Abstract

Radiocarbon-controlled stratigraphic data from Owasco Lake valley, New York, document two cycles of relative lake-level change during the Holocene in response to regional variations in effective precipitation. Lake highstands occurred at 10.5 and 6.9 ka, with an intervening lowstand at 9 ka. The 10.5 ka highstand occurred during the well-known Killarney–Younger Dryas cold interval (11.2–10.0 ka) in response to decreased evaporation and increased precipitation. The driest interval of the early-middle Holocene occurred ∼ 9 ka, at the time of maximum summer solar insolation. A second highstand occurred during the Hypsithermal (∼ 8.5–5.5 ka) in response to increased precipitation at a time when the interior of North America underwent maximum aridity. This out-of-phase relationship between northeastern North America and the midcontinent during the Hypsithermal may have been a consequence of a northward shift of the jet stream and a change of precipitation patterns in response to increased global warmth. If the Hypsithermal can be used as an analog for potential global warming, the northeastern United States may experience future increases in regional precipitation.

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