Permafrost

the extended duration of freezing periods. Only very few thermal shocks (i.e. temperature
changes of at least 2º C/minute) were observed and could not cause any weathering. Dynamic
Young's modulus measurements indicate a very low weathering rate after 4 years of exposure.
This poorly porous sandstone is not weathered by microgelivation, but by wedging of its
well-developed crack system.
The Troms transect includes three sites exposed to maritime climate (Kvaløya) and two
sites located in a much colder and drier region (Skibotndalen); sites are spread between sea
level and 530 m a.s.l. Both on Kvaløya and at in Skibotndalen, at around 500 meters a.s.l., frost
can occur at the rock surface from around mid-September until mid-May. At all elevations, a
large number of freeze / thaw cycles are observed at the rock surface over a one-year period:
between 35 and more than 60. This is considerable, and much larger than on Svalbard (about
20-25 per year); this reflects the fact that, in Troms, air temperature can fluctuate a lot also
during the winter, particularly in maritime locations. This parameter is important in the context
of the efficiency of cryogenic weathering, which is supposed to be higher at the Troms subarctic
sites than in the Svalbard high-arctic sites.
Characteristics of Cryogenic Soils in the Qinghai-Xizang Plateau, China
C.L. Ping 1 , L. Zhao 2 , O.A. Chadwick 3 and F.R. Paetzold 4
(1.Palmer Research Center, University of Alaska Fairbanks, Palmer, AK 99645; 2.Cold and Arid Regions
Environmental and Engineering Research Institute, Chinese Academy of Sciences, Lanzhou, China 730000;
3.Dept. of Geography, U.C. Santa Barbara, Santa Barbara, CA 93106; 4.Retired USDA-NRCS, College
Station, TX)
Abstract: The objectives of this study are (1): to investigate the soil-landscape relationship and
vegetation of Qinghai-Tibetan Plateau, (2): to find modern analog of Beringia environment, and
(3) to set up soil monitoring sites to study the effects of climate change on the soil environment
of the Plateau. Soil-vegetation sites were chosen along a N-S transect from 31 to 35 o N. Of all
the eight sites studied, 6 exhibit calcareous reactions and had pH values >8.2 (water). Free
carbonates, mostly pedogenic, were detected in 7 of the 8 sites. Soil morphological features
suggest the segregation, hence redistribution of carbonates in the profiles. The unusually high
carbonate contents in the buried organic horizons in the Qingxuehe site are marl formations
associated with a shallow lake sequences that frequently flooding produced stratified sedge
layers and fine sand layers. Each time the water level dropped a marl layer formed. In Kokexili
site, the carbonates are evenly distributed in the matrix without segregation due to the
carbonate-rich parent materials. On sites south of Tangula Pass where MAP increased to 350
mm and there are loamy soils overlying gravelly substratum, carbonates undercoatings on
gravel is common, indicating the movement of percolating water indicative of the semiaridic
environment. At the Liangdohe sites there is evidence of carbonates-leaching in a semihumid
(MAP~ 400 mm) environment. Permafrost presented in 4 of the 8 sites investigated with active
layers ranging from 50 to over 200 cm. Generally poorly drained organic soils have shallow
active layers.
Keywords: Cryogenic soils, alpine soils, soil property, Tibet Plateau, Cryosols
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