HR: 1340h
AN: PP33A-0918    [Abstracts]
TI: Deep-sea Coral Record of Paleoventilation Age of North Atlantic Deep Water During the Last Deglaciation
AU: * Cao, L
EM: lcao@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory, 205 New Core Lab Lamont-Doherty Earth Observatory Columbia University RT 9W, Palisades, NY 10964 United States
AU: Fairbanks, R G
EM: fairbanks@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory, 205 New Core Lab Lamont-Doherty Earth Observatory Columbia University RT 9W, Palisades, NY 10964 United States
AU: Risk, M J
EM: riskmj@mcmaster.ca
AF: Department of Geology, Department of Geology McMaster University, Hamilton, ON L8S 4M1 Canada
AU: Mortlock, R A
EM: mortlock@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory, 205 New Core Lab Lamont-Doherty Earth Observatory Columbia University RT 9W, Palisades, NY 10964 United States
AB: Wunsch (2003) posed a credible challenge to the paleoclimate community by suggesting that over zealous wiggle matching of the Greenland ice core \delta $^{18}$O records to far field proxy records grossly exaggerates the geographic relevance of the Greenland­_s millennial scale variability. Wunsch (2003) argues that regional wind fluctuations are a more reasonable cause of the millennial scale \delta $^{18}$O fluctuations (Charles et al., 1994) as well as other tracers trapped in Greenland ice. He asserts that the rapid fluctuations measured in Greenland ice cores need not be hemispheric or global in scope, nor be due to changes in North Atlantic Deep Water (NADW) production rates as is widely speculated. In order to test the proximal influence of the Greenland climate signal on NADW production rates, we estimate the NADW ventilation age at Orphan Knoll ($50\deg$26'N, $46\deg$22'W) using the radiocarbon tracer measured in deep-sea corals. Orphan Knoll is optimally located to record $\Delta$$^{14}$C variability on short timescales and deep-sea corals are abundant. Thus far we have calculated 400 year ventilation ages of NADW during the Bolling-Allerod interval (14.7-12.9 ka) using the $^{14}$C projection method (Adkins and Boyle, 1997), ventilation ages indistinguishable from modern estimates. These ventilation estimates are based on projections to our $^{230}$Th/$^{234}$U dated surface water coral $\Delta$$^{14}$C record from the tropics.
DE: 4875 Trace elements
DE: 4267 Paleoceanography
DE: 4283 Water masses
DE: 1030 Geochemical cycles (0330)
DE: 1065 Trace elements (3670)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting