GRGC: Holocene Paleoenvironments in the Central Midwest: Vegetation, Climate, and Landscape Evolution

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9316391 Baker Studies of Holocene paleoenvironments in the northern tier of states have relied heavily on palynology, which supplies relatively continuous and detailed records of vegetational and climatic change. In the central and southern Midwest, however, sites are relatively rare, and paleoenvironments are poorly known. The objectives of this study are 1) to sample a series of stream cutbanks along north-south and east-west transects for plant remains. These deposit constitute a relatively untouched and unknown source of excellent paleoenvironmental information; 2) to analyze these samples for pollen and especially for plant macrofossils, to provide information on past vegetation; 3) to reconstruct Holocene vegetation and climate for each site, along the transects, and for the entire central Midwest; 4) to add these data to the North American Pollen Database and the soon-to-be- formed North American Plant Macrofossil Database, so that models of Holocene vegetational and climatic change can be extended; 5) to continue to study the alluvial history and pedological development of these deposits, so that we can evaluate how the pattern of lithostratigraphy, soils stratigraphy, and landscape development (produced by E.A. Bettis) extends from Iowa to adjacent states. The project will be significant in several fields. 1) The ecological/paleoecological information will provide the first comprehensive picture of the development of vegetation across the central Midwest, including the Prairie Peninsula. 2) The paleoclimatic data will extend greatly the coverage of Holocene climates in the central United States. 3) The timing and extent of climatic and vegetational changes will be cross-checked with a completely independent source of evidence; carbon and oxygen isotopes from cave stalagmites across the same area, as outline in the accompanying Project Summary of the proposal by Gonzalez et al. 4) Both vegetation and climate will be correlated with soil formatio n and with Holocene changes in stream behavior over a broad area. 5) Changes in stream behavior and landscape development are critically important to archaeologists in locating sites and in understanding how and where to look for sites of specific ages.