Articles
The paper generalizes the data of the alluvium accumulation and soil formation rates in the flood plains of the plain rivers. The method of assessment is based on facies analysis of flood plain deposits containing series of buried soils. The Middle Oka, the Moscow, the Upper Don, and the Nepryadva rivers were investigated. The correlation of paleogeographic events with the conditions of soil formation and human activity in the Holocene were revealed, the stages of soil formation were discovered. We established that at the rate of accumulation more than 0.25 cm/y the soil formation doesn’t change the alluvium, at the rate of 0.1-0.25 cm/y the alluvium have traces of the soil, at the rate of 0.03-0.1 cm/y the cumulative sod-layered soils appear, and at the rate of 0.01-0.03 cm/y the well-developed sod and meadow soils are forming.
Mountain ridges of the region have an ambivalent nature, representing a product of the lengthy erosion-denudation dissection and partial transformation of Late Mesozoic and Late Mesozoic-Early Cenozoic arch-block and tectonic-magmatic uplifts by tectonic regime inversions (Eocene, Miocene) and during neotectonic phase of the development. From these positions it is necessary to estimate the total age of mountain constructions (from moment of the origin) in view of the object hierarchy and the duration of their constructive and destructive development phases. The morphological age of ridges depends on time of the formation of intermountain riftogenic basins limiting them and of the river network evolution.
Short communications
The existing hypotheses of beach cusps development are considered. Their formation is the combined action of the beach abrasion and accumulation processes depending on the bottom slope, bottom sediments, and wave parameters. In recent decades, there are active debates about the origin of cusps. However, none of the hypotheses fully explains the mechanism of their formation. Thence the existing of some yet poorly explored hydrodynamic processes near the water edge having a significant impact on the cusps formation is supposed. A dynamic equilibrium of the beach at given seaway and the presence of rhythmic splash having sufficient force to move sediments of a given fineness are the main factors of the cusps formation. It apparently depends also on the type of wave breaking. Thus, the emergence of the cusps, their sizes and wave step are directly dependent on local morphodynamic parameters. Scalloped landforms are well represented along the shores of the Curonian and Vistula spits at the South-East Baltic Sea, and they are particularly unique in the lagoon shores. The combination of wind effected phenomena and wave action with of certain slopes of the coastal zone, leads to the development of a special type of acuteangled cusps with long “rumps” on the underwater slope. Long-term observations show that the cusps formation on the lagoon shores is quite possible and regularly re-starts under favorable conditions. At the spit shores different underwater slope parameters and seaway conditions lead to the development of the cusps significantly different from the lagoon’s ones. They are mainly the large forms with smooth contours and rounded tops.
The New Moscow territory has low gully network density: 0.045 km/km2, number of gullies per unit area – 0.09 gullies/km2. The local natural conditions – dominance of flat or gradually sloping surfaces, low topographic range, dominance of relatively resistant glacial boulder clays on the surface, large percentage of forested areas – are unfavorable for linear erosion activity. Schemes of gully network density and number of gullies per unit area based on detailed topographic maps and satellite images have shown that the northern part of the New Moscow area has largest degree of gully network development, due to a combination of factors including largest topographic ranges and steepest slopes of some river valleys (mainly along the middle reaches of the Pakhra and Desna Rivers). At present, the New Moscow area becomes intensively altered by growing human activities associated with its new development. There are already some examples of reactivation of the existing gullies and formation of new ones as a result of uncontrolled anthropogenic activities and unsustainable land use within the existing gully-balka systems in the study area.
A map of naturally determined intensity of geomorphologic processes scale 1:8 million on the territory of the Russian Far East was done. The geomorphologic processes intensity is the readiness of geomorphologic system to pull out of the balanced condition and danger of catastrophic processes developing under the action of external and/or internal forces. Highlighted areas with different potential intensity of geomorphologic processes, the value of which in the region ranges from 3 to 16 conventional points and depends on the degree of ecology-geomorphologic hazard modern relief processes, depth of relief dissection, seismicity, precipitation, availability of loose thick permafrost. Study results confirmed the formerly stated supposition about increasing of nature-defined intensity of endogenous and exogenous processes of the North-Western Pacific Ocean coast area from West to East. Thus, potential processes intensity of the Western Okhotsk Sea coast area was estimated in 7-10 conditional points, in the Sakhalin – 10-12, in the Eastern Kamchatka – 13-15, and in separate Kuril Islands – 16 points. Intensity of geomorphologic processes distribution analysis totally shows near-normal distribution of spaces with different number of points, while maximum is 6-8 points areas, occupying totally near half of the territory (47% ). Potentially catastrophic areas (over 15 points) occupy near 0,3% of studied territory, but in certain regions such as the Kurils, the rate can rise up to 49% . Sites with extremely high intensity (10-15 points) extend on the 15,2% of the territory, sites with high intensity (5-9 points) – 76,2% , sites with low intensity (under 5 points) cover just near 8,3% of the territory.
Accumulative forms may be divided into two groups by their morphology, spatial-temporal stability, and the trend of development. The first group is represented by relatively steady forms: beaches, coastal terraces, inset underwater terraces, mouth bars, spits. The second group is represented by the storm swells, tails, and cones forming on the shallows in early spring after the active slumping of the coastal benches or due to discharge of sediment at the mouths of ravines and gullies. The volume of the largest steady forms (bars, spits, coastal terraces) can reach 12 000 m3. The surveyed coastal site is represented by two mineralogical zones. In northern zone a sector of coastal slope – part of the third terrace – serves as a source of sand-gravel and sandy sediments containing resistant minerals (tourmaline, staurolite, leucoxene). The southern mineralogical zone is characterized by clearly expressed prevalence of silicon and hydroxides of iron. The leading process of coastal morpholithogenesis here is longshore drift.
History of Science
The beginning of development of geomorphology as some other branches of physical geography in Azerbaijan it was founded by the Russian scientific researchers who for the first time have been here at the beginning of the 19th century geological search works. Their fundamental role is shown that in allocated with us in 6 stages the development of geomorphology in the initial of the third exclusive and inseparable role belongs to Russian scientists who having laid the foundation of this science developed its separate directions, both theoretical, and the applied contents. Thus in narrow sense, it is meant that the role of those scientists which researches were directly connected with studying relief of Azerbaijan territory and in a broad sense – the role of those leading figures in science, which works made at all times and make a scientific and methodological basis of geomorphological researches in our country. In this aspect the invaluable merit belongs to world-wide recognized Moscow geomorphological school and its leader to Institute of geography of the Russian Academy of Sciences. Meanwhile mission of the Russian scientists in geomorphology development of Azerbaijan was inseparably linked with a fundamental condition the development of science – with preparation of national shots. So, the first and leading geomorphologists of the republic graduated from higher education institutions and postgraduate studies in Russia and defended master's and doctoral dissertations under the scientific management and consultation of leading representatives of this school. Thanks to them the present generation of the Azerbaijani geomorphological school successfully realizes traditions of the predecessors.
Reviews
Soil erosion is a most important factor of environmental hazard. The number of publications is growing rapidly all over the world. Here and abroad new mathematical models of erosion processes are developed, knowledge on the physics of soil run-off is deepened; revolutionary soil protection measures are applied. It is a challenge to look about in this informational sea, so the monograph on the problems of erosiovedenie is up to date and actual. Wide scope of problems is a hallmark of this monograph – there were no one similar books previously.
Obituaries
Information
ISSN 2949-1797 (Online)