Home – Home – Jornals – Russian Geology and Geophysics 2018 number Неопубликованное

Several thermocirques have been detected in the Oymyakon Upland, in the basin of the upper reaches of the Indigirka River, based on space imagery. Two of these thermocirques were studied in the Suntar River valley. The thermocirqures formed in 2014-2016 after an increase in precipitation, and they continued to grow at a rate of 5-35 m/year until 2023-2024. Currently, they are 130-220 m long. The thermocirques were formed on the slope of a terminal moraine hill at an absolute height of approximately 900 m. The moraine deposits exposed in the back wall of the larger thermocirques consist of clastic material ranging from gravel to large boulders and blocks with a sandy-loamy fill. Two cryofacies were identified in the upper 5 m of the section based on their cryogenic structure: the lower cryofacies is an initially frozen moraine with a primary cryogenic structure, while the upper cryofacies is a taberated deposit of the lower cryofacies that has been re-frozen. Epigenetic ice wedges up to 2.5-3 m wide penetrate from the contact between the cryofacies, forming polygons with a size of approximately 30 m. It is assumed that the terminal moraine was formed during the first cryochron of the Late Pleistocene and is stratigraphically associated with the Yugler horizon, while partial thawing occurred in the first half of the Holocene.