Which territories were not centers of glaciation. The Valdai Glaciation is the last ice age of Eastern Europe. See what “glaciation center” is in other dictionaries
The land surface was repeatedly subjected to continental glaciation (Fig. 110). Evidence of the frequency of glaciations on the plain in the Pleistocene is the presence of remains of relatively heat-loving plants in intermoraine deposits.
During the era of maximum glaciation, glaciers covered more than 30% of the land area. In the northern hemisphere, they were located in the northern parts of Europe and America. The main centers of glaciation in Eurasia were on the Scandinavian Peninsula, Novaya Zemlya, the Urals and Taimyr. In North America, the centers of glaciation were the Cordillera, Labrador, and the area west of Hudson Bay (Keewatin Center).
In the relief of the plains, the traces of the last glaciation (which ended 10 thousand years ago) are most clearly expressed: the Valdai glaciation on the Russian Plain, the Wurm glaciation in the Alps, and the Wisconsin glaciation in North America.
The moving glacier changed the topography of the underlying surface. The degree of its impact was different and depended on the rocks that made up the surface, on its relief, and on the thickness of the glacier. The surface, composed of soft rocks, was smoothed by the glacier, destroying sharp protrusions. He destroyed fissured rocks, breaking off and carrying away pieces of them. Freezing into the moving glacier from below, these pieces contributed to the destruction of the surface.
Encountering hills composed of hard rocks along the way, the glacier polished (sometimes to a mirror shine) the slope facing its movement. Frozen pieces of hard rock left scars, scratches, and created complex glacial shading. The direction of glacier scars can be used to judge the direction of glacier movement. On the opposite slope, the glacier broke out pieces of rock, destroying the slope. As a result, the hills acquired a characteristic streamlined shape "mutton foreheads". Their length varies from several meters to several hundred meters, the height reaches 50 m. Clusters of “ram’s foreheads” form a relief of curly rocks, well expressed, for example, in Karelia, on the Kola Peninsula, in the Caucasus, on the Taimyr Peninsula, and also in Canada and Scotland.
A moraine was deposited at the edge of the melting glacier. If the end of the glacier, due to melting, was delayed at a certain boundary, and the glacier continued to supply sediments, ridges and numerous hills arose terminal moraines. Moraine ridges on the plain often formed near protrusions of subglacial bedrock relief. Ridges of terminal moraines reach a length of hundreds of kilometers and a height of up to 70 m. Sometimes they are located parallel to each other. The depressions separating the uplands in the area of the terminal moraine are often occupied by swamps and lakes. A striking example of a terminal moraine ridge is Salpausselskä (Finland). When advancing, the glacier moves in front of itself the terminal moraine and loose sediments it deposited, creating pressure moraine- wide asymmetrical ridges (steep slope facing the glacier). Many scientists believe that most terminal moraine ridges were created by glacier pressure.
When a glacier body melts, the moraine contained in it is projected onto the underlying surface, greatly softening its unevenness and creating relief main moraine. This relief, which is a flat or hilly plain with swamps and lakes, is characteristic of areas of ancient continental glaciation.
In the area of the main moraine one can see drumlins- oblong hills, elongated in the direction of glacier movement. The slope facing the moving glacier is steep. The length of drumlins ranges from 400 to 1000 m, width - from 150 to 200 m, height - from 10 to 40 m. Drumlins are located in groups in the peripheral region of glaciation, on the plain or in foothill areas. On the surface they are composed of a moraine covering a core of bedrock deposits or deposits of meltwater flows. Their origin is still unclear. It is assumed that the moraine, frozen into the bottom of the glacier, lingered at the heights of the glacier bed, enlarging them. sizes, and the glacier gave them a smoothed shape.
On the territory of Russia, drumlins exist in Estonia, on the Kola Peninsula, in Karelia and in some other places. They are also found in Ireland and North America.
The flow of water that occurs as the glacier melts washes away and carries away mineral particles, depositing them where the flow rate slows down. With the accumulation of meltwater deposits, layers of loose sediments appear, differing from moraine in the sorting of material. Landforms created by meltwater flows, both as a result of erosion and as a result of sediment accumulation, are very diverse.
Ancient drainage valleys melted glacial waters - wide (from 3 to 25 km) hollows stretching along the edge of the glacier and crossing pre-glacial river valleys and their watersheds. Deposits from glacial waters filled these depressions. Modern rivers partially use them and often flow in disproportionately wide valleys.
Ancient valleys can be observed in Russia (Baltic states, Ukraine), Poland, Germany.
Kams are round or oblong hills with flat tops and gentle slopes, externally resembling moraine hills. Their height is 6-12 m (rarely up to 30 m). The depressions between the hills are occupied by swamps and lakes. Kames are located near the glacier boundary, on its inner side, and usually form groups, creating a characteristic kame relief.
Kamas, unlike moraine hills, are composed of roughly sorted material. The diverse composition of these sediments and the thin clays found especially among them suggest that they accumulated in small lakes that arose on the surface of the glacier. When the glacier melted, the accumulated sediments were projected onto the surface of the main moraine. The question of the formation of kama is not yet clear.
Thawing individual blocks dead ice, hidden in the deposits of glacial waters, explain the origin of glacial baths (zolls) - relatively small rounded depressions (diameter - several tens of meters, depth - several meters). Glacial baths are also found in permafrost areas.
Ozy- ridges resembling railway embankments. The length of the eskers is measured in tens of kilometers (30-40 km), the width is in tens (less often hundreds) of meters, the height is very different: from 5 to 60 m. The slopes are usually symmetrical and steep (up to 40°).
The eskers extend regardless of the modern terrain, often crossing river valleys, lakes, and watersheds. Sometimes they branch, forming systems of ridges that can be divided into separate hills. The eskers are composed of diagonally layered and, less commonly, horizontally layered deposits: sand, gravel, and pebbles.
The origin of eskers can be explained by the accumulation of sediments carried by meltwater flows in their channels, as well as in cracks inside the glacier. When the glacier melted, these deposits were projected onto the surface.
Zandra- spaces adjacent to terminal moraines, covered with deposition of meltwater (washed out moraine). At the end of the valley glaciers, the outwash is insignificant in area, composed of medium-sized rubble and poorly rounded pebbles. At the edge of the ice cover on the plain, they occupy large spaces, forming a wide strip of outwash plains. Outwash plains are composed of extensive flat alluvial fans of subglacial flows, merging and partially overlapping each other. Landforms created by the wind often appear on the surface of outwash plains.
An example of outwash plains can be the strip of “woodlands” on the Russian Plain (Pripyatskaya, Meshcherskaya).
In areas that have experienced glaciation, there is a certain regularity in the distribution of relief, its zoning(Fig. 111). In the central part of the glaciation area (Baltic Shield, Canadian Shield), where the glacier arose earlier, persisted longer, had the greatest thickness and speed of movement, an erosive glacial relief was formed. The glacier carried away pre-glacial loose sediments and had a destructive effect on bedrock (crystalline) rocks, the degree of which depended on the nature of the rocks and the pre-glacial relief. The cover of a thin moraine, which lay on the surface during the retreat of the glacier, did not obscure the features of its relief, but only softened them. The accumulation of moraine in deep depressions reaches 150-200 m, while in neighboring areas with bedrock ledges there is no moraine.
In the peripheral part of the glaciation area, Iceland existed for a shorter time, had less power and slower movement. The latter is explained by a decrease in pressure with distance from the glacier's feeding center and its overload with debris. In this part, the glacier was mainly unloaded from debris and created accumulative relief forms.
Beyond the boundary of the glacier, directly adjacent to it, there is a zone whose relief features are associated with the erosion and accumulative activity of melted glacial waters. The formation of the relief of this zone was also affected by the cooling effect of the glacier.
As a result of repeated glaciation and the spread of the ice sheet in different glacial epochs, as well as as a result of movements of the edge of the glacier, forms of glacial relief of different origins turned out to be superimposed on each other and greatly changed.
The glacial relief of the surface freed from the glacier was affected by other exogenous factors. The earlier the glaciation, the more, naturally, the processes of erosion and denudation changed the relief. At the southern boundary of maximum glaciation, the morphological features of the glacial relief are absent or very poorly preserved. Evidence of glaciation are boulders brought by the glacier and locally preserved remains of heavily altered glacial deposits. The topography of these areas is typically erosive. The river network is well formed, the rivers flow in wide valleys and have a developed longitudinal profile. To the north of the boundary of the last glaciation, the glacial relief has retained its features and is a disorderly accumulation of hills, ridges, and closed basins, often occupied by shallow lakes. Moraine lakes fill up relatively quickly with sediment, and rivers often drain them. The formation of a river system due to lakes “strung” by the river is typical for areas with glacial topography. Where the glacier persisted the longest, the glacial topography was changed relatively little. These areas are characterized by a river network that has not yet been fully formed, an undeveloped river profile, and lakes that have not been drained by the rivers.
GLACIAL CENTER - largest district accumulations and the greatest power. ice, where it begins to spread. Usually C. o. associated with elevated, often mountainous centers. So, Ts. o. The Fennoscandian ice sheet were Scandinavian. On the territory of northern Sweden it reached power. at least 2-2.5 km. From here it spread across the Russian Plain for several thousand km to the Dnepropetrovsk region. During the Pleistocene ice ages, there were many color systems on all continents, for example, in Europe - Alpine, Iberian, Caucasian, Ural, Novaya Zemlya; in Asia - Taimyr. Putoransky, Verkhoyansky, etc.
Geological Dictionary: in 2 volumes. - M.: Nedra. Edited by K. N. Paffengoltz et al.. 1978 .
See what "GLACIAL CENTER" is in other dictionaries:
Karakoram (Turkic - black stone mountains), a mountain system in Central Asia. It is located between Kunlun in the north and Gandhisishan in the south. The length is about 500 km, together with the eastern extension of K. - the Changchenmo and Pangong ridges, passing into the Tibetan ... ... Great Soviet Encyclopedia
Collier's Encyclopedia
Accumulations of ice that move slowly across earth's surface. In some cases, the ice movement stops and dead ice forms. Many glaciers move some distance into oceans or large lakes and then form a front... ... Geographical encyclopedia
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They embrace the period of time in the life of the Earth from the end of the Tertiary period to the moment we are experiencing. Most scientists divide the Ch. period into two eras: the oldest glacial, colluvial, Pleistocene or post-Pliocene, and the newest, which includes ... ... Encyclopedic Dictionary F. Brockhaus and I.A. Ephron
Kunlun- Scheme of the Kunlun ridges. The rivers marked with blue numbers are: 1 Yarkand, 2 Karakash, 3 Yurunkash, 4 Keria, 5 Karamuran, 6 Cherchen, 7 Yellow River. The ridges are marked with pink numbers, see Table 1 Kunlun, (Kuen Lun) one of the largest mountain systems in Asia, ... ... Encyclopedia of tourists
Altai (republic) Altai Republic is a republic consisting of Russian Federation(see Russia), located in the south of Western Siberia. The area of the republic is 92.6 thousand square meters. km, population 205.6 thousand people, 26% of the population lives in cities (2001). IN … Geographical encyclopedia
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Katunsky ridge- Katunskie Belki Geography The ridge is located at the southern borders of the Altai Republic. This is the highest ridge of Altai, the central part of which for 15 kilometers does not fall below 4000 m, and the average height varies around 3200-3500 meters above ... Encyclopedia of tourists
History of ice sheets that appeared in Arctic and spread over vast expanses of the plains of Russia (total area about 30% of the territory), is associated with the last third of the Quaternary period (after 1 million years ago), See. Quaternary system (period). At this time, the periodicity (from 40 to 100 thousand years) and the amplitude of climate fluctuations associated with changes in the parameters of the Earth’s orbit (eccentricity, etc.) increased, which led to the development of ice sheets. The most ancient glaciations date back to the end Eopleistocene. On East European Plain The oldest is the Likovo moraine (Likovo glaciation), discovered in the Moscow region, its age is approx. 1.0–0.9 million years.
Early Neopleistocene. The Likovo glaciation is separated by the Akulov interglacial from the boundary of the paleomagnetic epochs Matuyama - Brunhes (beginning of the Neopleistocene), which is 780 thousand years old. The overlying horizon of the Setun moraine (Setun glaciation, ca. 750 thousand years ago) is correlated with the beginning of the Brunhes era. The most ancient glaciation on the planet dates back to this time. West Siberian Plain– Mansi (its moraine was found near the city of Khanty-Mansiysk). The exact boundaries of the distribution of these ancient ice sheets have not yet been established, but moraine deposits in the central regions of both plains indicate their wide distribution. On the East European Plain, the next one is the Don glaciation (about 650 thousand years ago), separated from the previous one by the Okatov interglacial (about 700 thousand years ago). The maximum distribution (up to 52° N) of the Don glaciation is clearly established in the eastern part of the plain. The center of this ice sheet was at New Earth And Polar Urals. After the degradation of the cover, the Muchkap interglacial began (about 600 thousand years ago). It is possible that on the West Siberian Plain the Don glaciation corresponds to the Early Shaitan, and the Muchkap interglacial to the Tiltim. The Late Shaitan glaciation (ca. 450 thousand years ago) can be compared with the Oka glaciation on the East European Plain, which extended here almost to 55° N. w. It is possible that the Navlina glaciation existed on the East European Plain between the Don and Oka (ca. 550 thousand years ago), the boundaries of which have not yet been established.
AverageNeopleistocene The Likhvin (on the East European Plain) and Tobolsk (on the West Siberian Plain) interglacials (about 400 thousand years ago) separate a series of Middle Neopleistocene glaciations from earlier ones. The first was the Pechora glaciation (about 350 thousand years ago), the center of which (like the Don glaciation) was located on Novaya Zemlya and the Polar Urals. It spread to the northern parts of the Tver and Yaroslavl regions. To 2nd half. The Middle Neopleistocene on the East European Plain dates back to the Dnieper Ice Age. It consisted of two main stages - the Dnieper proper (about 180 thousand years ago, the southern border in the western part of the plain is 49–50° N) and the Moscow stage (about 150 thousand years ago, the southern border is 55–56° s. sh.), separated by the Dnieper-Moscow interval of weak warming. A feature of the ice sheets of the Dnieper era, in contrast to the previous ones, is the shift of the center of glaciation to the west (the mountains of Scandinavia). On the West Siberian Plain, the Dnieper glaciation is compared with the Samarova glaciation (southern border is about 59–60° N), the Moscow glaciation is compared with the Taz glaciation, but here the interval separating them is considered as interglacial (Shirta).
Late Neopleistocene. The Ice Age began ca. 112–115 thousand years ago, when the last interglacial ended (Mikulinsky - on the East European Plain, Kazantsevsky - in Siberia). Within this era, two main glacial stages are distinguished: the first (45-40 thousand years ago) on the East European Plain includes the Early Valdai glaciation, in Siberia - the Ermakovsky (Zyryansky) glaciation, the second (ca. 25-23 thousand years ago ) – Late Valdai and Sartan, respectively. Both stages are separated by an interval (Middle Valdai - on the East European Plain, Karginsky - in Siberia), in certain phases of which climatic conditions approached modern ones; this interval is usually considered as a long interstadial (megainterstadial) within the Valdai glaciation. On the East European Plain, the Early Valdai ice sheet did not extend beyond the southern coast of the Baltic Sea; the boundary of the Late Valdai ice sheet in the west of the plain reached 55–56° N. latitude, with movement to the east it acquired a submeridional position (approx. 44° E, area of the Mezen Bay). On the West Siberian Plain, the Ermakovo glaciation extended to 65° N. sh., and Sartan was represented in the form of separate massifs in the Polar Urals, in Byrranga Mountains, on the plateau Putorana And Anabar plateau. In the northeastern part of Russia, where during the entire Pleistocene only mountain-valley and cirque glaciers formed (Olkhovo glaciation in the early Neopleistocene, Zuykovo and Ossor glaciations in the middle Neopleistocene), in the late Neopleistocene the size of the glaciers of the initial period (Zyryansk epoch) exceeded the size of the glaciers of the late (Sartan) era.
Dynamics of glaciations. Each subsequent ice age, as a rule, was characterized by a colder climate than the previous one. In areas where the boundaries of the maximum distribution of ice sheets have been determined, a decrease in the area of glaciations from older to younger ones can be noted. For example, on the East European Plain, the Early Neopleistocene Don glaciation was larger than the Middle Neopleistocene Dnieper glaciation, despite the fact that their southern borders were located almost at the same latitude. The extent of the Don glaciation from the southern border to the Ural-Novaya Zemlya center is ca. 2800 km, Dnieper (from the southern border to the East Scandinavian center) – 2200 km; for the Late Neopleistocene Late Valdai ice sheet, the corresponding value did not exceed 1600 km. A similar pattern is also characteristic of the Pleistocene ice sheets in Siberia. This is due to the fact that with increasing cooling, the area of sea ice increased, evaporation from the ocean surface and the amount of solid precipitation decreased. However, there are a number of exceptions: on the East European Plain, the Setun glaciation occupied a smaller area than the subsequent Don glaciation, and the Pechora glaciation occupied a smaller area than the subsequent Dnieper glaciation.
In the late Neopleistocene, spatial asymmetry of ice sheets was observed. In the early Valdai era on the East European Plain, the ice cover had minimal dimensions, and in Western Siberia at that time (Ermakov era) the extent of glaciation was significantly larger than later ones. In the late Valdai era, the area of ice cover increased on the East European Plain, while in Siberia (Sartan era) it decreased. At the beginning of the Ice Age, when the cooling did not reach its maximum, air masses from the Atlantic Ocean more easily penetrated into Siberia, providing solid sediments to the feeding areas of the glaciers. In the 2nd half. ice age, as cooling grew, the Siberian anticyclone ( Asian anticyclone) grew and blocked the flow of precipitation to the eastern regions, and on the East European Plain the amount of precipitation increased.
Glaciations and relief. Ice covers of the Quaternary period in their marginal parts left traces in the relief in the form of well-defined terminal moraine ridges (for example, in the Upper Volga region), to the north of them there are areas with hilly-western relief (for example, the basins of the Lovat and Msta rivers), near glaciation centers (at Kola Peninsula etc.) is noted special type processing of the land surface (a huge mass of moving ice destroyed older sedimentary strata and polished the surface of rock outcrops of the crystalline basement). Glacier meltwater flowed down relief depressions, partially using river valleys. In low areas, meltwater flows deposited material brought by the glacier, creating flat outwash plains (for example, Meshchera Lowland). During the glacial eras, the level of the World Ocean dropped significantly, because huge masses of water formed ice sheets and covers and were on long time removed from the moisture cycle. Even during the smallest area of the Late Valdai - Sartan glaciation, the volume of continental ice was 77.5 million km 3 and the ocean level dropped by 120–130 m. At this time, the amplitude of heights between the land surface and ocean level increased significantly; during the glacial epochs of the early and middle Neopleistocene it could increase by 200 m or more. In coastal areas (on the Pacific coast, etc.), slope processes intensified, and deep (several tens of meters) erosional incisions were formed; River valleys were deepened (for example, in the Volga and Dnieper basins). On the drained shelf of the Arctic Ocean, the river valleys of the Lena and Kolyma moved northward by 300–500 km (in modern times, their traces can be seen on the bottom of the marginal seas).
Dnieper glaciation
was maximum in the Middle Pleistocene (250-170 or 110 thousand years ago). It consisted of two or three stages.
Sometimes the last stage of the Dnieper glaciation is distinguished as an independent Moscow glaciation (170-125 or 110 thousand years ago), and the period of relatively warm time separating them is considered as the Odintsovo interglacial.
At the maximum stage of this glaciation, a significant part of the Russian Plain was occupied by an ice sheet, which, in a narrow tongue along the Dnieper valley, penetrated south to the mouth of the river. Aurelie. In most of this territory there was permafrost, and the average annual air temperature was then no higher than -5-6°C.
In the southeast of the Russian Plain, in the Middle Pleistocene, the so-called “Early Khazar” rise in the level of the Caspian Sea by 40-50 m occurred, which consisted of several phases. Their exact dating is unknown.
Mikulin interglacial
The Dnieper glaciation followed (125 or 110-70 thousand years ago). At this time, in the central regions of the Russian Plain, winter was much milder than now. If currently the average January temperatures are close to -10°C, then during the Mikulino interglacial they did not fall below -3°C.
The Mikulin time corresponded to the so-called “late Khazar” rise in the level of the Caspian Sea. In the north of the Russian Plain, there was a synchronous rise in the level of the Baltic Sea, which was then connected to Lakes Ladoga and Onega and, possibly, the White Sea, as well as the Arctic Ocean. The total fluctuation in the level of the world's oceans between the eras of glaciation and melting of ice was 130-150 m.
Valdai glaciation
After the Mikulino interglacial there came,
consisting of the Early Valdai or Tver (70-55 thousand years ago) and Late Valdai or Ostashkovo (24-12:-10 thousand years ago) glaciations, separated by the Middle Valdai period of repeated (up to 5) temperature fluctuations, during which the climate was much colder modern (55-24 thousand years ago).
In the south of the Russian Platform, the early Valdai is associated with a significant “Attelian” decrease - by 100-120 meters - in the level of the Caspian Sea. This was followed by the “early Khvalynian” rise in sea level by about 200 m (80 m above the original level). According to calculations by A.P. Chepalyga (Chepalyga, t. 1984), the moisture supply to the Caspian basin of the Upper Khvalynian period exceeded its losses by approximately 12 cubic meters. km per year.
After the “early Khvalynian” rise in sea level, there followed the “Enotaevsky” decrease in sea level, and then again the “late Khvalynian” increase in sea level by about 30 m relative to its original position. The maximum of the Late Khvalynian transgression occurred, according to G.I. Rychagov, at the end of the Late Pleistocene (16 thousand years ago). The Late Khvalynian basin was characterized by temperatures of the water column slightly lower than modern ones.
The new drop in sea level occurred quite quickly. It reached a maximum (50 m) at the very beginning of the Holocene (0.01-0 million years ago), about 10 thousand years ago, and was replaced by the last - “New Caspian” sea level rise of about 70 m about 8 thousand years ago.
Approximately the same fluctuations in the water surface occurred in the Baltic Sea and the Arctic Ocean. The general fluctuation in the level of the world's oceans between the eras of glaciation and melting of ice was then 80-100 m.
According to radioisotope analysis of more than 500 different geological and biological samples taken in southern Chile, mid-latitudes in the western Southern Hemisphere experienced warming and cooling at the same time as mid-latitudes in the western Northern Hemisphere.
Chapter " The world in the Pleistocene. The Great Glaciations and the Exodus from Hyperborea"
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Eleven Quaternary glaciationsperiod and nuclear wars
© A.V. Koltypin, 2010
1. What external processes and how do they affect the relief of Russia?
The relief of the Earth's surface is influenced by the following processes: the activity of wind, water, glaciers, organic world and man.
2. What is weathering? What types of weathering are there?
Weathering is a set of natural processes that lead to the destruction of rocks. Weathering is conventionally divided into physical, chemical and biological.
3. What effect do flowing waters, wind, and permafrost have on the relief?
Temporary (formed after rains or snow melting) and rivers erode rocks (this process is called erosion). Temporary streams of water cut through ravines. Over time, erosion may decrease, and then the ravine gradually turns into a gully. Rivers form river valleys. Groundwater dissolves some rocks (limestone, chalk, gypsum, salt), resulting in the formation of caves. The destructive work of the sea is ensured by the impacts of waves on the shore. The impacts of waves form niches in the shore, and from the remains of rocks, first rocky, and then sandy beaches are formed. Sometimes the waves form narrow spits along the shore. The wind performs three types of work: destructive (blowing and loosening of loose rocks), transport (transfer of rock fragments by wind over long distances) and creative (depositing of transported fragments and the formation of various aeolian surface forms). Permafrost affects the relief, since water and ice have different densities, as a result of which freezing and thawing rocks are subject to deformation - heaving associated with an increase in the volume of water during freezing.
4. What impact did ancient glaciation have on the relief?
Glaciers have a significant impact on the underlying surface. They smooth out uneven terrain and remove rock fragments, expanding river valleys. In addition, they create relief forms: troughs, pits, cirques, carlings, hanging valleys, “ram’s foreheads”, eskers, drumlins, moraine ridges, kamas, etc.
5. Using the map in Figure 30, determine: a) where the main centers of glaciations were located; b) where from these centers the glacier spread; c) what is the boundary of maximum glaciation; d) which territories the glacier covered and which it did not reach.
A) The centers of glaciation were: the Scandinavian Peninsula, the Novaya Zemlya Islands, and the Taimyr Peninsula. B) The movement from the center of the Scandinavian Peninsula was directed radially, but the southeastern direction received priority; glaciation of the Novaya Zemlya islands was also radial and generally directed south; glaciation of the Taimyr Peninsula was directed to the southwest. C) The boundary of maximum glaciation runs along the northwestern part of Eurasia, while in the European part of Russia it spreads more to the south than in the Asian part, where it is limited only to the north of the Central Siberian Plateau. D) The glacier covered the territories of the northern and central parts of the East European Plain, reached 600 north latitude in Western Siberia and 62-630 north latitude in the Serden-Siberian Plateau. Territories of the northeast of the country ( Eastern Siberia And Far East), as well as the mountain belt Southern Siberia, the south of Western Siberia and the East European Plain, the Caucasus found themselves outside the glaciation zone.
6. Using the map in Figure 32, trace what part of the territory of Russia is occupied by permafrost.
Approximately 65% of Russia's territory is occupied by permafrost. It is mainly distributed in Eastern Siberia and Transbaikalia; at the same time, its western border begins from sections of the extreme north of the Pechersk lowland, then goes through the territory of Western Siberia in the area of the middle reaches of the Ob River, and descends to the south, where it begins at the sources of the right bank of the Yenisei; in the east it turns out to be limited by the Bureinsky ridge.
7. Carry out the following work to define the concept of “weathering”: a) give a definition known to you; b) find other definitions of the concept in reference books, encyclopedias, and the Internet; c) compare these definitions and formulate your own.
Weathering is the destruction of rocks. Definitions taken from the Internet: “Weathering is a set of processes of physical and chemical destruction of rocks and their constituent minerals at their location: under the influence of temperature fluctuations, freezing cycles and the chemical action of water, atmospheric gases and organisms”; “Weathering is the process of destruction and change of rock in the conditions of the earth’s surface under the influence of mechanical and chemical influences of the atmosphere, ground and surface waters and organisms.” Synthesis of our own definition and definitions taken from the Internet: “Weathering is a constant process of destruction of rocks under the influence of external forces of the Earth, by physical, chemical and biological means”
8. Prove that the relief changes under the influence economic activity person. What arguments in your answer will be most significant?
The anthropogenic impact on the relief includes: A) technogenic destruction of rocks, through the extraction of minerals and the creation of quarries, mines, adits; B) movement of rocks - transportation of necessary minerals, unnecessary soils during the construction of buildings, etc.; C) accumulation of displaced rocks, for example, the construction of a dam, dam, formation of waste heaps (dumps) of empty, unnecessary rocks.
9. What relief-forming processes are most characteristic of your area in the modern period? What are they due to?
IN Chelyabinsk region, currently you can find all types of weathering: physical - destruction Ural mountains with constantly blowing winds, also constant temperature changes lead to the physical destruction of rocks, the flowing waters of mountain rivers, although slowly but constantly expand the bed and increase the river valleys, in the east of the region every spring with abundant melting of snow, ravines are formed. Also on the border with the Republic of Bashkortostan, in mountainous areas, karst processes occur - the formation of caves. Biological weathering also occurs in the region, for example, in the east, beavers create dams, and sometimes peat deposits burn out in swamps, forming voids. The developed mining industry of the region has a strong impact on the relief, creating quarries and mines, waste heaps and dumps, leveling uplifts.
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