Interlake Formation
{{Infobox rockunit
| name = Interlake Formation (Group)
| image =
| imagesize =
| caption =
| type = Geological formation
| age = {{Fossil range|Llandovery|Ludlow|Llandovery to Ludlow}}
| prilithology = dolomite
| otherlithology =
| namedfor = Interlake Region, Manitoba
| namedby = A.D. Baillie, 1951
| region = WCSB
Williston Basin
| country = Canada, United States
| coordinates = {{coord|51.4535|N|98.7603|W|display=inline,title|name= Interlake Formation}}
| unitof =
| subunits =
| underlies = Ashern Formation
| overlies = Stonewall Formation
| thickness = up to {{convert|335 |m|ft|-1}}
| extent =
| area =
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File:Williston Basin stratigraphic column.jpg stratigraphy]]
The Interlake Formation is a stratigraphical unit of Silurian age in the Western Canadian Sedimentary Basin.
It takes the name from the Interlake Region in Manitoba, and was first described in outcrop by A.D. Baillie in 1951.Ballie, A.D., 1951 Silurian geology of the Interlake area, Manitoba. Manitoba Department of Mines and Natural Resources, Mines Branch, Pub. 50-1.
Lithology
The Interlake Formation is composed of very finely crystalline dolomite.
{{Cite web
|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
}}
Oolitic, stromatolitic and biohermal interbeds also occur.
Distribution
Relationship to other units
The Interlake Formation is overlain with an angular unconformably by the Ashern Formation and sharply overlays the Stonewall Formation.
In the sub-surface it is given group status and contains, in different regions, the following subdivisions:
- Strathclair, Brandon and Cedar Lake Formations
- Lower, Middle and Upper Interlake
- Rupert, Hansen and Risser Formations
- Strathclair, Fife Lake, Guernsey, Cedar Lake and Taylorton Formations