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Yedoma

Yedoma (Russian: Едома) is an organic-rich (about 2% carbon by mass) Pleistocene-age permafrost with ice content of 50–90% by volume.[1] Yedoma are abundant in the cold regions of eastern Siberia, such as northern Yakutia, as well as in Alaska and the Yukon.[2]

Characteristics

Alas landscape in Megino-Kangalassky District, Yakutia

The landscape of Yedoma areas is of glacier plains and hills with shallow depressions known as alas.[3] Yedoma usually form in lowlands or stretches of land with rolling hills where ice wedge polygonal networks are present, in stable relief features with accumulation zones of poor drainage, severe cold and arid continental climate zones resulting in scanty vegetation cover, intense periglacial weathering processes, as well as the proximity of sediment sources, such as low mountain ranges and foothills.[2]

The amount of carbon trapped in this type of permafrost is much more prevalent than originally thought and may be about 210 to 450 Gt, that is a multiple of the amount of carbon released into the air each year by the burning of fossil fuels.[4] Thawing yedoma is a significant source of atmospheric methane (about 4 Tg of CH
4
per year).

The Yedoma region currently occupies an area of more than one million square kilometers from northeast Siberia to Alaska and Canada, and in many regions is tens of meters thick. During the Last Glacial Maximum, when the global sea level was 120 m lower than that of today, similar deposits covered substantial areas of the exposed northeast Eurasian continental shelves. At the end of last ice age, at the PleistoceneHolocene transition, thawing yedoma and the resulting thermokarst lakes may have produced 33 to 87% of the high-latitude increase in atmospheric methane concentration.[5]

See also

References

  1. ^ Walter KM, Zimov SA, Chanton JP, Verbyla D, Chapin FS (September 2006). "Methane bubbling from Siberian thaw lakes as a positive feedback to climate warming". Nature. 443 (7107): 71–5. Bibcode:2006Natur.443...71W. doi:10.1038/nature05040. PMID 16957728.
  2. ^ a b Science Direct - Deep Yedoma permafrost: A synthesis of depositional characteristics and carbon vulnerability
  3. ^ S. V. Tomirdiaro, Evolution of lowland landspapes in Northeastern Asia during late Quaternary time.
  4. ^ Seth Borenstein (7 September 2006). "Scientists Find New Global Warming "Time Bomb"". Associated Press.
  5. ^ Walter KM, Edwards ME, Grosse G, Zimov SA, Chapin FS (October 2007). "Thermokarst lakes as a source of atmospheric CH
    4
    during the last deglaciation". Science. 318 (5850): 633–6. doi:10.1126/science.1142924. PMID 17962561.

Further reading

  • Frederick West (1996), American Beginnings The University of Chicago Press, ISBN 0-226-89399-5, p52
  • Velichko 1984, p141, Chapter 15, Tomirdiaro: Periglacial Landscapes and loessa Accumulation in the late pleistocene arctic and subarctic
  • K. M. Walter, S. A. Zimov, J. P. Chanton, D. Verbyla & F. S. Chapin III, "Methane bubbling from Siberian thaw lakes as a positive feedback to climate warming", Nature, 443, 71-75, 2006
  • Lutz Schirrmeister, IPY, From the beginning of the Pliocene cooling to the modern warming – Past Permafrost Records in Arctic Siberia PAST PERMAFROST, Original IPY project no: ID 15,2011, APEX - Arctic Palaeoclimate and its EXtremes
  • Rutter&Velichko (1997) "Quaternary of northern eurasia: Late pleistocene and holocene landscapes, stratigraphy and environments, Nat W. Rutter, editor-in-chief, Guest editors A. A. Velichko et al., Vols 41/42 July/August 1997, ISSN 1040-6182
  • Late Quaternary environments of Soviet Union, A.A. Velichko, engl edition Wright&Narnosky, pp176-177, University of Minnesota Publ, Longman, London 1984, ISBN 0-582-30125-4
  • Climate change and Arctic ecosystems: 2. Modeling, paleodata-model comparisons, and future projections, J. O. Kaplan, N. H. Bigelow et al., JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 108, NO. D19, 8171, doi:10.1029/2002JD002559, 2003
  • K. M. Walter, M. E. Edwards, G. Grosse, S. A. Zimov, F. S. Chapin III "Thermokarst Lakes as a Source of Atmospheric CH4 During the Last Deglaciation" Science, 318, 633-636, 2007

External links