Permafrost formation

Gorbunov, A. P, Seversky, E. V. (2001). Influence of coarsely fragmental deposits on permafrost formation. Extended Abstracts, International Symposium on Mountain and Arid Land Permafrost (pp. 24-25). Ulanbatator Uriah Erdam Publishing. 

Early on, water existed at least periodically on the Martian surface. The formation of clay minerals in the Noachian and precipitation of sulfates and chlorides in the Hesperian were consequences of this water. Some fraction of the water evaporated and was lost to space, as indicated by the high D/H ratios in SNCs. Other water was apparently sequestered at the poles or underground as permafrost. The surface of Mars is effectively dry now, and chemical weathering of crustal rocks is minimal. 

Chapter 7 then considers the formation of hydrates in nature, such as in the permafrost and deep oceans of the earth. In such situations geologic time mitigates the necessity for kinetic formation effects and allows the use of thermodynamic conditions, such as those in the three-phase portions of the present chapter, for identification, exploration, and recovery. 

Because free gas (or gas-saturated water) is less dense than either water or sediments, it will percolate upward into the region of hydrate stability. Kvenvolden suggested that a minimum residual methane concentration of 10 mL/L of wet sediment was necessary for hydrate formation. The upward gas motion may be sealed by a relatively impermeable layer of sediment, such as an upper dolomite layer (Finley and Krason, 1986a) or the upper siltstone sequence, as in the North Slope of Alaska (Collett et al., 1988). Alternatively, permafrost or hydrate itself may act as an upper gas seal. These seals can also provide traps for free gas that has exsolved from solution, and the seals can subsequently act to provide sites for hydrate formation from the free gas. 

The western Siberian region of Russia is characterized by numerous intensive natural and anthropogenic sources of methane formation. These are marshes, tundra, permafrost, oil and gas deposits. In this region, flux FlCH4 varies widely both during the year and shorter time periods. From measurements carried out by Jagovkina et al. (2000) on the Yamal coastline in June 1996, the CH4 concentration in the atmosphere... 

As Table 15.3 indicates, the heat offormation of Ceramicrete-based permafrost cement is typically 50-60% of the heat of formation of conventional cement. Even though the acid-base reaction is highly exothermic, i.e., it releases a significant amount of heat during setting. In CBS compositions, the binder that produces heat is only a part of the entire CBS formulation, and the remaining components are extenders. Thus, the net amount of heat generated is about half that in the equivalent amount of conventional cement. 

Giant West Sak and Ugnu sands is trapped under the permafrost as gas hydrates. The amount of natural gas trapped as gas hydrate in northern Alaska Is estimated at 500 TCF (Lewin and Associates, 1983). The westward migration, on the other hand resulted In entrapment of hydrocarbons in older rocks such as Lisburne Formation (Mississippian age). 

In arid regions, impermeable geomembranes can be used as capillary breaks to stop the upward movement of salts where they would destroy the road surface. Geomembranes also can be used to prevent the formation of ice lenses in permafrost and other frost-prone regions. The geomembrane must be located below the frost line and above the water table. 

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