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Geography and Natural Resources

2025 year, number 2

Monitoring of the descending branch of the lithodynamic circulation of matter in the Baikal basin

O.I. BAZHENOVA1, E.M. TYUMENTSEVA2
1V.B. Sochava Institute of Geography, Siberian Branch, Russian Academy of Sciences, Irkutsk, Russia
2Irkutsk State University, Irkutsk, Russia
Keywords: modern rift zone, intra-secular cyclicity, mudflows, sediment runoff, coastal erosion, landslides, aeolian migration of matter

Abstract

The article considers the regular patterns of exogenous processes manifestation in the Baikal basin, established on the basis of monitoring data of their long-term dynamics. The analysis is based on an extensive database obtained on the western, southern and eastern shores of Lake Baikal. The research methods included experimental observations (runoff sites, benchmark method, dust collectors, etc.) on representative sites, interpretation of space images, and aerial photography from remotely piloted aircrafts. The main attention is paid to such characteristics as the rate of processes, direction and volume of transported matter as a result of mudflows, landslides, coastal abrasion, and the activity of water and wind flows. The article shows temporal organization of exogenous processes, expressed in a pronounced rhythmicity of their course, controlled by changes in secular and intra-secular cycles of water content in Lake Baikal. It is established that low-water periods are characterized by high intensity of aeolian migration of matter. Detailed observations during the last low-water period recorded its average value of 500 g/m2. During high-water periods, erosion processes are active, mudflows and landslides are recorded, and shore erosion occurs. Intensive mudflows were recorded in 1930-1938, 1960-1962, and 1968-1972, with a maximum in 1971, when the total volume of drift from the slopes along the river valleys between the towns of Baikalsk and Slyudyanka amounted to more than 1 million m3 of loose rock. The results obtained make it possible to predict the further course of processes and minimize the negative consequences of their manifestation.