Physical Sciences and Mathematics Commons^™

Gully, Scour Hole, And Pothole Development At The Base Of The Gering Formation (Miocene?), Southeastern Banner County, Nebraska, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Several sediment-filled paleovalleys belonging to the Arikaree Group of Miocene (?) age occur in southeastern Banner County, Nebraska. One gully and a main paleovalley exhibit, respectively, erosional features like those in modern gullies in the area and like those on the bedrock floors of modern straight streams carrying an appreciable sediment load. Scour holes and a pothole on the valley floor of the main paleovalley are similar to those produced experimentally on the bed of a straight stream.

Regional Implications Of The Geology Of The Ogallala Group (Upper Tertiary) Of Southwestern Morrill County, Nebraska, And Adjacent Areas, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

A part of a filled Ogallala Group (upper Tertiary) paleovalley system exhumed by recent stream erosion in southwestern Morrill County, Nebraska, and adjacent areas contains steep gradient gullies filled with locally derived sediments. Younger channels filled with granitic gravels derived by stream erosion of the Rocky Mountains to the west and southwest cut across and through these older filled gullies, indicating that there were at least two periods of downcutting followed by periods of filling during the development of this system.

Individual clasts from younger Ogallala gravels are often as large as or larger than clasts from Quaternary gravels transported …