TIMING AND FORMATION OF LATE QUATERNARY KAMES IN NORTHEASTERN OHIO: IMPLICATIONS FOR UNDERSTANDING THE SPATIAL AND TEMPORAL VARIABILITY IN GLACIER EROSION AND THE PRESERVATION OF GLACIAL LANDFORMS

The geomorphology, sedimentology and stratigraphy of kame deposits in northeastern Ohio were examined to determine the Late Quaternary history of an enigmatic terminal region of the Laurentide Ice Sheet. Debate surrounds the timing and origin of these deposits, specifically whether the region was ice-free during the last glacial. Optically Stimulated Luminescence (OSL) methods were applied to determine sediment ages and to help elucidate the history of these kame deposits. Interpretation of calculated OSL ages suggest that deposition of the kame field began at the end of the penultimate glacial cycle during the start of Marine Isotope Stage (MIS) 5 approximately 125 kya. Subsequent weathering and erosion altered the kame deposits during the last interglacial followed by a period of reworking and resedimentation during the early part of the last glacial cycle around 70 kya. Since approximately 70 kya, these kame deposits have only been slightly modified, probably by cryogenic and pedogenic processes, and were overridden by marginal, possibly, cold-based ice, during the Laurentide Ice Sheet’s maximum extent in MIS 2. This study highlights those significant areas along former ice sheet margin that remain relatively well preserved for a considerable duration (many 10,000’s years) despite the effective role of ice sheets on the evolution of continental landscape.