SBR-96001170 This award supports a detailed study to evaluate the climatic signal contained within the magnetic data from loess deposits of the central Great Plains, and to use these data in conjunction with nonmagnetic data to establish, to the extent possible, a quantitative link with climate. There are four specific objectives: to assess the mechanisms by which the loessal sediments attain the climatic signal in their magnetic record; to demonstrate how magnetic parameters and delta-13 C (a nonmagnetic, climate-sensitive parameter) vary stratigraphically and regionally; to extract temporal and regional climatic information; and to develop a time-stratigraphic framework for comparing the regional and global climate records. Temporally, the study includes three paleosols and modern soils, covering the Last Interglacial, Last Glacial Maximum of the Wisconsinian, and the Holocene climatic episodes. Spatially, the study includes sites located along two transects: the north-south transect yields a temperature gradient and the east-west transect yields a moisture gradient. Sites at the four end points of the transects will be studied intensively, with close-interval measurements of all parameters. Then, less-intensive data collection along the transects will serve to monitor change along them. Loess deposits are proving to be one of the best sources of detailed Quaternary climatic records on the continents. This project should improve the regional record of climate history and should provide theoretical, methodological, and technical improvements in loess studies in other settings.
