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Earth Sciences

Robert F. Diffendal, Jr., Publications

1994

Articles 1 - 2 of 2

Full-Text Articles in Physical Sciences and Mathematics

Environments Of Aeolian Deposition In South-Central Nebraska During The Last Glacial Maximum, Zhao-Dong Feng, William C. Johnson, Robert F. Diffendal Jr. Jan 1994

Environments Of Aeolian Deposition In South-Central Nebraska During The Last Glacial Maximum, Zhao-Dong Feng, William C. Johnson, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

The Peoria loess of south-central Nebraska, deposited approximately during the last Glacial Maximum, can be subdivided into three zones: an upper laminated loess and a lower massive loess, separated by a dark gley zone in which bison bones and spruce charcoal are found. The lower Peoria unit is characterized by high organic matter content, relatively high bulk density, and common root channels. The upper Peoria unit has rhythmic patterns of two orders: strongly gleyed and weakly gleyed zones alternating in couplets about 2-5 m thick, and coarse- and fine-grained laminae of second order, about 2-4 mm thick. The strongly gleyed …


Geomorphic And Structural Features Of The Alliance 1º × 2º Quadrangle, Western Nebraska, Discernible From Synthetic-Aperture Radar Imagery And Digital Shaded-Relief Maps, Robert F. Diffendal Jr. Jan 1994

Geomorphic And Structural Features Of The Alliance 1º × 2º Quadrangle, Western Nebraska, Discernible From Synthetic-Aperture Radar Imagery And Digital Shaded-Relief Maps, Robert F. Diffendal Jr.

Robert F. Diffendal, Jr., Publications

The digital shaded-relief map of the United States and the synthetic-aperture radar map of the Alliance Nebraska 1º x 2º area prepared by the U.S. Geological Survey (USGS) in the former case and for the USGS in the latter show oriented landforms and lineaments in northwest Nebraska. Parallel and subparallel hills and valleys developed on different geologic materials ranging from shales through sandstones to loess and eolian sand appear to be wind erosional features subsequently modified by running water. The long axes of these hills and valleys generally trend between N40"W and N50"W. Similar features also occur across major areas …