HR: 1340h
AN: GC13B-1239    [Abstracts]
TI: A 350-Year Record of Multidecadal to Centennial Variation in Lake Sediment Characteristics, Fourth Lake of the Fulton Chain, Adirondack Mountains, northern New York
AU: * Kanfoush, S L
EM: skanfoush@utica.edu
AF: Department of Geology Utica College, 1600 Burrstone Road, Utica, NY 13502 United States
AB: Mud-water interface cores 37- and 30-cm in length were recovered from 17.7- and 13.4-m water depth in Fourth Lake, one lake in a series of nine interconnected lakes (the Fulton Chain), located at 43-deg N, 74-deg W at an elevation of 520m in the Adirondack Park. Lead-210 dating indicates the cores record nearly 350 years of sediment accumulation. Sediment grain size was measured by laser diffraction (Malvern), magnetic susceptibility was measured using a Bartington MS2, and organic content and %carbonate were inferred from loss-on-ignition. The Fourth Lake record of % fine sediment shows variations on multidecadal timescales superimposed upon a longer-term trend toward lower % fines. The record bears a strong resemblance to records of annual precipitation and summer temperature inferred from pollen in Lake of the Clouds, Michigan (Gajewski, 1988). This lends support to the Pb-210 derived age model and enables transfer of the Fourth Lake record onto the varve-chronology of Lake of the Clouds for comparison of fluctuations in Fourth Lake sediment characteristics with inferred climate. The trend toward lower % fines coincides with a long-term trend toward reduced precipitation and higher summer temperatures over the past 350 years. The same relationship between grain size and climatic variables characterizes the shorter-term fluctuations. The precise duration of the short-term variations remains uncertain but, their estimated maximum duration (21-yr) makes the North Atlantic Oscillation (NAO) a candidate. Fluctuations in intensity of zonal and meridonal winds that accompany the NAO could explain the similarity between the inferred climate records from geographically remote lakes. Irregular multidecadal-to-centennial variation is exhibited by % carbonate which displays two notable maxima centered at 1825 and 1925. The long-term trend and centennial variations parallel solar variability and, to a limited extent, the Atlantic Multidecadal Oscillation (AMO).
DE: 0458 Limnology (1845, 4239, 4942)
DE: 1620 Climate dynamics (0429, 3309)
DE: 1637 Regional climate change
DE: 1861 Sedimentation (4863)
DE: 3344 Paleoclimatology (0473, 4900)
SC: Global Climate Change [GC]
MN: Fall Meeting 2005