Permafrost Terrain Stability and Thermokarst Monitoring: - Arctic LCC

26. Czudek, T., and Demek, J., 1970, Thermokarst in Siberia and its influence on the
development of lowland relief: Quaternary Research, v. 1, no. 1), p. 103–120.
This paper presents an overview on the development of thermokarst landforms and their role
in lowering the elevation of the regional land surface in the Siberian lowlands. Two modes
of thermokarst development are distinguished: (1) back-wearing and (2) down-wearing.
Back-wearing refers to the lateral development of thermokarst features and results in the
formation of gullies, thermocirques, and slump head walls. Down-wearing refers to
formation of thermokarst through an increase in the active-layer thickness or the top-down
thaw of permafrost that leads to development of “alas” terrain. Back-wearing features tend
to be more local in nature and down-wearing features tend to be more regional in nature.
The extent of the geomorphic changes for all thermokarst features depends on the tectonic
regime of the region (stable, rising, or lowering), the ice content of the soil and the presence
of epigenetic or syngenetic permafrost, and the rate of disequilbrium disturbance or the
disturbance to the ground thermal regime. The paper has several diagrams showing the
formation of various thermokarst features. This paper is mostly descriptive in nature and
does not contain information on the rates of thermokarst formation nor the regional
distribution.
27. Daanen, R.P., Grosse, G., Darrow, M.M., Hamilton, T.D., and Jones, B.M., 2012,
Rapid movement of frozen debris-lobes—Implications for permafrost degradation and
slope instability in the south-central Brooks Range, Alaska. Natural Hazards and
Earth System Sciences, v. 12, p. 1521–1537.
This paper describes reconnaissance-level investigations of unusual debris mass movement
features (referred to as “frozen debris-lobes”) in the south-central Brooks Range of Alaska.
A combination of ground-surveys, remote sensing, and field and laboratory measurements,
and time-lapse observations were used to document the movement indicators that include
toppling trees, slumps and scarps, detachment slides, striation marks on frozen sediment
slabs, buried trees and other vegetation, mudflows, and large cracks in the lobe surface.
Some of the frozen debris lobe features are greater than 100 m in width, 20 m in height, and
1,000 m in length. The features have responded to climate change by increasing in their
downslope movement during the last several decades. Mean annual rates of movement were
from 2 to 4 m/yr over decadal time periods. The features showed signs of creep, slumping,
viscous flow, blockfall and leaching of fines in warm seasons; and creep and sliding of
frozen sediment slabs in cold seasons. The potential hazard of one frozen debris lobe feature
as it encroached on the Dalton Highway was highlighted.
28. Dallimore, S.R., Wolfe, S.A., and Solomon, S.M., 1996, Influence of ground ice and
permafrost on coastal evolution, Richards Island, Beaufort Sea coast, NWT: Canadian
Journal of Earth Sciences, v. 33, no. 5, p. 664–675.
This paper provides information on the role of ground ice on coastal change for Richards
Island, Canada. Excess ice content for the coastal segment was estimated at 20 percent and,
when this was considered, the balance between headland erosion and coastal deposition was
in near equilibrium. The coastal part eroded by thermo-mechanical niche erosion and block
collapse as well as permafrost slumping. Parts of the coast with higher ice content tended to
erode faster than less ice-rich coastal area. Mean annual coastal erosion rates ranged from 1
to 2 m/yr between 1947 and 1985.
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