A new method is introduced to classify and map regions by the earth-crust types and recent endogenous regimes. Areas of certain regimes when compared with neotectonic structure and topography manifest a great variety of the corelation. The author concludes that the same neotectonic structures and similar types of topography (both positive and negative) may belong to areas of different endogenous regimes (both constructive and destructive). Some regions are indicated where neotectonic structures disagree with classes of recent endogenous regimes which accounts for possibility of autonomous topographic evolution of the regions.
Special features of Turanian large morphostructures are discussed and morphostructural types are identified in accordance with the orographic units relation to the basement topography and sedimentary mantle structure, morphostructural regions of various direction are outlined, the orientation being controlled by structural frame of the plain. Inherited morphostructures prevail at the western part of the plain, while those of inverse type are widespread at the sort-hern and eastern periphery. The author came to a conclusion that the morphostructural plan was relatively simple as compared with the sedimentary mantle structure, at the central part of the plain a regional sub-longitudinal zone is revealed where sublatitudinal morphostructures come into contact.
Short communications
The evolution of spits at the Azov northern coast is discussed considering relative importance of exogenous and tectonic processes. The rearrangement of the spits is shown to proceed at a considerable rate which is to be taken into account when planning the land's development.
The division of volcanic slopes of Armenia on morphological indication and origin, material composition, profile form and length is given. The volcanic slopes are formed very quickly («instantly»), they lack loose material for some time and well preserve their original form. The conclusion is drawn that the downwearing process is typical for volcanic slopes of Armenia. Parallel retreat can manifest only temporarily in vertical scarps of volcanic plateaus, necks, lava flows, in case of vertical columnar jointing and it is typical for early stage of their evolution. It can proceed longer if the debris is removed from the foot of slope quickly.
Data of loose sediments study and structural-geomorphic investigation permit to identify two planation stages (Paleogene and Pliocene-Early Pleistocene) and two stages of active evolution of topography (Miocene - Early Pliocene and Quaternary). The Quaternary stage is subdivided into two cycles of general uplift and valley erosion and two cycles of autonomous evolution of individual morphostructures, when terraces are formed at positive morphostructures and sedimentation takes place in basins.
The paper deals with the mechanism of the recent river downcutting into alluvium which filled preglacial valleys during the glacial time. The channel process type may change from one stage of the background channel deformations to another, the fact should be taken into consideration while predicting long term channel transformations.
A large Bichenag seismogenous structure is identified for the first time. It was formed during two seismic catastrophes, the later of which was of magnitude not less than 7.0. The structure is about 8 km long, up to 3.5 km wide, the vertical seismic-gravitational displacement exceeds 300 m. The structure came into being between 5000 and 500 years ago.
Analysis of digital model of the SE Indian floor topography using specially developed software revealed the range of the ocean floor vertical dissection to be related to the ocean depth. Six topographic levels have been indentified differing in the character of the relation. The paper describes the relation and tries to explain it by the earthcrust evolution.
On the base of mass analysis of morphometric characteristics of the basement relief of the World Ocean floor similarity and difference in the oceans structure as well as in its main morphostructures are described. The characteristics revealed can be accounted for by proceeding from the plate tectonic thesis about the dependence of relief pattern on the rate of the oceanic crust generation.
For the first time the map of buried troughs has been compiled for the Byelorussia's territory based on the space photoes data. These ancient landforms are established to be mostly of sub-latitudinal and sub-longitudinal directions, which correspond to the directions of main tectonic structures. The troughs were formed at the Pre-Quaternary stage. Deposits lying in the troughs are promising for the search for brown coal and other mineral resources.
3 dynamic zones are distinguished at talusus as well as 3 lithofacies are identified in the deposits. The subdivision is based on granulometric data, median size, sorting, elongation and flattening coefficients, long axes direction etc. The mechanism of the debris mozvement in the talus is explained which accounts for the separation into 3 facies.
Morphostructures and ancient very large mass displacements (rockfalls, landslides etс.) are briefly discussed; the displacements are mostly due to seismic and gravitative phenomena and proceeding on erosional-tectonic scarps and at recent grabens edges. In the absence of authentic seismotectonic dislocations they do not permit to estimate the ancient earthquakes magnitude as even weak quakes may induce the displacements on dissected and unstable slopes.
The ancient Martian craters evolution is shown to proceed about 3.5*109 to 3.8*109 yrs ago due to the pediplanation process (parallel slope retreat) according to the «semiarid» scheme, which is mostly under the action of sheet wash. A global planation surface of the pediplain type is shown to be formed at the time. The global scale of the «semiarid» pediplanation process on Mars during the period about 3.5*109 to 3.8*109 yrs ago suggests much denser atmosphere and higher temperature at the time than at present.
Geomorphology and Quaternary paleogeography of the submerged continental margin in the western Black Sea
Chronicle
Reviews
ISSN 2949-1797 (Online)
