Paleosols, Quaternary, Sangamon Soil, radiocarbon, southeastern Minnesota, soil descriptions
A recent roadcut along County Road 18 in northeastern Houston County has exposed two variants of a morphologically well-expressed, Sangamon Soil. The paleosol is covered by the equivalent of the Roxana Silt, as defined in Illinois. The Farmdale Soil is developed into the Roxana Silt. The section is capped by late Wisconsinan Peoria Loess. The Sangamon Soil was developed into slope wash deposits composed of, or derived from, pre-Wisconsinan loess. No direct evidence of pre-Wisconsinan glacial till was found at the site. Two radiocarbon ages, one from the Ab horizon of the Sangamon Soil and one from the Ab horizon of the Farmdale Soil yield results of 25,690 and 23,760 respectively. These are minimum ages that suggest that the Roxana Silt buried the older Sangamon Soil prior to 26,000 radiocarbon years ago and that the Peoria Loess buried the Farmdale Soil by 24,000 radiocarbon years ago.
Proceedings of the Iowa Academy of Science
© Copyright 1987 by the Iowa Academy of Science, Inc.
Lively, R. S.; Bettis, E. A. III; Hallberg, G. R.; and Hobbs, H.
"An Exposure of the Sangamon Soil in Southeastern Minnesota,"
The Proceedings of the Iowa Academy of Science: Vol. 94:
, Article 5.
Available at: http://scholarworks.uni.edu/pias/vol94/iss4/5