These sediments are cemented by permafrost and have accumulated periodically over the last 200, 000 years.

Soils are mostly fertile Mollisols and Fluvents, except in the more mountainous parts where they are poorly developed Orthents, as well as the extreme north where permafrost occurs and Orthels dominate.

" Fossil " cold anomalies in the Geothermal gradient in areas where deep permafrost developed during the Pleistocene persist down to several hundred metres.

The construction of the pipeline was one of the first large-scale projects to deal with problems caused by permafrost, and special construction techniques had to be developed to cope with the frozen ground.

Thick permafrost characterized by massive ice wedges has developed in these sediments.

Eemian lake sediments fill depressions, i. e. ice wedge casts and thermokarst lakes, which developed by the surficial thawing during Eemian interglacial climates of Saalian ice-wedges and other permafrost.

Thick permafrost characterized by massive ice wedges has developed in these sediments.

* Palsa, a low oval elevation in areas with permafrost, frequently peat bogs, where a perennial ice lens has developed within the soil.

The southern sea cliffs of Bolshoy Lyakhovsky Island, which were first studied by Baron von Toll, expose a complex sequence of fossiliferous Late and Middle Pleistocene floodplain, eolian, lake, and solifluction sediments cemented by permafrost.

These depressions formed as the result of the thawing of ice wedges and other permafrost during the Late Pleistocene-Holocene transition about 12, 000 to 10, 000 years ago.

Both Polar and Nether-Polar Urals are typically Alpine ; they bear traces of Pleistocene glaciation, along with permafrost and extensive modern glaciation, that includes 143 extant glaciers.

The island is subject to very high rates of coastal erosion due to the ice-rich nature of the underlying permafrost, and its surface heaves and rolls down its own hillsides from the effects of frost creep and solifluction.

Where thermokarst depressions have formed by melting of the permafrost, they are filled by Holocene solifluction and lake sediments.

The Kryal is the portion of a stream ( usually the upper portion ) fed by meltwaters from a glacier, permafrost or permanent ice-fields.

Naturally on Earth gas hydrates can be found on the seafloor, in ocean sediments, in deep lake sediments ( e. g. Lake Baikal ), as well as in the permafrost regions.

The presence of ice belts, reticulated ice interlayers, and wide, round-shouldered ice wedges indicate that permafrost formed in these sediments as they accumulated.

Because of the formation of permafrost in these sediments and their depositional environments, prehistoric bone, shell, and plant material are well preserved and abundant.

After a failed attempt to melt the permafrost, the crew used lumber from their ship to build a 7. 8x5. 5 metre lodge they called Het Behouden Huys ( The Saved House ).

" The abundant bones, even skeletons, of mammoth, rhinoceros, musk-ox, and other megafauna along with the mammoth ivory found in these islands are preserved by permafrost, in which they are encased.

The scrape must be deep enough that eggs are protected from the convective cooling caused by cold winds, but shallow enough that they and the parent bird are not too exposed to the cooling influences of ground temperatures, particularly where the permafrost layer rises to mere centimetres below the nest.

Despite the influence of glaciation in most areas where Gelisols occur, chemically they are not highly fertile because nutrients, especially calcium and potassium, are very easily leached above the permafrost.

The permafrost greatly restricts the engineering use of Gelisols, as large structures ( e. g. buildings ) subside as the frozen earth thaws when they are put in place.

* Histels: organic soils similar to Histosols except that they have permafrost within 2 meters below ground surface.

In all climates, whether they contain permafrost or not, the temperature in the lower levels of the soil will remain more stable than that at the surface, where the influence of the ambient temperature is greatest.

Of the Arctic lakes they include glacial lakes and permafrost lakes.

Organic matter is accumulated on top of the permafrost and ice wedges are a common features.

The interior of Alaska is largely underlined by discontinuous permafrost, which grades to continuous permafrost as the Arctic Circle is approached.

A subarctic climate has little precipitation, and monthly temperatures which are above for one to three months of the year, with permafrost in large parts of the area due to the cold winters.

For example, Mars may have regions in its deep subsurface permafrost that could harbor endolith communities.

Thermal erosion is the result of melting and weakening permafrost due to moving water.

Thermal erosion also affects the Arctic coast, where wave action and near-shore temperatures combine to undercut permafrost bluffs along the shoreline and cause them to fail.

Other reasons include: a ) changes in plant canopy caused by shifts in plant biomass production associated with moisture regime ; b ) changes in litter cover on the ground caused by changes in both plant residue decomposition rates driven by temperature and moisture dependent soil microbial activity as well as plant biomass production rates ; c ) changes in soil moisture due to shifting precipitation regimes and evapo-transpiration rates, which changes infiltration and runoff ratios ; d ) soil erodibility changes due to decrease in soil organic matter concentrations in soils that lead to a soil structure that is more susceptible to erosion and increased runoff due to increased soil surface sealing and crusting ; e ) a shift of winter precipitation from non-erosive snow to erosive rainfall due to increasing winter temperatures ; f ) melting of permafrost, which induces an erodible soil state from a previously non-erodible one ; and g ) shifts in land use made necessary to accommodate new climatic regimes.

Continuous ice sheet covers 84 % of the country ; the rest is permafrost.

Ground movement beneath a structure's foundations can occur due to shrinkage or swell of expansive soils due to climatic changes, frost expansion of soil, melting of permafrost, slope instability, or other causes.

The permafrost does not allow the taproot to get deeper than so this does not allow vertical growth.

The deep snow cover prevents any permafrost from developing despite a mean annual temperature slightly below freezing.

Most of Mongolia is covered by discontinuous permafrost ( grading to continuous at high altitudes ), which makes construction, road building, and mining difficult.

The virus was recently reconstructed by scientists at the CDC studying remains preserved by the Alaskan permafrost.

Stored for 50 years under the permafrost of the Yukon, the films turned out to be extremely well preserved.

Svalbard has permafrost and tundra, with both low, middle and high Arctic vegetation.

* Under the ice layer, in chemolithotrophic ( mineral-metabolizing ) ecosystems theoretically resembling those in existence in modern glacier beds, high-alpine and Arctic talus permafrost, and basal glacial ice.

In the south of the plain, where permafrost is largely absent, rich grasslands that are an extension of the Kazakh Steppe formed the original vegetation-most of it is not visible anymore.

Only the extreme northwest was glaciated during the Quaternary, but almost all is under exceptionally deep permafrost and the only tree that can thrive, despite the warm summers, is the deciduous Siberian Larch ( Larix sibirica ) with its very shallow roots.

Discontinuous permafrost is found in areas with mean annual temperature below 0 ° C, whilst in the Dfd and Dwd climate zones continuous permafrost occurs and restricts growth to very shallow-rooted trees like Siberian larch.

The Arctic region consists of a vast, ice-covered ocean, surrounded by treeless permafrost.

( A reported regeneration of Silene stenophylla ( narrow-leafed campion ) from material preserved for 31, 800 years in the Siberian permafrost was achieved using fruit tissue, not seed.

Arctic mosquitoes may be active for only a few weeks as pools of water form on top of the permafrost.