Central Russian Upland conclusion about the dependence of the relief. Where is the Central Russian Plain? General geology and minerals

Practical work number 3

Theme:"Explanation of the dependence of the location of large landforms and mineral deposits on the structure of the earth's crust on the example of individual territories."
Objectives of the work: establish the relationship between the placement of large landforms and the structure of the earth's crust; check and evaluate the ability to compare maps, explain the identified patterns; to determine the patterns of distribution of magmatic and sedimentary minerals using a tectonic map; explain the identified patterns.

^ Work progress

1. Having compared the physical and tectonic maps of the atlas, determine which tectonic structures correspond to the indicated relief forms. Make a conclusion about the dependence of the relief on the structure of the earth's crust. Explain the revealed pattern.

2. Fill out the results of the work in the form of a table.

Landforms	Prevailing heights	Tectonic structures at the base of the territory	Conclusion on the dependence of the relief on the structure of the earth's crust
the East European Plain
Central Russian Upland
West Siberian lowland
Caucasus
Ural mountains
Verkhoyansk ridge
Sikhote-Alin

3. Using the map of the atlas "Tectonics and Mineral Resources", determine what minerals the territory of our country is rich in.

4. How are the types of igneous and metamorphic deposits indicated on the map? Sedimentary?

5. Which ones are found on the platforms? What minerals (magmatic or sedimentary) are confined to the sedimentary cover? What are the protrusions of the crystalline basement of ancient platforms on the surface (shields and massifs)?

6. What types of deposits (magmatic or sedimentary) are confined to folded areas?

7. Fill out the results of the analysis in the form of a table, draw a conclusion about the established dependence.

^ Practical work number 4

Theme:“Determination of the regularities of the distribution of solar radiation, radiation balance by maps. Revealing the peculiarities of the distribution of average temperatures in January and July, the annual amount of precipitation over the territory of the country ”.
^ Objectives of the work: determine the patterns of distribution of total radiation, explain the patterns identified; study the distribution of temperatures and precipitation across the territory of our country, learn to explain the reasons for such a distribution; learn to work with various climatic maps, draw generalizations and conclusions based on their analysis.
^ Work progress

Review Figure 31 on page 59 in the tutorial. How are the values of total solar radiation shown on the map? In what units is it measured?
Determine the total radiation for points located at different latitudes. Draw up the results of the work in the form of a table.

Make a conclusion what pattern is seen in the distribution of total radiation. Explain the results obtained.
Review Figure 35 on page 64 of the tutorial. How is the distribution of January temperatures across the territory of our country shown? How are January isotherms in the European and Asian parts of Russia? Where are the areas with the highest January temperatures? The lowest? Where is the pole of cold in our country?
Make a conclusion, which of the main climate-forming factors has the most significant influence on the distribution of January temperatures. Write a brief conclusion in a notebook.
Review Figure 36 on page 65 in the tutorial. How is the distribution of air temperatures in July shown? Determine in which parts of the country the July temperatures are the lowest, in which - the highest. What are they equal to?
Make a conclusion, which of the main climate-forming factors has the most significant influence on the distribution of July temperatures. Write a brief conclusion in a notebook.
Consider Figure 37 on page 66 of the tutorial. How is the amount of precipitation shown? Where does the most precipitation fall? Where is the least?
Make a conclusion, which of the climate-forming factors have the most significant influence on the distribution of precipitation over the territory of the country. Write a brief conclusion in a notebook.

The relief of Russia is amazingly diverse. On its territory there are large mountain systems, vast lowlands, rocky plateaus and highlands. In the south-west of the European part of the country, Central Russian is located.It is about this form of relief that we will describe in detail in our article.

Central Russian Plain: description and geographic location

The Central Russian Plain stretches from north to south for almost a thousand kilometers, from the Oka River valley to the slopes of the Donetsk Ridge. In the west, it is limited by the Polesie lowland, and in the east by the Oka-Don plain. In the southwest, it smoothly passes into the Dnieper lowland. The absolute heights of the terrain are gradually decreasing in the southern and southwestern directions from 260 to 190 meters. The highest point is 303 meters above sea level.

About seven million people live within the Central Russian Plain (35% of them live in villages and villages). The main cities of the region are Belgorod, Tula, Bryansk, Yelets, Lipetsk, Stary Oskol, Kharkov, Sumy, Glukhov.

So, we have already found out where the Central Russian Plain is. Now let's take a closer look at the features of the geological structure and relief of this morphostructure.

General geology and minerals

As already mentioned, the plain is based on crystalline rocks of the ancient Precambrian basement (or the so-called Voronezh massif). From above, they are covered with a layer of sedimentary rocks insignificant in thickness - limestone, chalk, sandstone and clay.

The northern parts, western and partly eastern slopes of the plain were previously covered with glaciers. In this regard, in these territories today you can see numerous deposits of glacial origin - moraines, the thickness of which in some places reaches 15 meters. Classic moraine deposits are found on the right bank of the Oka, in the section between Serpukhov and Aleksin.

The Central Russian Plain is rich primarily in iron and the Mikhailovskoye iron ore deposit is the largest in terms of its reserves. In addition, significant deposits of limestone, brown coal, granite and other building materials are concentrated in the depths of the region.

Central Russian Plain: Key Features of the Terrain

In this area, nature has created all the necessary conditions for the active formation and development of water-erosion processes and landforms:

Elevated territory.
Significant differences in absolute heights.
Relatively soft rocks.
Heavy and heavy rainfall in summer.
Low percentage of forests.

As a result, classical gully-gully-valley landscapes have formed and continue to form in the region. At the same time, water erosion every year rapidly reduces the area of agricultural land. The depth of dissection of the earth's surface on the plain in places reaches 100-120 meters.

Within the Central Russian Upland, suffusion (steppe saucers and funnels), gravitational (precipices, landslides), aeolian (small sand dunes) relief forms are also common. Karst is found on the Ukrainian part of the plain (in particular, in the Sumy region). In the general relief, the hills are noticeably distinguished by their more picturesque views of the right banks of the rivers, as well as the terrain and tracts of Belogorye, Krivoborye, Galichya Gora, which we will talk about later.

Hydrography, flora and soil of the region

The climate of the Central Russian Plain is moderately continental. Summers are moderately hot here, and winters are frosty and snowy enough. The average annual amount of atmospheric precipitation ranges from 400 to 650 mm. The hydrographic network is well developed. The largest rivers of the region: Desna, Seim, Psel, Don, Vorskla, Oskol, Ugra, Zhizdra, Zusha, Seim. Within the plain is the source of the Oka - one of the main tributaries of the Volga.

The soil cover of the upland is represented mainly by chernozems and gray forest soils (in the north). Sod-podzolic soils are widespread under large forests, and archery-chernozem, marsh and sandy soils in river valleys. Most of the plain is today plowed up.

About 80% of the area of the Central Russian Upland is located in the natural forest-steppe zone. Significant areas are also occupied by swamps. In forests, the main tree species are oak, pine and birch. Maple, linden and ash are less common. Willow and alder groves grow along the banks of rivers and streams.

Natural reserve "Belogorye"

The reserve with the beautiful name "Belogorye" covers an area of 2 thousand hectares in the Belgorod region. An ancient oak grove, which is at least 300 years old, is under the special attention of scientists. For several centuries in a row, it was the private hunting property of the Sheremetevs, and therefore it is perfectly preserved. Another unique corner of the reserve is the so-called Yamskaya steppe. This is how the reference meadow steppe of Central Russia looks like. The botanical diversity of this area is simply amazing: there are about 80 plant species per square meter of territory!

In general, there are 370 plant species, 150 bird species and 50 species of various mammals within the borders of Belogorie.

Krivoborye tract

Krivoborye is an amazing corner of the Russian forest-steppe. It is located in the Ramonsky District of the Voronezh Region. The tract is a steep right slope of the Don, overgrown with sparse forest and bushes. The height of the coastal cliff reaches 50 meters, and the steepness of the slope is 75 degrees. The river bed in this place also deserves attention: here it is very winding and complicated by numerous rifts.

The Krivoborye tract was included in the list of geological natural monuments back in 1969. Its total area is 15 hectares.

Reserve "Galichya Gora"

Galichya Gora is the smallest nature reserve on the planet, its area is only 19 hectares. It is located in the Lipetsk region. At the same time, a huge number of unique natural landscapes and objects are concentrated in such a small area. Within the reserve there are plant species that are completely uncharacteristic for the rest of the Central Russian Plain. And this is the main mystery of Galich Mountain, over which scientists have been fighting since 1925. It was then that the reserve was founded.

The main attraction of Galich Mountain is a picturesque rocky hill located on the high right bank of the Don. It is composed of Devonian limestones. The outcrops of these breeds "sheltered" about 650 species of plants on their cliffs. An impressive figure - botanists at the local museum of nature will tell you. Here you can also learn about all the diversity and uniqueness of the natural landscapes of this reserve.

EARTH SCIENCES

REGULARITIES OF FOREST-STEPPE LANDSCAPE FORMATION IN THE TERRITORY OF THE MIDDLE RUSSIAN HILLS (according to the results of soil-evolutionary studies)

SOUTH. Chendev

Belgorod State University, Belgorod, st. Victory, 85

[email protected]

A comparative analysis of the ancient and modern soils of the watersheds, studied on the territory of the Central Russian Upland, showed that the modern forest-steppe of the region is a formation of different ages. In the northern half of the Central Russian Upland, the age of the forest-steppe is estimated at 4500-5000 years, and in the southern half - less than 4000 years. During the formation of the forest-steppe, the linear rates of forest advancing on the steppe were less than the rate of frontal displacement of the climatic boundary between the forest-steppe and steppe, which occurred at the end of the Middle Holocene. For the southern part of the Central Russian Upland, the existence of an initial stage of a homogeneous soil cover of the forest-steppe (3900-1900 years ago) and a modern stage of a heterogeneous soil cover with the participation of two zonal soil types - chernozems and gray forest soils (1900 years ago - 16th century) was revealed.

Key words: forest-steppe, Central Russian Upland, Holocene, soil evolution, rate of soil formation.

Despite more than a century history of studying the natural evolution of the vegetation cover and soils of the forest-steppe of the East European Plain, discussions about the origin and evolution of gray forest-steppe soils, the stages of Holocene evolution of forest-steppe chernozems, and the duration of the existence of the modern vegetation cover of the forest-steppe zone continue to this day. Researchers of the natural evolution of forest-steppe landscapes use a wide range of objects and research methods. However, for more than 100 years, the main objects of study of the origin and evolution of the region's landscapes have been soils - unique formations in which information is "recorded" not only about the modern, but also about the past stages of the formation of the natural environment.

At the center of the ongoing discussions about the origin of the forest-steppe landscape lies the disclosure of the following questions: What comes first - forest or steppe, gray forest-steppe soils or meadow-steppe chernozems? What is the age of the Eastern European forest-steppe as a zonal formation within its present-day borders? The data and a number of other issues are highlighted in the proposed article, which summarizes the results of many years of research to the authors of the Holocene evolution of soils on the territory of the forest-steppe of the Central Russian Upland (Central forest-steppe).

To date, two opposing points of view have been identified on the origin of the automorphic (zonal) gray forest soils of the Central forest-steppe.

B.P. and A.B. The Akhtyrtsevs defend the opinion about the ancient (Middle Holocene) age of the watershed oak forests of the typical forest-steppe and the resulting ancient age of the gray forest-steppe soils, which originated from the forest-meadow soils of the first half of the Holocene. These authors note the fact of the late Holocene advance of forests on the steppe (due to natural climate change), but it is not recognized that the chernozems that became forest chernozems during the Holocene subatlantic period could have transformed into the type of gray forest soils. Aleksandrovsky (1988; 2002), Klimanov, Serebryannaya (1986), Serebryannaya (1992), Sycheva et al. (1998), Sycheva (1999) and some other authors express an opinion about the forestlessness of the Central forest-steppe in the first half of the Holocene and the beginning of expansion of forests on the steppe only in the subboreal period of the Holocene (later 5000 years ago). At the same time, Aleksandrovsky (1983; 1988; 1994; 1998, etc.) proves the possibility of late Holocene transformation of chernozems into gray forest soils, but does not discuss in detail the mechanism of the emergence of insular forest tracts with forest soils among meadow-forb chernozem steppes of the late Holocene.

Objects and research methods

The objects under study are ancient soils preserved under uneven-aged earthen embankments of artificial (ramparts and mounds) or natural (emissions from the burrows of forest animals), as well as modern full-Holocene soils formed in natural conditions near the embankments. We also studied soils formed on the substrate of earthen embankments, which contributed to the refinement and detailing of paleosoil and paleogeographic reconstructions. The auxiliary objects of the study were maps of reconstructed areas of forests of the "pre-cultural" period (16th - first half of the 17th centuries) and archaeological monuments (mounds), the geography of distribution of which in the zones of atmospheric humidification of the modern period is considered to identify the differentiation of the forest-steppe territory according to the speed of forest advancing on the steppe and the age of forest soil formation.

In the course of the work, a wide range of research methods were used: genetic analysis of the soil profile, comparative-geographical, chrono-series of daytime and buried soils, historical-cartographic, various methods of laboratory analysis of soils, as well as methods of mathematical statistics.

Laboratory analyzes of soil samples taken at key sites were carried out at the Belgorod Agricultural Academy, Belgorod Research Institute of Agriculture, at the Departments of General Chemistry, Environmental Management and Land Cadastre of Belgorod State University.

Results and its discussion

In a number of key areas studied, the paleosols of the Late Bronze and Early Iron Ages, located in automorphic positions of the relief (flat watersheds, watershed slopes, upland areas of watersheds near river valleys), were identified by us as steppe chernozems without signs of forest peodogenesis, or as chernozems, which were at the initial stages of degradation under forests (already with signs of textural differentiation of profiles and the presence of a grayish coating of bleached grains of the skeleton in the lower half of their humus profiles). The modern soil cover surrounding the soils studied under the earth embankments is represented by gray or dark gray forest soils (Fig. 1). In a number of other key areas, the background analogs of steppe paleochernozems buried for 35002200 years are chernozems podzolized at the early stages of degradation under forests. The found differences between the buried and background soils indicate the process of the late Holocene expansion of forests on the steppe and regular transformation

in the time of the original steppe chernozems of the Middle - Late Holocene into podzolized (degraded) chernozems, and then into gray forest soils. According to the study of the evolution of soils on rocks of different lithological composition, the period of evolutionary transformation of automorphic "forest" chernozems into gray forest soils (in the context of climatic fluctuations of the late Holocene) had the following duration: on sands and sandy loams - less than 1500 years, on light loams ~ 1500 years, on medium and heavy loams - 1500-2400 years, on clays - more than 2400 years. The degradation transformation of chernozems into gray forest soils was accompanied by a decrease in the content and reserves of humus, leaching, acidification, redistribution of silt, an increase in the eluvial-illuvial part of the profiles, and an increase in the total thickness of the soil profiles. The results of a comparative analysis of the morphometric characteristics of forest paleochernozems and gray forest soils of the modern period are shown in Fig. 2.

Rice. 1. Location of a number of studied objects and profile distribution of characters in modern gray forest soils (column of soils on the right) and their paleosimilars of the end of the Subboreal - beginning of the Subatlantic period of the Holocene (column of soils on the left)

Rice. 2. Series of differences in morphometric characteristics of modern gray forest soils and their chernozem paleosimilars at the early stages of degradation under forests. Parent rocks are loams and clays. The difference in thickness and depth (cm) at each site is shown by columns, the column numbers correspond to the numbers of the sites on the diagram, the reliable average differences are underlined (author's data)

The speed of forest advancing on the steppe, which has taken place over the past 4000 years, has not been constant over time. During the episodes of climate aridization (3500-3400 years ago; 3000-2800 years ago; 2200-1900 years ago, 1000-700 years ago),

The linear rates of forest advancing on the steppe decreased, and even a reduction in forest areas was probable. For example, judging by the properties of paleosols confined to archaeological sites of different ages in the upland part of the river. Voronezh, during the Sarmatian period of climate aridization (2200-1900 years ago), there was a break in afforestation of the watershed slope and the restoration of steppe soil formation conditions in areas occupied by forests at earlier and later periods. In this area, the paleosols buried under the earthen mounds of the Scythian (earlier) time have a more “forest” appearance than the soils buried under the embankments of the Sarmatian (later) time, buried by mole rats and with thicker humus horizons. After the Sarmatian period of aridization, the forest again occupied the upland part of the Voronezh valley. Modern background soils studied near archaeological sites are fully developed gray forest soils, reflecting a long forest development stage over many centuries.

In order to consider in detail the tendencies and regularities of the natural evolution of the natural environment and zonal soils of the Central forest-steppe in the second half of the Holocene, it was necessary to carry out a number of calculations.

Three independent methods were used to estimate the position of the climatic boundary between the forest-steppe and steppe 4000 years ago. - during the last significant advance of the steppes to the north, which coincided with an episode of sharp climate aridization - the most significant in the entire Holocene. The first method (Fig. 3, scheme A) consisted in calculating the time of occurrence of upland forests in the south, in the center and in the north of the forest-steppe zone. For this, the results of personal observations of the author were used, as well as information from a number of works, which give the characteristics of forest soils buried under the defensive ramparts of Scythian settlements on the upland parts of river valleys (contacts of the slopes of valleys and watersheds). Information on the morphogenetic characteristics of the paleosols of the Belsk settlement was provided to the author of the work by F.N. Lisetskiy, who conducted research on this site in 2003.

By the time of burial, all studied paleosols were altered to varying degrees by forest soil formation and were at different stages of transformation of chernozems into gray forest soils - from the initial stage of formation of leached textured differentiated chernozems (at the Belsk and Mokhnachansk fortified settlements) to the final stage of the formation of dark gray soils. and gray forest soils (on the settlements of Verkhneye Kazachye, Ishutino, Perekhvalskoe-2, Pereverzevo-1). Knowing the time of soil overlap with artificial sediments (dates of occurrence of the monuments) and the time intervals necessary for the transformation of automorphic chernozems of various textures into gray forest soils after forest settling on steppe sites, we calculated the approximate time of forest settlement at each studied site. Since the forests of the upland type, in our understanding, already serve as indicators of the forest-steppe natural and climatic situation, the reconstructed time characterizes the initial stages of the formation of forest-steppe landscapes in various regions of the Central forest-steppe. According to the proposed reconstruction, in the north of the forest-steppe zone (southern part of Tula, northern part of Lipetsk and Kursk regions), forest-steppe conditions could already exist at the beginning of the Holocene Subboreal period, and near the southern border of the forest-steppe zone, forest-steppe landscapes apparently appeared only at the end of the Subboreal period. ... Thus, the border between the steppe and the forest-steppe is 4000 years. n. could be located 140-200 kilometers north of its present position.

Rice. 3. Location of the studied sites, characteristics of automorphic paleosols with signs of forest pedogenesis and the reconstructed time of the emergence of forests (A), places of study of 4000-year-old black soil under barrows and the distance from them (km) to the nearest areas of modern analogs (B). Legend:

1 - modern southern and northern boundaries of the forest-steppe zone;

2 - the time of the appearance of upland forests, thousand years. n. (reconstruction);

3 - hypothetical line of the southern boundary of the distribution of upland deciduous forests 4000 y. n. (author data)

The identification of the components of the ancient soil cover conserved under the mounds of the Middle Bronze Age and the calculation of their distance from the area of modern distribution of close zonal analogs (the second reconstruction method, Fig. 3, Scheme B) suggest that the boundary between the forest-steppe and steppe is 4000 years ago. n. was located 60-200 km northwest of its present position.

The third method of reconstruction consisted in correlating the thickness of humus profiles of modern and ancient chernozems with linear gradients of fall from northwest to southeast of the thickness of humus profiles of chernozems of the modern period near the border between the forest-steppe and steppe. In modern conditions, the magnitude of the power drop for every 100 km of distance varies from 18 to 31%. If 42003700 l. n. the thickness of humus profiles of steppe chernozems was 69-77% of the background values, then, according to our calculations, the steppe zone at that time could be located 100-150 km northwest of its present position. Thus,

Thus, all three reconstruction methods give a close deviation of the southern boundary of the forest-steppe zone from the present position 4000 years ago. - 100-200 km.

In conditions of high natural dissection of the Central Russian Upland, an invariable attribute of the steppe landscape that existed in the Middle Holocene in its most part was the presence of ravine-type forests, gravitating towards the upper reaches of the gully systems. It is from such forests, as well as forest islands on the slopes of river valleys, that, in our opinion, the advancement of forest vegetation on the steppe began under conditions of a humid climate in the second half of the Subboreal and Subatlantic periods of the Holocene. An idea of the high degree of natural dissection of the territory is given in Fig. 4, which shows the valley-girder network of one of the sites in the south of the Central Russian Upland (within the boundaries of the Belgorod region). For forested areas of the modern period (reconstruction as of the middle of the 17th century), the average minimum linear growth rate of forests from girder systems was calculated, the merger of which led to the creation of large forest areas in the southern half of the Central forest-steppe. For this, the average distance between the beams was found within the forests that were widespread in the "pre-cultivated" period, which turned out to be 2630 ± 80 m (n = 800), and the maximum time required for the confluence of forests was calculated as a difference of 4000 (3900) l. n. - 400 (350) years ago ~ 36 centuries (the deducted date reflects the end of the natural development of landscapes before the beginning of their intensive economic transformation).

The calculation of the average minimum linear growth rate of forests is as follows: 2630: 2: 36 ~ 40 m / 100 years. However, as noted above, this rate varied in time: it decreased during the episodes of climate aridization, and increased during the periods of humidification and (or) cooling of the climate. For example, one of the intervals when the fastest possible afforestation of the territory of the Central forest-steppe could take place was the Little Ice Age - in the XUT-XVIII centuries. ... Nevertheless, the rate of the frontal displacement of the border of the forest-steppe and steppe to the south, which occurred at the end of the Subboreal period of the Holocene (as a result of rather rapid evolutionary climate changes), far outstripped the linear rates of forest advancing on the steppe within the forest-steppe zone.

In our opinion, the spatial irregularity of moisture in the region's territory in the Late Holocene was one of the main reasons for the uneven afforestation of the landscapes of the Central forest-steppe, which resulted in the formation of a mosaic of forest islands among meadow-forb steppes. This assumption is confirmed by the following observations. On the territory of the southern forest-steppe, the overwhelming majority of the known burial mounds were created on the steppe watersheds in the time interval of 3600-2200 years. n. However, out of 2450 kurgans in the Belgorod region, 9% of the kurgan embankments are still in forest conditions. We have established mathematical relationships between the number of forest burial mounds and moisture zones, as well as between moisture zones and forest cover of the modern period (Fig. 5). One gets the impression that the rate of forest advancing on the steppe had a spatial variation in accordance with the spatial change in the amount of atmospheric precipitation of the modern period. It is no coincidence that most of the areas of gray forest soils in the Belgorod, Kharkov, Voronezh, Kursk and Lipetsk regions are confined to zones of increased moisture. These zones arose as a result of local features of atmospheric circulation that developed in the late Holocene. Among the reasons for the spatial differences in the amount of atmospheric precipitation falling on the Central Russian Upland, the authors name the factor of unevenness of the surface relief.

As already noted, on the Central Russian Upland, afforestation of watersheds came from river valleys and gullies. In the south of the region under consideration (Belgorod and Voronezh regions), forests appeared in the valley zones of the watersheds 3500-3200 years ago. The middle parts of the plakors of the forested territory of the modern forest period could occupy only 1600-1700 years ago. or even a little later. Zones of forested spaces of the Central forest-steppe, which at different times entered the forest stage of formation, can probably be

to identify relict signs of steppe pedogenesis in the form of second humus horizons and paleo-rats by different preservation in the profiles of forest soils.

According to our calculations, the period of transformation of loamy chernozems into gray forest soils is 1500-2400 years. Provided that forest-steppe conditions appeared in the southern half of the forest-steppe zone only after 4000 years ago, the first areas of gray forest soils on the watersheds should have appeared here no earlier than 2000 years ago. Indeed, in the south of the Central forest-steppe, under the forest mounds of the Scythian Sarmatian period and under the ramparts of Scythian settlements located in a forest setting, we have not encountered a single case of description of full-profile loamy gray forest soils that could be identified with modern zonal equivalents. Were described either buried chernozems of steppe genesis, or chernozems that were at different stages of degradation under forests (Fig. 1). At the same time, studies carried out on the steppe interfluves of the region showed that the evolution of steppe subtypes of chernozems into forest-steppe ones (with the change of dry-steppe climatic conditions to meadow-steppe ones in the time interval 40003500 years ago) occurred no later than 3000 years ago. ... Consequently, on the territory under consideration, the age of the gray forest soils as a zonal type is approximately 4 times less than the age of chernozems (originated in the early Holocene) and 1.5-1.7 times less than the age of chernozems of the forest-steppe appearance (originated at the end of the Subboreal period of the Holocene).

Thus, the existence of two stages of the natural evolution of the forest-steppe cover was revealed: the initial stage of a homogeneous soil cover, when, when the forest moved onto the steppe, the chernozems that turned out to be under the forests, due to the inertia of their properties, continued to retain their morphogenetic status for a long time (3900-1900 years ago). ), and the stage of a heterogeneous soil cover with two zonal types of forest-steppe soils - gray forest soils under deciduous forests and chernozems under meadow-steppe vegetation (1900 years ago - present). The detected stadiality is schematically shown in Fig. 6.

Rice. 4. Valley-girder network and forests of the "pre-cultural" period (first half of the 17th century) on the territory of the Belgorod region (compiled by the author on the basis of an analysis of modern large-scale topographic maps and manuscript sources of the 17th century)

Rice. 5. Dependences between forest cover (mid-17th century) and the average annual precipitation of the modern period (A), zones of different moisture content of the modern period and the number of "forest" mounds within them (B) (Belgorod region)

STEPPE 4300-3900 years ago

FOREST STEPPE 3900-1900 years ago 1900 BP-XVI century

Chernozems

Chernozems of meadow steppes

Forest chernozems

Gray forest soils

Rice. 6. Scheme of the staging of the formation of zonal soils of the forest-steppe on the territory of the southern half of the Central Russian Upland (according to the author's data)

The study showed the complex nature of age and evolutionary relationships that exist in the modern soil-vegetation geospace of the Central forest-steppe.

1. The soil cover of the forest-steppe of the Central Russian Upland consists of the northern (older) and southern (younger) chronopodzones, differing in the age of forest-steppe soil formation for a period of at least 500-1000 years. In the era of medium

subboreal climate aridization (before the onset of modern bioclimatic conditions), the border between the forest-steppe and steppe was located to the north of its present position by 100-200 km.

2. The linear velocity of the late Holocene distribution of forests emerging from gullies and river valleys to watersheds was characterized by spatial and temporal specificity. It was higher in places of increased atmospheric humidification of the modern period and was subject to dynamics due to short-period climate changes.

3. The linear rate of the Late Holocene forest spread was lower than the rate of the frontal displacement to the south of the border between the forest-steppe and the steppe, which occurred as a result of rapid evolutionary climate changes at the end of the Middle Holocene. Therefore, the formation of forest-steppe landscapes within the forest-steppe zone lagged behind the formation of a climate corresponding to the zonal conditions of the forest-steppe landscape.

4. Gray forest soils of the Central forest-steppe on the watersheds originated from chernozems as a result of the late Holocene expansion of forests on the steppe. The transformation of chernozems under forests into gray forest soils was complicated by natural climate fluctuations - during short-term episodes of its aridization, soils returned to the subtypes of the previous stages of their evolution.

5. Within the southern half of the Central Russian Upland, two late Holocene stages of the natural formation of the soil cover of the forest-steppe are distinguished: the initial stage of a homogeneous chernozem soil cover (3900-1900 years ago), and the modern stage of a heterogeneous soil cover with the participation of two zonal types of soils - chernozems and gray forestry (1900 years ago - XVI century).

Bibliography

1. Akhtyrtsev B.P., Akhtyrtsev A.B. Evolution of soils of the Central Russian forest-steppe in the Holocene // Evolution and age of soils in the USSR. - Pushchino, 1986 .-- S. 163-173.

2. Milkov F.N. Physical geography: landscape studies and geographic zoning. - Voronezh: Voronezh Publishing House. University, 1986. - 328 p.

3. Akhtyrtsev B.P. On the history of the formation of gray forest soils in the Central Russian forest-steppe // Pochvovedenie. - 1992. - No. 3. - S. 5-18.

4. Serebryannaya T.A. Dynamics of the boundaries of the Central forest-steppe in the Holocene // Century dynamics of biogeocenoses. Readings in memory of academician V.N. Sukacheva. X. - M .: Nauka, 1992 .-- S. 54-71.

5. Aleksandrovsky A.L. The development of soils in Eastern Europe in the Holocene: Author's abstract. dis. doct. geogr. sciences. - M., 2002 .-- 48 p.

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7. Khotinsky N.A. The relationship between forest and steppe according to the study of the paleogeography of the Holocene // Evolution and age of soils in the USSR. - Pushchino, 1986 .-- S. 46-53.

8. Dinesman L.G. Reconstruction of the history of recent biogeocenoses from long-term shelters of mammals and birds // Century dynamics of biogeocenoses: Readings in memory of academician V.N. Sukachev. X. - M .: Nauka, 1992 .-- S. 4-17.

9. Golyeva A.A. Phytoliths as indicators of soil-forming processes // Minerals of soil genesis, geography, significance in fertility and ecology: Nauch. works. -M .: Soil Institute im. V.V. Dokuchaeva, 1996 .-- S. 168-173.

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26. Aleksandrovsky A. L., Golyeva A. A. Paleoecology of ancient man according to the data of interdisciplinary studies of soils of archaeological sites of the Upper Don // Archaeological sites of the forest-steppe Don region. - Lipetsk, 1996. - Issue. 1. - S. 176-183.

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LAWS GOVERNING FOREST-STEPPE LANDSCAPE FORMATION WITHIN CENTRAL RUSSIAN UPLAND (ACCORDING TO SOIL-EVOLUTIONAL STUDIES)

Belgorod State University, 85 Pobeda Str., Belgorod, 308015 [email protected]

Comparative analysis of ancient unequal-age and contemporary soils of watersheds, studied in the territory of Central Russian Upland, has shown that modern forest-steppe of the region is unequal-age formation. Within northern half of Central Russian Upland age of forest-steppe landscapes is evaluated at 4500-5000 years, while on its southern half - less than 4000 years. During forest-steppe zone formation linear speeds of forests invasion on steppes were less than frontal shift speed of climatic border between forest-steppe and steppe zones, which occurred at the end of Middle Holocene. For southern part of Central Russian Upland existence of two stages has discovered: initial stage of homogeneous soil cover of forest-steppe landscape (3900-1900 years ago) and modern stage of heterogeneous soil cover with participation of two zonal types of soils - chernozems and gray forest soils (1900 years ago - XVI century).

The keywords: forest-steppe, Central Russian Upland, Holocene, evolution of soils, speed of soil formation.

The Central Russian Upland occupies a central position among the Russian Plain. It stretches from the north-north-west to the south-south-east from the right bank of the Oka valley (Kaluga - Ryazan) to the Donetsk ridge. From the west and east it is bordered by the Dnieper and Oka-Don lowlands. In the north, it serves as the watershed of the Desna, Oka and Don, to the south it forms the watershed of the Dnieper, Donets and Don.

The central part of the region can be considered the outskirts of Orel, where its higher points are located. This is the so-called Plavskoe plateau with heights of 310 m, where the rivers Zusha and the Beautiful Sword originate. The most common heights for the watersheds of the Central Russian Upland vary within 220-250 m. Thus, the Central Russian Upland rises above the lowest elevations of the Dnieper and Oka-Don lowlands by an average of 120-150 m.

In the southeast, the Don, cutting through the Central Russian Upland, separates the Kalach Upland with heights of up to 234 m from it, which serves as a watershed between the Don and Khopra.

The surface of the Central Russian Upland is an undulating plain dissected by deep valleys of rivers, gullies and branching ravines. The depth of the incision in some places reaches 100 and even 150 m.Rivers such as the Oka with their numerous tributaries (Zusha, Upa, Zhizdra), Don with tributaries Krasivaya Mecha, Sosna, Tikhaya Sosna, Kalitva and others, originate from the Central Russian Upland. , Severny Donets, Vorskla, Psel, Seim and a numerous network of smaller rivers and gullies and ravines confined to them.

As noted in the general part of this work, the main orographic units of the Russian Plain, as a rule, correspond to the main structural units of the Russian Platform.

In this case, we observe the following: in the center of the Central Russian Upland, in the region of Kursk, Orel and Voronezh, crystalline rocks, which make up the Voronezh anteclise, lie high. Its axial part runs approximately along the line Pavlovsk (on the Don) - Kursk, where the cover of sedimentary rocks does not exceed 150-200 m. And in Pavlovsk, as is known, crystalline rocks are exposed by the Don. In all directions from the axis, the sedimentary stratum greatly increases in thickness, and the Precambrian rocks gradually recede to greater depths (Fig. 1). The Voronezh anteclise has an asymmetrical structure. Its northern slope is the southern wing of the Moscow syneclise, and the southern one falls steeply to the Dnieper-Donetsk syneclise.

Rice. 1. Section through the Voronezh anteclise along the Don from Zadonsk to Pavlovsk and further south to Kantemirovka (according to AD Arkhangelsky, 1947): 1 - granite; 2 - Devonian (Voronezh, Semiluksky and Shchigrovsky layers); 3 - Devonian (Evlanovskiy and Yeletsk layers): 4 - Carboniferous rocks; 5 - Mesozoic sandy-clayey rocks of the ancient Cenomanian; 6 - upper chalk; 7 - Paleogene; 8 - Quaternary deposits

The northern slope of the Voronezh anteclise is covered by Devonian and Carboniferous layers, which are hidden by thin Jurassic and Cretaceous sediments.

The southern slope of the Voronezh anteclise descends very sharply, and with it the Paleozoic rocks that overlap it quickly go to depth, and the terrain is composed of Cretaceous and Tertiary rocks, which reach considerable thickness here.

On the northern slope of the Voronezh anteclise, the Devonian deposits are represented by dense thick-bedded limestones with rare interlayers of clay. In the Oka and Don basins, they are exposed by rivers. Near the axis of the Voronezh anteclise, the Devonian strata lie almost horizontally. Towards the Moscow syneclise, they detect a fall and increase their power. On the southern slope of the Voronezh massif, the Devonian layers fall steeply towards the Dnieper-Donets syneclise.

Recent studies have established an extremely uneasy Devonian surface. This is largely due to the existence on the northern slope of the Voronezh block of the Eletsk-Tula and Orel tectonic uplifts, which create the Middle-Russian swell of the Russian platform. Within this swell, the absolute elevations of the Devonian roof reach 266 - 270 m at the absolute elevations of the modern elevation surface of 290-300 m. area of the sea, then the sea completely bypassed it. According to BM Danshin (1936), this uplift significantly influenced the spread of the Quaternary glacier. It turned out to be the focus that made the glacier of the Dnieper time split into two large languages: Dnieper and Don.

In addition to the Middle Russian swell, a number of secondary uplifts and troughs are distinguished. Such are the Lipitsko-Zybinskoe uplift, located in the upper reaches of the Zusha, and the Oka depression, which is used by the upper reaches of the Oka. In addition, in the basin of the river. Zushi, Devonian sediments were found, with which the consistent direction of the river valleys is associated. Small anticlines are also found on the river. Oka and in other places.

Coal deposits in the area under consideration are represented by limestones and the coal-bearing suite lying between them with alternating sand, clay and coal interlayers. In the northern part of the Central Russian Upland, the Carboniferous rocks fall unevenly. M.S.Shvetsov (1932), and then V.A.Zhukov (1945) indicate the existence of sharp bends in the Carboniferous layers, one of which coincides with the Oka valley. In the south, Carboniferous falls sharply towards the Dnieper-Donetsk syneclise.

Mesozoic rocks (Upper Jurassic and Cretaceous) are represented mainly by sands, as well as writing chalk and marls with rare interlayers of clay. In the center of the Voronezh anteclise, they have an insignificant thickness and lie horizontally. Towards the Dneprovsko-Donetsk syneclise, their thickness increases extremely rapidly, and the strata receive a southwestern slope. In Shchigry, the thickness of the Mesozoic is 52.4 m, in Stary Oskol - 152.2, in Kursk - 225, and in Belgorod - 360 m. On the southern slope of the Voronezh syneclise, in some places, flexure-like bends in the layers of the Mesozoic are observed. They are known near Belgorod, Pavlovsk, but they are especially well pronounced within the Kalachekoy Upland, where folds in Cretaceous deposits stretch parallel to each other through the cities of Kalach and Boguchar.

Paleogene rocks, lying transgressively on Cretaceous rocks, are developed only in the southern part of the Central Russian Upland and are represented mainly by sands with rare interlayers of clays, sandstones and marls. They are generally much less thick than the Mesozoic rocks, reaching a maximum of 70 m.

The Central Russian Upland in its northern parts and partly along the western and eastern slopes was covered with a glacier. Therefore, in these territories, we find deposits of glacial origin in the form of a washed moraine, the thickness of which varies within the range of up to 15 m. Typical moraine deposits are noted in a limited number of places, including the right bank of the Oka between Aleksin and Serpukhov. More often on the Central Russian Upland, you can find strips of fluvioglacial sands stretched along river valleys.

The surface formations of the upland are loess-like loams, which turn into loess in the south. Their power is variable. On watersheds, it decreases to 2-3 m, while on the slopes of river valleys and gullies it reaches 10-12 m.

Judging by the distribution and thickness of sedimentary deposits that compose the Middle Russian Upland, it can be assumed that the Voronezh anteclise intensively influenced the geological development of the territories adjacent to it. Despite the fact that the Central Russian Upland, with its core in the form of the Voronezh projection, the Precambrian experienced either positive or negative movements, throughout geological history it was a positive element of the relief, which prevented the spread of the southern seas to the north, and the northern ones to the south. This is evidenced not only by the thickness, but also by the facies composition of the sediments.

On the basis of this, it can be concluded that the Middle Russian Upland as a well-expressed geomorphological formation has existed in any case since the Paleozoic.

The geomorphological peculiarity of the Central Russian Upland lies in its very sharp and young erosional dissection superimposed on ancient erosional forms. The upland is a classic region of the development of gully-ravine relief; therefore, the process of its development, as well as of the valley relief, is one of the main issues in the analysis of the relief of the upland.

Even SN Nikitin (1905) established the ancient erosional nature of the Central Russian Upland, especially the ancient one along the northern slope of the Voronezh anteclise. On the southern and southwestern slopes, the hydrographic network is of a younger age.

In fact, in the northern regions of the Central Russian Upland, we observe bright traces of a long stage of continental development of the territory, which lasted from the end of the Carboniferous period to the beginning of the transgression of the Jurassic Sea. This period left a very uneven surface, based on limestones of the Carboniferous and Devonian times. This surface testifies to the intensive erosion and karst processes taking place here. Along with the pre-Jurassic valleys, there are valleys of the pre-Cretaceous and, finally, pre-Quaternary ages.

Analyzing the data characterizing the pre-Jurassic, pre-Cretaceous and pre-Quaternary relief of the northern part of the Central Russian Upland, and comparing it with the modern relief, one can draw a conclusion about their proximity to each other, explained by the fact that the modern hydrographic network in most cases was laid in the ancient, often pre-Jurassic erosion. This applies to the rivers Oka, Proni, Shati, etc.

In the Oka basin, where chalk deposits are also developed, it was found that the valley of the upper Oka, as well as its largest tributaries and the lower reaches of large ravines, received clear outlines even before the beginning of the deposition of chalk sands, which lined the irregularities of the pre-Cretaceous relief and, in many cases, smoothed it out. It is very interesting that the pre-Cretaceous valley of the Oka had asymmetric slopes.

The modern erosion network of the Central Russian Upland was established after the sea finally retreated from this territory, and in the north only after the glacier left. In this regard, the central, most elevated part of the Central Russian Upland, which entered the continental period of development earlier (the Lower Paleogene), has the most ancient hydrographic network; it is followed by the south of the upland (Upper Paleogene). Most recently, the river network of the north began to form (after the glacier of the Dnieper period left it).

However, when studying the history of the development and age of the valley-girder network of the Middle Russian Upland, it is necessary, in addition, to take into account that in the center and in the north of the upland, where the Mesozoic deposits are thin, the ancient pre-Jurassic and pre-Cretaceous network brightly shines through in the modern relief. ... Thanks to this, the rivers, using it, quickly form their valleys. On the contrary, in the southern part, where the strata of Cretaceous and Tertiary deposits are extremely powerful, the ancient Upper Paleozoic valley network does not appear in the modern relief, and the rivers are forced to make their way in a new place. Because of this, the young rivers of the north have more developed valleys than the rivers of the south that arose at an earlier time.

The development of the hydrographic network of the Central Russian Upland was greatly influenced by the glacier. For the Dnieper glacier, the Middle Russian Upland, and in particular the Eletsko-Tula and Oryol uplifts, were a serious obstacle in its advance to the south. In this regard, the glacier was able to cover only the northern part of the Central Russian Upland, as well as its western and eastern periphery. The glacier descended in tongues to the south along the Oka, Narucha, Nugra, Zusha and Seim rivers, leaving behind a thin layer of moraine. No accumulative glacial landforms are currently observed on the Central Russian Upland. The main role of the glacier affected the restructuring of the hydrographic network. There was a damming of the rivers flowing from the hill to the north, east and west. So, for example, BM Danshin (1936) believes that there was an overflow of water from the Oka basin into the Desninsky basin across the river. Nerussu and R. I will. At the same time, according to M.S.Shvetsov (1932), Oka acquired its latitudinal sections between Kaluga and Aleksin and below Serpukhov.

According to M.S.Shvetsov, in the preglacial time there were two meridional valleys. One is currently used by the upper reaches of the Oka and further in the north of the river. Sukhodrev, the second is used by the meridional section of the river valley. Upy and Okoy from Aleksin to Serpukhov. The flooding of the rivers by glacier and then by the end-bed material forced the rivers to look for a way out to the east and west. As a result of this, latitudinal sections of the river were created. Upa in its lower reaches, Ugra and Oka on the section between Kaluga and Aleksin, Protva and Oka below Serpukhov.

The view of M.S.Shvetsov, which became firmly established in the literature, was later refuted by V.G. Lebedev (1939), who in the area of the Kaluga-Aleksin Oka valley discovered a clearly developed series of ancient alluvial terraces, the heights of which coincide with the heights of the terraces of the pre-Kaluga Oka and the segment, lying below Aleksin. Thus, according to V.G. Lebedev, the Oka valley is of the same age, and its existing morphological differences are explained by various lithological conditions encountered on its way.

Along the western and eastern outskirts of the Central Russian Upland, in the place of its contact with the body of the glacier, a network of glacial water runoff valleys has been traced. P. Ya. Armashevsky wrote about this in his time (1903). He pointed to the existence of a once bypass valley along the edge of the glacier, which received the waters of the dammed rivers. The Seim River was connected through channels with Psel and Vorskla. A similar picture was in the east of the Central Russian Upland, where the rivers flowing into the Don lowland were dammed latitudinally and flowed in the meridional direction along the edge of the glacier to Oskol (Sosna, Devitsa, Tikhaya Sosna, Potudan).

After the glacier left, the northern part of the Central Russian Upland, as well as the southern one, underwent intense erosional erosion. Due to this, the modern relief of the Central Russian Upland is primarily an erosional relief (Fig. 2). AI Spiridonov (1950) writes in this regard that "its (relief - MK) forms are determined by the main pattern, the density and depth of the erosion network, as well as the shape of valleys, gullies and ravines."

Rice. 2. Gully-ravine network of the Central Russian Upland near the town of Belev.

A.F. Guzhevaya (1948) on the Central Russian Upland distinguishes two types of river network patterns: in the north and in the center, where the slope of the initial surface is insignificant and not quite definite, the direction of surface water runoff was influenced by minor slopes of the terrain, rock composition, fracturing ... In this case, a tree-branching pattern of the river network developed (Zusha, Sosna, Upa, Oka).

A characteristic feature of the hydrographic network of the northern part of the territory, according to A. F. Guzheva, is the narrowness of the valleys, their strong tortuosity and changing asymmetry. Sharp changes in the direction of rivers are also typical. The slopes of the valley-girder network have a convex shape due to the increasing steepness of the slope towards the bottom. The upper reaches of the gullies are narrow, gentle hollows, the slopes of which imperceptibly merge with the watershed area.

For the southern and southwestern slopes of the Central Russian Upland, where the slope of the seams and the topographic surface is sharper, the pattern of the river network is simpler; it is poorly developed in width, elongated, according to the slope of the terrain, in the form of a narrow strip (Oskol, Vorskla). Sometimes there are rivers with an asymmetrically developed basin. AF Guzhevaya (1948) calls this drawing "flag" (Tikhaya Sosna, Kalitva, etc.). Convex-concave or concave slopes prevail here. Towards the bottom, the steepness of the slope decreases.

The southern and southwestern slopes of the upland are characterized by a pronounced asymmetry of the interfluves. The tops of the beams here are distinguished by a circus-like structure.

These differences in the direction and pattern of the hydrographic network, according to A.F.Guzheva (1948). are explained by the difference in the initial surface on which the river network lay. In the southern and southwestern parts of the Central Russian Upland, there has long been a pronounced slope of the surface to the south and west, as a result of which basins elongated in the same direction were created. In the northern part of the Central Russian Upland, the surface was smoother, slightly inclined towards the Moscow Basin, due to which the basin developed evenly, acquiring the pattern of a branching tree.

The density of the dissection of the Central Russian Upland is not the same in its different regions. According to AI Spiridonov (1953), the most dissected area is located to the west of the Oka, where gullies and valleys of the Oka's tributaries are widely developed. The density of dissection here is determined by the value of 1.3-1.7 km per 1 sq. km. A lesser density of dissection is observed on the coast of the Seim, to the west and north of Kursk, in the south of the upland, in the basins of Psela, Northern Donets and Oskol, where the density of the valley-girder network is 1.1-1.5 km per 1 sq. km. The basin of the Zushi and Sosna is even less dissected (1.0-1.2 km per 1 sq. Km). The central watershed part of the upland is dissected even weaker (up to 0.8-0.9 km, and in some places further up to 0.3-0.7 km per 1 sq. Km). A similar division is observed on the watersheds of the Nerucha, Sosna, Seim, and right tributaries of the Don.

The incision depth of the main valleys in different parts of the Central Russian Upland is also not the same. According to S.S.Sobolev (1948), we observe the deepest valleys and gullies within the Kalach Upland in the Oskol basin, where the incision reaches 150 m in places. Oskol, Northern Donets, Pselo and their tributaries. The smallest amplitude of relief fluctuations is observed in the upper reaches of the Oka and Don, where the incision is usually 50-75 m.

Along with the ancient erosional network, the Middle Russian Upland is crossed by young erosional forms - ravines and gullies (Fig. 3). It is extremely important to note that modern erosion is associated in the overwhelming majority of cases with the ancient hydrographic network.

Rice. 3. Ravines in the Voronezh region (photo 3. 3. Vinogradov)

The morphological appearance of the ravines of the Central Russian Upland depends on the morphology of the gullies that they cut through, on the size of their catchment area and on the lithological composition of the rocks in which they have to make their way.

A.S. Kozmenko (1937) distinguishes between two groups of ravines: bottom and coastal. The former cut the bottom of the ancient ravine, the latter cut its slope. AI Spiridonov (1953) distinguishes between two types of bottom ravines. Ravines of the first type inherit well-developed ancient forms of erosion with developed gully alluvium. Ravines cut into their bottom by 2-3 m and often reach several kilometers in length. Bottom ravines of the second type cut through the bottoms of poorly developed beams. They are characterized by a steep longitudinal profile, 10-15 meters deep and often cut not only into alluvium, but also into bedrocks.

Slope or coastal ravines on the Central Russian Upland usually extend for several hundred meters and have a depth of 8 - 25 m. The morphology of these ravines is largely determined by the lithology of the rocks they cut through. When loose and hard rocks alternate, they often form a stepped longitudinal profile.

A.F. Guzheva (1948) compiled a map of the gully of the Middle Russian Upland, from which it is clear that the northern part of the Central Russian Upland, belonging to the Oka basin, and the southwestern part, located in the Sula and Psela basins, are distinguished by the least development of gullies. This is followed by the southeastern section of the upland within the left bank of the Northern Donets, in its lower reaches, where only high, steep right slopes of the valleys of the left tributaries, basins of the middle reaches of the Psela, Vorskla are covered by modern erosion. This is followed by the entire central part of the Central Russian Upland, which includes the basin of the Zushi, Sosna, Seim, the upper reaches of the Psela, where the length of the ravine network is 1 sq. km of the area ranges from 0.2 to 0.4 km. Finally, the most ravine area is the Pridonskaya part of the Central Russian Upland and the Kalachev Upland. Here the length of the ravine network is 1 sq. km of the area reaches 0.5-1.2 km.

“Modern erosion,” writes A. F. Guzhevaya (1948, p. 63), “which has reached such large dimensions in this area, is truly a real disaster. A section of the right slope of the river. Podgornaya, about 3 km wide, is dissected by 25 ravines up to 20 m deep ”. The ravines of this region are characterized by strong branching of their tops. The bottoms of all the beams have been cut with ravines.

The Central Russian Upland has all the necessary conditions for the vigorous development of modern erosion processes: 1) a tendency to uplift, 2) the unevenness of the initial relief, 3) the soft composition of the surface rocks, 4) the speed of melting of the snow cover, 5) heavy summer rains, 6) more the recent predatory deforestation and improper plowing. According to AF Guzheva (1948), not just one, but the manifestation of all the above factors in a complex explains the wide distribution of ravines within the Central Russian Upland. However, the depth of the basis of erosion is still one of the most important factors affecting the intensity of the development of the ravine network. Black Sea lowland

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Practical work No. 3.

Theme: Explanation of the dependence of the location of large landforms and mineral deposits on the structure of the earth's crust using the example of individual territories.

Objectives of the work:

1. To establish the relationship between the placement of large landforms and the structure of the earth's crust.

2. Check and evaluate the ability to compare maps, explain the identified patterns.

3. Using the tectonic map to determine the patterns of distribution of magmatic and sedimentary minerals.

4. Explain the identified patterns.

Sequence of work

2. Fill out the results of the work in the form of a table.

Landforms	Prevailing heights	Tectonic structures at the base of the territory	Conclusion on the dependence of the relief on the structure of the earth's crust
OPTION 1
the East European Plain
Central Russian Upland
Khibiny mountains
OPTION 2
West Siberian lowland
Caucasus
Ural mountains
OPTION 3
Altai
Sayan
Verkhoyansk ridge
OPTION 4
Chersky ridge
Sikhote-Alin
Middle ridge

1. On the map of the atlas "Tectonics and Mineral Resources", determine what minerals the territory of our country is rich in.

2. How are the types of igneous and metamorphic deposits indicated on the map? Sedimentary?

3. Which ones are found on the platforms? What minerals (magmatic or sedimentary) are confined to the sedimentary cover? What are the protrusions of the crystalline basement of ancient platforms on the surface (shields and massifs)?

4. What types of deposits (magmatic or sedimentary) are confined to folded areas?

5. Fill out the results of the analysis in the form of a table, draw a conclusion about the established dependence.