Climatic-geomorphic zonality of the Earth: principles and approaches

The paper deals with geomorphological methods and aerial-space imagery applied to mineral deposits forecasting in the context of the plate tectonics. On the basis of space images interpretation morphostructural maps have been compiled showing collision orogens with characteristic frontal overthrusts, nappes, various fault zones, and landforms resulting from intense compression. Geomorphological (morphostructural) prognostic models of Central Kazakhstan and Oimyakon-Kolyma regions have been developed with consideration for the principal geomorphic factors controlling the mineralization ( layer removed by erosion and structural control).

Graded long profile and progressive vertical deformations of river channels

Spatial distribution d renal population over area of the Volga drainage basin is mostly controlled by environmental and historical factors; there have beam found however some distinct anomalies, both positive and negative, which are azonal in essence and depend on local geomorphic and geological characteristics.

Some feedback; are ago traced: the rural population density determines the scale of its agricultural activities, which in turn control direction and rate of many geomorphic processes, the erosion first of all. The processes account for changers in topography along with changes in the surficial deposits composition.

The paper deals with geomorphic structure as an element of environment and a factor which exerts control over town’s location and development in the Moscow region. Eight geomorphologically controlled features of town location are discussed. Eastern asymmetry of the Moscow region urbanization is shown to result from geomorphic structure. The degree of urbanization calculated from the ratio between occupied and vacant areas suggests the eastern part of the region to be deficient in territorial resources for the urban infrastructure development.

The alluvial palcers exploitation by dredging interferes with natural course of channel processes, especially in valleys of IV to VI orders. lt has been established by calculation that repeated dredging of a placer over considerable length of a valley may result in decrease of liquid discharge by 40 to 50%, and affects sediment budget as well. The changes could have serious repercussions in the lower links of the drainage network.

Structural-geomorphological works carried out with view to forecast mineral deposits suggest the Lembolov morphostructure (Karelian Isthmus) to be promising for search for diamonds in solid rocks. The morphostructure is located within an area complicated in geological structure, at a node of deep-seated faults which delimit earthorust blocks different in characteristics. The Lembolov morphostructure was formed as an elevation during the post-Cambrian time (probably in the Lower Paleozoic) , when molten magma penetrated the earthcrust. The present appearance of the morphostructure is due to denudation and glacial deposition processes.

The findings of investigations into erosion processes suggest the active cultivation of the land resulted in the erosion' acceleration (sheet wash, erosion due to irrigation). The rates of erosion are as high as 12 mm per war in case of mechanical cultivation and 10.3 mm per year if only manual cultivation used. Within non-cultivated areas (archeological objects) the rate of erosion does not exceed 0.08 to 0.09 mm/yr.

The author gives critical overview of the 19th century publications which contain information of raised coastlines and marine terraces on the Kola Peninsula.

The paper describes topography and genesis of the young - Late Valdai - Constructional landforms and ancient erosional buried surfaces, regional geological cross-sections being given. Paricular attention has been given to drainage pattern, probably affected by recent faulting. Analysis of longitudinal profile of the largest drainage system (Oyat - Tuksha - Oshta rivers) revealed maximum in the North-West region number of terraces; analytical data are given on the age of floodplains and two lower terraces.

It has been established that the meander asymmetry in plan may be quantitatively assessed using the meander's apex deviation from the axis of symmetry and unequality of the angles of entry and exit. The contributions of the two factors to the meander asymmetry are abount the same. An index of asymmetry is introduced - A_Ft, which takes into account both factors, and another index - AF: which approximates regularities of AF: changes. The two indices may be applied both to describe meanders' pattern, along with other morphometric characteristics, and to investigate into importance of asymmetry in the meander evolution.

A remnant of Devonian celesta located in the Pskov lowland and along the southern shore of the Pskovskoye Lake is rather well preserved because of its position «in the shade» of the Pskov-Chudskaya depression. During the glaciation the depression was filled with a vast block of stagnant («dead») ice, which was overflowed by an active ice; the latter however could not exert considerable erosion on the bedrock. The preservation of the Baltic-Ladoga glint bordering the Guld of Finland from the south and another glint south-west of the Ilmen' Lake may be explained in a similar way.

Repeated sounding along 54 sections across the offshore margin of the Nile delta (1975 to 1979) revealed considerable variations in the sea floor topography changes in time and space. In general, erosion prevailed in the west of the outer delta and sedimentation (accretion) in the east. New trends in the delta distal margin morphodynamics became evident after the Nile discharge had been regulated by the dam; .they are mostly result from the earlier accumulated sediments redistribution by waves and currents, the coast outlines being of considerable importance.

Four stages are distinguished in the relief development in the Zaisan Lake basin, each of them being associated with a complex of built-up surfaces: 1) glacial-fluvioglacial-lacustrine stage ( Kiinzhirian) - the end of the Middle Pleistocene; 2) glacial-alluvial - lacustrine (Katonian) - beginning of the Late Pleistocene; 3) lacustrine-alluvial stage (post-glacial) - the end of the Late Pleistocene; 4) alluvial - the Holocene. Geomorphic structure and the Quaternary sediments distribution suggest general upwarping of the area during the Quaternary, the movement amplitudes decreasing gradually.

Principal information is given or the structure, function and history of development of the morpholithodynamic systems of the World Ocean. The author's theory is substantiated with geodynamic constants derived from results of planetary morphometric studies carried out simultaneously by the LGU and MGU teams in 1970s.

A major synthesis of geographic materials on the channel processes

The Xth conference on the placer geology

The Baikal Region problems discussed at the Irkutsk Geomorphological Seminar