HR: 0800h
AN: PP31A-0172    [Abstracts]
TI: A 2000-year record of temperature and salinity variation in Chesapeake Bay
AU: * Hayo, K M
EM: khayo@usgs.gov
AF: U.S. Geological Survey, 12201 Sunrise Valley Dr. MS 926A, Reston, VA 20192, United States
AU: Cronin, T M
EM: tcronin@usgs.gov
AF: U.S. Geological Survey, 12201 Sunrise Valley Dr. MS 926A, Reston, VA 20192, United States
AU: Dwyer, G S
EM: gsd3@duke.edu
AF: Duke University, Division of Earth and Ocean Sciences, Nicholas School of the Environment and Earth Sciences 318 Old Chem Box 90227, Durham, NC 27708, United States
AU: Thunell, R C
EM: thunell@geol.sc.edu
AF: University of South Carolina, Department of Geological Sciences 700 Sumter St., Columbia, SC 29208, United States
AB: Paleoclimatic records for the past 2000 years, including the Medieval Warm Period and Little Ice Age, were reconstructed from Marion-Dufresne cores from Chesapeake Bay (eastern North America). Mg/Ca ratios from the ostracode, Loxoconcha, and oxygen isotopes from the benthic foraminfer, Elphidium, are used as proxies of spring temperature and salinity, respectively. In the bay, salinity is directly related to Susquehanna River discharge, itself a function of regional rainfall. Chronology was constrained using radiocarbon dates derived from the mollusk, Mulinia lateralis, and historical pollen records of colonial land clearance. Mg/Ca ratios range from ~12 to 41 mmol/mol resulting in a temperature range of ~4 to 23° C. δ¹⁸ O values ranged from ~2.84 to +0.20‰ (VPDB) with a mean value of -1.16‰. Fluctuations in both the Mg/Ca and δ¹⁸O records confirm multidecadal climate variability during the Medieval Warm Period and Little Ice Age. These patterns are similar to those seen during 20th century NAO events, suggesting long term NAO climatic forcing for the region. The 20th century temperature and NAO-variability will be discussed in the context the last 2000 years of North Atlantic-wide climate variability.
DE: 1637 Regional climate change
DE: 4901 Abrupt/rapid climate change (1605)
DE: 4944 Micropaleontology (0459, 3030)
DE: 4954 Sea surface temperature
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting