma No. 8, Saskatchewan, Canada that held village status prior to August 2018. The community shares its name with the nearby Alma Lake and surrounding rural municipa ...

area.

Relationship to other units

The Herald Formation is disconformably overlain by the

Stony Mountain Formation 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 ...

and conformably overlays the

Yeoman Formation Yeoman is a noun originally referring either to one who owns and cultivates land or to the middle ranks of servants in an English royal or noble household. The term was first documented in mid-14th-century England. The 14th century also witn ...

. It can be correlated with the Fort Garry Member of 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 b ...

Manitoba , image_map = Manitoba in Canada 2.svg , map_alt = Map showing Manitoba's location in the centre of Southern Canada , Label_map = yes , coordinates = , capital = Win ...

and in the

Williston Basin The Williston Basin is a large intracratonic sedimentary basin in eastern Montana, western North Dakota, South Dakota, southern Saskatchewan, and south-western Manitoba that is known for its rich deposits of petroleum and potash. The basin is a ...

Subdivisions

In south-eastern

Saskatchewan Saskatchewan ( ; ) is a province in western Canada, bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, to the northeast by Nunavut, and on the south by the U.S. states of Montana and North ...

, the formation is divided in three units, corresponding to three sedimentation cycles: *

Lake Alma Member 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 ...

* Coronach Member *

Redvers Unit 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 Geologic formations of Saskatchewan Ordovician Saskatchewan Western Canadian Sedimentary Basin