HR: 0800h
AN: C21A-0055    [Abstracts]
TI: Increased Active Layer Development Associated with Thermokarst Activity in Continuous Permafrost Region in the Brook Range foothills, Alaska
AU: * Bouchier, A
EM: abouchie@mines.edu
AF: Colorado School of Mines, Department of Geology and Geologic Engineering 1516 Illinois Street, Golden, CO 80401, United States
AU: Gooseff, M
EM: mgooseff@engr.psu.edu
AF: Pennsylvania State University, Civil and Environmental Engineering Department 212 Sackett Building, University Part, PA 16802, United States
AU: Bowden, W B
EM: breck.bowden@uvm.edu
AF: University of Vermont, Rubenstein School of Environmental and Natural Resources 304 Aiken Center, Burlington, VT 05405, United States
AU: Jones, J
EM: ffjbj@uaf.edu
AF: Institue of Artic Biology, University of Alaska Fairbanks IAB 311 Irving I, Fairbanks, AK 99775, United States
AU: Balser, A
EM: Andrew.Balser@uaf.edu
AF: Institue of Artic Biology, University of Alaska Fairbanks IAB 311 Irving I, Fairbanks, AK 99775, United States
AB: We documented the distribution of hill slope thermokarst features in tundra landscapes across the western Brooks Range of Alaska. Previously we observed that thermokarst features in the Noatak River basin were often associated with the presence of a zero-order stream (water track). During the 2007 field season, fourteen thermokarst features within the southwest Noatak River drainage in north western Alaska were characterized. The thermokarst features were located on a variety of lithologies, but mainly on non-carbonate sedimentary slopes. We measured the depth of thaw along multiple transects through each thermokarst feature and found thaw depth to be deeper by an average of 10 to 30 cm within features compared to the surrounding hill slopes. The relative deepening of the thaw was more pronounced further down slope within each thermokarst feature. This increased thaw beneath thermokarst features creates an exaggerated upper surface of the permafrost compared to the ground surface. This exaggeration is especially pronounced where up to three meters of material has been removed by erosion within thermokarst features, and could lead to increased geomorphic incision in these locations. The presence of a hill slope thermokarst feature is associated with a loss of vegetation, reduction in surface albedo, and potential for erosion of mineral soil. All of these affect hill slope's hydrologic function, likely leading to extension of stream networks and may contribute to the further deepening of the upper surface of the permafrost these areas.
DE: 0702 Permafrost (0475)
DE: 0706 Active layer
DE: 0708 Thermokarst
SC: Cryosphere [C]
MN: 2007 Fall Meeting