HR: 08:00h
AN: U31A-01 INVITED     [Abstracts]
TI: Interhemispheric correlation of glacial terminations using in-situ Be-10
AU: * Schaefer, J M
EM: schaefer@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory, Route 9W, Palisades, NY 10964 United States
AU: Denton, G H
U31A-01 AF: University of Maine, Departement of Geological Sciences, Orono, ME 04469 United States
AU: Ivy-Ochs, S
EM: ivy@phys.ehtz.ch
AF: ETH Zuerich, Particle Physics, Zuerich, ZH 8092 Switzerland
AU: Kubik, P W
U31A-01 AF: Paul Scherrer Institut, c/o Institute of Particle Physics, ETH-Hoenggerb, Zuerich, ZH 8092 Switzerland
AU: Barrell, D J
U31A-01 AF: Institute of Geological and Nuclear Sciences, Dunedin Research Center, Dunedin, 1930 New Zealand
AU: Phillips, F
U31A-01 AF: New Mexico Tech, Department of Earth and Environmental Sciences, Soccoro, NM 87801 United States
AU: Schluechter, C
U31A-01 AF: University of Berne, Institute of Geology, Bern, BE 3012 Switzerland
AU: Anderson, B
U31A-01 AF: University of Oslo, Geological Institute, Oslo, 8000 Norway
AU: Lowell, T
U31A-01 AF: University of Cincinnatti, Department of Geology, Cincinnatti, OH 45221 United States
AB: Glaciers are very sensitive recorders of climate change. The global distribution of glacial systems offers the opportunity to establish a global map of past and current climate change by reconstructing the timing and amplitude of past glaciations. The Be-10 database of mountain glacier events has become large and reliable enough to extract hemisphere-wide to inter-hemispheric conclusions. Exemplarily, we present an inter-hemispheric compilation of new and existing in-situ Be-10 chronologies of the termination of the Last Glacial Maximum (LGM), arguably the most prominent climate event recorded in the moraine record. The Be-10 ages of the final LGM stage are remarkably consistent in southern- and northern mid-latitudes, suggesting inter-hemispheric synchrony of this climate event. The timing of this termination is consistent with the increase of temperature and atmospheric greenhouse gas concentration as recorded in Antarctic ice core records, the latter indicating tropical climate change. These effects are best explained by a near-global summer temperature rise as the primary driver for this glacial termination. No significant temperature change is recorded in the Greenland ice-cores that would reflect the inter-hemispheric LGM termination. We propose that Greenland ice-core temperature records are winter-biased during glacial, insensitive to moderate summer temperature rise. I.e. current glacial-interglacial temperature gradients are based on comparing winter-dominated glacial temperature to a mean-annual temperature during interglacials.
DE: 0394 Instruments and techniques
DE: 0720 Glaciers
DE: 1105 Quaternary geochronology
DE: 1165 Sedimentary geochronology
DE: 1605 Abrupt/rapid climate change (4901, 8408)
SC: Union [U]
MN: Fall Meeting 2005