TERRESTRIAL SENSITIVITY TO ABRUPT COOLING RECORDED BY AEOLIAN DUNES IN NORTHWEST OHIO, USA

Non-pollen paleoclimate proxies in late Pleistocene–early Holocene time east of the prairie–forest ecotone are rare within the Great Lakes region. Eleven OSL ages from sand dunes and Pleistocene beach ridges in an inland site of northwest Ohio record significant landscape modification more than 4–8 ka after deglaciation. Sand dunes downslope on the basinward or eastern side of deglacial lake strandlines record uniformly westerly winds. Four of the 11 OSL ages cluster around the Younger Dryas cold event (11.1–13.3 ka cal), five ages (8.2–10.8 ka cal) cluster around the early Preboreal, one young age (0.7–0.9 ka cal) records more recent aeolian activity, and one age of 13.1­–15.1 ka cal dates a barrier spit in Lake Warren. In northwest Ohio both landscape instability recorded by aeolian activity and a vegetation response as recorded by pollen are coeval the Younger Dryas, however the climate conditions during the Preboreal resulting in aeolian activity are not recorded in the available pollen records. From this we conclude that aeolian dunes and surfaces susceptible to deflation are more sensitive to cooler, drier episodes of climate than is recorded in the pollen data. Younger Dryas aged aeolian activity in northwestern Ohio coincides with aeolian records elsewhere in the Great Lakes region east of the prairie-forest ecotone. Systematic sampling of dunes and deflation-susceptible surfaces east of the prairie-forest ecotone in mid-latitude North America may provide greater insight to past landscape stability modulated by abrupt climate change.