HR: 08:00h
AN: PP11C-01 INVITED    [Abstracts]
TI: Dynamic Paleoceanographic History of the Eastern Tropical Pacific – Is the confusion clearing?
AU: * Mix, A C
EM: mix@coas.oregonstate.edu
AF: College of Oceanic & Atmospheric Sci., COAS Admin Bldg. 104 Oregon State University, Corvallis, OR 97331, United States
AU: Klinkhammer, G P
EM: gklinkhammer@coas.oregonstate.edu
AF: College of Oceanic & Atmospheric Sci., COAS Admin Bldg. 104 Oregon State University, Corvallis, OR 97331, United States
AU: Prahl, F
EM: fprahl@coas.oregonstate.edu
AF: College of Oceanic & Atmospheric Sci., COAS Admin Bldg. 104 Oregon State University, Corvallis, OR 97331, United States
AU: Pisias, N G
EM: npisias@coas.oregonstate.edu
AF: College of Oceanic & Atmospheric Sci., COAS Admin Bldg. 104 Oregon State University, Corvallis, OR 97331, United States
AU: Kienast, M
EM: markus.kienast@dal.ca
AF: Dalhousie University, Dept. of Oceanography 1344 Oxford Street, Halifax, NS B3H 4J1, Canada
AB: In spite of the importance of the ENSO-sensitive region of the eastern tropical Pacific as an indicator of mechanisms tropical climate change, reconstructing the paleoceanographic history here has provoked controversy and confusion. Various authors claim that the glacial system is more like La Nina, or more like El Nino, or with little temperature change, or that it was much colder with links to the Antarctic, or the North Atlantic, or that the ITCZ moved Southward, or Northward, or not at all. Similar controversy has accompanied reconstruction of paleoproductivity, biogenic fluxes, and other fundamental properties, as well as with the timing and mechanisms of transient changes during the deglacial transition, and inferences about mechanisms (upwelling, advection, preformed properties of source waters, radiative forcing and greenhouse gases, etc). Models disagree too. Why is this place so confusing? We review some of this controversy, using multiple paleo proxies, and attempt to outline a possible solution including new data. We think the difficulty reflects biases in all the various paleo proxies related to interaction among oceanic processes (for example, productivity, pycnocline depth, and temperature), in the ways the proxies are measured, and in modifications due to sediment diagenesis fueled by high organic rain in this biologically productive region. Work toward resolving these issues in this controversial area leads us to think about paleo proxies in new ways, and we hope it will lead to more precise and accurate ways of reconstructing past conditions that will provide useful for better reconstructing the rest of the world. Simply understanding the difference between glacial and interglacial states is not sufficient, as this area – as with many others – has substantial transient and millennial-scale variations superimposed on longer-term changes. Looking at the full spectrum of variability in both data and models yields important insights.
DE: 1041 Stable isotope geochemistry (0454, 4870)
DE: 1055 Organic and biogenic geochemistry
DE: 1065 Major and trace element geochemistry
DE: 4954 Sea surface temperature
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting