HR: 1340h
AN: PP13B-1493    [Abstracts]
TI: Interhemispheric Anti-phased Climate Changes During the Last Deglaciation
AU: * Wang, X
EM: wang0452@umn.edu
AF: Department of Geology & Geophysics, University of Minnesota, 108 Pillsbury Hall, 310 Pillsbury Dr. SE, Minnepolis, MN 55455 United States
AU: Auler, A S
EM: aauler@terra.com.br
AF: CPMTC, Instituto de Geociˆncias, Universidade Federal de Minas Gerais, Av. Antonio Carlos 6627, Belo Horizonte, MG 31270-901 Brazil
AU: Edwards, R L
EM: edwar001@tc.umn.edu
AF: Department of Geology & Geophysics, University of Minnesota, 108 Pillsbury Hall, 310 Pillsbury Dr. SE, Minnepolis, MN 55455 United States
AU: Cheng, H
EM: cheng021@umn.edu
AF: Department of Geology & Geophysics, University of Minnesota, 108 Pillsbury Hall, 310 Pillsbury Dr. SE, Minnepolis, MN 55455 United States
AU: Ito, E
EM: eito@umn.edu
AF: Department of Geology & Geophysics, University of Minnesota, 108 Pillsbury Hall, 310 Pillsbury Dr. SE, Minnepolis, MN 55455 United States
AU: Solheid, M
EM: maniko@umn.edu
AF: Department of Geology & Geophysics, University of Minnesota, 108 Pillsbury Hall, 310 Pillsbury Dr. SE, Minnepolis, MN 55455 United States
AB: We have obtained a high-resolution oxygen isotopic record of cave calcite from Gruta Do Padre (PAD), central Brazil. The chronology was determined by 20 U-Th ages from 2 stalagmites. Tests for equilibrium conditions show that oxygen isotopic variations are primarily caused by climate change. We interpreted the PAD record, spanning the last 16 thousand years, in terms of meteoric precipitation changes at this low-latitude location. The oxygen isotopic profile shows clear abrupt millennial-scale variations with amplitudes as large as 3 per mil. Using independent age scales, we compare the record to contemporaneous records from caves in eastern China and high latitude ice cores. During the last deglaciation, PAD calcite δ¹⁸O anti-correlates remarkably with δ¹⁸O in the Hulu Cave (Wang et al., 2001, Science), indicating that precipitation histories at the two sites are anti-phased, similar to our previous observations from southern Brazil speleothems. As Greenland temperature has been shown to correlate with Hulu precipitation, PAD precipitation anti-correlates with Greenland temperature. The timing of the main transition at PAD is synchronous within error with the Hulu and Greenland records. For instance, the rapid PAD transitions into a dry "Bolling-Allerod", and the beginning and the end of a wet "Younger Dryas", occur at about 14620±60 yr B.P., 12750±60 yr B.P., and 11600±100 yr B.P., respectively. Such anti-correlations support the bipolar see-saw mechanism through the last glacial-interglacial transition. However, the millennial-scale climate variability probably involves both ocean thermohaline and atmospheric circulation changes.
DE: 4901 Abrupt/rapid climate change (1605)
DE: 4938 Interhemispheric phasing
DE: 4958 Speleothems
DE: 4962 Thermohaline
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005