Red River Formation
Geologic formation in Canada
title: "Red River Formation" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["geologic-formations-of-manitoba", "ordovician-southern-paleotropical-deposits", "geologic-formations-of-saskatchewan", "dolomite-formations-of-canada", "limestone-formations-of-canada"] description: "Geologic formation in Canada" topic_path: "philosophy" source: "https://en.wikipedia.org/wiki/Red_River_Formation" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0
::summary Geologic formation in Canada ::
::data[format=table title="Infobox rockunit"]
| Field | Value |
|---|---|
| name | Red River Formation |
| type | Geological formation |
| age | |
| period | Ordovician |
| prilithology | limestone, dolomite |
| otherlithology | Breccia |
| namedfor | Red River of the North |
| namedby | A.F. Foerste |
| year_ts | 1929 |
| region | WCSB |
| Williston Basin | |
| country | Canada |
| United States | |
| coordinates | |
| subunits | Fort Garry Member |
| Selkirk Member | |
| Cat Head Member | |
| Dog Head Member | |
| underlies | Stony Mountain Formation |
| overlies | Winnipeg Formation |
| thickness | up to 215 m |
| :: |
| name = Red River Formation | image = | imagesize = | caption = | type = Geological formation | age = | period = Ordovician | prilithology = limestone, dolomite | otherlithology = Breccia | namedfor = Red River of the North | namedby = A.F. Foerste | year_ts = 1929 | region = WCSB Williston Basin | country = Canada United States | coordinates = | unitof = | subunits = Fort Garry Member Selkirk Member Cat Head Member Dog Head Member | underlies = Stony Mountain Formation | overlies = Winnipeg Formation | thickness = up to 215 m | extent = | area = | map = | map_caption =
The Red River Formation is a lithostratigraphical 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 by A.F. Foerste in 1929.
Lithology
Subdivisions
The Red River Formation is composed of the following subdivisions from top to base: |url = http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl? |title = Formation |author = Lexicon of Canadian Geologic Units |accessdate = 2010-02-01 |url-status = dead |archiveurl = https://web.archive.org/web/20090416121153/http://cgkn1.cgkn.net/weblex/weblex_litho_detail_e.pl |archivedate = 2009-04-16
- Fort Garry Member: crystalline and micritic dolomite with an argillaceous dolomite breccia in the middle
- Selkirk Member: fossiliferous, dolomitic limestone
- Cat Head Member: cherty dolomite, becoming calcareous to the south
- Dog Head Member: fossiliferous dolomitic limestone
Distribution
The Red River Formation reaches a maximum thickness of 215 m in the center of the Williston Basin. It extends throughout the Manitoba outcrop belt, and can be correlated throughout the entire Williston Basin area. It is 150 m thick and thins out to less than 50m (164 ft) northwards.
Relationship to other units
The Red River Formation is slightly unconformably overlain by the Stony Mountain Formation and sharply overlays the Winnipeg Formation in Manitoba, the Deadwood Formation in western Saskatchewan and the Canadian Shield in northern Manitoba.
The lower Red River Formation is equivalent to the Yeoman Formation, while the Fort Garry Member correlates with the Herald Formation.
References
References
- Foerste, A.F., 1929. The Ordovician and Silurian of the American arctic and sub-arctic regions. Denison Univ. Sci. Lab J., v. 24, p. 27-79.
- Foerste, A.F., 1929b. The cephalopods of the Red River Formation of southern Manitoba. Denison Univ. Sci. Lab J., v. 24, p. 129-235.
- "Red River Formation".
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