Home – Home – Jornals – Geography and Natural Resources 2022 number 4

New results from studying the possible mechanisms of formation and degradation of the Chuya-Kurai ultra-high-pressure ice-dammed lake are presented. The conclusions are based on the analysis of the climatic hydrothermal regime which governs the development of the processes of self-freezing of the ice-dam and its subsequent degradation. According to updated data, at the maximum filling to the absolute level of 2133 m, the depth of the paleolake was 657 m, the volume of water was 753 km³, the water area was 3054 km², and the maximum hydrostatic pressure was 65 kg/cm² (6.37 MPa/cm²). The drainage of the lake basin was accompanied by the formation of 200 abrasive-accumulative terraces on the slopes of the basins in the height range of 1530-2133 m. A quantitative assessment of the formation time of one abrasive terrace in periglacial conditions is made as well as estimating the duration of the action of wind-wave processes for the development of abrasion: it did not exceed 90 days of a warm season. The water layers drained during the year through the thermal erosion channels of the ice dam were determined by the difference in the heights of the abrasive terraces. The duration of the existence of an ice-dammed lake has been clarified. The study used current quantitative data on measuring the average annual flow rate of the Chuya River at the nearest Chagan-Uzun hydrological post. Calculations have shown that the filling of the lake basin to the maximum volume of water of 753 km³ (taking into account the water accumulating in the ice dam, 68 km³ (total V = 821 km³)) was carried out for 5324 years. The duration of water discharge, determined by the number of abrasion terraces, was no more than 200 years. The frequency of retrogression of the lake level, equal to 20 years, has been revealed. Apparently, it was caused by climatic fluctuations: changes in cooling and warming.