As part of an investigation into the effect of environmental changes of landscape and soils on the Des Moines lobe (Cary till), three deep bogs (Colo, Jewell, McCulloch) were examined in detail. The center profile of each has a surface peat underlain by deep, dark-colored, calcareous silts; these in turn are underlain by a second peat zone which passes into basal calcareous silts and eventually to till. Preliminary pollen data on the Colo bog shows six zones. The key zones are Zone 1 (0 to 75 inches), in which the pollen is of dominantly herbaceous genera indicating an open grassland environment, and Zones IV and V (102 to 155 to 212 inches) dominated by pollen of forest species. The changes in bog and pollen strata were probably related to a marked change from a cool climate in the early postglacial to a warmer climate in the latter part of the postglacial continuing to the present.
Proceedings of the Iowa Academy of Science
©1963 Iowa Academy of Science, Inc.
Walker, P. H. and Brush, Grace S.
"Observations on Bog and Pollen Stratigraphy of the Des Moines Glacial Lobe, lowa,"
Proceedings of the Iowa Academy of Science, 70(1), 253-260.
Available at: https://scholarworks.uni.edu/pias/vol70/iss1/50