A HIGH-RESOLUTION SEDIMENT VARVE RECORD OF LAURENTIDE DEGLACIATION FROM GLACIAL LAKE IROQUOIS

Oneida Lake is located in Central New York and is a valuable freshwater laboratory utilized in early work from Walter E. Dean, Jr. The lake is a shallow depression that was part of larger Glacial Lake Iroquois that formed in the late Pleistocene. Glacial Lake Iroquois developed from the blockage of meltwater drainage outlets, following the readvance of the Laurentide Ice Sheet. Thick stratigraphic units documented by high-resolution seismic reflection data suggest the Oneida Basin was a primary outlet for Laurentide Ice Sheet meltwater released into the Hudson Valley. Oneida Lake's record of Glacial Lake Iroquois is useful in outlining meltwater dynamics of the southern margin of the Laurentide Ice Sheet. Four Livingstone and Bolivia cores collected in 2019 capture a 150-250-year period of pro-glacial Lake Iroquois deposition, and contain a well-preserved glacial varve section. These varves are annual sediment structures that allow for high-resolution analysis of meltwater dynamics of a large ice sheet. Additionally, these varves have the potential for correlation to other regional glacial varve chronologies in the northeast such as the North American Varve Chronology. Based on age estimates, potentially significant portions of the varve sequences likely capture of-interest climate events, such as the Younger Dryas and Intra-Allerod intervals. A detailed look at these varve sequences including quantitative thickness estimates, identification of diagnostic patterns, and analysis of XRF elemental data characterize sedimentological changes during periods of glacial retreat and advance of the Laurentide Ice Sheet.