Rosebud Formation Explained

Rosebud Formation
Period:	Miocene
Prilithology:	pink siltstone
Region:	Nebraska, South Dakota
Country:	United States
Unitof:	Arikaree Group
Underlies:	Valentine Formation

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.^[1] Possibly named for its color, no type location has been set for this unit, 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.^[2]

See also

• Paleontology in Nebraska
• Paleontology in South Dakota
• List of fossiliferous stratigraphic units in Nebraska
• List of fossiliferous stratigraphic units in South Dakota

Notes and References

1. Web site: Geologic Unit: Rosebud . Geolex — Significant Publications . National Geologic Database . United States Geological Survey . 2024-02-24 .
2. Web site: Geologic Formations . Niobrara National Scenic River . . 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. .