TIMING OF ESKER AND DUNE FORMATION AT THE EASTERN END OF ONEIDA LAKE, NEW YORK STATE, DEFINED BY OPTICALLY STIMULATED LUMINESCENCE DATING

Impressive Late Quaternary glacial landforms, beach ridges and fossil dunes are present at the eastern end of Oneida Lake in central New York State. These provide important archives for Late Pleistocene and Holocene paleoenvironment change, and in particular have the potential to help in reconstructing the nature of Ontario Lobe recession and subsequent evolution of Lake Iroquois in this region. However, these landforms and their associated sediments have not been adequately dated. This is partially because of the scarcity of preserved organic matter in the sediments needed for radiocarbon dating. To help address this problem, optically stimulated luminescence (OSL) method was applied to date dune and esker sediments at selected locations. In addition, AMS radiocarbon ages were determined beneath two dune deposits within shell bearing (beach) gravelly sands. To determine blue light stimulated luminescence ages Single Aliquot Regenerative (SAR) method was applied using coarse-grained quartz (90-150µm). Many of the sediment samples that were dated exhibited problems due to inadequate bleaching of quartz. Nevertheless, ages were determined for all samples, albeit some with large uncertainty. The OSL ages on eskers show that they formed during the Last Glacial Maximum (~19-24 ka). Ages on dune sands show that they formed during the Lateglacial and early Holocene and that the dunes young westwards. These new OSL ages contrast with previous estimates (not based on numerical dating) that argued that the dunes had been mobile during the middle to latter part of the Holocene. The application of Optically Stimulated Luminescence (OSL) methods illustrates the potential to develop high quality chronological data for this region, which in turn may be used to aid in developing paleoenvironmental, climate and landscape models during the late stages of glacial Lake Iroquois.