Geomorphology and quarternary Geology

Glacial landscape of Tigertysh mountain junction (south part of Kuznetsk Alatau mountains)

Adamenko M.M.

Kuzbass state Pedagogical Academy, Novokuznetsk, Russia

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The Kuznetsk Alatau is the largest geomorphological terrain. It occupies the third part of Kemerovo region, western part of Hakhasia and western part of Krasnoyarsk region. It stretches across Kuznetsk and Minusinsk syncline. The typical modern landscape of the area is presented by dome-shaped or flattop mountains that rise up to 1600-1900 m and more. As far as glacial geomorphology and paleogeography are concerned the Kuznetsk Alatau is the least explored area in North-Western Siberia. Glacial landscape hasn’t been purposely studied. Only the eastern macroslope of the Kuznetsk Alatau with isolated cirques near the upper forest level was described [2]. According to Ivanovsky [4] these cirques have been predominantly appeared owing to the process of nivation. There is little information about Pleistocene glaciation that doesn’t allow to conceive geography and size of Pleistocene glaciation [5]. In the works of some scientists [3, 6], who visited the central part of the terrain, one can come across records that glaciated forms of landscape could be found rather often. This opinion is proved by this research. Thus, in some mountain regions of the Kuznetsk Alatau, namely in Tygertysh mountainous junction one can meet Alpine landscape with all characteristic elements.

Research of Kuznetsk Alatau glaciation during the last glacial period of late Pleistocene has been carried out by the Geological laboratory in Kuzbass State Pedagogical Academy since 2002. Research has been carried out in southern part mostly in Tigertysh mountainous junction. To estimate the area and features of paleoglaciation we described and analyzed location peculiarities of cirques, U-valleys and moraine landforms. Basic material for research was collected during expeditions. The valleys of 5 rivers (Karatas, Perehodnaya, Ozernaya, Shirokaya Berezovaya and Maly Kazur) that have all kinds of glacial landforms were studied. Satellite images, aerial photos, topographic maps (scale 1: 100000, 1:25000) and photos of other scientists were also analysed. At the initial stage of research an orographical study of the area was carried out. Thus, we made up an orographical scheme of Tigertysh mountainous junction, which hadn’t existed before. It allowed to assess better the dependence of modern and ancient glaciers on the physical-geographical features of the terrain.

The most typical form of glacial landscape is cirque. In the Tigertysh mountain junction there are about 132 cirques. Cirques have mostly an ellipsis form with a lake at the bottom. Their area is from 0,2 km² to 2,2 km². Peculiar feature of cirques is that they are usually located one above the other, forming a kind of a stair widening at the top. Such stairs usually have 2-4 levels. At the bottom there is a single cirque, at the next step there are 2 or 4 cirques in proportion. Single cirques are rather rare. In the central part of this mountain junction the cirques and lakes are located at 4 elevations. The lowest elevation of water 1391-1335 m - is the lakes: Karatas, Krugloye, Harlygkol, Hunul-Huzuh. P. Shin [6] pointed out that such lakes have glaciation genesis. Though he didn’t explain how they had been formed. In our opinion the hollow of these lakes has a complex origin. They are not moraine blocked.

Peculiar feature of single cirques is their small size. The largest single cirque in the Tigertysh mountainous junction is covering an area of 2,6 km². Absolute hight of dorsum wall doesn’t exceed 1570 m. Its bottom is occupied by the lake Hahzir-Teren that is delineated by a large moraine. 500 m lower the valley there is one more moraine complex. This cirque is rather old. Its high walls are smoothed down. They are covered by screes of stones. Its western wall is made of rock. It has been rejuvenated by an existing snow field. Dorsum wall is damaged and forms a gentle sloping pass to the adjacent valley. These gentle sloping passes from one side of the ridge to the other can be the evidence of long term existence of a glacier [4].

U-valleys are typical for north slope of Tigertysh range (Fig.). U-valley can be seen near the rivers Perehodnaya, Right Surgas, Karatas. U-valleys end with ancient moraines. The average length of the troughs is 4-6 km. But the valleys of the rivers Karatas and Nizhnaya Tayzhasy have U shape lower terminal moraine complexes.

Ancient moraines are widely spread in the Kuznetsk Alatau. They delineate cirques and are located lower along the river valleys. Moraines are clearly visible in the landscape. They are not covered by loess. In all five monitored valleys the moraines are structured in a definite way. Best of all this structure can be observed in the valley of the Ozernaya river (Fig.). It has a form of a narrow deep trough without any tributaries 650-850 m wide, 4,8 km long. From the upper end it finishes with a complex of 3 step stair of cirques. The cirques bottom of the second step is on the level of the trough shoulders that can indicate that they are of the same age [4]. The lower terminal moraine delineates the trough. It looks like an amphitheatre 300 m in radius and consists of a big outside moraine and 5-6 smaller oscillation moraine mounds. The moraine is limited by a brook that can be a marginal canal that delineates the boundaries of an ancient glacier. On both sides of the valley there is a lateral moraine. 500 m up the valley there is one more moraine complex. Near it there is a round shallow swamp that could have been a lake blocked by a moraine that was filled with deposits and became a swamp. Up the valley from 1100 m above sea level there is a medial moraine mound. It appeared in the place of confluence of 2 sources of the glacier. Comparatively young moraines delineate the cirques of the 2^nd and 3^d steps.

Up to present time there is enough material collected that proves that the Tigertysh mountain junction was the big glacial terrain in the last glaciation epoch. Depending on concrete conditions (absolute elevation, slope exposition, slope steepness, etc) glaciation was represented by different types of glaciers: valley glaciers, cirque glaciers, hanging glaciers and rounded peaks glaciers. After studying the lay out of old moraine complexes we found 56 glaciers with total area of 245,3 km² which had existed during last glaciation epoch.

Most glaciers (22 in number) were located in the basin of the river Bolshoy Kazir and its tributaries, 11 glaciers were located in the basin of the river Belsu, 8 glaciers – near the river Terensu, 5 glaciers – in the Upper Karatas and 2 glaciers near the river Turalyg. While studying cirques and moraines location it became evident that glaciated landscape in Tigertysh mountain junction is typical for leeward stopes in northeast, east and north. The same exposure have recent glaciers and long-term snowfields. It proves that during last glaciation main direction of winds carrying precipitation was similar to the present - is south west and swept snow was very important for glaciers existence. The largest glaciers are concentrated in places where high elevation is combined with good conditions for snow accumulation. The largest glacier that existed here had an area of 50,3 km². It occupied the valleys of rivers Karatas and Hunul-Huzuh.

Detailed research of paleoglaciers moraine structure confirms that glaciation in the Kuznetsk Alatau developed by several stages. We selected four moraines of different age in Tigertysh mountain junction. The conclusion about different age of moraines was made on the basis of phytoindication and lichenoindication. Four moraines of different age are found in the valleys of the rivers Ozernaya, Karatas and Perehodnaya. Moraines of maximum stage are well seen in the landscape. Though there is no exact dating one can suppose that they were formed in maximum of last glaciation epoch. In our opinion moraines of the 2^nd and 3^d stages are recessional moraines that were formed in postglaciation and early Holocene time. Recessional moraines can be the evidence that the glaciers had existed for a long period and were in a balance with climate. Moraine complexes of the 4^th stage are the youngest. These moraines often delineate modern glaciers and perennial snowfields. In our opinion moraine complexes of the 4^th stage consists of external moraine referred to Historical stage (V BC – V AD) and internal moraine, that was formed in XVII- XIX (maximum of Little Ice Age). Modern glaciers also have small oscillation moraines that show their fluctuations in the XX century. In the valleys of the rivers Shirokaya Berezovaya and Maly Kazur there are moraines of three stages only. There are no moraines of the youngest 4^th stage. At present in these two valleys there are no perennial snowfields. It suggests that during the Little Ice Age glaciers didn’t not evolve here.

The structure of exarational landforms, namely stepped cirques and troughs, can witness about repeated glaciation of this region. One can suppose that large cirques and troughs that are at lower elevation were formed during the large period of Quaternary. The upper steps of cirques occupied by snowfields and glaciers are being formed at present time. Northeastern and northern sides (walls) of ancient cirques where there were small cirques glaciers and cirques with hanging glaciers due to snow accumulation are younger in comparison with southern sides.

Due to the erosional effect of glaciers the mountain landscape of Tigertysh mountain junction was notably changed. The landscape of northwestern and central part was changed most of all. Slopes exposed to wind and in Tigertysh ridge even leeward slopes are carved by cirques. On the whole the landscape is similar to the Alpes. Before the glaciation the landscape had rounded ridges and peaks. This kind of scenery is still preserved in the outlying districts where the effect of glaciation was weaker. Small fragments of unglaciated mountain region can be seen in Verhny Zub peak, Molnia mountain ridge and in the south of Karatas ridge and in south of Karatas mountain ridge.

Fig. Moraine complex in the valley of the river Ozernaya.

1- cirques; 2- moraines; 3- paleo moraine-block lakes; 4- snow fields; 5- lakes.

References:

1.Adamenko, M.M., 2011. Glacial morphogenesis of Central part of Kuznetsk Alatau mountains: Nature and Society: The View from the Past to the Future. Proceedings of the XVII Scientific Conference of Young Geographers of Siberia and the Far East. Irkutsk, 6-7. (in Russian).

2.Burov V.P., 1964. Curques in upper stream of river Tom (Kuznetsk Alatau). Glaciology of the Altai 3. Tomsk. 208-211. (in Russian).

3.Churakov A.N., 1932. Kuznetsk Alatau: the history of its geological evolution and geochemical era. Leningrad: Academy of Sciences SSSR. 323 pp. (in Russian).

4.Ivanovski L.N., 1981. Glacial mountain geomorphology (for example, Siberia and the Far East). Novosibirsk: Nauka. 173 pp. (in Russian).

5.Okishev P.A., Dmitriev V.E., 1987. Pleistocene glaciations of the Kuznetsk. Glaciers and climate in Siberia. Tomsk. 90-93. (in Russian).

6.Spin P.S., 1980. Glaciation of the Kuznetsk Alatau. Results of researches of the program international geophysical year. Moscow: Nauka. 83 pp. (in Russian).

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