Karst Landforms Of The Sinyaya River Valley, Prilenskoe Plateau

Unique karst evolution in Siberia is attributed to climatic factors and the presence of permafrost. Climatic fluctuations in Northern Eurasia had occurred during the Quaternary period and significantly influenced the processes of permafrost aggradation and degradation, as well as the karst activity. Despite their wide popularity and impressive manifestations, the karst landforms on the Prilenskoe Plateau still remain tenuously studied in terms of landform classification and obtaining their morphometric characteristics. The article presents the results of field studies of karst terrain in the Sinyaya River valley in Central Yakutia. Based on field observations and the analysis of the generated digital surface models, we have determined the median relative heights of different types of karst ridges in the Sinyaya River valley: “incipient ridges” - 34 m, “young ridges” - 42 m, “mature ridges” - 79 m and “old ridges” - 58 m. Most ridges that exceed 100 m are “mature and old”. The highest ridges are located on the concave parts of river meanders and belong to the type of “mature ridges”. In addition, our observations in the Sinyaya River valley have shown “old ridges” are the most common, accounting for over 58% of the overall ridge length. “Mature ridges” make up approximately 25%, “young ridges” 13%, and “incipient” ridges only 4% of the total. This distribution reflects the long history of topographic development in the valley and the significant influence of erosion processes on these features. The most prominent forms of this landscape include karst ridges, which present as rock pillars formed through physical and chemical weathering, with very active frost shattering, gravitational, and erosion processes. Using field surveys conducted with unmanned aerial vehicles (UAVs) and subsequent processing in a geographic information system (GIS), it was determined that the highest ridges are located in the lower reaches of the Sinyaya River, where it cuts through the axial, most elevated part of the Prilenskoe Plateau. The morphometric characteristics of the identified types of karst ridges and their spatial change along the river meanders are associated mainly with the activity of lateral river erosion, which ensures the removal of weathering material and slope deposits.