Yedoma / ˈ j ɛ d ə m ə / ( Russian : е́дома ) is an organic-rich (about 2% carbon by mass) Pleistocene -age permafrost with ice content of 50–90% by volume. Yedoma are abundant in the cold regions of eastern Siberia , such as northern Yakutia , as well as in Alaska and the Yukon .
6-434: The landscape of yedoma areas is of glacier plains and hills with shallow depressions known as alas . 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
12-555: Is a stub . You can help Misplaced Pages by expanding it . Alas (geography) Alas ( Yakut : Алаас ) is a shallow depression which occurs primarily in Yakutia , which is formed by subsidence of the Arctic permafrost owing to repeated melting and refreezing. An alas first develops as a shallow lake as melt water fills the depression. The lake eventually dries out and is replaced by grasses and other herbaceous vegetation. An alas
18-656: Is different from thermokarst depressions found elsewhere in the Arctic in that the lake is only temporary. Due to the aridity of Yakutia, the lake will dry up once the underlying ice has been depleted. Alases are often used for pasturage for horses as well as hay-fields. They are common in the Central Yakutian Lowland . The largest alas in the world is Myuryu , located in Ust-Aldan District . The alas also hold great cultural importance. During
24-632: 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 the last ice age , at the Pleistocene – Holocene transition, thawing yedoma and the resulting thermokarst lakes may have produced 33 to 87% of the high-latitude increase in atmospheric methane concentration. This Siberian Federal District location article
30-482: The festival of Ysyakh , the traditional Yakut New Year’s day celebrated in the summer, as many as 20,000 gather to an alas in the general vicinity of Yakutsk . Other minor celebrations occur at other alas across the Republic of Sakha . Once set up there, temporary Uraha ( Yakut : Ураһа), which are homes made of birch bark are constructed among other wooden idols and structures. This Sakha Republic location article
36-590: The proximity of sediment sources, such as low mountain ranges and foothills. The amount of carbon trapped in this type of permafrost is much more prevalent than originally thought and may be about 210 to 500 Gt , that is a multiple of the amount of carbon released into the air each year by the burning of fossil fuels . 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
#573426