Permafrost

properties, and is able to move both with water flow and by itself. in this system water as a
polar liquid appears to be a wetting phase. Being combined with mineral particles, water
possesses lower mobility than oil. The oil-contamination distribution in cryolithozone soils has
its peculiarities. They are concerned with the climatic conditions and cryogenic factors, i.e.
permafrost and seasonal freezing of the upper soil horizons. In cryolithozone soils, oil
contaminations are under conditions of low-positive and negative temperature diapason – that
means close to or lower than hardening temperature of the majority of oils. at present properties
of oil in these conditions are scantily investigated.
This study takes up the aspects of oil behavior in a low-positive and negative temperature
diapason and physicochemical interactions of the components of freezing and frozen soils.
An investigation of oil viscosity in low-positive and negative temperature diapason (from
+20 to -15°c) has been carried out. oils with different compositions and properties (hardening
temperature from +5 to –27°c) were used. Tests were made on apparatus of rotary model with
measuring instrument of “cylinder-cylinder” type. The lowering of temperature was gradual.
During the test the values of transverse strain (τ, pa) and dynamical viscosity of oil (η, mpa*s)
were obtained. The dependence of structural strength of oil on its hardening temperature was
observed.
The study of migration and cryogenic transformation of oil pollution in permafrost and
seasonal freezing and thawing soils has been carried out.
Permafrost is permeable to oil pollution. Sufficiently high accumulations of oil
hydrocarbons, and their long-term intact there are possible in permafrost soils. Oil redistribution
in freezing soils (mainly cryogenic expulsion), and migration of oil components into frozen
soils are accompanied by cryogenic transformation of oil – that means isolation from its bulk
the most active fractions and components. This process is determined by temperature conditions,
oil consistence, composition of oil components, composition and structure of soils. Naphthenes
- saturated hydrocarbons which do not reveal associative properties with temperature lowering -
are most likely to have the greatest mobility within this system.
Key words: Permafrost, frozen soils, oil contamination, migration, cryogenic transformation
The kind and distribution periglacial features and alpine permafrost in
eastern tibet and mongolia
F. Lehmkuhl, G. Stauch
(Department of Geography, RWTH Aachen University, Germany)
Abstract: Comprehensive studies concerning the distribution of periglacial features and alpine
permafrost for Central and High Asia are still rare. In the humid Eastern Tibet two sub belts of
periglacial phenomena can distinguished: the lower limit of bound solifluction (occurs roughly
above the timberline) and the zone of unbound solifluction, dominated by blockfields, patterned
ground, and bare bedrock. The upper limit of the periglacial belt results from steep high
mountain topography or from the extent of perennial snow and ice in the higher altitudes
(glacial belt). Alpine permafrost is present in all these mountains, but is very small in the humid
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