HR: 0800h
AN: PP51F-1369    [Abstracts]
TI: A Reconstruction of Millennial-scale Changes in Sub-surface Watermasses Off of Central Chille
AU: * Phipps, M E
EM: mphipps@coas.oregonstate.edu
AF: COAS, Oregon State University, 104 COAS Admin. Building, Corvallis, OR 97331 United States
AU: Mix, A C
EM: mix@coas.oregonstate.edu
AF: COAS, Oregon State University, 104 COAS Admin. Building, Corvallis, OR 97331 United States
AB: Here we examine millennial scale changes in subsurface watermasses off central Chile during the last ice age, based on stable carbon and oxygen isotopes from benthic foraminifera. ODP sites 1235: (489m water depth) and 1234 ( 985 m water depth) bracket the modern extent of Antarctic Intermediate Water. The core top \delta 18O at 1235 and 1234 are 2.7 \permil and 3.3 \permil respectively. This 0.6 \permil difference between the two cores corresponds to a modern 2.4 $^{\circ}$ C temperature offset between sites. Variations in \delta 18O from Site 1234 resemble similar high-resolution records from the deep Atlantic, which suggests Southern Ocean linkage of deep ocean temperatures in the two ocean basins. High amplitude \delta 18O variations at Site 1234 indicate a larger change in temperature in the intermediate Southeast Pacific than the deep North Atlantic, whereas Site 1235 varies with lower amplitudes. If glacial ice volume accounts for 1.1 - 1.3 \permil of the observed change in benthic foraminiferal \delta 18O, Site 1235 may have experienced temperature changes of 2 - 3 $^{\circ}$ C and that Site 1234 experienced changes of 3-4 $^{\circ}$ C.
DE: 9355 Pacific Ocean
DE: 9360 South America
DE: 3344 Paleoclimatology
DE: 4267 Paleoceanography
DE: 1520 Magnetostratigraphy
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting