THE COURSE OF SEDIMENTS DEPOSITION IN THE AZAU VALLEY IN THE CENTRAL CAUCASUS OVER THE LAST 1000 YEARS

The Azau Valley is located in the Central Caucasus Mountains between the strongly glaciated mountain ridge (4450 m a.s.l.) and the volcanic cone of the Elbrus Mountain (5643 m.a.s.l.) of the Quaternary age, covered with an ice cap. The length of the valley is 7 km long and its bottom is at the altitude of 2000-2500 m a.s.l. The valley has been modelled by direct and indirect influence of the volcano activity, as well as by glaciers and very intensive slope processes. The author has determined the main phases of the valley modelling over the last 1000 years. Particular attention has been given to the periods of intensive deposition at the valley bottom. The deposited material originated from rapidly degrading lateral moraines, and it was also supplied at the time of large floods generated by increased activity of the volcano. The frontal moraine ridges, formed during the Little Ice Age, helped to retain the deposits in the valley. The ridges, after their partial destruction, have been almost completely covered by fluvioglacial material, which thickness reached at least several meters. Deposition of material on the slopes of the Azau Valley was most intensive during the transgression of glaciers, while at the valley bottom it was the most intensive during regression of the glaciers and during great floods. The Azau Valley, as other valleys located at the foot of Elbrus, has played the role of deposits accumulator. Episodic and catastrophic great floods have tended to uniform the valley bottom level, however they have not been able to remove the accumulated material much farther.