HR: 1340h
AN: PP13A-0594    [Abstracts]
TI: Multiproxy deglacial record of climate change in central Florida from fresh water ostracodes using paired Mg/Ca, Sr/Ca, and O-18.
AU: * Hastings, D W
EM: hastindw@eckerd.edu
AF: Eckerd College, 4200 54th Ave S., St. Petersburg, FL 33713 United States
AU: Hollweg, T
EM: hollweta@eckerd.edu
AF: Eckerd College, 4200 54th Ave S., St. Petersburg, FL 33713 United States
AU: Flower, B P
EM: bflower@marine.usf.edu
AF: College of Marine Science, University of South Florida, St. Petersburg, FL 33701 United States
AU: Cronin, T M
EM: tcronin@usgs.gov
AF: U.S. Geological Survey, 12201 Sunrise Valley Drive, Reston, VA 20192 United States
AU: Edgar, N T
EM: tedgar@usgs.gov
AF: U.S. Geological Survey, 600 4th St. South, St. Petersburg, FL 33701 United States
AU: Quinn, T M
EM: tquinn@marine.usf.edu
AF: College of Marine Science, University of South Florida, St. Petersburg, FL 33701 United States
AB: An 11.28 m core collected in Tampa Bay, FL reveals lacustrine sediments during the deglacial warming. Mg/Ca, Sr/Ca and O-18 were measured on two species of brackish water ostracodes. Our interpretation is that variations in Sr/Ca reflect changes in water chemistry and Mg/Ca variations reflect changes in both water temperature and chemistry. Applying Sr distribution coefficients results in virtually identical records of (Sr/Ca)$_ {water}$ for both species. (Sr/Ca)$_{water}$ is relatively constant from 20 to 14.1 ka, increases by a factor of two from 14.1 to 12.5 ka. High Sr/Ca values imply increased salinity due to higher evaporation during drier climates and vice-versa. The major trend in Mg/Ca for both species is a doubling of Mg/Ca starting at 13.8 ka with a relative maximum at 12.5 ka. Reliable Mg distribution coefficients as a function of temperature do not exist for these species so we can only infer relative temperature changes. There is a 2.0\permil decrease in O-18 from 13.7 to 11.5 ka. The overall scenario depicted by these three proxies is a relatively cool and wet climate during the Bolling/Allerod from 14.3 to 13.8 ka, changing to a warmer and drier climate during the Younger Dryas, with the driest and warmest period centered at 12.6 ka. These results will be compared with pollen data from the same core. This contrasts with high latitude pollen and ice core data indicating a cold Younger Dryas. These results support the observation that western tropical Atlantic SST was out-of phase with Greenland climate during the deglaciation.
DE: 4267 Paleoceanography
DE: 3030 Micropaleontology
DE: 1600 GLOBAL CHANGE (New category)
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting