Dominance of an similar to 150-year cycle of sand-supply change in late Holocene dune-building along the eastern shore of Lake Michigan

Outcrops of buried soils on lake-plains and glacial headlands along Lake Mi chigan's eastern shore suggest that periodic dune-building has occurred the re after relatively long (greater than or equal to 100 yr) periods of low s and supply. We located, described, and radiocarbon dated 75 such buried soi ls that crop out in 32 coastal dune fields beside the lake. We assume that peaks in probability distributions of calibrated C-14 ages obtained from wo od, charcoal, and other organic matter from buried A horizons approximate t he time of soil burial by dunes. Plotted against a late Holocene lake-level curve for Lake Michigan, these peaks are closely associated with many simi lar to 150-yr lake highstands previously inferred from beach ridge studies. Intervening periods of lower lake levels and relative sand starvation appa rently permitted forestation and soil development at the sites we studied. While late Holocene lake-level change led to development and preservation o f prominent foredunes along the southern and southwestern shores of Lake Mi chigan, the modern dune landscape of the eastern shore is dominated by perc hed dunes formed during similar to 150-yr lake highstands over the past 150 0 yr (C) 2000 University of Washington.