HR: 17:40h
AN: PP54A-07    [Abstracts]
TI: Luminescence Dating Tests of Detrital Grains From Sediment Traps, Andvord Bay and Brialmont Cove, Antarctic Peninsula
AU: * Draucker, S
EM: Sara.Draucker@dri.edu
AF: Desert Research Institute, Division of Earth and Ecosystem Sciences 2215 Raggio Parkway, Reno, NV 89512-1095 United States
AU: Berger, G W
EM: Glenn.Berger@dri.edu
AF: Desert Research Institute, Division of Earth and Ecosystem Sciences 2215 Raggio Parkway, Reno, NV 89512-1095 United States
AU: Gilbert, R
EM: gilbert@lake.geog.queensu.ca
AF: Queen's University, Dept. of Geography, Kingston, ON K7L 3N6 Canada
AU: Domack, E
EM: edomack@hamilton.edu
AF: Hamilton College, Dept. of Geology 198 College Hill Road, Clinton, NY 13323 United States
AB: Difficulties (e.g., large, diverse, erratic reservoir corrections) with radiocarbon dating have prompted photonic dating tests on Antarctic glaciomarine sediments. This technique (clock zeroing is based on the last exposure to daylight of quartz and feldspar grains) was applied to modern-age sediments collected in two well-characterized fjords on the western side of the Antarctic Peninsula. Our deployed sediment traps collected approximately 14 months of deposition between January 2002 and March 2003. We conducted a series of multi-aliquot infrared-stimulated luminescence tests on polymineral silt-sized grains to evaluate the extent of the clock-zeroing process in this setting, to provide a foundation for applications elsewhere in the region. Comparisons were made between samples on the basis of seasonal differences and trap depth. Samples were also characterized by SEM-EDX data. Had the sediments been exposed to sufficient sunlight at deposition, sediment grains collected by these traps would exhibit very low equivalent-dose (DE) values. Experiments done thus far have produced high (and variable) DE values for both Andvord Bay and Brialmont cove, which yield erroneously old ages, rather than zero. Apparent ages for Andvord Bay ranged between 42 $\pm$ 9 ka and 60 $\pm$ 11 ka (DE = 63 - 90 Gy), while Brialmont Cove DE values ranged between 14 $\pm$ 3 ka and 39 $\pm$ 8 ka ( DE = 21 - 58 Gy), depending on season and depth of deposition. This indicates that these glaciomarine sediments were unevenly and poorly bleached at deposition. Variations in luminescence traits between seasons and with trap depth may, however, be helpful for studying sedimentation processes in these fjords.
DE: 4207 Arctic and Antarctic oceanography
DE: 3022 Marine sediments--processes and transport
DE: 1035 Geochronology
SC: Paleoceanography and Paleoclimatology [PP]
MN: 2004 AGU Fall Meeting