Yedoma

Yedoma /ˈjɛdəmə/ (Russian: е́дома) 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.

[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.

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.