The geographical setting of the study area

Altai Mountains (Figure 2), Russian Altay, Mongolian Altayn Nuruu, Chinese Altai Shan, complex mountain system of Central Asia extending approximately 2,000 km in a southeast-northwest direction from the Gobi Desert to the West Siberian Plain, through China, Mongolia, Russia, and Kazakhstan. The jagged mountain ridges derive their name from the Turkic-Mongolian altan, meaning “golden.”

Figure 2. Location and Physiography of the Altai region.

The Russian Altai represent the highest part of the Altai-Sayan mountain system. They are located between 48–52° N and 84–90° E, and cover an area about of 200 000 km2. The region has borders with Mongolia and China in the south and Kazakhstan in the west

The climate of the Russian Altai is determined by three major factors: (1) its location in temperate latitudes of the Northern hemisphere; (2) a dominant direction of water-carrying air mass transport from the Atlantic to the east; (3) the effect of the powerful Asian anticyclone with frosty weather and a cloudless sky in winter-time (an absolute minimum air temperature of −62°C was recorded at the Kosh-Agach meteorological station in 1969). The rate of precipitation decreases from west to east and the glaciers’ equilibrium-line altitude increases from 2200 up to 3200 m above sea level in the same west to east direction. Accordingly, the accumulation rate at the glaciers equilibrium-line altitude decreases from 3500 to 500–1000 mm in water equivalent.

In the central part of the area, mountain ridges and massifs reach elevations of 3000–4000 m. Numerous forms of recent glaciation are obvious here. The highest peak is Mount Belukha (4506 m above sea level, the highest point in Siberia), where the largest glaciers in the area, with a size of 12 to 21 km2, are located. In the Central Altai (where the Katunsky, North-Chuysky and South-Chuysky Ranges are situated), the Alpine type of glaciation is characteristic, with a prevalence of valley and cirque-valley glaciers with extensive, steep accumulation zones and less steep glacier tongues located at the bases of ancient cirques and trough valleys. The glaciers are non-uniformly distributed over the territory being grouped around the highest mountain peaks and massifs (World Atlas, 1997). According to the Catalogue of glaciers, about 1030 glaciers with a total area of 805 km2 and volume of 42.5 km3 have been recorded in the Altai region (Catalogue of glaciers of the USSR, 1978; Narozhniy and Nikitin, 2003).

The Mongolian Altai is a mountain system consisting of several parallel ridges, stretching for 1000 km from North to South-East and separated by longitudinal tectonic valleys. The main ridges of The Mongolian Altai are 3200-3500 m high, the peaks are mainly plateau-shaped, and the highest mountains are characterized by Alpine relief. Rocks consist of granite, porphyry, porphyrite and shale. The Mongolian Altai is continued by the lower ridges of the Gobian Altai, which do not form a single massif. The North-Eastern part of the system is bordered by the Great Lakes Depression. The Mongolian Altai is adjacent from the North to The Russian Altai. The Tavan Bogd massif is the main orographic knot of the Mongolian Altai, the highest point – Nairamdal mount — 4356 m.

Atmospheric circulation of the region of research has a characteristic feature, the predominance throughout the year of westerlies air mass transfer and the development of cyclonic activity on the arctic and polar fronts. Annual precipitation is typical for areas with continental climate. Winter precipitation falls in the first half of winter (November to December), more than half of the total, this period is characterized by unstable cyclonic weather. Winter passes against a background of high pressure, during the main period (from January to March). Precipitation amount during this period is small. Cyclonic activity is enhanced in the spring, as a result, the amount of precipitation increases slightly and reaches a maximum by July.

Features of the relief have the main influence on the thermal regime of the region, these are the values of the absolute height and characteristics of the snow cover. Minimum air temperatures are observed in January, the maximum in July. Air temperatures accurate calculation is possible for the slopes of the ranges Sutay and Tsambagarav according to the data from nearest weather stations, taking into account the established gradient (0,58-0,59 0C per 100 meters of climb), in the summer.

Tsambagarav mountain node is located in the central part of The Mongolian Altai (Figure 2), bordering to Great Lakes Depression. Mountain knot is separated from the main ridges straight tectonogenic the gully/hollow.  The ridge stretches in the North-Western direction for 30-35 km, and in the meridional 25 km, and has a trapezoidal shape in the scheme. The ridge refers to the system Hungin-Nuruu, according to their morphostructural elements and is a strongly dissected highland. Mountain knot Tsambagarav consists of 3 massifs: Tsast-Uul, Huh-Nuruu-Uul, Yamat-Uul. The absolute height within the mountain knot Tsambagarav change from 2840 m to 4193 m.

Figure 3. The glaciers of the Northern slope of Tsast-Uul mountain knot.

The 40 glaciers are concentrated in the nival-glacial belt of the Tsambagarav mountain knot. Regional climatic conditions and features of the ridge structure determined the spatial distribution (up to 40% of the rock glaciers are confined to the slopes of the Northern and North-Eastern expositions) and the morphology of glacial formations (valley, corrie-valley, corrie, hanging and flat-tops glaciers).

The Sutay ridge is located in the southern part of the Mongolian Altai and belongs to the area of epiplatformic orogenesis. This area composed of strongly dislocated sedimentary-volcanic rocks of the lower and middle Paleozoic and is distinguished by a complex tectonic structure. The ridge has a typical Alpine appearance with characteristic attributes — a dense network of corries, narrow ridges — arets and deeply embedded troughs. The Sutay ridge was subjected to repeated glaciation in Quaternary time, as evidenced by a number of classical forms (glacial-exarational, glacial-accumulative and fluvioglacial), preserved in the relief of glacial valleys and intervalley spaces.

Figure 4. Hanging and flat-tops glaciers on the Northern slope of Sutai ridge.

The Sutay ridge is the most southern center of the glaciation of the Mongolian Altai. The lower limit of the nival-glacial belt of the ridge is 150-200 m higher than in other glacial regions of Western Mongolia. Modern glaciation of the Sutay ridge is 14 glaciers of the four morphological types: flat-top, hanging, corrie, and corrie-valley. The glaciers are concentrated in the altitude belt from 3600-4150 m and have North exposure. The most important features of the relief, determining the morphological features of the Sutay glaciers:

  • flat, plateau-like apical part of the watershed, which are the basin of accumulation for snowdrift, corrie and hanging glaciers;
  • stepped slopes near to the tops, which contributes to the concentrated accumulation of snow-firn masses;
  • inherited the orientation of the main snow accumulation basin related to the dominant Western moisture transfer.

The Alpine zone of the Sutai and Tsambagarav ranges is characterized by significant amplitudes of daily temperatures, frequent zero mark crossing in spring and autumn create favorable conditions for the development of mechanical weathering, and as a result, lead to the formation of numerous rock-falls, placers and scree on the watersheds and slopes of the valleys. Modern relief formation zoning processes causes high values of altitude and relative height, differences in the compose and structure of rocks, changes in the height of temperature conditions and precipitation regime.

The ranges of the Mongolian Altai are considerable amplitude of the elevations that defines a highly dissected terrain and extensive development of the phenomena of vertical zonation. The mountain system has a high position above the ocean level and even with relatively small fluctuations in heights (200 — 300 m) it is possible to observe a natural belt change of vegetation. North-Western Mongolia region with are extended continental climate, here is widely represented arid type of altitudinal zonation. This type of altitudinal zonation is characterized by large amplitude of belt shifts — from deserts or desert steppes in the foothills to high-mountainous wolds on the summit surfaces. Some belts are reduced or completely absent, on the ranges of Sutai and Tsambagarav, especially forest, when there is direct contact of the Alpine belt with the dry and desert steppe. The exposure of the slopes is of particular importance in the distribution of plant communities of the Mongolian Altai. Permafrost occupies about 35% of the area of mountain structures of the Altai mountais.

Permafrost is so widespread here, largely due to the extreme continental climate of the region. Average annual air temperatures fall in some regions to -10 ° C, and a small amount of precipitation is distributed over the territory is extremely unequally. Mosaic climatic characteristics affect the specificity of the properties of frozen ground — from seasonally to permanently frozen ground, having a continuous, discontinuous and island bedding (Figure 5).

Figure 5. The distribution of the permafrost rocks in the Altai Mountains

1 – the belt of discontinuous permafrost; 2 – the belt of island spread of permafrost and continuous permafrost; 3 – the area of seasonal ground freezing.