HR: 15:25h
AN: C23B-08    [Abstracts]
TI: Stable isotope characteristics of pre last interglaciation ice wedges near Fairbanks Alaska
AU: * Yoshikawa, K
EM: ffky@uaf.edu
AF: Water and Environmental Research Center, Institute of Northern Engineering, University of Alaska Fairbanks, Fairbanks, 99775 United States
AU: Meyer, H
EM: hmeyer@awi-potsdam.de
AF: Alfred Wegener Institute for Polar and Marine Research, Research Unit, D-14473 Potsdam, Germany, Potsdam, 14473 Germany
AU: Schirrmeister, L
EM: lschirrmeister@awi-potsdam.de
AF: Alfred Wegener Institute for Polar and Marine Research, Research Unit, D-14473 Potsdam, Germany, Potsdam, 14473 Germany
AU: Andreev, A
EM: aandreev@awi-potsdam.de
AF: Alfred Wegener Institute for Polar and Marine Research, Research Unit, D-14473 Potsdam, Germany, Potsdam, 14473 Germany
AU: Wagner, D
EM: dwagner@awi-potsdam.de
AF: Alfred Wegener Institute for Polar and Marine Research, Research Unit, D-14473 Potsdam, Germany, Potsdam, 14473 Germany
AU: Hubberten, H
EM: hubbert@awi-potsdam.de
AF: Alfred Wegener Institute for Polar and Marine Research, Research Unit, D-14473 Potsdam, Germany, Potsdam, 14473 Germany
AB: Permafrost preserves many signals for reconstructing late Quaternary environments and climatic record. Especially ice wedge contained isotopic information for winter environments during process of the ice wedge developed. This paper discussed the characteristics of the stable isotope (?18O and ?2H) composition of ice wedge from different units of late Quaternary sediments and of present climatic conditions. The frost contraction crack (ice wedge developing process) is not very active present climatic conditions in Fairbanks area. However, some of cold winter and/or less snow year had strong enough frost contraction crack occur for ice wedge process. This marginal condition to develop ice wedge is aid to understand for snow and ice isotopes during ice wedge developed stages. Currently, permafrost dominates valley bottom or north facing slopes, but is largely absent on south facing slopes. The annual mean ground surface temperature varies -4.0 to 2.5§C, depending on slope aspect. Many of late Quaternary relict ice wedges is preserved in Wisconsinan loess and retransported silty sediments around valley bottom. Four different ice wedges group are classified by the stable isotope signals: 1) humid and warmer periods but colder than present, 2) cold and humid periods, 3) colder and dryer period, 4) warm and humid period. The favourite condition for the ice wedges development seems cold and humid period when just before LGM. The possibility of the heavier stable isotope indicated the source of the snow only would be from Gulf of Alaska. The frequency of jet stream circulations to Alaska may important function for Alaskan warm winter and bring heavier isotope components.
DE: 0700 CRYOSPHERE (4540)
DE: 0702 Permafrost (0475)
DE: 0710 Periglacial processes
DE: 0724 Ice cores (4932)
DE: 0738 Ice (1863)
SC: Cryosphere [C]
MN: Fall Meeting 2005