Geotectura are the largest landforms of the Earth, reflecting the most important differences in the structure of the earth's crust that arose as a result of the manifestation of Ch. arr. geophysics planetary processes, in interaction with others (geological and geographical). There are four types of geology: continental (see Continent), oceanic (see Ocean Bed), transition zones (from the continent to the ocean) and mid-ocean ridges. Geological structures are subdivided into smaller forms—morphostructures and morphosculptures—the leading formation processes of which will be primarily geological. and geographical. MORPHOSTRUCTURE

Relatively large landforms continents or ocean floors, owing their origin to Ch. arr. geol. factors, i.e. endogenous processes - structure, lithology, new text. movements interacting with geographical exogenous processes. Compared to the largest elements of the Earth's relief - geotextures, are forms of the second order, but they themselves, in turn, are divided into a number of suborders (from large ones - ridges, depressions, plains, etc. to small ones, such as domes, small depressions, etc.)

MORPHOSCULPTURE

Relatively small landforms III order, which arose under the influence of Ch. arr. geographical factors (exogenous processes), in interaction with geol. factors (endogenous processes ). Complicating things relief morphostructures, belong to the types of exogenous forms of the earth's surface, for example. river, glacial, aeolian, etc.

DENUDATION PLAIN

Leveled surface formed as a result of impact agents of denudation on tectonically elevated terrain under conditions of temporary or long-term predominance of denudation processes, R.D. represents part of the polygenetic leveling surfaces in the case when the leveled region. demolition - R.D. - corresponds to its own leveled area. accumulation - accumulative plain. With a temporary predominance of denudation processes over tectonic ones, a pediplen, with long-term - peneplain. Depending on the structure of the region. demolition R.D. can be formed by dislocated G.P., which are protrusions of the foundation (Baltic crystalline shield, Kazakhstan folded region) or almost horizontally lying g..p. platform cover (Central Siberian Plateau, Volga elevation). In the first case, the R.D., according to Gerasimov, will be basement, in the second - reservoir

Basement Plains

The plains that arose on the shields of ancient and young platforms are called basement plains. They are composed of hard crystalline rocks, crushed into folds. In appearance, these are hilly or undulating plains with residual elevations such as hills, the formation of which is associated either with lithological features - harder stable rocks, or with structural conditions - in place of former convex folds or microhorsts. These are the Kazakh small hills, the plains of the Canadian and Baltic shields, the plains in southwest Africa, etc.

Stratified plains

Different appearance plains depends on their origin and internal structure. Most of the plains are located on slabs of ancient and young platforms and are composed of layers of hard sedimentary rocks high power- hundreds of meters and even the first kilometers. According to the classification of I.P. Gerasimova and Yu.A. Meshcheryakov, such plains are called reservoir plains. From the surface they are often covered with loose Quaternary continental sediments of low thickness, which have virtually no effect on their height and orographic features, but determine their appearance due to morphosculpture (East European, West Siberian, etc.)

Plateaus are elevated, leveled, relatively weakly dissected blocks earth's crust, limited by ledges from the adjacent plains. In the marginal parts, their dismemberment can be significant. Plateaus form on platform plates as they rise along faults. They are composed of sedimentary, usually dense, rocks (the Ustyurt plateau in Central Asia), or volcanic rocks (volcanic plateaus of the Deccan, Putorana, Columbia, etc.

Task 1. Get acquainted with the concepts of “Geotecture”, “Morphostructure” and “Morphosculpture”, give their definition, explain the principles underlying them. Provide examples of various categories of geotextures, morphostructures and morphosculptures on the world map.

Task 2. Give an analysis tables 10. Indicate which types of geotexture or morphostructure (plain-platform or mountainous) are most common on the land surface, what is the relationship between them within each continent. Construct bar graphs of the distribution of the main types of geotexture and morphostructure across the continents.

Table 10. Areas of the main types of geotexture and morphostructure

(according to G.M. Belyakova)

Task 3. Write down the main folding epochs in a notebook, correlate them with geochronological table. .

Task 4. A. Draw on a contour map the morphostructure of North America (or any other continent - to choose from). Use geomorphological, geological and tectonic maps to compile. The following morphostructures should be shown on the map (the recommended color for shading the contours of the morphostructures is given in parentheses):

I. Morphological structures of platform plains, plateaus and plateaus: denudation plains: basement (pink), strata (gray); accumulative plains (green). Plateaus: strata (orange), volcanic (chaotic streaks), plateaus (blue).

II. Morphostructures of mountains and highlands: young folded (Kz) (yellow); rejuvenated block-fold mountains (Mz) (dark green); revived fold-block mountains (Pz) (purple); regenerated blocky (Pt) (red); highlands (shading).



B. Give examples of corresponding morphostructures on other continents.

Q. What morphostructures include the Ural Mountains, the East European Plain, the West Siberian Plain, and the Verkhoyansk Range?

Task 5. Analyze Table 11, showing the distribution of the main types of land morphosculpture: A. What types of land morphosculpture are most and least widespread on Earth?

B. What are the patterns of distribution of the main types of morphosculptures within each continent?

Table 11. Distribution of the main types of land morphosculpture

Part of the world Type of morphosculpture
cryogenic glacial (ancient) fluvial arid
thousand km % thousand km % thousand km % thousand km %
Europe 52,2 0,5 4794,0 45,9 5441,5 52,1 156,7 1,5
Asia 608,6 1,4 7434,3 17,1 24867,7 57,2 10564,4 24,3
Africa - - - - 17356,0 57,6 12776,0 42,2
North America 617,5 2,8 11643,4 52,8 8269,5 37,5 1521,6 6,9
South America - - 1509,3 8,5 14703,0 82,8 1544,7 8,7
Australia - - 107,6 1,2 4862,3 54,2 4001,1 44,6
Land in general 1278,3 1,0 25488,6 19,1 75500,0 56,9 30564,5 23,0

FLUVIAL MORPHOSCULPTURE- type morphosculptures created by the erosion and accumulative activity of flowing waters.

Benefits

1. Physico-geographical atlas of the world. M., 1964.

2. Contour maps of continents

Geotectura are the largest landforms of the Earth, reflecting the most important differences in the structure of the earth's crust that arose as a result of the manifestation of Ch. arr. geophysics planetary processes, in interaction with others (geological and geographical). There are four types of geology: continental (see Continent), oceanic (see Ocean Bed), transition zones (from the continent to the ocean) and mid-ocean ridges. Geological structures are subdivided into smaller forms—morphostructures and morphosculptures—the leading formation processes of which will be primarily geological. and geographical.
MORPHOSTRUCTURE

Relatively large forms of relief of continents or the bottom of the oceans, which owe their origin to Ch. arr. geol. factors, i.e. endogenous processes - structure, lithology, new text. movements interacting with geographical exogenous processes. Compared to the largest elements of the Earth's relief - geotextures, are forms of the second order, but they themselves, in turn, are divided into a number of suborders (from large ones - ridges, depressions, plains, etc. to small ones, such as domes, small depressions, etc.)

MORPHOSCULPTURE

Relatively small relief forms of the third order, which arose under the influence of Ch. arr. geographical factors (exogenous processes), in interaction with geol. factors (endogenous processes). Make the terrain more difficult morphostructures, belong to the types of exogenous forms of the earth's surface, for example. river, glacial, aeolian, etc.

DENUDATION PLAIN

Leveled surface formed as a result of impact agents of denudation on tectonically elevated terrain under conditions of temporary or long-term predominance of denudation processes, R.D. represents part of the polygenetic leveling surfaces in the case when the leveled region. demolition - R.D. - corresponds to its own leveled area. accumulation - accumulative plain. With a temporary predominance of denudation processes over tectonic ones, a pediplen, with long-term - peneplain. Depending on the structure of the region. demolition of a river valley can be formed by dislocated g.p., which are projections of the foundation (Baltic crystalline shield, Kazakhstan folded region) or almost horizontally lying g.p. of the platform cover (Central Siberian Plateau, Volga Upland). In the first case, the R.D., according to Gerasimov, will be basement, in the second - reservoir

Basement Plains

The plains that arose on the shields of ancient and young platforms are called basement plains. They are composed of hard crystalline rocks, crushed into folds. In appearance, these are hilly or undulating plains with residual elevations such as hills, the formation of which is associated either with lithological features - harder stable rocks, or with structural conditions - in place of former convex folds or microhorsts. These are the Kazakh small hills, the plains of the Canadian and Baltic shields, the plains in southwest Africa, etc.

Stratified plains

The different appearance of the plains depends on their origin and internal structure. Most of the plains are located on slabs of ancient and young platforms and are composed of layers of hard sedimentary rocks of great thickness - hundreds of meters and even a few kilometers. According to the classification of I.P. Gerasimova and Yu.A. Meshcheryakov, such plains are called reservoir plains. From the surface they are often covered with loose Quaternary continental sediments of low thickness, which have virtually no effect on their height and orographic features, but determine their appearance due to morphosculpture (East European, West Siberian, etc.)

Plateau

Plateaus are elevated, leveled, relatively weakly dissected blocks of the earth's crust, limited by ledges from the adjacent plains. In the marginal parts, their dismemberment can be significant. Plateaus form on platform plates as they rise along faults. They are composed on top of either sedimentary, usually dense, rocks (stratified Ustyurt plateau in Central Asia), or volcanic rocks (volcanic plateaus of the Deccan, Putorana, Columbia, etc.

Accumulative plains

Along with strata and basement plains, I.P. Gerasimov and Yu.A. The Meshcheryaks are distinguished by accumulative plains. They arose in those areas of plates (usually syneclises) that experienced intense subsidence in the Pliocene-Quaternary, resulting in the accumulation of thick layers of loose sediments. Along the coasts of the seas they are usually low, flat and composed of marine clays and sands (Caspian Lowland, northern West Siberian Lowland, Kolyma Lowland). In basins among the mountains and at the foot of the mountains, accumulative plains are composed of loose continental sediments: alluvium, proluvium, and lake sediments. For example, the Mesopotamian and La Plata alluvial lowlands, the Tarim and Dzungarian plains with thick sand accumulations brought from neighboring mountains. On accumulative plains, the deeply submerged platform foundations do not affect the modern relief, which is completely formed in loose sediments that have not undergone diagenesis (sediment compaction) in contrast to strata plains

Fold Mountains

Fold Mountains

folded mountains, the uplift of which occurred as a result of the collapse of layers of rock into folds. Basic The mechanism for the formation of folded mountains is horizontal compression of the layered strata, although vertical movements of deeper layers may also take part in this. Folding is possible if the rocks subjected to compression forces are sufficiently plastic, which is typical either of young, recently formed sedimentary rocks, or of highly heated rocks saturated with liquid and gaseous inclusions. In their pure form, folded mountains are quite rare - as a rule, the formation of folds is accompanied by the appearance of faults. If displacements along faults make a noticeable contribution to the formation of mountainous relief, such mountains are called block-folded.

Fold-block mountains

mountains formed by folded rock strata, broken along young fault lines into blocks raised to different heights. Usually they are so-called. revived mountains formed within epiplatform orogenic belts

block mountains

are formed as a result of breaking rock layers into separate blocks (blocks) and raising them to different heights. They arise, as a rule, where rocks, as a result of a long and complex development, have lost their plasticity (consolidated) and, under the influence of endogenous forces, behave like a fragile body, splitting into blocks. The faults separating the blocks can be deep. from 1–3 km to several tens of kilometers, they can be vertical (faults) or inclined (thrusts). In the relief, faults are expressed either as ledges or as linear valleys developed by erosion. Block mountains often have relatively flat, horizontal or slightly inclined peaks, representing the undisturbed surface of raised blocks; They are characterized by steep slopes and relatively sparse dissection. If the raised blocks as a whole form a gently convex shape, such mountains are called vaulted blocky.

[o1]

Predominant types of morphostructures

are accumulative plains and strata plains and plateaus. Accumulative plains

confined to areas of recent subsidence or slow uplift. They occupy large areas in the Aral Sea region: the northern regions of Kyzylkum, the Aral Sea Karakum, B. and M. Barsuki. Accumulative plains stretch in a continuous strip along mountain structures from the Caspian coast to lake. Alakol. From the side of the mountains, low ridges penetrate into the strip of accumulative plains: the Chu-Ili Mountains, Karatau, Nuratau, spurs of the Kopet Dag, dividing it into isolated sandy deserts - “Kums”: the Caspian Karakums, the Central and South-Eastern Karakums, the Moyynkums, the sands of the southern Balkhash region. The sands of the Aral Karakum region arose as a result of weathering of Cretaceous and Paleogene sandstones. In all other massifs, sands were carried out of the mountains by rivers. These are alluvial, deltaic and alluvial-lacustrine sands. They reach a thickness of 700-900 m and are of Quaternary age.

Plateau-shaped strata plains and plateaus

raised above younger accumulative plains by 100-200 m. Their surface is usually armored with horizontally occurring layers of denudation-resistant rocks. Most often these rocks are limestones and ferruginous sandstones. This type of morphostructure predominates in the western and northern parts of the country. It includes: the Krasnovodsk plateau, the Mangyshlak plateau, Ustyurt, the Turgai plateau, the western part of Betpak-Dala. Often plateaus have clearly defined steep edge ledges (chinks) usually 50-80 m high. The formation of chinks is associated with tectonic, denudation or abrasion processes.

An intermediate position between these two types of morphostructures is occupied by stratified plains and plateaus, covered by a cover of loose sediments of low thickness (10-20 m). This type includes the Zaunguz plateau and the Kyzylkum plateau ( central part Kyzylkum).

Remnant hills, low mountain ranges and ridges

are confined to the zone of the deep Gissar-Mangyshlak fault, along which intense recent uplifts occur. This type of morphostructure includes the Kyzylkum Hills, Sultan-Uvays, Mangystau and other low-mountain ridges in Mangyshlak.

The development of the relief of the Turan Plain during the Pliocene-Quaternary occurred mainly in arid conditions. This is reflected in the character morphosculptures both accumulative and denudation plains and remnant massifs, in the formation of which the leading role belongs to the wind.

Denudation plains

The northern and western parts of the country are an area of ​​destructive wind activity. They are located where wind speeds are maximum (5.5-8.0 m/sec). At such speeds, deflation—blowing—prevails. The main amount of fine earth lifted by the wind from the surface is carried hundreds and thousands of kilometers away. Here it accumulates only in areas with rich vegetation (in valleys, deltas). During deflation, predominantly negative relief forms appear.

The wind carrying grains of sand has enormous destructive power. It knocks out closed depressions of various sizes (from several centimeters to many kilometers in diameter) even on the granites of the Kazakh hillocks. This process occurs even more intensely on the sedimentary rocks of the Turanian Plain, especially in cases where they are dispersed during the process of salt accumulation. This is precisely what accounts for the abundance of drainless closed basins on the Turanian Plain, especially in its western part. Calculations carried out for the Karynzharyk depression, which has a relative depth of about 300 m, showed that with a material blowing rate of only 1 mm per year, it could have formed in 300 thousand years.

They consist of two tiers: a crystalline plate of Precambrian, Caledonian or Hercynian age and a sedimentary sequence. On the Russian Plain, the sedimentary sequence is represented by marine or lagoonal-continental deposits of all geological periods. On the outskirts of the Baltic shield, near the Gulf of Finland, Cambrian clays are exposed, further to the south, southeast and east Ordovician and Silurian limestones, Devonian sandstones, and Carboniferous clays occur successively. In the Cis-Ural region, the surface is composed of Permian deposits, in the central part of the plain - Mesozoic, and in the south - in the Black Sea and Caspian lowlands - Paleogene and Neogene.

If the platforms had been stationary since their formation, their relief would have been buried under sedimentary strata and not reflected on the surface. In fact, during Meso-Cenozoic time the basement experienced repeated tectonic movements associated with ocean floor movements and Alpine orogeny.

Neotectonic movements manifested themselves in the differentiation of platforms into low and high, in the formation of protrusions and depressions in the foundation of each plate. The newly emerged relief of the basement changed the position of sedimentary strata and created hills and lowlands within the large plains.

The world map clearly shows patterns in the location of high and low plains: 1) on the Laurasian continents, high plains adjoin the Great Ocean (Eastern Siberia and the mid-west of America), and low plains (Eastern European, Western Siberian and western part of America) adjoin the Atlantic. This is due to the formation of oceanic trenches at the end of the Mesozoic, from under which mantle material flowed under the nearest continental massifs (Khain, 1964). This process is currently occurring in the Indian Ocean and is affecting the altitude of the surrounding plains.

Under the influence of lateral pressure from the Meso-Cenozoic orogenic belts, all the plates were broken into blocks by cracks complex system. This can be clearly shown using the example of the Baltic Shield, where the plate comes to the surface. This is the Kola Peninsula. The White Sea, the Gulf of Bothnia, and the grabens of Lakes Ladoga and Onega are limited by planes of subsidence.

The protrusions of the foundation are called anteclises, dives - syneclises. They are very large blocks bounded by fault planes. In addition to them, there are protrusions and depressions of smaller sizes, comparable to those listed on the Baltic Shield. The protrusions of the foundation correspond to uplands (Donetsk and Timan ridges. Central Russian and Volga uplands, Siberian ridges, etc.), and the depressions correspond to lowlands (Pechora, Caspian, Oka-Don, etc.).

Morphostructure

– a large relief form formed as a result of the interaction of external and internal forces under the predominant influence of internal (endogenous) forces.

Morphological structures of flat-platform areas:

Stratified plain

– the plain, confined to the platform slab, is composed of layers of the platform cover, lying almost horizontally or slightly inclined. Within the strata plains, separate accumulative lowlands and strata-denudation hills are distinguished.

Basement Plain

– a denudation plain formed on dislocated rocks of the crystalline basement of ancient platforms.

Accumulative plains

– plains formed as a result of the accumulation of layers of loose sediments. They are divided according to the leading agent of accumulation - endogenous (volcanic plains) or exogenous (marine, alluvial, lake, glacial, etc.); There are also accumulative plains of complex genesis (lacustrine-alluvial, deltaic-sea, alluvial-proluvial, etc.), as well as underwater accumulative plains (for example, abyssal); They are also distinguished by the place of formation (marginal, intermountain, foothill, on slabs of young platforms).

Denudation plains

– leveled surfaces formed on the site of a once more elevated and contrasting (for example, mountainous) relief as a result of its destruction and the removal of destruction products under conditions of temporary or long-term predominance of denudation processes.

Stratified denudation plain

– an elevated plain on the structures of the Precambrian platform plate, with the predominant development of the surface under the influence of denudation processes.

Monoclinal-stratal-denudation plain

(cuesta) - a plain on which there are rows of cuestas parallel to each other - ridges asymmetrical in cross section, produced by erosion and denudation in a gently monoclinal formation of layers of unequal resistance to denudation processes.

Stratified plain

– a type of strata-denudation plain, formed in humid and variable-humid climates of the temperate zone.

Stratified step plain

(table-step plain) is a type of strata-denudation plain that forms in the humid and variable-humid climates of the tropical zone.

Table relief

- a relief dissected by erosion of an elevated plain or plateau composed of horizontally occurring layers of rocks. Characterized by wide flat (table) watersheds, dissected by a few, mostly narrow and steeply sloped valleys. Characteristic of areas of arid climate, as well as areas of development of porous or fractured permeable rocks

Reversed type of morphostructure(inversion relief) – modern character.

Morphostructure mountain folded areas:

fold mountains

– 1) the type of structure of the newly formed mountains in the region of Alpine folding. Folded mountains arise in mobile zones of the earth's crust and are formed by plicative (without strata ruptures) folded dislocations with a subordinate role of disjunctive dislocations (with strata ruptures - fault, shear, etc.). Rock layers, crushed into folds of varying sizes and steepness, are raised to a certain height, forming ridges - anticlines, intermountain valleys – synclines. In the process of further mountain building, this correspondence is violated. 2) Primary uplifts during bending earth layers tectonic movements mainly in zones of collision of lithospheric plates

Fold-block mountains- a type of mountain structure in the areas of the Hercynian folding, which underwent peneplanation in the Mesozoic and experienced block tectonics in the neotectonic stage. Mountains and mountainous areas that arise during repeated tectonic movements, when folds of rocks that have lost their plasticity and hardened are subject to younger faults into large blocks of the earth's crust, which either rise to form horsts, or are omitted in the form grabens. Block-fold mountains- type of structure of mountains in areas of Mesozoic folding, which were not characterized by the stage of complete peneplanation. Block Mountains

- a type of mountain structure associated with ancient platforms or areas of the Baikal and Caledonian folds, which were repeatedly subjected to processes of peniplanation and vertical dismemberment. Block mountains - fault mountains are formed by blocks of the earth's crust, raised along tectonic faults. There are block mountains formed by: a) blocks of horizontally lying rocks, and b) previously folded mountains, later peneplanated. Block mountains are characterized by massiveness, steep slopes and relatively weak dissection. Arising during repeated mountain building, block mountains are usually horsts, separated by grabens - intermountain depressions and tectonic valleys.

Appalachian landform– an inverted type of morphostructure of a mountain region, synclinoria in relief are represented by mountain ranges, and anticlinoria are represented by intermountain plains. Rejuvenated Mountains

– an intermediate (middle) stage of mountain development, currently these are mountainous areas of Mesozoic folding, which were not characterized by the stage of complete peneplanation.

Reborn Mountains

Epiplatform mountains, activated platforms, are mountain structures that arose on the site of ancient, peneplanated mountain areas as a result of recent movements of the earth's crust. From the era preceding the latest mountain building, highly elevated areas of ancient peneplains (planing surfaces) are preserved in the revived mountains. Examples: Tien Shan, Altai, Rocky Mountains, East African Highlands.

Young (newly formed) mountains- folded mountains formed during the Alpine folding. Young mountains have significant heights, sharp ridge tops, steep slopes, and numerous river gorges. For M.g. characteristic processes of volcanism. Horst– an elevated section of the earth’s crust, bounded by tectonic faults (usually faults). Elevated relative to adjacent areas. Horst often appears in the relief in the form of mountain ranges. Graben– a section of the earth’s crust limited by tectonic faults (faults) and lowered relative to adjacent sections. In relief, large grabens are expressed in the form of depressions occupied by lakes or developed by rivers.