Curtis Formation
| Curtis Formation | |
|---|---|
| Stratigraphic range: | |
| File:Curtis Formation type.jpg Curtis Formation type | |
| Type | Formation |
| Unit of | San Rafael Group |
| Underlies | Summerville Formation |
| Overlies | Entrada Sandstone |
| Lithology | |
| Primary | Sandstone |
| Other | Mudstone, limestone |
| Location | |
| Coordinates | Lua error: callParserFunction: function "#coordinates" was not found. |
| Region | Utah |
| Country | United States |
| Type section | |
| Named for | Curtis Point, Emery County, Utah |
| Named by | Gilluly and Reeside |
| Year defined | 1928 |
The Curtis Formation is a geologic formation in Utah. It preserves fossils dating back to the Callovian age of the Jurassic period.
Description
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The Curtis Formation is composed of shallow marine sandstone, with thin beds of mudstone and minor limestone and gypsum. The sandstone is grayish-green in color and flat bedded or cross bedded. The presence of glauconite and marine invertebrate fossils indicates it was laid down in a shallow marine environment that became hypersaline towards the end of deposition. It represents a high stand of the Sundance Sea in the Callovian.[1]
History of investigation
[edit | edit source]The formation was first described by Gilluly and Reeside in 1928 and named for exposures in the northeast San Rafael Reef at Curtis Point (Lua error: callParserFunction: function "#coordinates" was not found.). Pipiringos and Imlay reassigned the Curtis as a member of the Stump Formation in 1979,[2] but this was rejected by Peterson in 1988.[3]
Footnotes
[edit | edit source]See also
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References
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Entrada (orange) and Curtis formations exposed in a road cut, Green River Cutoff Road. They are separated by the J3 unconformity.
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Lower and middle members of the Curtis Formation, Green River Cutoff Road, Emery County, Utah.
