The Gypsum Spring Formation is a stratigraphical unit of Middle Jurassic age in the Williston Basin.
| Gypsum Spring Formation | |
|---|---|
| Stratigraphic range: | |
 Gypsum Spring Formation (in grey on top of red colored Spearfish Formation), near Devils Tower National Monument (Wyoming) | |
| Type | Geological formation |
| Underlies | Sundance Formation |
| Thickness | up to 76 metres (250 ft)[1] |
| Lithology | |
| Primary | Gypsum |
| Other | Shale, dolomite, limestone |
| Location | |
| Region | Williston Basin |
| Country |  United States |
| Type section | |
| Named for | Gypsum Spring, Wyoming |
| Named by | J.D. Love, 1939 |
It takes the name from Gypsum Spring in Wyoming, and was first described in outcrop in Freemont County by J.D. Love in 1939.[2]
Lithology
editThe Gypsum Spring Formation is composed of massive white gypsum in the lower part, and alternating gypsum, red shale, dolomite and limestone. [1]
Distribution
editThe Gypsum Spring Formation reaches a maximum thickness of 76 metres (250 ft) in central Wyoming.[1] It occurs from the Black Hills in South Dakota through Wyoming and into southern Saskatchewan.
Relationship to other units
editIt is equivalent to the upper part of the Watrous Formation and the lower part of the Gravelbourg Formation in Saskatchewan.
References
edit- ^ a b c Lexicon of Canadian Geologic Units. "Gypsum Springs Formation". Retrieved 2010-02-01.
- ^ Love, J.D., 1939. Geology along the southern margin of the Absaroka Range. Wyoming. Geological Society of America, Spec. Paper 20, p. 45.