Various kinds of the asymmetry in topography are discussed which are typical of glacial, periglacial, humid temperate and semiarid zones. Differences in insulation of differently f acing slopes account for various rates of glacial erosion, solifluction landslides and earthflows, creep and fluvial erosion. In general case most heated are the slopes facing SSW. The direction of maximum disymmerty deviates from S-N line by 25o on the average, probably due to discrepancy between diurnal march of insulation and surf ace heating (peaks of these curves do not coincide in time).

Seismic disjunctive deformations formed during the Spitak earthquake are recorded over large area. Total length of the outlined fault zone (including normal and reverse richt- and left-slip faults) adds up to 35 km. Maximum displacement in reverse faults is up to 2 m, in strike-slips — 1,8 m. The zone consists of three sections of active dislocations, each section having distinct morphological features. While the seismic faults vary widely in near-surface structure, the main fault mostly coincides with older fault-line. The downthrown wall to the latter reveals a sequence of buried soils which suggests repeated movements in the past probably due to earthquakes similar to Spitak one.

Morphology and spatial pattern of seismic dislocations as well as data on the aftershock activity indicate that the Spitak earthquake focus is situated on the intersection of two large fault zones (Sevan - Pambak and Alavar).

A morphostructural analysis of three young platformian plains (i. e. West-Siberian, Turanian and Scythian ones) revealed besides a certain similarities also considerable differences. The West-Siberian and Turanian plains have relatively elongated Outer morphostructural belt, relatively low inner morphostructural area, the two units differing essentially in the sets of morphostructures. The Scythian platform has different structure, the mentioned Outer and Inner areas lacking there. We consider the differences in the surface topography and morphostructures of those plains to result from their position within regional (in Eurasian continent) and global systems of geotectures, the morphostructural plan of the platformian plains was also significantly influenced by development of adjacent orogens differing in age and also (which is more important) in activity.

In the process of underground mining considerable soil displacements take place above mines, the land surface being sagged, locally collapsed, with steps and ruptures at the periphery. The surf ace deformations pattern varies widely in space and time and depends on interaction of numerous natural and technogenic factors. A quantitative assessment of individual natural factors significance for the character and rate of topographic deformations have been attempted using multivariant statistics. Most significant groups factors are identified which are to be considered when predicting surface deformations at mineral deposits which differ in engineering-geomorphic conditions of mining.

The paper states basic results of investigations into anthropogenic and technogenic morphogenesis in the SE European USSR. An evolution of characteristic natural-anthropogenic processes is considered, such as water and wind erosion, wave abrasion on water reservoirs banks, and also technogenic processes (mining, constructional works, land reclamation). Direct effect on natural processes and indirectly induced results are analysed. Some geotechnical (engineering) systems are outlined, the Volgograd and Aksarai (Astrakhan) ones are discussed in detail. Quantitative characteristics of technogenic morphogenesis are determined for the region for the first time.

A subdivision of the Byelorussian territory has been accomplished based on the data obtained during the special enginneering-geological survey. The regions are distinguished by landforms combinations, relief-forming f actors, lithology and f acres of surficial deposits. Types of exogenic geological processes and degree of their development are proved to be directly connected with the regions identified.

A new technique is described of solid rocks strength assessment in natural position using portable device for dynamic tests of rocks. The analysis of the lithomorphic topography in mountains of Soviet Central Asia, Kazakhstan and the Great Caucasus carried out using both traditional structural geomorphological method and the new technique confirms the notion that the unhomogeneity of rocks strength in a leading factor in lithomorphogenesis. The introduced method appears to be expedient for unbiased identification of lithomorphic elements of micro- and mesorelief.

On the basis of established correlation between the absolute height of the day surf ace and this of the Middle Miocene deposits base at the southern Nlangyshlak peninsula, a new technique is introduced intended for the primary tectonic relief reconstructions, it can be applied to regions where the modern relief is dominated by negative landforms due to erosion process.

Methods are discussed of calculation of vertical deformation of river channel bottom (along the fairway) within the limits of morphologically uniform segments of rivers under natural conditions and with disturbed hydrological regime and channel processes due to hydrotechnical constructions. The results can be used to determine how deep must be installed pipelines, cables and masts foundations of power lines, crossing the river, they may be also applied to water ways designing and dredging organization.

A certain correlation has been proved to exist between Caspian Lowland morphostructures and reconstructed morphostructural elements of the Pre-Early Permian topography of Astrakhan vault. The correlation may be important for the analysis of structure and modern evolution of the gas condensate field which is the largest one in the USSR.

Some horizons (1 to 3) with increased density and clay content (up to 50%) are well pronounced in coarse slope deposits in various regions of the Sikhote-Alin uplands. Their mean depth of occurence ranges from 1 to 2,5 m. Their formation is related to a number of factors and processes, such as 1) elastic material outwash from upper layers of the slope cover and its accumulation on the contact with more compact rocks, 2) interchanging saturation - drying up of surface stratum (0,4-0,6 m) which goes along with swelling and shrinkage of the ground, 3) «cryogenic packing» of sediments at the contact of the active layer with frozen ground or with solid rocks. Sequences of slope deposits demonstrate superimposed results of all processes varied in space and time or having acted simultaneously. The second group seems to be most important, with most distinct lithogenetic effect on the western macroslore of Sikhote-Alin. A great number of these formations appear to be inherited of relict, their origin being related to former permafrost or cryogenesis.

Lower reaches of some large rivers (such as Amur, Amazon etc.) are characterized at present with alluviation which leads to formation of inner deltas, near-floodplain lakes, increased thickness of floodplain faces of alluvium etc. In such a rivers the floodplain soon comes to the dynamic equilibrium state, after that its elevation above the channel remains constant, the morphology, dynamics and alluvium sequence differ essentially from those observed in the downcutting rivers. In the Amur valley the length of the alluviation zone is up to 1200 km and the rate of sedimentation averages 0,56 mm per year. Some differences in the floodplain dynamics are established between plain and mountain segments of the Amur valley.

Results of paleo-geomorphological analysis of a region within the Siberian platform are discussed. Main morphostructural elements are identified which existed in the Rhaetic — Liassic paleorelief. Development of main morphostructures is proved to be inherited as well as the placers' formation. Main ways of minerals migration and accumulation have been traced and their connection - or the lack of connection - with known sources has been established.

Quantitative data are given on the sheet wash in an arid region under natural environmental conditions. The data were obtained by various methods including markers, phytoindicators, «natural traps». Recent dynamics was studies using the «painted square» technique. The values refer to the average rate of process for various time intervals (from a year to one thousand years) and suggest the dynamics of the process in the region to be of complicated wave-like pattern. The relief evolution proceeded irregularly.

A geomorphic subdivision of the deltaic plain have been attempted based on studies of the Pleistocene history of the Caspian Sea, neotektonics in the SW Caspian Lowland, structural geomorphology of the delta, history of its relief and changes during the last century in particular. Four geomorphological zones are suggested to distinguish: 1) floodplain — channeled gently undulating deltaic plain, 2) hummocky deltaic plain, 3) gently rolling plain with koultuks (narrow bays), 4) fluvial marine undulating plain (delta shoreline and front).

Новый труд по овражной эрозии

Актуальные вопросы развития северо-западных берегов Черного моря

Алексей Иванович Спиридонов (к 80-летию со дня рождения)