HR: 0800h
AN: PP11B-1452 [Abstracts]
TI: An In-Situ Intercomparison of Planktonic Foraminiferal Mg/Ca and Alkenone UK'37 Temperature
Estimates
AU: * Hardee, M L
EM: michelle.hardee@msci.sc.edu
AF: Marine Science Program,
University of South Carolina, 712 Main St., Columbia, SC 29208
United States
AU: Thunell, R C
EM: thunell@geol.sc.edu
AF: Department of Geology,
University of South Carolina, 701 Sumter St., Columbia, SC 29208
United States
AB:
Interpreting paleoceanographic and paleoclimatic conditions as they are preserved in the sediments directly hinges on our
understanding of the present-day factors that influence the climate proxies used to make estimates of past ocean conditions.
In this study, we compare temperatures estimated using the UK`37 alkenone paleotemperature index and the
planktonic foraminiferal Mg/Ca paleothermometer, using a suite of 141 samples from a time series (1993-2004) sediment trap
experiment in the Santa Barbara Basin (SBB). The UK`37 and Mg/Ca values are correlated to temperatures
measured concurrently during sediment trap deployment in SBB and to previously published calibration equations in order to
evaluate the consistency and interannual variability of these two paleothermometers. Results show that the Mg/Ca ratio of
Globigerina bulloides reliably records SST changes on seasonal and inter-annual time scales at SBB, as an exponential
relationship in the form of Mg/Ca = 1.13 exp (0.048T), equivalent to a 4.9 ± 0.02 change in Mg/Ca for a 1°C
change in temperature. The UK`37 alkenone paleotemperature index shows a good correlation between the
in-situ SSTs and the UK`37 index measured from trap cups, as well as to the Mg/Ca ratio measured from the
foraminifera. Our results indicate that there is a high degree of concordance between these temperature proxies in the Santa
Barbara Basin.
DE: 1065 Major and trace element geochemistry
DE: 4900 PALEOCEANOGRAPHY (0473, 3344)
DE: 4922 El Nino (4522)
DE: 4954 Sea surface temperature
DE: 4994 Instruments and techniques
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005