Rosebud Formation
Appearance
Rosebud Formation | |
---|---|
Stratigraphic range: | |
![]() Along the north banks of the Niobrara River in northern Nebraska, the pink of the Rosebud Formation is commonly seen with many seeps, trickles, and waterfalls emitting from the Ogallala Aquifer in the overlying Valentine Formation[1] | |
Type | Formation |
Unit of | Arikaree Group |
Underlies | Valentine Formation |
Lithology | |
Primary | pink siltstone |
Location | |
Region | Nebraska, South Dakota |
Country | United States |
The Rosebud Formation is a geologic formation of cemented pink silt in Nebraska and South Dakota, dating to the early middle Miocene epoch of the Neogene period.[2] Possibly named for its color, no type location has been set for this unit,[2] but it is associated with the Valentine Formation along the Niobrara River. The fine silt of the formation forms an aquitard beneath the Ogallala Aquifer carried by the Valentine Formation. Many springs from the Valentine sands flow down the Rosebud outcrop into the Niobrara River.[1]
See also
- Paleontology in Nebraska
- Paleontology in South Dakota
- List of fossiliferous stratigraphic units in Nebraska
- List of fossiliferous stratigraphic units in South Dakota
References
- ^ a b "Geologic Formations". Niobrara National Scenic River. National Park Service. Retrieved 2024-02-24.
A finer-grained siltstone, the reddish-hued Rosebud forms the "floor" of the Ogallala aquifer. Water cannot seep into the rock as easily as it can in the Valentine, and a stream cannot cut down through it as quickly. There are more than 200 spring-fed waterfalls found along the scenic portion of the river, and most are "held up" by the Rosebud formation.
- ^ a b "Geologic Unit: Rosebud". National Geologic Database. Geolex — Significant Publications. United States Geological Survey. Retrieved 2024-02-24.