HR: 10:50h
AN: PP42B-03    [Abstracts]
TI: Midge-Inferred Temperatures from Three Interglacial Periods in the Eastern Canadian Arctic
AU: * Axford, Y
EM: axford@colorado.edu
AF: INSTAAR and Department of Geological Sciences, University of Colorado, UCB 450, Boulder, CO 80309 United States
AU: Briner, J P
EM: jbriner@buffalo.edu
AF: Department of Geology, University at Buffalo, 876 Natural Sciences Complex, Buffalo, NY 14260 United States
AU: Francis, D R
EM: dfrancis@geo.umass.edu
AF: Department of Geosciences, University of Massachusetts, 233 Morrill Science Center, Amherst, MA 01003 United States
AU: Baker, G
PP42B-03 AF: Department of Earth and Planetary Sciences, University of Tennessee, 1412 Circle Drive, Knoxville, TN 37996 United States
AU: Miller, G H
EM: gmiller@colorado.edu
AF: INSTAAR and Department of Geological Sciences, University of Colorado, UCB 450, Boulder, CO 80309 United States
AB: Lake sediments recovered from a Canadian Arctic lake are providing a rare opportunity to reconstruct Holocene, last interglacial, and earlier temperature changes at centennial to decadal resolution. Lake CF8 (informal name) is a small (0.5 km²) lake situated on an inter-fjord lowland in northeastern Baffin Island at 70^o N latitude. Sediment cores from Lake CF8 contain three organic lake sediment units, separated by non-lacustrine sands. Radiocarbon ages from the uppermost organic unit span the entire Holocene. The middle organic unit is beyond the limit of radiocarbon dating. Comparison with a similar lacustrine record from Fog Lake, Baffin Island, indicates that this middle unit most likely records the last interglacial (Eemian) period. The lowest organic unit was only partially recovered, but may record the late stages of the penultimate interglacial. Subfossil midges (Chironomidae) are abundant and well-preserved throughout the organic sediments, providing a quantitative means for temperature reconstruction. Midge-based temperature reconstructions indicate that summer temperatures at Lake CF8 surpassed modern values by 10 cal kyr BP. Summer temperatures during the first half of the Holocene were as much as 5^oC warmer than present. Similarly, the early part of the last interglacial was several degrees warmer than the latter part of the period. The bottommost lake sediments we recovered, which were presumably deposited during the late stages of a prior interglacial period, record summer temperatures similar to those of the latter parts of the Holocene and last interglacial. The magnitude of early Holocene and last interglacial warmth at this high-latitude site lends support to concerns about Arctic amplification of future warming.
DE: 4914 Continental climate records
DE: 4936 Interglacial
DE: 4942 Limnology (0458, 1845, 4239)
DE: 4950 Paleoecology
DE: 9315 Arctic region (0718, 4207)
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005