Document Type



Holocene, paleocology, vegetational history, palynology, plant macrofossils, Iowa


Pollen and plant macrofossil analysis from three sites along an east-west transect in southeastern Iowa provide evidence for Holocene vegetational development. Colo Marsh at the west end of the transect is relatively complete, with a late-glacial spruce zone ending about 11,500 yr B.P.; a deciduous forest zone from about 11,500 to 8300; a prairie zone from 8300 to 4500, and prairie with oak from 4500 to presettlement times.

Sediments from the site at the Indian Creek Nature Center, midway in the transect, date only from about 6000 to 1600 yrs B. P. This site also was dominantly prairie from 6000 (and probably before) to 4500 yr B.P. Oak and hickory were present from 4500 to 3500, and were joined by more mesic trees from 3500 to 1600 yr B.P.

Mud Creek occupies a very gently sloping drainage basin at the east end of the transect; the site there includes three dated levels ranging in age from about 9300 and 5500 yr B.P. The vegetation during that entire time was apparently mesic deciduous forest with abundant basswood.

Apparently an important vegetational boundary existed in eastern Iowa during early and middle Holocene time. In western and central Iowa prairie was dominant and climate was driest between about 8300 and 4500 yr B.P. At this same time, mesic deciduous forest prevailed in eastern Iowa.

Publication Date

December 1990

Journal Title

Journal of the Iowa Academy of Science





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© Copyright 1990 by the Iowa Academy of Science, Inc.



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