New geochemical evidence for the origin of North America's largest dune field, the Nebraska Sand Hills, central Great Plains, USA

Geomorphology
By:  and 

Links

Abstract

The Nebraska Sand Hills region is the largest dune field in North America and has diverse aeolian landforms. It has been active during both the late Pleistocene and late Holocene. Despite decades of study, the source of sediment for this large sand sea is still controversial. Here we report new trace element compositions of aeolian sand that are compared to four hypothesized sediment sources, Tertiary rocks of the Arikaree Group and Ogallala Group, unconsolidated sands of Pliocene age, and Platte River system sands. All four potential sources have a mineralogy that is similar to the Nebraska Sand Hills. K/Rb, K/Ba, Sc-Th-La, Eu/Eu*, LaN/YbN, As/Sb, and Fe/Sc values show, however, that Pliocene sediments and sands from the Platte River system are not likely sources. The Arikaree Group could be a minor contributor, but sands from the Ogallala Group appear to have the best compositional fit to the Nebraska Sand Hills. Although past studies have proposed the Ogallala Group as an important sand source, the hypothesis has been questioned, because the unit is well cemented by calcrete in its upper part. However, examination of the landscape upwind of the Nebraska Sand Hills shows that the Ogallala Group, where it occurs at the land surface, is highly dissected in much of this region, which makes sand-sized particles available for aeolian entrainment whenever drought conditions diminish a protective vegetation cover.

Study Area

Additional publication details

Publication type Article
Publication Subtype Journal Article
Title New geochemical evidence for the origin of North America's largest dune field, the Nebraska Sand Hills, central Great Plains, USA
Series title Geomorphology
DOI 10.1016/j.geomorph.2019.02.023
Volume 332
Year Published 2019
Publisher Elsevier
Contributing office(s) Geosciences and Environmental Change Science Center
Description 25 p.
First page 188
Last page 212
Country United States
State Nebraska