HR: 1340h
AN: PP13A-1478    [Abstracts]
TI: Pollen and stratigraphic evidence for abrupt climate changes in the Northeastern United States: Lake Champlain
AU: * Willard, D A
EM: dwillard@usgs.gov
AF: US Geological Survey, 926A National Center 12201 Sunrise Valley Drive, Reston, VA 20192 United States
AU: Cronin, T M
EM: tcronin@usgs.gov
AF: US Geological Survey, 926A National Center 12201 Sunrise Valley Drive, Reston, VA 20192 United States
AU: Manley, P L
EM: patmanley@middlebury.edu
AF: Middlebury College, Geology Department, Middlebury, VT 05753 United States
AB: Lake Champlain, located between New York and Vermont in the northeastern United States, was formed during the last deglaciation. Sediments deposited in Lake Champlain preserve a detailed record of climate intervals including deposition from pro-glacial Lake Vermont, a marine excursion represented by the Champlain Sea, and Holocene lacustrine sedimentation of Lake Champlain. Short sediment cores (<5 m) from southern Lake Champlain were recovered in 2004 by the R/V Melosira in a joint USGS-Middlebury College study. These cores include sediments deposited during the Champlain Sea and Lake Champlain phases of deposition, and pollen assemblages are used to a) establish an independent dating tool and b) evaluate timing of plant community responses to post-glacial climate change and centennial-scale climate variability. Pollen records from five sediment cores collected in southern Lake Champlain are compared with well-dated records from other lakes and bogs within the limits of Champlain Sea deposition, and sites bordering the sea, to establish a pollen-based chronology for the area. Radiocarbon dates on shells from the cores are compared to the pollen-based chronology to evaluate local reservoir effects on shell dates and redefine the timing of marine and lacustrine depositional phases. Sequences of radiocarbon dates from these cores suggest that temporal resolution at these sites is sufficient to interpret patterns of successive colonizing forests following ice-margin retreat and centennial-scale climate variability at the end of the deglacial interval.
DE: 1135 Correlative geochronology
DE: 1851 Plant ecology (0476)
DE: 3305 Climate change and variability (1616, 1635, 3309, 4215, 4513)
DE: 3344 Paleoclimatology (0473, 4900)
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005