HR: 08:45h
AN: C51C-04    [Abstracts]
TI: Solifluction Processes in Seasonally Frozen Ground, Dovrefjell, Norway
AU: * Harris, C
EM: harrisc@cardiff.ac.uk
AF: Cardiff University, School of Earth, Ocean and Planetary Sciences, Cardiff, CF10 3YE, United Kingdom
AU: Kern-Luetschg, M A
EM: LuetschgM@cf.ac.uk
AF: Cardiff University, School of Earth, Ocean and Planetary Sciences, Cardiff, CF10 3YE, United Kingdom
AU: Smith, F W
EM: f.w.smith@dundee.ac.uk
AF: University of Dundee, School of Engineering, Dundee, DD1 4HN, United Kingdom
AU: Isaksen, K
EM: ketil.isaksen@met.no
AF: Norwegian Meteorological Institute, Blindern, Oslo, 0313, Norway
AB: Continuous monitoring of soil temperatures, frost heave, thaw consolidation, pore water pressures and down slope soil movements are reported from a turf-banked solifluction lobe at Seinhoi, Dovrefjell, Norway from August 2002 to August 2006. Mean annual air temperatures over the monitored period were slightly below 0° C, but mean annual ground surface temperatures were around 2° C warmer, due to the insulating effects of snow cover. Winter frost penetration was around 30 cm at the monitoring station, so that the site may be considered close to the limit of active solifluction in this area. Average rates of downs slope surface movement over the four year period 2002-2006 ranged from 0.5 cm yr^-1 at the rear of the lobe tread to 1.6 cm yr^-1 just behind the lobe front, with corresponding soil transport rates of 5.9 cm³ cm^-1 yr^-1 and 45.7 cm³ cm^-1 yr^-1. Pore water pressure measurements indicated seepage of snowmelt beneath the seasonally frozen ground in spring, with artesian pressures beneath the confining layer. Soil thawing was associated with surface settlement and down slope soil displacements. Further surface settlement in early summer was accompanied by retrograde movements. Down slope surface displacements exceeded maximum potential frost creep values and it is concluded that gelifluction was an important component of slow near-surface mass movements at this site. Temporal and spatial variations in solifluction rates across the area are likely to be considerable, and are strongly influenced by snow distribution and thickness.
DE: 0700 CRYOSPHERE (4540)
DE: 0704 Seasonally frozen ground
DE: 0710 Periglacial processes
DE: 1823 Frozen ground
SC: Cryosphere [C]
MN: 2007 Fall Meeting