EROSIONAL PROCESSES IN SMALL TUNDRA CATCHMENTS IN THE NORTH OF YAKUTIA
A.M. Tarbeeva1, V.S. Efremov2, L.S. Lebedeva2, V.V. Shamov2,3
1Lomonosov Moscow State University, Faculty of Geography, Moscow, Russia
2Melnikov Permafrost Institute, Siberian Branch of the Russian Academy of Sciences, Yakutsk, Russia
3Pacific Geographical Institute, Far East Branch of the Russian Academy of Science, Vladivostok, Russia
Keywords: water tracks, rills, gullies, small rivers, thermal erosion, Arctic, permafrost, climate change
Abstract
Erosion plays an important role in removing permafrost degradation products. In order to identify the rates and mechanisms of erosion in degrading permafrost, fluvial landforms in small catchments at the foothills of the Kharaulakh Range were typified, and their morphology, formation conditions, and dynamics for 2019-2022 were characterized. The most dynamic landforms associated with melting ice wedges were thermokarst runoff troughs (water tracks), rills, and thermoerosional gullies. Thermoerosional gullies forming in sediments without wedged ice grow upon very high floods; in the rest of the time, their sides slowly slide down under the action of snowfields. Sediments from gullies and rills are deposited in the upper reaches of small rivers. The channels of small rivers are relatively stable, which is also typical of other permafrost regions. Differences in the dynamics of erosional landforms can be explained by an increase in the thermal rather than mechanical impact of water on frozen deposits, which is observed with the rise in air temperature against the background of relatively stable precipitation in the north of Yakutia.
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