HR: 0830h
AN: PP31B-0252    [PDF]
TI: The end of the Early Eocene Climatic Optimum: Evidence for Concomitant Cooling of Southern Ocean Surface Waters and Global Deep Waters From Dinoflagellate Endemism.
AU: * Brinkhuis, H
EM: H.Brinkhuis@bio.uu.nl
AF: Laboratory of Palaeobotany and Palynology, Utrecht University, Budapestlaan 4, Utrecht, 3584 CD Netherlands
AU: Warnaar, J
EM: J.Warnaar@bio.uu.nl
AF: Laboratory of Palaeobotany and Palynology, Utrecht University, Budapestlaan 4, Utrecht, 3584 CD Netherlands
AU: Huber, M
EM: mhuber@purdue.edu
AF: Earth & Atmospheric Science, Purdue University, 1397 Civil Engineering Bldg., Lafayette, IN 47807-1397 United States
AU: Zachos, J C
EM: jzachos@es.ucsc.edu
AF: Department of Earth Sciences, University of California at Santa Cruz, 1156 High Street, Santa Cruz, CA 95064 United States
AB: ODP Leg 189 drilling around Tasmania retrieved quasi-continuous Eocene records from the Southern Ocean - Antarctic Margin. The shallow marine, pro-deltaic successions of Sites 1170, 1171 and 1172 include the interval representing the onset ($\sim$55 Ma) and termination ($\sim$50 Ma) of the Early Eocene Climatic Optimum (EECO). The end of the EECO is globally reflected in the oceans by the onset of increasingly cooler deep-water temperatures, and marks the onset of the trend towards the Icehouse world. Here we show that a strong increase of endemic Antarctic dinoflagellates precisely matches the termination of the EECO in the Southern (Pacific) Ocean. The record of these surface-dwelling organisms thus indicates that changes of surface water parameters, notably temperature, occurred near simultaneously with global deep-water temperature changes. Comparison of the field data with predictions from fully coupled climate model simulations, and a new basic understanding of Eocene Southern Ocean circulation, suggests that changes in atmospheric greenhouse gasses may have been driving the apparently coupled surface- and deep-water signals.
DE: 1635 Oceans (4203)
DE: 3030 Micropaleontology
DE: 4267 Paleoceanography
DE: 9355 Pacific Ocean
DE: 9604 Cenozoic
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2003 Fall Meeting