(periods), duration, million years.	Major events history of the earth	Tectonic cycles (mountain building epochs)	Characteristic useful fossils
Cenozoic era 70 million years
Anthropocene or Quaternary (2 million years.)	General rise of land. Formation of cover glaciers in the Northern Hemisphere. The emergence of man	Alpine	Peat, gold, diamonds, gems
Neogene (25 million years.)	The emergence of young mountains in areas of Alpine folding. Mountain-building processes continue to this day, as evidenced by earthquakes and volcanism. Distribution of birds, mammals, flowering plants	Alpine	Brown coals, oil, amber
Paleogene (41 million years.)	Destruction of the mountains of Mesozoic folding. Beginning of Alpine folding. Widespread development of flowering plants, birds and mammals	Alpine	Phosphorites, brown coals,
Mesozoic era 165 million years
Chalky (75 million years.)	The emergence of young mountains in areas of Mesozoic folding. Extinction of reptiles. Development of birds and mammals		Oil, oil shale, chalk, coal, phosphorites, non-ferrous metal ores
Jurassic (50 million years.)	Formation of modern oceans. Hot and humid climate over most of the land. Continuation of the Mesozoic era of folding. Dominance of giant reptiles (dinosaurs), gymnosperms		Gas, coal, oil, phosphorites
Triassic (40 million years.)	The greatest retreat of the sea, rise of land in the entire history of the Earth, changing of the climate, the formation of vast deserts. Destruction of the mountains of the Caledonian and Hercynian folds, the beginning of the Mesozoic era of folding. The dominance of giant reptiles and gymnosperms began. The appearance of the first mammals		Rock salts
Paleozoic era330 million years
Permian (45 million years.)	The emergence of young folded mountains in the areas of the Hercynian folding. Rise of ancient platforms on continents, glaciation Southern Hemisphere. Dry climate over most of the land. The emergence of gymnosperms	Hercynian	Stone and potassium salts, gypsum
Carboniferous (carbon) (65 million years.)	Widespread marshy lowlands due to the hot and humid climate over most of the land. Intensive mountain building of the era of the Hercynian folding (Appalachians, Urals, Tien Shan, etc.), formation of the foundation of young platforms (West Siberian). Tree ferns. The first reptiles, the rise of amphibians	Hercynian	Coal, oil, ore minerals fossils.
Devonian (55 million years.)	Reduction of sea area, hot climate, first deserts. The beginning of the Hercynian folding. Submergence of ancient platforms, splitting of the earth's crust, eruption of lavas, formation of basalt traps. The appearance of amphibians and fish	Hercynian	Salts, oil
Silurian (35 million years)	The emergence of young folded mountains in the areas of the Caledonian folding. The first land plants (mosses and ferns)	Caledonian	Non-ferrous metal ores
Ordovician (60 million years.)	Reduction in the area of ​​sea basins, climate change, continuation of the Caledonian folding. Appearance of the first invertebrates.	Caledonian	Sedimentary rocks
Cambrian (70 million years.)	The emergence of young mountains in the areas of the Baikal fold. The flooding of vast spaces by seas, the beginning of the platform stage in the development of the earth's crust, the destruction of ancient mountains formed in the Archean and Proterozoic eras. The flourishing of marine invertebrate animals Baikal	Baikalskaya	Rock salt, gypsum, phosphorites.
Proterozoic era 2000 million years	The beginning of the Baikal folding. Powerful volcanism, lava outpouring Development of bacteria and algae, appearance of the first multicellular	Baikalskaya	Iron ores, mica, graphite, precious stones and metals.
Archean era 1800 million years	The predominance of the ocean, massive outpouring of lava, volcanic activity. Formation of the Earth's crust Time of primitive bacteria and algae		Iron ores

Self-control tests

Establish the correct sequence in the alternation of geological periods.

1. Paleogene

2. Identify metamorphic rocks

gneiss, granite

dolomite, chalk

marble, gneiss

quartzite, pumice

3. To what geological period does the time of 75 million years belong?

Paleogene

4. Select the states where the most destructive earthquakes can occur

Finland 2) Honduras 3) Japan 4) Kazakhstan

5. What platforms or plates were formed in Archean - Proterozoic times?

Turanskaya

Scythian

Siberian

South China

6. Indicate a feature common to the continental and oceanic crust:

there is a granite layer;

the average thickness is 30-40 km;

characterized by a three-layer structure;

continuous under continents and oceans.

7. Select the mountains that are the most ancient:

2. Cordillera;

   Scandinavian;

8. The age of modern mountains coincides with the age of folds in the areas of ... folding

Baikal

Hercynian

Mesozoic

Cenozoic

9. Seismic belts of the Earth are formed:

only at the boundaries of the collision of lithospheric plates

only at the boundaries of the separation and rupture of lithospheric plates

at the boundaries of collision and rupture of lithospheric plates

in areas with the highest speed of movement of lithospheric plates

10. The eruption of which volcano led to the destruction of the city of Pompeii?

Etna 2) Hekla

3) Vesuvius 4) Krakatoa

11. The distribution of platform and folded areas on Earth is the main content of ... maps

1) soil 2) physical

3) geological 4) tectonic

12. Minerals of predominantly igneous origin include

1) hard and brown coal 2) copper and tin ores

3) natural gas and oil 4) salt and asbestos

13. The age of modern mountains coincides with the age of folds in the areas .... folding

1) Baikal 2) Hercynian 3) Mesozoic 4) Cenozoic

14. Currently, zones of rift faults in the earth’s crust on land are most clearly expressed on the continents

Australia and Africa

Africa and Eurasia

Eurasia and South America

South America and North America

15. Mountain systems formed into one fold...

1) Ural and Cordillera 2) Cordillera and Andes

3) Andes and Caucasus 4) Caucasus and Urals

Development of the earth's crust

Science has established that more than 2.5 billion years ago, planet Earth was completely covered by ocean. Then under the influence internal forces The uplift of individual sections of the earth's crust began. The uplift process was accompanied by violent volcanism, earthquakes, and mountain building. This is how the first land masses arose - ancient cores modern continents. Academician V. A. Obruchev called them "the ancient crown of the Earth."

As soon as the land rose above the ocean, external processes began to act on its surface. Rocks were destroyed, the products of destruction were carried into the ocean and accumulated along its outskirts in the form of sediments. rocks. The thickness of the sediments reached several kilometers, and under its pressure the ocean floor began to bend. Such giant troughs of the earth's crust under the oceans are called geosynclines. Formation of geosynclines in history The earth is coming continuously from ancient times to the present. There are several stages in the life of geosynclines:

– embryonic– deflection of the earth’s crust and accumulation of sediments (Fig. 28, A);

– maturation– filling of the trough with sediments, when their thickness reaches 15–18 km and radial and lateral pressure arises;

– folding– the formation of folded mountains under the pressure of the internal forces of the Earth (this process is accompanied by violent volcanism and earthquakes) (Fig. 28, B);

– attenuation– destruction of the emerging mountains by external processes and the formation in their place of a residual hilly plain (Fig. 28).

Rice. 28. Scheme of the structure of the plain formed as a result of the destruction of mountains (the dotted line shows the reconstruction of the former mountainous country)

Since sedimentary rocks in the geosyncline area are plastic, as a result of the resulting pressure they are crushed into folds. Fold mountains are formed, such as the Alps, Caucasus, Himalayas, Andes, etc.

The periods when active formation of folded mountains occurs in geosynclines are called eras of folding. Several such eras are known in the history of the Earth: Baikal, Caledonian, Hercynian, Mesozoic and Alpine.

The process of mountain building in a geosyncline can also cover non-geosynclinal areas - areas of former, now destroyed mountains. Since the rocks here are hard and lack plasticity, they do not fold into folds, but are broken by faults. Some areas rise, others fall - revived block and folded block mountains appear. For example, during the Alpine era of folding, the folded Pamir mountains were formed and the Altai and Sayan mountains were revived. Therefore, the age of mountains is determined not by the time of their formation, but by the age of the folded base, which is always indicated on tectonic maps.

Geosynclines at different stages of development still exist today. Thus, along the Asian coast of the Pacific Ocean, in the Mediterranean Sea there is a modern geosyncline, which is going through a maturation stage, and in the Caucasus, in the Andes and other folded mountains the process of mountain formation is completing; The Kazakh small hills are a peneplain, a hilly plain formed on the site of the destroyed mountains of the Caledonian and Hercynian folds. The base of ancient mountains comes to the surface here - small hills - “witness mountains”, composed of durable igneous and metamorphic rocks.

Vast areas of the earth's crust with relatively low mobility and flat terrain, called platforms. At the base of the platforms, in their foundations, lie strong igneous and metamorphic rocks, indicating the processes of mountain building that once took place here. Usually the foundation is covered by a thick layer of sedimentary rock. Sometimes basement rocks come to the surface, forming shields. The age of the platform corresponds to the age of the foundation. Ancient (Precambrian) platforms include the East European, Siberian, Brazilian, etc.

The platforms are mostly plains. They experience mainly oscillatory movements. However, in some cases, the formation of revived block mountains is possible on them. Thus, as a result of the emergence of the Great African Rifts, there was a rise and fall of certain sections of the ancient African platform and blocky mountains and highlands were formed East Africa, volcano mountains Kenya and Kilimanjaro.

Lithospheric plates and their movement. The doctrine of geosynclines and platforms is called in science "fixism" since, according to this theory, large blocks of bark are fixed in one place. In the second half of the 20th century. many scientists supported theory of mobilism, which is based on the idea of ​​horizontal movements of the lithosphere. According to this theory, the entire lithosphere is divided into giant blocks - lithospheric plates - by deep faults reaching the upper mantle. Boundaries between plates can occur both on land and on the ocean floor. In the oceans, these boundaries are usually mid-ocean ridges. In these areas, a large number of faults have been recorded - rifts, along which the material of the upper mantle pours out to the ocean floor, spreading across it. In those areas where the boundaries between plates pass, mountain building processes are often activated - in the Himalayas, Andes, Cordillera, Alps, etc. The base of the plates is in the asthenosphere, and along its plastic substrate the lithospheric plates, like giant icebergs, slowly move in different directions. directions (Fig. 29). The movement of the plates is recorded by precise measurements from space. Thus, the African and Arabian shores of the Red Sea are slowly moving away from each other, which has allowed some scientists to call this sea the “embryo” of the future ocean. Space images They also allow us to trace the direction of deep faults in the earth’s crust.

Epochs of folding and their role in the development of the structure of the earth's crust. The structure of folded regions of different ages (Caledonides, Hercynides, etc.)

THE AGE OF FOLDING- a set of folding phases (a phase of increased tectonic activity), covering the end of the development of geosynclinal systems and constituting a turning point, after which only platform or other non-geosynclinal forms and formations develop in a given region.

The entire history of the existence of the earth's crust is conventionally divided into several geological folds. In the history of the Earth, the following are distinguished: Archean (Precambrian) folding, Baikal, Caledonian, Hercynian, Mesozoic and Alpine folding. The last of them, the Alpine one, has not been completed and is currently ongoing.

folded area- a section of the earth's crust within which layers of rocks are folded. The formation of most folded areas is a natural stage in the development of mobile zones of the earth's crust - geosynclinal belts. Due to the uneven intensity of development of tectonic processes, the formation of folded areas is confined mainly to certain epochs, called folding epochs. In addition to folds, the folded region is characterized by the presence of tectonic nappes, regional metamorphism of rocks, and increased manifestation of magmatic activity.

Archean folding- the most ancient, it ended about 1.6 billion years ago. In diagrams it is usually indicated pink. All were formed during the Archean folding platforms- the ancient cores of continents, their most stable (usually the smoothest) areas. For more than a billion years, sections of the crust formed in Archean were completely leveled by the external forces of the Earth, their surface turned into plains, and all geological processes of volcanism and mountain building stopped long ago.

Associated with deep metamorphism and granitization. Most geologists associate with the Archean the pre-Karelian and pre-Huronian folded complexes of the Baltic and Canadian shields, respectively, and the complexes of other regions correlated with them. The phases of folding within the Archean are only hypothesized.

Based on geochronological data, Tugarinov and Voitkevich (1966) identified 3 tectono-magmas in the Archean. epochs, which they believe have a planetary distribution. This is the Kola epoch with an age of 3000 ± 100, Belozersk - 3500 ± 150 and Rhodesian - 2600 ± 100 million years.

Baikal folding- lasted from 1200 to 500 million years ago. It is named after Lake Baikal, since the area of ​​Siberia where the lake is located was formed during this period. The Baikal fold also includes the Yenisei Ridge, the Patom Highlands, the Khamar-Daban Ridge, part of the territory of the Arabian Peninsula and the Brazilian Plateau.

Baikal folding - the era of tectogenesis. Folding occurred within geosynclinal areas that developed at the end of the Precambrian (Riphean) and early Cambrian. During this era, as a result of the intensification of the processes of mountain building, folding, faulting, granitization, volcanism, seismicity and other geodynamic processes, belts of mountain structures were formed, now mostly destroyed, but in some places rejuvenated, bordering large platforms.

Caledonian folding- 500-400 million years ago. Named after Caledonia on the island of Great Britain, where it was first discovered. Great Britain, Ireland, Scandinavia, Newfoundland, South China, East Australia.

Caledonian folding is an era of tectogenesis, expressed in a combination of geological processes (intense folding, mountain building and granitoid magmatism). It completed the development of geosynclinal systems that existed from the end of the Proterozoic - the beginning of the Paleozoic, and led to the emergence of folded mountain systems - the Caledonides.

Classical Caledonides - structures of the British Isles and Scandinavia, Northern and Eastern Greenland. Typical Caledonides are developed in Central Kazakhstan and Northern Tien Shan, in Southeast China, and in Eastern Australia. The Caledonian fold played a significant role in the development of the Cordillera, especially South America, the Northern Appalachians, the Middle Tien Shan and other areas.

The earliest phases of folding belong to the middle - end of the Cambrian (Salairian or Sardinian), the main phases cover the end of the Ordovician - the beginning of the Silurian (Takonian) and the end of the Silurian - the beginning of the Devonian (Late Caledonian), and the final phase is the middle of the Devonian (Orcadian or Svalbardian).

The most characteristic features of the Caledonides are the unconformity at the base of the Silurian or Devonian and the accumulation of thick red continental sediments (Devonian ancient red sandstone of the British Islands and its analogues). Young platforms formed on the site of the Caledonides were characterized by increased mobility. They experienced tectonic activation in the late Paleozoic in connection with the Hercynian folding and in Neogene-Quaternary time.

Deposits of Fe, Ti, Au, and Mo ores are associated with Caledonian tectogenesis. In serpentinized massifs of peridotites and gabbro, deposits of asbestos, talc, magnesite and small ore occurrences of chromium, platinum, titanomagnetites, nickel and native Cu are known.

Hercynian folding- 400-230 million years ago.

Hercynian folding, or Variscan (Variscan) folding, is an era of tectogenesis (end of Devonian - beginning of Triassic), manifested in Paleozoic geosynclines; ended with the emergence of folded mountain systems - the Hercynides (variscide). Geosynclinal systems that experienced Hercynian folding arose in the early - early middle Paleozoic, mainly on an older, Baikal foundation and were filled with thick strata of marine sedimentary and volcanic rocks.

The first era of Hercynian folding - the Acadian (mid-Devonian) appeared in the Appalachians, the Canadian Arctic Archipelago, and the Andes. The next era (phase) - the Bretonian (end of the Devonian - beginning of the Carboniferous) most intensively manifested itself in the Central European zone of uplifts.

The main epoch (phase) of the Hercynian folding - the Sudeten (late Early - early Middle Carboniferous) played a major role in the creation of the folded structure of the European Hercynian and the transformation of Paleozoic geosynclines into folded mountain structures.

From the middle of the Early or Late Permian, a platform regime was established in most of the regions (Central and Western Europe) covered by the Hercynian folding, while in southern Europe were still continuing, but in eastern Europe, the Urals and the Donetsk Ridge, the processes of folding and mountain building had just begun.

In the Carpatho-Balkan region, in the Greater Caucasus, Altai and in the Mongol-Okhotsk system, mountain building began at the end of the Early Carboniferous; the orogenic period covered the entire Late Paleozoic and the beginning of the Triassic.

Minerals are sulfide deposits of Cu, Pb, Zn in the Urals, Altai and others, and the formation of basic and ultrabasic intrusions was associated with the formation of industrial concentrations of platinum, chromites, titanomagnetites, asbestos in the Urals and other areas.

Granite formation during the orogenic period of the Hercynian cycle contributed to the formation of ore deposits of Pb, Zn, Cu, tin, tungsten, Au, Ag, uranium in Europe, Asia (Tien Shan, etc.), and eastern Australia. Large coal basins - Donetsk, Pechora, Kuznetsk, as well as basins of stone and potassium salts(Pre-Ural trough).

Mesozoic folding- 160-65 million years ago. Correlates with the Mesozoic era, when dinosaurs roamed the Earth. During this period the Cordilleras were formed, Most of From the Russian Far East, many mountain ranges appeared that are now located in Central Asia.

The era is believed to have begun 200-150 million years ago (mostly Jurassic period), when the Cimmerian Plate collided with the southern coast of Kazakhstan and the North and South China continents, closing the ancient Tethys paleo-ocean. This plate consisted of what is now known as Turkey, Iran, Tibet and the western part South-East Asia Most of the northern plate boundary formed mountain ranges, which were higher than the modern Himalayas, but were subsequently destroyed. Folding continued until the Cretaceous and early Cenozoic.

Mesozoids in Russia are the mountain ranges of the Northeast (Momsky, Chersky, Verkhoyansky), as well as Primorye (Sikhote-Alin).

Alpine folding- began 65 million years ago. During the Alpine folding, the youngest, and therefore most turbulent, sections of the earth's crust were formed. Volcanic processes are active in these places, earthquakes often occur, and mountains continue to form. For the most part, they are located in areas where lithospheric plates collide. These are the Aleutian Islands, the Caribbean Islands, the Andes, the Antarctic Peninsula, the Mediterranean Sea, Asia Minor, the Caucasus, Southwest Asia, the Himalayas, the Greater Sunda Islands, the Philippines, Japan, Kamchatka and the Kuril Islands, New Guinea and New Zealand.

Alpine folding is the last major epoch of tectogenesis, spanning the Paleocene - Cenozoic. Folding occurred within geosynclinal areas that developed in the Mesozoic and Early Paleogene.

Pre-geological and geological periods development of the Earth. The main stages in the history of the geological development of the Earth. Cryptose and phanerozoic. Archean and early Proterozoic. Neoproterozoic. Epochs of folding. Formation of ancient platforms. Ideas about the global structure of the earth's crust (Rodinia). The most ancient continental glaciations. Evolution of the composition of the hydrosphere and atmosphere. The emergence of life and the formation of the organic world.

The age of the Earth is 4.6–4.7 billion years. Its entire history of development is divided into two huge periods:
1) pre-geological period ~ until the turn of 4.0 billion years;
2) geological period

EXAMPLE OF A TASK USING SPACE IMAGES

(According to the textbook "GEOGRAPHY OF CONTINENTS AND OCEANS" edited by I.V. Dushina Section III. Oceans and continents. Topic 8. Eurasia. Lesson No. 46.)

Goals and objectives: To form an idea of ​​the relief and mineral resources of the continent, to establish the relationship between tectonic structures and landforms, to consolidate the skill of comparing physical and tectonic maps. Using space images, form an idea of ​​the young folded mountains of the Alpine-Pacific belt.

Equipment: Physical map of Eurasia, map of the structure of the earth's crust, Atlas. M.: Bustard, 2007 (7th grade), multimedia projector, screen, computer
TsOR: Alpine-Himalayan belt.
Progress:
1. Students analyze the map of the structure of the earth’s crust in Eurasia and answer the teacher’s questions:
— On what lithospheric plates does Eurasia lie?
— What plates does the Eurasian lithospheric plate collide with?
— What seismic belts are located at the boundaries of lithospheric plates?
— What platforms are there in Eurasia? What landforms do they represent?
— What folded areas of different ages are there in Eurasia?
— Which mountains belong to the ancient folding, which ones belong to the middle folding, and which ones belong to the new, Cenozoic folding?
2. Students find young mountains of the Alpine-Himalayan mountain belt on a physical map, list them from west to east, name the average height and maximum height marks. They are then asked to view the DOR Alpine-Himalayan belt.
3. Teacher questions:
—What signs of the mountains you saw indicate that these are young folded mountains?(The presence of ridges clearly expressed in the relief, sharp peaks, strongly dissected by the relief, mountain glaciation, traces of earthquakes (Sarez Dam Lake) and volcanism.
— Why do young mountains have a folded structure and, as a rule, are they higher than ancient mountains?(Young mountains are formed at the boundaries of collisions of lithospheric plates, where the earth’s crust is crushed into folds, and since they are weathered for a relatively short time, they are high and have sharp peaks, peaks, ridges extending along the folds.)
4. Based on the analysis of the cards, students are asked to fill out a table "Relief and minerals of Eurasia"

Tectonic structure	Appropriate landform	Minerals
Ancient folding	Ural, Scandinavian mountains	Iron and copper ore
Average folding	Verkhoyansk ridge	tin
New folding	Caucasus, Pamir, Apennines, Pyrenees, Alps, Himalayas	Polymetallic ores
Platforms: 1. Eastern European 2. Siberian 3.West Siberian Plate 4. Chinese 5.Indian 6. African-Arabian	The East European Plain, Caspian lowland, East Siberian Plateau, West Siberian Plain, Great Chinese Plain, Deccan, Indo-Gangetic Plain, Arabian plateau	Brown and coal, oil, gas, salt.

Homework: on the contour map of Eurasia, label all landforms and indicate minerals with icons.

Tectonic structures - These are large areas of the earth's crust bounded by deep faults. The structure and movements of the earth's crust are studied by the geological science of tectonics. Geological bodies, typical forms of occurrence of rocks of different ages and compositions, repeated in different regions and created by tectonic forces. Tectonic structures are studied by geological mapping, geophysical methods, especially seismic exploration, and drilling. Tectonic structures as structural forms are studied and classified structural geology, which studies predominantly small and medium-sized forms (approx. 10 km across), and tectonics, studying large (over 100 km) forms. The first are called tectonic faults, or dislocations, of various types (folded, injective and discontinuous). The second includes anticlinoria and synclinoria within folded areas, anteclises, syneclises and aulacogens within shields, plates, pericratonic subsidence on platforms; folded geosynclinal belts, orogens, platforms, continents, oceans, underwater active and passive continental margins, mid-ocean ridges, oceanic plates, as well as deep continental faults, rifts, transform faults and ruptures. These largest tectonic structures can cover the earth's crust and lithosphere and are called deep tectonic structures.

The largest tectonic structures can be ranked in the following order according to their significance.

l Superglobal structures - have an area of ​​tens of millions of square kilometers and a length of thousands of kilometers. Their development takes place throughout the entire geological stage of the planet’s history.

l Global structures - occupy areas of up to ten or more million square kilometers, stretching for several thousand kilometers. Their lifetime coincides with previous structures.

l Subglobal structures - cover several million square kilometers, their length reaches a thousand kilometers or more. The development time exceeds one billion years.

In addition to those mentioned, structures of smaller orders are also distinguished.

First of all, based on the unity of movement, as well as comparative solidity, it is necessary to highlight such super-global structures as lithospheric plates. It is customary to distinguish seven largest plates and from eleven to thirteen smaller ones. The largest plates are the Eurasian, African, North American, South American, Indo-Australian, Antarctic, and Pacific. Among the small plates are the Philippine, Arabian, Cocos, Nazca, Caribbean, etc. Secondly, the most important are the fault structures that separate the lithospheric plates.

Among the fault structures, first of all, rifts stand out, which are divided into mid-ocean and continental. Mid-ocean rifts form a global system with a length of more than 64,000 km. Examples of continental rifts include the largest on the planet, the East African rift, as well as the Baikal rift. Another type of fault structures are transform faults, which cut rifts perpendicularly. Along the lines of transform faults, horizontal sliding (shear) of the adjacent parts of the lithospheric plates occurs.

Within areas of lithospheric plates with a continental structure of the earth's crust, global structures such as platforms and folded mountain areas are distinguished.

Tectonic platforms

Platforms are rigid, slow-moving blocks of the earth's crust that have gone through a long stage of geological development and have a three-tier structure. The platforms consist of a crystalline basement (basalt and granite-gneiss layers) and a sedimentary cover. The crystalline basement is composed of folded layers of metamorphic rocks. All this complexly dislocated strata is intruded in many places by intrusions (mostly acidic and intermediate in composition). Based on the age of formation of the crystalline basement, platforms are divided into ancient (Precambrian) and young (Paleozoic and, less commonly, Early Mesozoic). Ancient platforms are the cores of all continents and occupy their central part. Young platforms are located on the periphery of ancient ones or between ancient platforms. The sedimentary cover is dominated by undisplaced layers of shelf, lagoonal, and, less commonly, continental sediments.

Within the ancient platforms, based on the characteristics of the geological structure, subglobal structures such as shields and slabs are distinguished.

Shield– a section of the platform where the crystalline basement reaches the surface (i.e. where there is no sedimentary layer). Shields arise during tectonic uplift of the territory, as a result of which denudation processes dominate. In relief, shields are usually represented by plateaus (Brazilian Shield), and less often by hills (Donetsk Shield).

Plates– these are platforms (or sections thereof) with a thick sedimentary layer. The formation of plates is associated with tectonic subsidence of the platform, and, accordingly, with marine transgression. On the surface of platforms, slab territories most often correspond to lowlands and also uplands. Lithospheric plates are constantly in motion (for more information about the movement of plates, see the article).

Smaller structural units within the sedimentary cover of ancient platforms are represented by super-regional structures, the area of ​​which is hundreds of thousands of square kilometers, and the length is up to several hundred kilometers. Their development occurs during the accumulation of sedimentary cover and is measured over hundreds of millions of years. Super-regional structures are divided into regional ones, and the latter, in turn, into structures of even smaller orders. Among the superregional structures it is necessary to mention anteclises, syneclines and monoclines.

Anteclises– the largest positive structures of slab areas with a convex shape of the foundation surface and a sedimentary cover of low thickness.

Relationship between the main landforms and tectonic structures (page 1 of 2)

Anteclises are formed in the regime of tectonic uplift of the territory, so they may lack many horizons represented on neighboring negative structures. Within the anteclises, regional structures such as massifs and protrusions can be distinguished.

Arrays are the highest parts of anteclises in which the basement either comes to the surface or is covered by Quaternary sedimentary rocks.

Ledges- these are parts of massifs, anteclises, which are isometric or elongated basement uplifts with a diameter of up to 100 km. Sometimes buried protrusions are identified, over which the sedimentary cover, although present, is represented by a greatly reduced section (compared to the surrounding negative structures).

Syneclises– the largest negative super-regional structures of slab areas with a concave basement surface, a flat bottom and very gentle (fractions of a degree) angles of incidence of layers on the slopes. Syneclises arise in the regime of tectonic subsidence of the territory, due to which they are characterized by an increased thickness of the sedimentary cover. Regional structures similar to syneclises are depressions with an isometric shape and linearly elongated troughs. Monoclines are tectonic structures with one-sided inclination of layers, the angle of dip of which rarely exceeds 1°. Depending on the rank of positive and negative structures between which the monocline is located, its rank can also be different. Among the regional structures of the sedimentary cover, it is necessary to mention horsts, grabens (see “Disjunctive dislocations”) and saddles. Saddles – regional entities, occupying an intermediate position in terms of the relative height of their surface. Saddles lie above the surrounding negative structures, but below the surrounding positive ones.

Mountain folded areas, characterized by a sharp increase in the thickness of the earth’s crust, are formed during the convergence of lithospheric plates. Most folded mountain areas, especially young ones, are characterized by increased seismicity.

The fundamental principle of their division is the age of folding, established by the age of the youngest layers crumpled into folds. Accordingly, the mountain ranges are divided into Baikal, Caledonian, Hercynian, Cimmerian and Alpine. This division is quite conditional, since most scientists recognize the continuity of folding over time. In other words, in the history of the Earth there were no general planetary stages of tectonic activity and rest. Mountain formation occurs continuously, appearing in one place or another. Consequently, the identification of the Baikal and other folds determines only the time frame for the beginning and completion of major historical stages of the tectonic development of the planet.

Based on their tectonic structure, the currently existing mountain-fold regions can be divided into folded and folded-block structures.

Folded arrays are presented in young (Alpine and, partly, Cimmerian stages of folding) mountain fold belts.

Folded-block (rejuvenated, revived) structures are formed during the revival of vertical and horizontal tectonic movements within previously formed and, often, already destroyed folded systems. Therefore, the folded-block structure is especially characteristic of the regions of the Paleozoic and more ancient stages of folding. The relief of folded massifs generally corresponds to the configuration of the bends of rock layers, which is not always manifested in folded block formations. Thus, in young folded mountains, the structures of anticlinal folds (or anticlinoriums) correspond to mountain ranges, and the structures of synclinal folds (or synclinoriums) correspond to intermountain valleys (troughs).

Inside the folded mountainous regions and on their periphery, intermountain and foothill (marginal, forward) troughs and depressions are distinguished, respectively. On the surface of these structures lie coarse clastic products of mountain destruction - molasse. The formation of foothill troughs occurs as a result of the subduction of lithospheric plates, that is, in fact, foothill troughs are relics of deep-sea trenches.

Each of the major natural complexes Russia is a single geostructural area of ​​large size (a platform or folded system of a certain geological age), appropriately expressed in relief - lowlands or high plains, folded, blocky or folded-blocky mountains. All of them have certain climate features and corresponding features of soil and vegetation cover.

Mountains of folded regions

Era	The era of folding	Basic landforms	Tectonic structure	Relative age
Proterozoic	Baikal	Yenisei Ridge Eastern Sayan Yablonovy Ridge	blocky, folded-blocky	Revived (in Neogene-Quaternary times)
Paleozoic	Caledonian	Western Sayan
Hercynian	Ural Mountains Altai
Mesozoic	Mesozoic	Byrranga mountains Sikhote-Alin mountains of North-Eastern Siberia Verkhoyansk Range Chersky Range Kolyma Plateau Chukotka Plateau, etc.
Cenozoic	alpine and pacific	Caucasus Mountains mountains about. Sakhalin mountains of Kamchatka (Sredinny Range) mountains of the Kuril Islands	folded	Young (emerged in the Neogene-Quaternary time)

Platform plains

Foundation age	Tectonic structures	Basic landforms
Precambrian	Russian platform	Baltic shield	East European (Russian) Plain	low and high plains of Karelia and the Kola Peninsula
mountains of the Kola Peninsula
Russian platform plate	the rest of the territory
East European Plain
Siberian platform	Anabar shield	Central Siberian Plateau	Anabar plateau
Aldan shield	Aldan Highlands
Stanovoy Ridge
Siberian platform plate	the rest of the territory
Central Siberian Plateau
Paleozoic (Caledonian and Hercynian folding eras)	West Siberian Plate	West Siberian Plain North Caucasus Plain
Scythian plate	Caspian lowland

Minerals of the Oryol region

According to geological exploration data, the Oryol region has various types of minerals: iron ores, refractory and fusible clays, tripoli, mineral paints, cement raw materials, building stones, chalk, sands for construction work and the production of silicate products, clays and loams for the production of mineral wool. Many of them are currently industrially are not developed and are reserved. Limestones, sands and clays have a variety of uses in the production of building materials. Deposits of limestone and dolomite (calcium carbonate) are found in almost all areas of the region. Reserves of pure white chalk, as well as white clay (kaolin) are located in the Dolzhansky district. Kaolin can be used as a feedstock for the production of porcelain and earthenware products and electrical products (as an insulator). Refractory clays of the Maloarkhangelsk region are used for the production of dishes, facing tiles, tiles, sewer pipes, etc. In addition to the noted minerals, the region has reserves of brown coal in the Bolkhovsky district (depth of occurrence 35-40 meters, layer thickness from 0.3 to 3.2 meters), phosphorites in the Dmitrovsky, Bolkhovsky and Glazunovsky districts (layer thickness up to 0.4 meters , the content of phosphorus anhydride P2O5 is up to 17%), as well as peat, the largest deposits of which are located in the Khotynetsky and Shablykinsky regions. In the depths of the region there are: limestones, dolomites, kaolin (raw materials for the production of porcelain and earthenware products and electrical products), phosphorites, tripoli (reserve - 57 million cubic meters), peat.

Limestones, sands and clays have a variety of uses in the production of building materials. Deposits of limestone and dolomite (calcium carbonate) are found in almost all areas of the region. They are used for the production of ordinary concrete of grades “100” - “400”, for the construction of local roads. Sands are generally suitable as fine aggregate for ordinary concrete grades “150” and below. Refractory clays of the Maloarkhangelsk region are used for the production of dishes, facing tiles, tiles, sewer pipes, etc.

The total reserves of the Butyrskoye deposit of mineral paints are 93 thousand tons. The deposit is represented by clayey ocher of yellow and brown color. The average thickness of the useful thickness is 0.83 m, the average thickness of the overburden is 0.53 m. Ocher is suitable for the production of:

- clay-lime facade paints - yellow, beige and brown colors;

— adhesive paints for interior decoration of buildings;

- thickly grated oil paints in red-brown colors.

The deposit is not exploited, there are prospects for increasing the reserves of the deposit.

In the Dmitrovsky, Trosnyansky, Glazunovsky and Maloarkhangelsk districts, a deposit of phosphorites suitable for the production of phosphate rock has been studied in detail.

IN last years Oryol geologists discovered the Khotynetskoe deposit of zeolite-containing tripoli. This is the only deposit in the European part of Russia and represents a completely new, highly valuable type of mining chemical raw material with a wide range of uses, great demand on the world market and a sharp increase in production. The deposit's reserves in three studied areas: Obraztsovsky, Bogoroditsky, Vorotyntsevsky amount to 56,533 thousand cubic meters.

The “tail” of the formation of the Kursk magnetic anomaly is located in the Oryol region, but the ore in it is difficult to extract and has a low iron content (30-32%, according to specialists from Voronezh State University). In particular, in the Novoyaltinskoye field, according to geologists, there are 117.6 million tons of proven reserves. Ore in Dmitrovsky district lies at a depth of 180-260 meters, the thickness of the layer ranges from 2.5 to 19 meters, the average iron content is about 58%. The deposit is of industrial importance, but is not currently being developed. The reserves of brown iron ore in the Verkhovsky region are similar in geological structure and iron content to the Lipetsk ores: occurrence depth is from 8 to 40 meters, the thickness of the layer is from 0.5 to 7 meters, the iron content is about 42%.

Date of publication: 2015-02-03; Read: 823 | Page copyright infringement

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The general features of the relief of the Russian Plain are predetermined by tectonics, the fact that the plain belongs to the ancient Precambrian platform, which has not experienced mountain building processes for a long time. Therefore, the Russian Plain is devoid of high mountain ranges; over vast areas it is characterized by slight fluctuations in heights. Average absolute altitude its about 170 m.

Despite the general flat nature of the surface, the Russian Plain cannot be called monotonous in relief. On its territory, hills alternate with lowlands.

An example of a task using space images in the lesson "Relief and minerals of Eurasia"

Central Russian, Valdai, Volga, Volyn-Podolsk and other elevations reach highest points 300-400 m above sea level. Lowlands - the Black Sea, Dnieper, Oka-Don, Caspian, Pechora, etc. - do not exceed 100-200 m. Of these, the Caspian lowland is the most depressed; its southern half has absolute elevations below sea level.

The complex orography of the Russian Plain is due to the tectonic features of the platform - the heterogeneous nature of its structure, the unequal manifestation of the latest tectonic movements. As it turns out upon closer examination, the platform itself consists of heterogeneous elements: shields, anteclises, syneclises and other smaller structures.

Of the shields on the Russian platform, two are known: Baltic and Ukrainian. The Baltic Shield includes Karelia and the Kola Peninsula; outside the USSR it continues in Finland and Sweden. Crystalline rocks of the Archean and Proterozoic appear everywhere on the surface here, except for a thin and not continuous cover of Quaternary sediments. The Ukrainian shield stretches from the shores of the Sea of ​​Azov to the Dnieper and Volyn-Podolsk uplands and southern Polesie. Unlike the Baltic shield, the Ukrainian shield is covered with tertiary sediments and the granites and gneisses composing it do not come to the surface everywhere, but mainly near river valleys.

Between the two shields - the Baltic and the Ukrainian - the crystalline basement lies at a shallow depth, usually less than 1000 m, and in Belarus no deeper than 500 m (Belarusian anteclise).

East of the Ukrainian shield, behind the deep trough of the Ukrainian syneclise, is the Voronezh anteclise, where crystalline rocks are located at a depth of 100-200 m from the surface. In the Don Valley south of the city Pavlovsk granites and gneisses of the Voronezh anteclise emerge on the surface in several places.

From the Voronezh anteclise, through the Middle Volga region towards the Urals, there runs a strip of relatively shallow (less than 2000 m) occurrence of crystalline rocks - the Volga-Ural anteclise. To the north of it, the foundation of the platform undergoes subsidence, forming an extensive Moscow syneclise, the axial part of which is clearly visible in the distribution of Mesozoic deposits in the Northern Uvaly area. To the south of the Volga-Ural anteclise, the crystalline basement drops sharply and deeply towards the Caspian syneclise.

The Caspian syneclise is one of the deepest on the Russian Platform. The Precambrian basement presumably lies here at a depth of 10 km or more. The Novouzenskaya reference well at a depth of 2986 m uncovered only the lower part of the Jurassic (Bakirov, 1954).

As support drilling has shown, the buried crystalline foundation of the Russian Platform has an uneven, mountainous terrain, with elevation fluctuations of up to 1500-2000 m at a distance of 100-150 km. As an illustration, the following example can be given: in the Zhigulevsko-Pugachevsky ledge of the basement, in the west of Samara Luka, crystalline rocks have an elevation of 1430-1600 m below sea level, and in the Saratov depression (Elshanka) their surface drops to -2718 m, and in the Volga region, Soka-Kinel depression, even lower - 2900 m: (Pritula, 1955). Such sharp fluctuations in the foundation surface are explained by tectonic disturbances, and not by erosion.

The sedimentary rocks covering the crystalline foundation of the platform have a quiet, nearly horizontal occurrence. However, in a number of places they are collected into gentle swells, dome-shaped uplifts, flexures, and in some places more abrupt tectonic disturbances of the sedimentary cover in the form of faults are observed. They are best expressed along the outskirts of the platform, and especially in the southeast of it - on the Volga Upland and in the Trans-Volga region.

The tectonics of the Donetsk Ridge is extremely interesting. Although it is located on a plain, it is a folded mountain structure of Paleozoic age, currently heavily peneplanated. Recently, in the territory of Ciscaucasia and to the north of it, a folded Paleozoic complex composed of highly metamorphosed rocks was discovered. In this regard, the Donetsk Ridge is usually considered as the northern edge of this Paleozoic folded zone;

Recently, volcanic effusive rocks have been found among the sedimentary cover of the Russian Platform. This suggests that the Russian platform experienced manifestations of volcanism already in post-Proterozoic times. Volcanism was especially vigorous in the Devonian, during the era of the Caledonian folding. A comparison of tectonic and hypsometric maps of the Russian Plain leads to the conclusion that its orography is tectonic. Almost all large hills and lowlands of the Russian Plain are not of erosional or glacial-accumulative, but of tectonic origin. Moreover, a significant part of them is inherited from the structure of the crystalline foundation: the protrusions correspond to the highlands, the depressions - the lowlands. Thus, significant uplifts of Karelia and the Kola Peninsula coincide with the Baltic shield, the Azov and Dnieper uplands are associated with the Ukrainian shield, the Central Russian Upland corresponds to the center of the Voronezh anteclise, the Black Sea depression, the Ukrainian and Caspian syneclises are located on the site of the Black Sea depression, the Dnieper and Caspian lowlands, etc. However, in the central parts of the Russian Plain such a correspondence modern forms It is not always possible to establish the relief of ancient structures, and in some cases there is a sharp discrepancy between the modern relief and the ancient structures. Northern Uvaly, for example, is located on the site of the most submerged, axial part of the Moscow syneclise, a significant part of the Volga Upland represents the Ulyanovsk-Saratov syneclise, the Oka-Don lowland took shape on the eastern slope of the Voronezh anteclise.

The discrepancy between the modern relief and ancient structures in most cases was established relatively recently and clearly became apparent only from the middle of the Tertiary period. In the central and northwestern parts of the plain, the tectonic conditioning of modern orography is less clearly expressed. In the formation of large relief features, the role of erosion and denudation increases here. The Silurian klint in the Baltic states and the Leningrad region, as well as the Carboniferous klint - the western cliff of the Valdai Upland, can be considered as steep ledges of huge cuestas, worked out in Paleozoic rocks of varying densities, showing a slight dip in the south-southeast direction. As in other places of the USSR, the modern relief of the Russian Plain is largely determined by the latest tectonics. On the Russian Plain it manifests itself in the form of small-scale epeirogenic movements.

B. L. Lichkov (1931, 1934) connects epeirogenic movements on the Russian Plain with glacial loads that arose in the north. In this regard, he speaks of the presence of zonality in epeirogenic movements: during glaciation, the north, under the influence of glacial load, experienced subsidence, the non-glacial south experienced a compensatory rise; in post-glacial times, the picture changed: the north, having lost the glacial load, began to rise, the south, on the contrary, began to fall.

G. F. Mirchink and N. I. Nikolaev showed the inconsistency of B. L. Lichkov’s views. Epeirogenic movements in the Quaternary period, as in the past, occur depending on the geological structure. Nearby areas that differ from one another structurally also have different types of epeirogenic movements. As a rule, in modern times (Neogene - Quaternary periods), the highlands retained the previously existing tendency to rise, and the lowlands to fall. Signs of Quaternary subsidence have been established for the Black Sea, Dnieper, Oka-Don, Caspian and other lowlands; traces of young uplifts have been noted in the Volyn-Podolsk, Central Russian and Volga uplands, in the Donetsk Ridge, and the High Trans-Volga region. Neotectonic movements reached their greatest extent in the Carpathian region, the Urals and in the north-west of the Russian Plain, in the region of the Baltic shield. Here the amplitude of movements is at least 200-300 m. The inland regions of Karelia and the Kola Peninsula experienced a rise of more than 150 m only during post-glacial times.

The heights of the Russian Plain, with their long-standing tendency to rise, represent areas of demolition and vigorous erosion processes. On geological maps they are outlined by the outcropping of more ancient bedrock than the rocks that make up the adjacent lowlands. On the contrary, many lowlands with a tendency to subsidence are areas of accumulation of loose upper tertiary and quaternary sediments and areas of weakened erosion processes.

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The entire history of the existence of the earth's crust is conventionally divided into several geological folds. In the history of the Earth, the following are distinguished: Archean (Precambrian) folding, Baikal, Caledonian, Hercynian, Mesozoic and Alpine folding. The last of them, the Alpine one, has not been completed and is currently ongoing.

Archean folding- the most ancient, it ended about 1.6 billion years ago. On diagrams it is usually indicated in pink. All were formed during the Archean folding platforms- the ancient cores of continents, their most stable (usually the smoothest) sections. For more than a billion years, sections of the crust formed in Archean were completely leveled by the external forces of the Earth, their surface turned into plains, and all geological processes of volcanism and mountain building stopped long ago.
Baikal folding- lasted from 1200 to 500 million years ago. It is named after Lake Baikal, since the area of ​​Siberia where the lake is located was formed during this period. The Baikal fold also includes the Yenisei Ridge, the Patom Highlands, the Khamar-Daban Ridge, part of the territory of the Arabian Peninsula and the Brazilian Plateau.
Caledonian folding— 500-400 million years ago. Named after Caledonia on the island of Great Britain, where it was first discovered. Great Britain, Ireland, Scandinavia, Newfoundland, South China, and Eastern Australia were formed into this folding.
Hercynian folding- 400-230 million years ago.

Test “Tectonic structures, geological structure, relief of Luhansk region” for 8th grade students

During this period, a significant part of Europe, the Urals, the Appalachians, the Great Dividing Range, and the Cape Mountains were formed
Mesozoic folding— 160-65 million years ago. Correlates with the Mesozoic era, when dinosaurs roamed the Earth. During this period, the Cordilleras, most of the Russian Far East, were formed
Alpine folding- began 65 million years ago. During the Alpine folding, the youngest, and therefore most turbulent, sections of the earth's crust were formed. Volcanic processes are active in these places, earthquakes often occur, and mountains continue to form. For the most part, they are located in areas where lithospheric plates collide. These are the Aleutian Islands, the Caribbean Islands, the Andes, the Antarctic Peninsula, the Mediterranean Sea, Asia Minor, the Caucasus, Southwest Asia, the Himalayas, the Greater Sunda Islands, the Philippines, Japan, Kamchatka and the Kuril Islands, New Guinea and New Zealand.

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Article on the topic "Relief: tectonic basis."

Patterns of distribution of relief forms. The modern relief of Ukraine was formed as a result of the interaction of internal and external forces who acted Cenozoic era. The origin and patterns of distribution of various forms and types of relief are studied by the branch of physical geography - geomorphology .

By comparing tectonic and physical card Ukraine, you can be sure that overall plan The relief structures of Ukraine - the location, direction of strike and height of lowlands, hills and mountains - are determined by the tectonic structure. Most of the major landforms of Ukraine ( Volynskaya, Podolskaya And Dnieper Upland, Donetsk Ridge, Dnieper Lowland And Ukrainian Carpathians) extend from northwest to southeast in accordance with the direction of occurrence of tectonic structures. Plays a big role oldest structure — Ukrainian crystal shield, Which set the main direction for other structures.

Basically, large landforms of Ukraine have a direct connection with tectonic structures: hills and mountains are located within the shield and folded structures, and lowlands correspond to tectonic depressions.

At the same time, in the western part of Ukraine the relationship between relief and tectonic structures is reversed: Volyn-Podolsk plate, Galicia-Volyn depression And Pre-Carpathian trough correspond to relief forms inconsistent with them - hills and humpback strands. This is due to the so-called neotectonic movements- Uplifts of the earth's crust that occurred there in the Cenozoic. Then almost the entire territory of Ukraine, except for the coastal strip, underwent uplift Black Sea region. Total rose Carpathians And Ciscarpathia , Crimean Mountains, Donetsk And Podolsk Upland. This led to active “incision” of rivers into the earth’s surface, which formed deep valleys with steep slopes, and in the south of the Podolsk Upland - canyons.

Main types of relief. The influence of internal and external forces on the earth's surface caused the spread of relief various types. Tectonic and volcanic types, and with external ones - gravitational, water-rosy and water-accumulative, karst, glacial and water-glacial, Aeolian, coastal, anthropogenic.

Tectonic formsrelief formed as a result of tectonic movements of the earth's crust. These are the mountain ranges and intermountain valleys in Ukrainian Carpathians(Alternating folds returned up and down), fold-block Crimean mountains , Slovechansko-Ovruch Ridge on the site of a horst (blocky uplift of crystalline rocks of the Ukrainian shield) , Donetsk Ridge(raised fold), Pridneprovskaya, Black Sea And Transcarpathian lowland(In place of depressions), etc.

Volcanic landforms is the result of direct volcanic activity ( Volcanic ridge in the Carpathians, Beregovskoe Gorbogirya in Transcarpathia, Mount Karadag in Crimea) or the penetration of magma between layers of sedimentary rocks ( Mount Ayudag in Crimea). Specific volcanic forms are mud volcanoes. Their cones are not high – up to 50 m. There are several dozen such mud volcanoes on Kerch Peninsula in Crimea.

Amazing Ukraine

Mud volcanoes

Most of the mud volcanoes of the Kerch Peninsula are extinct. However, there are also permanent or periodically operating ones. Gases escaping from depths of 5 - 7 km along breaks in the earth's crust push a rarefied clay mass with rock fragments to the surface, forming small conical hills or inclined elevations. The eruption of such volcanoes is sometimes accompanied by explosions, local earthquakes or spontaneous combustion of gas.

Rice. Mud volcano on the Kerch Peninsula

Gravitational formsrelief caused by processes occurring under the influence of gravity (gravity). These include collapses And hoarseness, Which is promoted by active weathering of rocks. Large landslides often occur in the mountains. They originate in areas of rocky cliffs, broken into blocks by a dense network of cracks. For the time being, these blocks are monolithic. The impetus for a collapse can be the penetration of rain or melt water into the cracks, which softens the clay layer. Then giant boulders and stones fly and roll down, destroying everything in their path. In the mountains and on the steep right-bank slopes of large river valleys there are often landslides .

Amazing Ukraine

Stone Chaos

Landslides have repeatedly occurred on the rocky cliffs of Mount South Demerdzhi in Crimea. The foot of the mountain near the village. Radiant hidden by the chaos of huge stone blocks the size of a three-story house. In 1966, blocks weighing 2 - 3 thousand tons fell with a roar from a height of more than 100 m. The rolling roar of a powerful collapse was like a strong explosion, and the seismic station in Alushta registered the tremors it caused as an earthquake.

Water-erosion formsrelief Associated with the destructive work of permanent (river) and temporary water flows. These forms are river valleys, canyons, ravines, ravines. At the same time, water accumulation occurs—the accumulation of sediments, as a result of which water accumulative shapes: wide floodplains And terraces in river valleys, deltas at the mouths Danube And Dnieper .

Records of Ukraine

The long canyon in Ukraine is the Dniester, whose length is 250 km. The Dniester from the mouth of the Zolotaya Lipa River to the Zbruch River cuts into the surface rocks, forming a narrow valley 150 - 180 m deep.

Karst forms are formed as a result of the dissolution of rocks by water. Karst caves, sinkholes, wells, mines extended to Volyn , Podolia, IN Crimean mountains, Donbass,- where rocks come close to the surface, they easily dissolve and are washed away by water (chalk, gypsum, limestone, salts). In middle Transnistria, at the junction of the Podolsk and Khotyn Uplands, there are almost fifty significant underground voids with total length explored passages over 465 km. Among them are the three largest gypsum caves in the world: Optimisticheskaya (217 km), Ozernaya (121 km) and Zolushka (90 km). Cave explorers - speleologists are constantly exploring new labyrinths in them, and also opening new caves.

Nature records

The world's largest cave in gypsum rocks is Optimistic, located in Ukraine on the Podolsk Upland (Ternopil region). Her underground labyrinths have a length of more than 165 km.

Rice. Optimistic - the longest gypsum cave in the world (165 km),

With. Korolevka, Borshchevsky district, Ternopil region.

Glacial formsrelief Associated with mountain and continental icing. The direct action of the glacier created former glacial beds — Executions(Recesses similar to large chairs) and circuses ( cup-shaped recesses). They occur in the highest mountain ranges Ukrainian Carpathians . Water-water-water-forms is a consequence of long-standing continental glaciation in past geological epochs. With climate warming after glacier retreat melt water formed oz- Long, narrow sand banks and kami-Sandy hills. They are common on Polesie Lowland .

Aeolian formsrelief – sand hills And strands—Arise as a result of wind activity. They are on Polesie, in the lower reaches Dnieper, On the sea spits.

Interesting geography

Oleshkovsky Sands

In the lower reaches of the Dnieper on the left bank large areas have long been occupied by sands. In the past, forests grew on them (Herodotus called them Hylea, which means Polesie or Oleshye). During the XIII - XVIII centuries. they were completely destroyed as a result of human economic activity. Then aeolian landforms began to actively develop there - moving hills up to 20 m high. In the 20th century. A pine forest was planted to stabilize the loose sand. However, in the hot summer of 2007, the forest suffered again - this time from numerous fires.

Coastal landforms are formed on sea coasts as a result of destructive and creative work sea ​​waves and surf. The destruction of the coast causes landslides and landslides. The coast gradually retreats, and due to marine accumulation, beaches , sand spits , shafts .

Anthropogenic (man-made )formsrelief — These are uneven surfaces of the earth formed by human activity. Quarries, waste heaps, dumps arising as a result of mining, and embankments, dams, shafts— As a result, the laying of communication routes, the construction of reservoirs, etc.

Rice. Landslides on the Black Sea coast, p. Kryzhanovka, Kominternovsky district

Rice. Shear coast in Western Crimea

The study of relief is of great importance for human life. This knowledge is important for searching for oil and gas areas and deposits of building materials. Relief research is necessary to justify the construction of engineering structures, prevent the consequences of natural disasters, carry out agricultural work, and solve environmental problems. The relief, primarily mountainous, is a significant factor in the development of tourism, sports and resort and sanatorium facilities.

Main tectonic structures. Tectonic structures“These are large areas of the earth’s crust, bounded by deep faults. The structure and movements of the earth's crust are studied by geological science tectonics .

As you already know, the largest tectonic structures are platforms and mobile belts. Platform “This relatively stable section of the earth’s crust with a fairly flat surface lies on the site of destroyed folded structures. It has a two-layer structure: below lies a crystalline foundation composed of ancient hard rocks, above it is a sedimentary cover formed by younger sediments. There are shields and slabs on the platform. Shield there is a section of the crystalline foundation of the platform raised to the earth's surface. the sedimentary cover on it is thin and not continuous. Plate - This is a section of the platform where the foundation is submerged to depth and is covered everywhere by sedimentary cover.

Movable belt - This is an elongated section of the earth's crust, within which long time happened anciently and continues modern movements earth's crust.

In the movable belt there are folded structures , marginal (foothill) troughs .

On the territory of Ukraine, tectonic structures such as depressions- deeply concave areas of the earth's crust filled with sedimentary and volcanic strata. Depressions are common both on platforms and in moving belts, as well as in the areas of their junctions.

The boundaries of tectonic structures are shown in tectonic map . It also indicates the folding during which they formed.

Platforms. The largest tectonic structure underlying the territory of Ukraine is the ancient Eastern European platform . Its foundation consists of Precambrian crystalline rocks (granites, basalts, gneisses, crystalline schists, labradorites, quartzites). On the platform rises Ukrainian shield. This is one of the oldest areas of the earth's crust in Europe. The crystalline foundation is covered here by an insignificant (several tens of meters) thickness of sedimentary deposits, and in many places Precambrian rocks reach the earth's surface. The shield, a strip 250 km wide, extends almost 1,000 km along the right bank of the Dnieper and reaches the Sea of ​​Azov. Ancient deep faults split the shield into large blocks.

On the western slope of the shield lies Volyn-Podolsk plate. On it, the depth of immersion of the crystalline foundation under the thickness of sedimentary rocks gradually increases from tens of meters (in the north and east) to 4 km (in the southwest). The deposits of sandstone and limestone are especially thick there. In the western part of the East European Platform, the plate transitions into Galicia-Volyn depression. The thickness of sedimentary rocks (sands, marls, chalk) grows there up to 6 km. In the south of the platform is Black Sea depression, which is also filled with sedimentary deposits - from 1 to 11 km (On the Black Sea shelf).

Along the northeastern border of Ukraine, it includes Voronezh crystalline massif. As in the shield, the crystalline foundation there comes close to the surface, but is everywhere covered by a thickness of sedimentary rocks of half a kilometer or more. Between the Ukrainian shield and the Voronezh massif there is a long, narrow and deep Dnieper-Donetsk depression. It is one of the deepest depressions within the entire East European Platform. The depression is filled with sedimentary rocks, the maximum thickness of which reaches 20 km.

In the extreme east of our country, the depression turns into Donetsk folded structure , Which was formed at the site of the deflection of the earth's crust. There, numerous layers of rocks (sandstones, limestones, gypsum, coal, etc.) were crushed into folds during the Hercynian folded era.

In addition to the Eastern European ancient platform, parts of young platforms extend into Ukraine. Their foundations are destroyed folded structures that were formed during the Hercynian folded era. Western European platform wedges in a narrow “tongue” in the west of Ukraine and plunges under the rock mass of the Cis-Carpathian trough. Scythian platform covers the flat part of Crimea, the adjacent part of the Black Sea shelf and most of the bottom of the Azov Sea.

Records of Ukraine

In terms of the number and diversity of the main tectonic structures that collide on the territory of Ukraine, our country is a leader among European countries.

Amazing Ukraine

Earthquakes on platforms

Despite the stability of the platform’s foundation, sometimes shifts of layers occur in its long-standing deep faults. This causes local earthquakes of up to magnitude 5 at the epicenter. In particular, in 2002, the epicenter of such an earthquake was in the village of Mykulyntsi in the Ternopil region, and in 2007 - in the city of Krivoy Rog.

Rice. Tectonic structure

The main tectonic structures of the belt are the Carpathian fold system, the folded-block structure of the Crimean Mountains and the Black Sea depression.

Carpathian fold system , Located in the far west of the country, is a component general structure— Alpine folded region. Long geological development and the manifestation of the mountain-virgin processes of several eras entailed very complex structure systems, distribution of thick rock strata of various origins and ages. Along with relatively young sedimentary deposits (sandstones, clays, shales), the system is composed of Precambrian gneisses, granites, quartzites, and crystalline shales. Its axial part is Carpathian fold structure. In it, many kilometers of sedimentary rocks are crushed into folds, often torn and displaced. They push in a northeast direction onto the adjacent Ciscarpathian trough. The trough is filled with sedimentary rocks (up to 4.5 km thick) and is the junction zone of the Carpathian system with the East European Platform. In the southwest it is adjacent to the folded structure Transcarpathian depression, Which is part of the Middle Danube depression. It is composed of strata of sedimentary and volcanic rocks that were formed by the penetration of magma along fault lines.

Fold-blockconstruction of the Crimean Mountains occupies the south of the Crimean Peninsula. Its western and southern parts are submerged under the bottom of the Black Sea. The structure is formed by sedimentary and volcanic rocks. Its folds are disturbed by numerous faults, landslides and thrusts.

Black Sea depression , which occupies the deepest part of the Black Sea, is the remnant of an ancient trough - Tethys sea. The earth's crust underneath is part of the oceanic type (i.e., it does not have a granite layer).

Zone of modern seismic activity. The zone of modern seismic activity is associated with the Mediterranean mobile belt. In the Carpathians and the Crimean-Black Sea region, earthquakes with a magnitude of 6-8 points on the 12-point international scale are possible. The last destructive earthquakes on the territory of Ukraine were in 1927p. Their epicenters were in the water area Black Sea at a short distance from the southern coast of Crimea. IN Carpathians The epicenters of the 1977 and 1986 earthquakes were located in Romania. Then vibrations of the earth's crust were felt in a significant part of Right Bank Ukraine.

Records of Ukraine

3 IV Art. BC. and to this day, about 80 strong earthquakes have been recorded in Crimea.

Amazing Ukraine

Earthquakes in Crimea

In 1927, two earthquakes occurred in Crimea, causing destruction on the coast from Sevastopol to Feodosia. In particular, part of the rock under the famous Swallow's Nest palace collapsed. Since then destructive earthquakes did not have. However, sensitive seismic instruments record dozens of weak tremors every year. Most of their epicenters are located in the Black Sea between Yalta and Gurfuz at a depth of 10 to 40 km below the seabed - where the Black Sea Trench plate plunges under the continental crust.

Epochs and phases of folding

In the geological history of the Earth, several eras of intense folding and mountain building are distinguished. Each epoch of folding consists of several phases that are close in time to manifestation. In Precambrian times, folding occurred repeatedly, as a result of which all Archean and Proterozoic rocks were intensively metamorphosed. The most famous folding of the Precambrian is the last one - Baikal , which appeared at the end of the Proterozoic and ended in the Cambrian. During the Baikal era of folding, folded structures of the Yenisei Ridge, Eastern Sayan, Baikal-Patom Highlands, etc. were formed. Since the beginning of the Paleozoic, four eras of folding have been distinguished: Caledonian, Hercynian (Variscan), Mesozoic (Cimmerian), or Pacific, and Alpine.

Caledonian(Early - Middle Paleozoic) folding includes several phases that appeared at different times and in different places: salair - at the end of the Cambrian, Tacona – at the end of the Ordovician, Caledonian – at the end of the Silurian. Folded structures of the Scandinavian Mountains, the mountains of East Greenland, Scotland and Wales, Kuznetsk Alatau, Western Sayan, the northern arcs of the Tien Shan, etc. were formed.

Hercynian(Late Paleozoic) folding includes phases: Acadian - in the middle of the Devonian Sudeten - at the end of the Early Carboniferous, Saal - in the middle of the Early Permian. Folded structures of the Urals, Dzhungar Alatau, Altai, southern arcs of the Tien Shan, etc. were formed.

Mesozoic(Cimmerian), or Pacific, folding covers the Jurassic and Cretaceous periods. Folded structures were formed in North-Eastern Siberia and the Far East (Verkhoyansk-Chukotka region, Mongol-Okhotsk belt, Sikhote-Alin, etc.).

Alpine folding is the youngest, manifested in the Cenozoic (mountain formation began in the Oligocene). The Alps, Apennines, Carpathians, Caucasus, Kopetdag, Pamir, Himalayas, etc. are formed.

3.2. EARTHQUAKES

Earthquakes - vibrations of the Earth caused by sudden release potential energy earth's bowels In the thickness of the Earth, stress accumulates for a long time (tens and hundreds of years), having reached the limit of rock strength, the energy is released by the rupture of rocks at a speed of 3-4 km/s, and an instantaneous displacement of solid matter occurs at the source of the earthquake. Such breaks are called seismogenic. Outside the source, reversible deformations of rocks occur, spreading in the form elastic vibrations - seismic waves. Hypocenter or hearth- a certain volume of rocks (this is not a point), within which, as a result of the action inelastic deformations cause destruction of rocks. Epicenter- projection of the hypocenter onto the earth's surface.

The speed of propagation of seismic waves mainly depends on the composition, structure, and physical state of rocks. In dense rocks, seismic waves travel faster than in loose rocks, but the destructive force of earthquakes is greater in loose rocks than in rocky rocks. The length of seismogenic ruptures varies: from several kilometers (during the Tashkent earthquake of 1966 - 8 km), to hundreds of kilometers (during the Chilean earthquake of 1960). Seismogenic ruptures are often confined to long-lived ancient faults. For example, the San Andreas fault in California arose at least 40 million years ago. Along it happened major earthquakes in San Francisco in 1906, in the Los Angeles area in 1957 and 1971.

The duration of earthquakes is from several seconds to several months. Along with the main shocks, the preceding (foreshocks) and subsequent (aftershocks) are recorded, and this entire period is called the earthquake period. During the Alma-Ata earthquake of 1887, more than 600 tremors were recorded. Based on the depth of their sources, earthquakes are divided into: 1) shallow-focus (ordinary) with a source depth of up to 60 km; 2) intermediate - from 60 to 150 km; 3) deep-focus - more than 150 km. The maximum known value is 720 km, according to other sources 620 km. The overwhelming majority of earthquakes (80%) occur in the crust, most of them at a depth of less than 8 - 10 km.

Strength, energy and magnitude of earthquakes

Force(intensity) - the external effect of an earthquake on the Earth’s surface, manifested in soil displacement, the appearance of cracks on the surface, the degree of destruction of buildings, etc. To determine strength there are “earthquake intensity scales”, which are based on the results of direct observations of the destruction caused and “psychological sensations of people.” Currently, Russia has adopted a 12-point scale of earthquake intensity MSK - 64. Earthquakes reach their greatest strength at the epicenter. In all directions from the epicenter, the strength of tremors decreases. Points where the earthquake occurred with equal strength are connected by lines - isoseists. Isoseisms separate isoseismic zones (areas of equal earthquake strength). Due to the heterogeneous composition of the earth's crust, isoseist maps can have a complex configuration. Pleistoseist region – area bounded by isoseism highest value, i.e. the area surrounding the epicenter.

Energy earthquakes - this is the amount of potential energy that is released in the form of kinetic energy after the tension in the source is discharged, and reaching the surface of the Earth, causing its vibrations. Energy propagates in the form of elastic seismic waves. The energy of earthquakes is usually expressed in ergs (oe) or joules (J) and varies widely - from 1010 to 1025 oe (i.e. 1018 J). For the 1964 Alaskan earthquake with a magnitude of 8.5, the energy was 1018 J (1 J = 107 erg), i.e. was equivalent, according to N.I. Nikolaev, the explosion force of 100 nuclear bombs of 100 megatons each.