A SEDIMENT RECORD OF ENVIRONMENTAL CHANGE SPANNING THE TRANSITION FROM THE LATE GLACIAL TO THE HOLOCENE FROM THE UPPER BLACKWATER RIVER BASIN, WEST VIRGINIA

A 150 cm long sediment core was recovered from a wetland located in the upper catchment of the Black Water River in West Virginia at 962-m above sea level. The sediment core was analyzed to investigate the changes in landscape morphology in response to climate change during the transition from the late Pleistocene to the Holocene. Recent work in the region focused on understanding the environmental implications and timing of soil development in these high elevation wetlands. Earlier work used palynological records to investigate ecological responses of the central Appalachian region to abrupt climate changes during the deglacial period and the transition to the Holocene. This previous work in the eastern United States has greatly improved our understanding of the mechanisms of rapid climate change during this transition. Our work focuses on using physical and geochemical proxies to investigate changes in water level during the transitional period to help understand how water balance changed and the forcing mechanisms causing the observed changes. Measurements include magnetic susceptibility, organic matter concentration, bulk density, elemental concentrations by X-ray fluorescence, greyscale, visual analysis of smear slides, grain size, sediment color, and radiocarbon dating. We find that water level varied considerably over this period, ranging from an open lake system to a peatland. Starting between 18 and 15 ka during the Heinrich Stadial 1, water levels were stable but higher relative to today forming a hydrologically open lake system. At around 15ka, during the Bølling-Allerød transition, there was an abrupt increase in water level that remained high during this period of warmer climate. Beginning around 13 ka, during the Younger Dryas period, water levels fluctuated considerably while remaining an open lake system until the transition to the Holocene at around 11.7 ka. It is at this point that the open lake system fully transitioned into a peatland, similar to what can be seen at the site today. These preliminary results suggest that the sediment record of current peatlands may help assess landscape, hydrologic, and ecosystem response to abrupt transition from periglacial to more temperate climate.