Late Pleistocene dune activity in the central Great Plains, USA

J. A. Mason, J. B. Swinehart, P. R. Hanson, D. B. Loope, R. J. Goble, X. Miao, R. L. Schmeisser

Research output: Contribution to journalArticlepeer-review

Abstract

Stabilized dunes of the central Great Plains, especially the megabarchans and large barchanoid ridges of the Nebraska Sand Hills, provide dramatic evidence of late Quaternary environmental change. Episodic Holocene dune activity in this region is now well-documented, but Late Pleistocene dune mobility has remained poorly documented, despite early interpretations of the Sand Hills dunes as Pleistocene relicts. New optically stimulated luminescence (OSL) ages from drill cores and outcrops provide evidence of Late Pleistocene dune activity at sites distributed across the central Great Plains. In addition, Late Pleistocene eolian sands deposited at 20-25 ka are interbedded with loess south of the Sand Hills. Several of the large dunes sampled in the Sand Hills clearly contain a substantial core of Late Pleistocene sand; thus, they had developed by the Late Pleistocene and were fully mobile at that time, although substantial sand deposition and extensive longitudinal dune construction occurred during the Holocene. Many of the Late Pleistocene OSL ages fall between 17 and 14 ka, but it is likely that these ages represent only the later part of a longer period of dune construction and migration. At several sites, significant Late Pleistocene or Holocene large-dune migration also probably occurred after the time represented by the Pleistocene OSL ages. Sedimentary structures in Late Pleistocene eolian sand and the forms of large dunes potentially constructed in the Late Pleistocene both indicate sand transport dominated by northerly to westerly winds, consistent with Late Pleistocene loess transport directions. Numerical modeling of the climate of the Last Glacial Maximum has often yielded mean monthly surface winds southwest of the Laurentide Ice Sheet that are consistent with this geologic evidence, despite strengthened anticyclonic circulation over the ice sheet. Mobility of large dunes during the Late Pleistocene on the central Great Plains may have been the result of cold, short growing seasons with relatively low precipitation and low atmospheric CO2 that increased plant moisture stress, limiting the ability of vegetation to stabilize active dune sand. The apparent coexistence of large mobile dunes with boreal forest taxa suggests a Late Pleistocene environment with few modern analogs.

Original languageEnglish (US)
Pages (from-to)3858-3870
Number of pages13
JournalQuaternary Science Reviews
Volume30
Issue number27-28
DOIs
StatePublished - Dec 2011

Keywords

  • Dunefield
  • Eolian activity
  • Great Plains
  • Late Pleistocene
  • Nebraska Sand Hills
  • OSL dating

ASJC Scopus subject areas

  • Global and Planetary Change
  • Ecology, Evolution, Behavior and Systematics
  • Archaeology
  • Archaeology
  • Geology

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