Vegetation Changes Associated with the Younger Dryas from the Sediments of Silver Lake, Summit County, Ohio, USA

Abstract

As the climate was warming during the last deglaciation, a millennium-long return to near-glacial conditions—called the Younger Dryas (YD) stadial—occurred about 12.9 to 11.7 ka ago. Prior studies have characterized the vegetation and climatic impacts of the YD stadial in the US upper Midwest from a network of fossil pollen records. The goal of this study was to locate the pronounced rise in organic matter and Pinus (pine) pollen—associated with the latter part of the YD event—in a sediment core from Silver Lake, a kettle lake in Summit County, Ohio. Based upon radiocarbon dating of the Silver Lake sediment core, an increase in sediment organic matter at 1,070 cm (35.1 ft) core depth dates to 12,130 calibrated years (cal yr) BP within the latter part of the YD stadial. A pollen study spanning the change in organic matter displays a gradual decline in Picea (spruce) pollen as well as a pronounced increase in Pinus pollen, similar to published records of the latter part of the YD event. Thus, the Silver Lake pollen record adds a new site to the network of fossil pollen sites, and further refines the vegetation changes within the Allegheny Plateau of Ohio that occurred during the latter part of the YD event. Furthermore, identifying the pronounced rise in Pinus pollen allows for biostratigraphic correlation between the Silver Lake record and another local dated pollen record. This biocorrelation adds further support to the Silver Lake radiometric age model.