Causes and Processes of Thermo‐Erosional Gully Initiation Near Tiksi Settlement, Arctic Eastern Siberia

• Published in: Permafrost and Periglacial Processes
• Main Authors: Tarbeeva, Anna, Tikhonravova, Yana, Lebedeva, Lyudmila, Kut, Anna, Shamov, Vladimir
• Other Authors: Lomonosov Moscow State University, Russian Foundation for Basic Research
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 2024
• Subjects: Ice; permafrost; Permafrost and Periglacial Processes; Tiksi; wedge*; Siberia
• Online Access: http://dx.doi.org/10.1002/ppp.2229; https://onlinelibrary.wiley.com/doi/pdf/10.1002/ppp.2229

ABSTRACT Climatic and environmental change is leading to increased frequency and intensity of permafrost degradation processes; however, our knowledge of their mechanisms and rate is still limited. We examined structure of deposits, surface topography, and weather conditions during the initiation of a thermo‐erosion gully in eastern Siberia and monitored its changes between 2020 and 2022. The initiation of the gully was caused by a combination of processes: (1) the catchment area of the gully was artificially increased several decades ago as a result of the interception of runoff by the winter road; (2) ice‐wedge degradation led to surface runoff concentration above the gully head, while a large volume of ground ice remained in other parts of the slope, and frost cracking continued; (3) the entry of water into frost cracks formed underground tunnels; and (4) high air temperatures and heavy rainfall immediately before the gully appearance resulted in the expansion of the tunnels and collapse of their roof. In 2 years, the volume of the gully reached 1000 m 3 at least 40% of that volume consists of ground ice. The gully development did not significantly change the water chemistry due to significant water freshening caused by melting of ground ice.