Physical Sciences and Mathematics Commons^™

Duer Ranch, Morrill County, Nebraska: Contrast Between Cenozoic Fluvial And Eolian Deposition, James B. Swinehart, R. F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

The Duer Ranch locality contains some of the finest and most easily accessible examples of different styles of alluvial cuts and fills in the Cenozoic rocks of Nebraska. It offers a unique area in which to examine the geometries and alluvial fills of several Miocene and Pliocene age paleovalleys and paleo-gullies. Good exposures of eolian volcaniclastic siltstones and a regionally important volcanic ash of the Oligocene age Brule Formation are also present at the Duer Ranch locality. In addition, Quaternary ephemeral stream development and deposits can be studied.

Location and Accessibility

Significance of the Locality

Locality Information

Measured Sections [I-IV] …

Paleohydrology Of Some Ogallala (Neogene) Streams In The Southern Panhandle Of Nebraska, R. G. Goodwin, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

Stratification and estimated paleoflow conditions for valley-fill deposits suggest that Ogallala Group streams in western Nebraska were similar to modern streams of south-central Alberta.

Ogallala stratification includes medium-scale (0.5 to 2.0 m thick) trough crossbedded sand and gravel, tabular indistinctly horizontally bedded and imbricated gravel, and horizontally bedded sand and pebbly sand. Valley fills are 15 to 55 m thick and 800 to 1800 m wide at the top. Some are in bedrock-floored channels resembling the “inner channels” of Shepherd and Schumm (1974).

Gradients for three well exposed paleovalley floors range from 0.0014 to 0.0020 (m/m) after tectonic correction. This …