The dynamic geomorphology is defined as one of main oranches of the geomorphology Unsteady character of the man geomorphic processes is emphasized as well as the fact that systems involved are multiphase Main f actors of the relief formation are outlined.
Three principal schemes (models) of the topographic evolution are considered on the basis of the matter's budget: ascending evolution (endogenous factors dominate), equilibrium (uplifts compensate erosion), descending evolution (exogenous f actors prevail over endogenous ones).
The paper summarizes quantitative data obtained up to now on rates and amplitudes of 13 types (causes) of hydrocratic and geocratic ocean level changes during the Cenozoic. Some types of the level changes are of global character and long duration, others are local and short-term.
Geomorphology and economy
The paper deals with technogenous processes and landforms within the zone of the Kara-Kum channel which is the largest man-made channel of the Central Asia, Causal relations are analysed in connection with the hydrotechnical construction impact on the environment. A classification of technogenous processes and landforms is developed. The processes and forms studies in the zone of existing irrigation construction permits to approach the forecast of similar formations in future channel zones (if the environments resemble those under consideration) with view to nature's conservation.
Mean annual rate of various types of gullies growth has been determined by aerial photoes comparison for several f arms of the Kursk region made during 20 years period. Some recommendations are given how to apply the results to economic estimate of the fluvial erosion and its control.
Short communications
Some problems are discussed considering studies of complex sand waves and other structures in sandy channels. The author proposesto subdivide the landforms hierarchy into components taking in to account both characteristic and maximum length of the channel bed forms as well as a principle of double change of the bed slope. The technique applied to the ridges natural assembly permits to unify methods of identification of bedforms of the same order at different rivers. The morphogenetic analysis of ridges of various orders has been fulfilled at the lower reaches of the Dnestr River and the sand ridges evolution was investigated. Some data are given on linear size and movement rate of most mobile sand ridges as observed in the summer 1983 at the lower Dnestr.
The analysis of angles of channels and erosional landforms convergence as well as those of water divides indicates the angles to be in close relation with the channels and watersheds orders. As the order becomes higher the angles increase from 30-40o (for the 1st order) to 80-90o (for the 6th order and higher). The regularity can be used while reconstructing paleohydrographic network and paleo-watersheds for any buried topographic surface.
Mapping of morphogenetic types of relief using space images permits to delimit areas more precisely than using traditional techniques, space images however reveal mostly morphological differences, the genetic ones being only roughly indicated. Data on the relief genesis were obtained using results of field survey as well as aerial photoes interpretation. The authors based their studies on structural and geomorphological interpretation of space images, together with morphostructural analysis. For the first time they identified (on the basis of the whole complex of criteria) morphostructural lineaments; established isometric configuration and precise position of boundaries of higher order block structures as well as some blocks of lower order (Sierra de los Organos, Pinar marine plain).
The reconstruction of the neotectonic pattern is ascribed to the Pleistocene sheet glaciations. The main geomorphic features of the West Siberian north are considered as created by Pleistocene ice sheets or by glacioisostasy. The adjacent mountains are supposed to be compensation uplifts that developed around the central isostatic depression of the coastal lowlands. The glacial loading apparently caused the spatial separation of oil and gas reserves. Possible influenses of glaciotectonics on reconnaissance of structural traps are discussed.
The paper gives results of study of regional topography of the Trans-Baikalian region using nonpolynomial trend-analysis model. The regional plan is defined and improved evaluations of hypsometric location of mineralization are obtained.
A widespread planation surface reliably dated from Cretaceous. Paleogene is located at watersheds of the Central Transbaikalian periferic ridges. Late Jurassic surface is established at two levels-within depressions and at ridges, their jointing can be traced along the summit surface. Angle discordance is established between the Late Jurassic surface and younger ones. Outer and inner limits of the young surf aces are traced, which predetermined stepped topography of the ridges and reflect the succession of their formation.
Correlation analysis of neotectonic movements rates differentiation according to density and geothermal regime of mantle-crustal blocks suggests the geodynamic processes to be based on thermodynamic ones, the latter induce a complex of associated processes. Tectonic processes rate and character as well as manifestation depend on thermodynamic processes and on the depth of their development, lithosphere's permeability, heat and mass transfer mechanism and thermal characteristics of the matter at depth. Various combinations of the factors control the variety and development of tectonic processes (neotectonic crustal movements included) an different layers.
The paper summarizes the author's many years’ stationary observations on bank erosion at free-meandering rivers of the Middle Baltic region. Various types of the banks destruction are distinguished depending on the geology, elevation, vegetation cover on the floodplain (or terrace) surface, the erosion processes being described in details.
Reviews
Obituaries
ISSN 2949-1797 (Online)
