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Title: Midwestern Holocene paleoenvironments revealed by floodplain deposits in northeastern Iowa

Journal Article · · Science (Washington, D.C.); (USA)
;  [1];  [2]
  1. Univ. of Iowa, Iowa City (USA)
  2. Iowa Dept. of Natural Resources, Iowa City (USA)

Pollen analysis of pond deposits in the upper reaches of a stream from northeastern Iowa, an area beyond the last glacial margin, provides a nearly complete record of vegetational changes during the last 12.5 thousand years. Sixty-one radiocarbon dates provides good chronological control. Spruce forest was replaced by deciduous forest before 9.1 thousand years ago, followed by prairie from 5.4 to 3.5 thousand years ago, and oak savanna from 3.5 thousand years ago until presettlement times. The prairie invasion was nearly 3 thousand years later here than at other sites in Iowa and Minnesota, documenting a late Holocene, rather than an early-middle Holocene, period of maximum warmth and dryness for the southern part of the upper Midwest.

OSTI ID:
6151596
Journal Information:
Science (Washington, D.C.); (USA), Vol. 249:4966; ISSN 0036-8075
Country of Publication:
United States
Language:
English