Reconstructing Low Lake Levels of Lake Michigan

The goals and objectives are to reconstruct the paleo-lake elevations of Lake Michigan   which has fluctuated significantly since deglaciation ~17,    calendar years ago. (Note   ages in this proposal are given in calendar years unless followed by 14C BP indicating   radiocarbon years.) A very detailed lake level record of Lake Michigan (and Huron) has   been reconstructed for the last 47   years by using the age and elevation of foreshore   sediments in beach ridges in various embayments around Lake Michigan (Baedke and   Thompson, 2    and references therein). However, this lake-level record only goes back   47   years when lake level dropped from the Nipissing II level. The lake level between the   Nipissing II level and the Algonquin is not well constrained. This low lake level (initially   ~8  m below modern values [Colman et al., 1994a,b]), known as the Chippewa, has no   subaerially exposed geomorphic indicators from which the lake level can be reconstructed.   The first objective is to reconstruct the lake level curve for the time between the Chippewa   and Nipissing II levels.  The second objective is to look for the ~16  yr lake-level   fluctuation or other quasi-periodic fluctuations in lake level between the Chippewa and   Nipissing II phases of Lake Michigan that have been documented for the last 47   years   (Thompson, 1992; Baedke and Thompson, 2   ). The third objective is to identify the low   lake levels in estuaries of the southwestern coast of Michigan since 1918 using   sedimentologic indicators constrained by 21 Pb and 137Cs dating. Then use this   calibrated methodology to search for low lake stands older than the instrumented record.