HR: 09:30h
AN: PP31C-07    [Abstracts]
TI: Interplanetary Dust Particles in the EPICA Dronning Maud Land Ice Core
AU: * Winckler, G
EM: winckler@ldeo.columbia.edu
AF: Lamont-Doherty Earth Observatory, Columbia University, 61 Route 9W, Palisades, NY 10964 United States
AU: Fischer, H
EM: hufischer@awi-bremerhaven.de
AF: Alfred Wegener Institute for Polar and Marine Research, Columbusstrasse, Bremerhaven, 27568 Germany
AB: Polar ice cores and marine sediments provide an archive of the influx of extraterrestrial material in the form of interplanetary dust particles. Interplanetary dust particles are marked by extremely high helium concentrations, and this signal can be used to reconstruct a record of the extraterrestrial Helium-3 flux. Determination of accurate extraterrestrial Helium-3 fluxes from marine sediment cores is limited by the uncertainties in the accumulation rates of marine cores. Ice cores, with their very well known age models and accumulation rates, provide a unique opportunity for accurate and independent estimate of the IDP-related Helium-3 flux. Previous measurements of helium isotopes in samples from the Vostok ice core (Brook et al., GRL, 2000) demonstrated the suitability and potential of ice cores and found Helium-3 fluxes similar to results from marine sediments (e.g. Marcantonio et al., Paleoceanography, 2001). A limiting factor for ice core studies so far has been the access to ice core material and, related to this, the size of the available samples. In order to overcome this limitation, we developed a new extraction method based on filtering dust particles from the "waste water" stream from the melt head of a continuous flow analysis for aerosol chemistry (Roethlisberger et al., 2000). This gives access to bulk samples allowing in principle to analyze a continuous record of Helium-3 accretion and to integrate over longer timescales (500a) thereby improving the particle statistics and thus the over-all precision. We report results of helium isotope measurements of a high-resolution record from the EPICA (European Project for Ice Coring in Antarctica) Dronning Maud Land ice core using 4-5kg samples from 400 to 1100 m depth corresponding to the time period from the LGM to the middle Holocene. We also present a pilot study comparing results from the new sampling technique to measurements on real ice samples.
DE: 0724 Ice cores (4932)
DE: 2129 Interplanetary dust
DE: 4914 Continental climate records
DE: 4924 Geochemical tracers
SC: Paleoceanography and Paleoclimatology [PP]
MN: Fall Meeting 2005