HR: 11:50h
AN: PP12A-07    [Abstracts]
TI: Indonesian Throughflow dynamics of the last 25 kyr: New Uranium Series results from the Indonesian Seas
AU: * Muller, J
EM: jmuller@whoi.edu
AF: Woods Hole Oceanographic Institution, Geology and Geophysics, Clark Lab, Woods Hole, MA 02543, United States
AU: McManus, J
EM: jmcmanus@whoi.edu
AF: Woods Hole Oceanographic Institution, Geology and Geophysics, Clark Lab, Woods Hole, MA 02543, United States
AU: Opdyke, B
EM: bno@ems.anu.edu.au
AF: Australian National University, Department of Earth and Marine Sciences, Canberra, ACT 0200, Australia
AB: In the modern ocean the Indonesian Throughflow (ITF) is a key component of thermohaline circulation (THC) that transports large amounts of heat from the Pacific to the Indian Ocean and is the only tropical connection between major ocean basins. This oceanographic system is known to influence a number of climatic conditions, one significant example being El Niño Southern Oscillation (ENSO). Undoubtedly, the Indonesian seas are important for climate, yet we have only a modest understanding of how this region operated in the past. During the Last Glacial Maximum (LGM) the Indonesian Seas experienced significant sea level regression with consequent changes in boundary conditions (De Deckker et al., 2002). Previous paleo-studies within the Indonesian Seas implied a weakening of the ITF during the LGM (Müller and Opdyke, 2000; Gingele et al., 2001). These interpretations focus on paleoproductivity and sedimentology proxies rather than proxies that more directly measure paleocirculation. In addition, previous interpretations of paleoproductivity may require clarification due to possible post depositional sediment focusing in this region. We present two down core records from the Timor (MD-982167) and Flores Seas (VM33-80) that span back ~25 kyr. We use 231Pa/230Th as a more direct paleocirculation tracer and apply 230Th normalized fluxes and biogenic opal in order to look at paleoproductivity during the LGM, through the deglaciation and into the Holocene. These records extend on current paleooceanographic knowledge from the equatorial realm of the climate system. More specifically the records aim to better understand an important segment of the THC, namely the ITF, and how its strength has interacted with climates of the past. De Deckker P., Tapper N. J., and van der Kaars S. (2002) The status of the Indo-Pacific Warm Pool and adjacent land at the Last Glacial Maximum Global and Planetary Change 35, 25-35. Gingele F. X., De Deckker P., and Hillenbrand C. D. (2001) Clay mineral distribution in surface sediments between Indonesia and NW Australia - source and transport by ocean currents. Marine Geology 179, 135-146. Müller A. and Opdyke B. N. (2000) Glacial-interglacial changes in nutrient utilization and paleoproductivity in the Indonesian Throughflow sensitive Timor Trough, eastmost Indian Ocean. Paleoceanography 15(1), 85-94.
DE: 4922 El Nino (4522)
DE: 4924 Geochemical tracers
DE: 4926 Glacial
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2007 Fall Meeting