Abstract
Gas accumulation and pressurized unfrozen rocks under lakes (sublake taliks) subject to freezing in shallow permafrost may lead to explosive gas emissions and the formation of craters. Gas inputs into taliks may have several sources: microbially-mediated recycling of organic matter, dissociation of intrapermafrost gas hydrates, and migration of subpermafrost and deep gases through permeable zones in a deformed crust. The cryogenic concentration of gas increases the pore pressure in the freezing gas-saturated talik. The gradual pressure buildup within the confined talik causes creep (ductile) deformation of the overlying permafrost and produces a mound on the surface. As the pore pressure in the freezing talik surpasses the permafrost strength, the gas-water-soil mixture of the talik erupts explosively and a crater forms where the mound was. The critical pressure in the confined gas-saturated talik (2–2.5 MPa for methane) corresponds to the onset of gas hydrate formation. The conditions of gas accumulation and excess pressure in freezing closed taliks in shallow permafrost, which may be responsible for explosive gas emissions and the formation of craters, are described by several models.
Highlights
The Arctic permafrost stores large amounts of hydrocarbon gases, especially methane [1,2,3], which can be released into the air
The gas components of permafrost are currently classified terms of and their depositional origin: (i) biogenic gas, which is generated bycoalbed and migrates into permafrost throughintectonic discontinuities; and (iii) thethat microbially-mediated recycling offrom buried organic matter and accumulates due tolocalized cryogenicbeneath methane rises along discontinuities coal-bearing sediments and becomes concentration in cold periods; (ii) deep gas, which is released during the maturation of sediments and impermeable permafrost [29,31]
Freezing sublake taliks allow for gas storage in shallow permafrost and the related pressure buildup leads to explosive gas emissions and the formation of craters
Summary
The Arctic permafrost stores large amounts of hydrocarbon gases, especially methane [1,2,3], which can be released into the air. Gas can migrate through permeable zones in accumulate and remain scientific and practical interests In this respect, thepermafrost, recently discovered deep craters as markers of sealed emissions attractinmuch attention, such free as theorhuge crater that 40 m in diameterbecome produceddissolved by a in somegas confined zones different forms: adsorbed onissome surfaces, in sudden explosive emission of gas in continuous permafrost of the. The gas components of permafrost are currently classified terms of and their depositional origin: (i) biogenic gas, which is generated bycoalbed and migrates into permafrost throughintectonic discontinuities; and (iii) thethat microbially-mediated recycling offrom buried organic matter and accumulates due tolocalized cryogenicbeneath methane rises along discontinuities coal-bearing sediments and becomes concentration in cold periods; (ii) deep gas, which is released during the maturation of sediments and impermeable permafrost [29,31]. Such as drained lakes, poorly flowing river channels, thermokarst depressions transformed into lakes, etc
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