eolian, grain-size distribution, optically stimulated luminescence, OSL, sand prairie
Grain-size distributions and optically stimulated luminescence (OSL) dates were obtained for the sand from Iowa's five sand prairie state preserves, which are Behren's Ponds and Woodland, Cedar Hills Sand Prairie, Kish-Ke-Kosh Prairie, Marietta Sand Prairie and Rock Island. OSL dates ranged from the late Pleistocene (15,560 years B.P.) to the very late Holocene (as recent as 590 years B.P.), indicating that the late Pleistocene and Holocene Epochs in Iowa have seen multiple episodes of aridity, which is consistent with results from the Nebraska Sand Hills and eolian sand stringers in southeastern Minnesota. The grain-size distributions were anomalous in that, compared with typical eolian deposits, the transition grain sizes between the traction I saltation populations and saltation I suspension populations were shifted toward coarser grains, and the percentage of sand in the suspension population was high. The anomalous grain-size distributions could not be explained by post-depositional weathering or poor sorting in the source region, but were consistent with the eolian transport of sand through grass prior to deposition. It is suggested that the anomalous grain-size distribution could be one of a set of criteria for distinguishing paleo-sand prairies from other buried bodies of eolian sand or sandstone.
Journal of the Iowa Academy of Science
© Copyright 2005 by the Iowa Academy of Science, Inc.
Emerman, Steven H.; Depew, Brian R.; and Anderson, Lisa K.
"Iowa's Sand Prairie State Preserves: Anomalous Grain-Size Distributions and Optically Stimulated Luminescence (OSL) Dates,"
The Journal of the Iowa Academy of Science: JIAS: Vol. 112:
, Article 5.
Available at: http://scholarworks.uni.edu/jias/vol112/iss1/5