The geological structure of the southern half of the Far East contains a variety of sedimentary and metamorphic rocks, intrusive and volcanic formations of different geological ages from the most ancient (Archean) to the youngest (modern). The formation of the surface of the Far East covered a huge period of geological time. Since the Precambrian, the western part of the territory is a continent. In subsequent periods, there was an increase in the territory in the east as a result of folding and volcanism.
The age of the geological structures reflected in the relief is not uniform. Precambrian and Paleozoic structures prevail in the western part. The main and largest part of the southern half of the Far East lies in the zone of development of Mesozoic folding, the eastern periphery of the mainland and the island belongs to the zone of Cenozoic folding and volcanism.
The different nature and age of the structures are reflected in the general appearance of the relief, creating a variety of types of the Far Eastern mountains. Zonal features are superimposed on the relief created during the geological history of mountain building. Each physical-geographical zone has its own complex of relief-forming processes.
The complex geological structure has led to a great wealth and variety of mineral deposits (ferrous, non-ferrous and noble metals, coal and brown coal, building materials, etc.).
During the years of Soviet power, much has been done to develop the mineral resources of the Far East, but nevertheless, the degree of exploration by prospecting is still extremely low. V. A. Yarmolyuk (1960) notes not without reason: “... only a weak study should explain the fact that until now in the Amur Region and the Khabarovsk Territory, no deposits of a number of minerals have been discovered, including oil and gas, diamonds and phosphorites, while the geological setting for their identification is quite favorable ”(p. 240).
In the southern half of the Far East, the Aldan shield, which represents the eastern part of the Siberian platform, belongs to the Precambrian structures. It is composed of crystalline rocks, overlapped in places by Jurassic sandstones, occupies the western part of the Aldan-Okhotsk watershed, and is located north of the Stanovoy ridge. To the south lies the Zeisko-Bureya plate, the Precambrian core of which is associated by many researchers with the Chinese shield and the Manchurian platform.
Deposits of iron and manganese ores, graphite, mica, magnesite, dolomite, limestone, oil shale are associated with the most ancient: Archean, Proterozoic, Precambrian rocks.
Iron ore deposits include the Garinskoye magnetite deposit in the Zeya basin with reserves of about 400 million tons with 41.7% iron content and the accompanying Lebedinskoye, Imchikanskoye, Selemdzhinskoye and Partizanskoye small deposits, the last of which has a content of up to 68% iron. Also of significant importance is the Kimkanskoe deposit of ferruginous magnetites and magnetite-martite quartzites in the Bureya basin with total reserves of 221.7 million tons. Little-studied deposits in the Bureya ridge system have total reserves of at least 800 million tons.
Recently, two large iron ore deposits have been discovered in the Zeya basin: the Sivakanskoe deposit with quartz-amphibole-magnetite and quartz-magnetite ores and the Gilyui deposit of magnetite quartzites with an iron content of 60-70%, the reserves of the first and second deposits have not yet been determined.
In the lower reaches of the Ussuri, the Khekhtsyr iron ore deposit of rich magnesite ores with an iron content of 63% was discovered; reserves have not been calculated.
Within the limits of the Bureinsky ridge, together with the iron ones, manganese ores also occur, forming over 30 deposits. On the Small Khingan, ‘along the left tributaries of the Amur, deposits of Proterozoic graphite and marble can be traced. Deposits of graphite, iron sedimentary ores, roofing shales and limestones of Proterozoic age are found in Primorye (Here and below, we only list minerals of different geological ages. For a more detailed list of deposits and their reserves, see Udovenko (1958) and Yarmolyuk (1960)).
Many billions of tons of oil shale reserves are found in the Mai Basin.
Ancient Paleozoic structures are noted in the Stanovoy and Dzhugdzhur ridges and within the Khanka massif, they are formed by orthogneisses. Ancient Paleozoic structures are strongly disturbed by Mesozoic fold and block movements. The Old Paleozoic gneiss core is found in the anticlinorium of the Lesser Khingan and Bureinsky ridges.
Strongly metamorphosed crystalline schists of the Lower and Middle Paleozoic are prominent in the South Verkhoyansk region on the Aldan-Okhotsk watershed.
The structures of the New Paleozoic (Variscian) folding are best preserved in the south of the Far East in the Yankan, Tukuringra-Dzhagdy ridges, in the southern part of the Dzhugdyr ridge, in the Ayan region and on the Shantar Islands, as well as on the northeastern edge of the Zeisko-Bureya plate.
Deposits of manganese and limestones are associated with rocks of the Paleozoic age. The introduction of Paleozoic granites is the cause of gold and rare-metal mineralization in many areas of the Amur Region and the western part of the Khabarovsk Territory.
Lower Cambrian manganese deposits have been discovered in the Small Khingan. Middle Cambrian limestones come out in Maly Khingan, Sikhote-Alin; in the eastern part of the Tukuringra-Jagdy system, in Dzhugdzhur, Lower Cambrian limestones, sandstones and marls are found, they are suitable as a building stone and as a cement material.
The Cambrian strata contain limestones, dolomites, marbles, iron ores, facing and decorative stones, roofing and slate slates, graphite, bauxite, aluminum and manganese ores. Only limestones and dolomites are exploited.
On Sakhalin, gold, manganese, iron, and limestone are associated with the Lower Paleozoic deposits. Igneous rocks, both Precambrian and Cambrian, strongly weathered, cannot be used as building material, but can be used as facing. There are signs of Cambrian oil and rock salt.
On the Aldan-Okhotsk watershed (Setta-Daban ridge) there are large, but undiscovered reserves of Ordovician limestone suitable for construction. In the western part, there are deposits of Silurian gypsum, and in the Setta-Daban ridge, Silurian and carbonic building limestones. Silurian quartzites, suitable as raw materials of dinas, sandstones, limestones and shales are developed in. basin of the upper Amur, Zeya and Selemdzhi. Copper ores are confined to the Silurian deposits in the Far East. In the basin of the Upper Amur and between the Zeya and Selemdzhi rivers, there are Devonian limestones and sandstones that can be used as building stones.
Mineral resources of the Carboniferous and Perm in the south of the Far East have been studied Unevenly and insufficiently. There are known deposits of building stone - tuff-sandstone - on the Aldan-Okhotsk watershed, in the Amur and Primorye regions.
Mesozoic structures are especially widespread. These include the Khingan-Bureinsky anticlinorium. It predetermines the main orographic features of the Bureya ridge system, composed of rocks from the Archean to the Upper Silurian inclusive (gneisses, granites, crystalline schists, conglomerates, sandstones). The Mesozoic Bureya Foredeep, formed at the edge of the Zeyoko-Bureya Plate, created conditions for the development of the intermountain Upper Bureya Plain; it is filled with Upper Jurassic and Lower Cretaceous sediments overlain by loose Cenozoic formations. The system of ridges of Badzhal and others, parallel to it, developed on the Badzhal anticlinorium. In the basin of the lower Amur, the Lower Amur synclinal zone extends (PN Kropotkin, 1954), within which rock outcrops from the Archean to the Carboniferous are confined to the ridges, and from the Upper Jurassic to the Upper Cretaceous to depressions. The Mesozoic trough is the Suifun depression. On the Mesozoic structures formed the South Ver-khoyan and Dzhugdzhur, the Shantar Islands, the valley of the river. Udy, plains along the coast of the Sea of Okhotsk to Ayan and the large western part of Sikhote-Alin.
The southern half of the Far East is located within the Pacific ore belt, which encircles the Pacific Ocean in a ring-like manner (S.S.Smirnov, 1946) and is very rich in metal deposits.
There are known deposits of ore and placer gold in the Aldan-Okhotsk watershed, in the basin of the upper Amur and Zeya, in the Sikhote-Alin, many of these areas are associated with ore occurrences of tin, tungsten, molybdenum and some other metals.
These manifestations are mainly associated with the mineralization of the Mesozoic age caused by the introduction of granitoids and main intrusions. The mining of tin, lead, zinc and gold is of allied importance. Known polymetallic deposit in the area of the Tetyukhe Bay, in the south of Primorye, tin - near Obluchye, in the western part of the Jewish Autonomous Region, molybdenum - in the upper reaches of the river. Selemdzhi (Umalta). Gold has been mined in the Far East since the development of the region, more than a hundred years ago. However, the extraction was carried out on a predatory basis, with incomplete extraction of metal. During the years of Soviet power, gold mining has been carried out using the latest technology: powerful steam and electric dredges are working on the development of placers, the development of ore deposits is also mechanized. The use of new economical technology resulted in the commissioning of alluvial deposits with a relatively low gold grade. The main areas of gold mining at present are the upper reaches of the Zeya and its tributary Selemdzhi, the area of the river. Iman and, to a lesser extent, the lower reaches of the Amur.
Geological strata of the Mesozoic age are coal-bearing. In particular, deposits of fossil coal are associated with Triassic deposits within Primorye and there are signs of phosphorite content. Deposits of Jurassic coals are found in the basin of the Upper Bureya.
Jurassic intrusive rocks: granites, syenites, granite porphyries and granodiorites can serve as building and facing materials.
Coal deposits (Sakhalin, Bureinsky, Suchansky and Suifunsky basins) have the Lower and Upper Cretaceous age.
Of the coal deposits, the largest is the Bureya coal basin with total geological reserves of 22-23 billion tons. The Tyrma coal basin with industrial reserves of 1.15 million tons belongs to the Bureya river basin. There are 4 coal deposits on the upper Amur. all are insufficiently studied. In the Zeya-Depsky coal-bearing basin, the total geological reserves of coal are 345 million tons. Ogodzhanskoye is being developed in the Selemdzhi basin. coal deposit, but its reserves have not been calculated. Upper Mesozoic felsite porphyry, quartz porphyry, trachyte, etc. can be used as a building stone.
The eastern part of the Sikhote-Alin belongs to the Cenozoic Primorsky fold zone, which is characterized by the development of volcanogenic formations.
According to the latest data, fold dislocations of the Laramian phase (end of Cretaceous - beginning of Paleogene) played an important role in the Lower Amur fold zone.
On Sakhalin Island, the North Sakhalin and Tym-Poronayskaya plains develop within the Central Sakhalin Cenozoic synclinal zone. The West Sakhalin anticlinorium is expressed in relief in the form of the Western Ridge. The East Sakhalin anticlinorium, which developed in the Mesozoic folding zone, is traced in the form of a system of ranges of the East Sakhalin, Susu, Tonino-Anivsky, etc.
The Kuril island ridge reflects in the relief the Cenozoic zone dominated by faults and volcanism.
Tertiary deposits have industrial coal content. The largest paleogene brown coal deposit in the Amur basin is the Raichikhinskoe field on the Zeisko-Bureinskaya plain with industrial reserves of 460 million tons, nearby is the Erkovskoye field with 3.5 million tons of industrial reserves and Apxapo-Boguchanskoye, which is currently not exploited. In the Ussuri basin, the Bikinskoye brown coal deposit with reserves of 550 million tons and the Khabarovsk deposit with reserves of over 300 million tons were again discovered.
Eocene-Oligocene deposits of long-flame coals and high-quality Neogene coals are exploited on Sakhalin.
In Primorye, there are deposits of Paleogene and Neogene diatomites, which have high heat and sound insulation qualities, this is a good addition to cement raw materials, as well as a good filter, adsorbent, catalyst, absorbent and grinding material. In the same place, deposits of ocher, mummy, and cinnabar are associated with Tertiary and partly with Quaternary deposits. The latter simultaneously ‘represents the raw material for the production of mercury. In the Amur basin, reserves of Neogene-Quaternary mineral paints have not yet been sufficiently studied. Ocher deposits have been explored near Pereyaslavka, near Soyuznoye on the Amur, where the reserves are 7 thousand tons. Semichevskoye with reserves of 2100 m 3 and Deciduous - 3400 m 3 are located in the Bureinsky district of the Amur region.
The most valuable deposits of the Neogene period in the Far East are Sakhalin oil and gas.
There is a deposit of Neogene coals and lignites in Primorye. The coals of Sakhalin contain amber inclusions. On the lower Amur near Nikolaevsk there is a deposit of neogenic-Quaternary sedimentary iron ores - brown iron ores with reserves of 14.8 million tons. There are gypsum deposits on Sakhalin; deposits of Neogene kaolin and porcelain-faience clays in Primorye. Bentonite clays and flasks in the Amur basin are found in the lower reaches of the Arkhara; diatomites, suitable as adsorbents, have been found on the lower Amur, on the Zeya, near Lake Khanki. Deposits of molding and glass sands confined to Neogene rocks are located in the Amur-Zeya interfluve: "Progress Yuzhny" has a silica content of 98% (it has been developed for a long time and currently has reserves of only 50 thousand tons), "Progress-I" and "Progress- II "have total reserves of 250 thousand tons. Located to the east of the Darmakan deposit of molding sands with a silica content of 97.3% has reserves of 896 thousand tons. In the Bureinskoye deposit, the sands are somewhat ferruginous, their reserves amount to 400 thousand m 3 (Yarmolyuk, 1960) ...
For small and medium iron casting, quartz-feldspar sands with a silica content of 80.54% are used. The reserves of such sands in the basin of the Zeya, the upper and middle Amur are very large. Within the basin of the lower Amur, sand deposits have a low content of silica (75-80%), only in the Oborskoye (Ussuri basin) deposit it reaches 93%.
Among the Quaternary minerals, the most important are placer gold deposits on the rivers of the Aldan-Okhotsk watershed, in the lower reaches of the Amur, in the Zeya basin. tin - in Primorye. Widely developed loose deposits are of particular value as a building material: various sands, pebbles and boulders. Clays suitable for brick and tile production are especially developed in Primorye and in the Amur basin. Quaternary volcanic rocks are used as building stone: andesite-basalts, basalts, etc. Native sulfur deposits are known on the Kuril Islands.
Quaternary peatlands, widespread in the southern half of the Far East, have huge, but completely unexplored reserves.
Within the limits of the Soviet Far East, neotectonic (We are talking about neotectonics in the understanding of V.A.
In the Stanovoy Ridge and Sikhote-Alin, they developed along the lines of ancient folded systems. In the Sikhote-Alin ridge, the role of the latest movements in the formation of the modern relief is very great. In the ridges located to the west (Tukuringra-Jagdy), the amplitude of the newest movements is less. Here, general slow fluctuations of the territory were captured, which affected the formation of some terraces and incised meanders along the rivers (It should be noted that not all terraces on the Far Eastern rivers were formed due to oscillatory movements. Some levels were formed as a result of climate change).
The immersion areas are the central parts of the intermontane plains of the Verkhne-Zeya, Sredne-Amurskaya, Prikhankayskaya.
For the mountainous region of Sikhote-Alin, the amplitude of the newest movements was calculated by P.N. Kropotkin, K.A. Popov and others, they determined it equal to 1000-2000 m.The coastal and the marine insular part of the territory of the Far East are distinguished by high seismicity, here not only slow neotectonic uplifts and subsidences, but also modern fast tectonic movements and volcanism were of great importance in the formation of the modern relief ...
Tectonic movements strongly affected the change in the boundaries of the Sea of Okhotsk and the Sea of Japan, on the relief of their bottom.
The southern parts of the Sea of Okhotsk and the Sea of Japan have depths below 3000 m; they therefore share some common features with the deepest parts of the oceans. Although these areas of the seas are Cenozoic geosynclinal areas, they have been occupied by the sea throughout the entire geological history, or, as G.U. Lindberg (1947) suggests, they were only temporarily laced up and turned into freshwater or highly saline reservoirs. Young formations are only narrow coastal zones of subsidence along the shores of Sikhote-Alin and Sakhalin.
From all that has been said, we can conclude that both in the creation and distribution of mineral deposits and in the structure of the surface of the southern half of the Soviet Far East, the role of geological structures, neotectonic movements and volcanism is very great: the main lines of orography, the general direction of water flow, conditions for the development vertical zoning is determined by these factors.
Forms of glacial gouging ...
But the importance of climate in transforming the relief of the Far East cannot be underestimated either. Climatic changes in the past and the processes associated with them have left an indelible imprint on the original appearance of the south of the Far East and in some places have greatly changed it. Since the beginning of the existence of the Far East as a continent, climatic agents have been exerting their influence on the surface of mountains and plains.
In tectonic depressions, now occupied by river valleys (Amur, Zeya, Ussuri, etc.) and lakes (Khanka, Petropavlovskoe, etc.), at the beginning of continental existence, there is an increased accumulation of sediments in a hot subtropical climate. The rivers were calm; the rivers meandered; Obviously, the filling of the depressions with sediments occurred under subsidence conditions, apparently, the drift was from the north and from the mountains of the Big and Small Khingan. This direction of drift is evidenced by the absence of large accumulations of loose sediments north of the Upper Zeya depression, in the mountains of the Aldan-Okhotsk watershed.
Processes of slow leveling took place in the mountains, and a kaolin weathering crust was formed.
The first rivers chose their way along natural depressions predetermined by tectonic structures. Two directions of runoff prevailed: along the ridges of the west-north-west strike, according to the structures of the New Paleozoic folding, and also to the south and north, along the Mesozoic structures with the north-north-east strike.
In the south of the Soviet Far East, there are numerous areas of accumulation, apparently before the beginning of the Quaternary period.
In the Upper Tertiary, characterized by a complete tectonic restructuring of the relief, some movement of the hydrographic network occurs, which was often associated with volcanic eruptions within the valleys.
At this time, mountain ranges and adjacent plains are drawn into the uplift, as a result, thick strata of loose sediments are brought out to the day surface, at the same time a series of incised meanders are formed on the upper Amur, as deep erosion begins to prevail.
In the process of the continued uplift of the mountains in the south of the Far East in the middle of the Quaternary period, they underwent ancient glaciation. Signs of ancient glaciation are found in the mountains and on the Upper Zeya Plain (V. K. Flerov, 1938; V. V. Nikolskaya and I. N. Shcherbakov, 1956), but it seems to be an exception. Apparently, there was only one glaciation, which had several phases, as indicated by the presence of traces of two types of glaciers - cover and valley, as well as two moraines, which are traced at many points, separated by alluvial deposits.
Evidence of multiphase glaciation is found not only on the mainland (Yu. A. Bilibin, 1939; VV Nikolskaya, 1946; VV Nikolskaya and IN Shcherbakov, 1956), but also in the adjacent sea basins; For example, the works of A.P. Zhuze (1958), who carried out diatom analysis of two columns of marine sediments from the Okhotsk and Bering seas from depths of 3355 and 3638 m, show that the ages of glaciation correspond to horizons of shallower sediments, in which cold-loving diatom flora are present and the Pliocene redeposited diatoms washed out from the coast, as well as the fact that the phases of the onset of glaciation were accompanied by regressions of sea basins, and retreats were accompanied by transgressions; the most significant in terms of size is the modern, post-glacial, transgression.
The coincidence in time of the regressions of the seas with glaciations, apparently, has an indirect connection. The most favorable conditions for glaciation in the mountains were created, as noted by D. M. Kolosov (1947), in those cases when they rose above the belt of anticyclone dominance into a higher layer of the atmosphere, where cyclonic phenomena manifested themselves. Therefore, the maximum of mountain glaciation could coincide with the maximum of the newest rise of coastal mountain ranges, which was accompanied by the regression of the sea.
Quaternary glaciation was not the same in different parts of the Far East. It was of a cover nature in the Dzhugdzhur region, in the mountains of the South Verkhoyansk region, in the Tukuringra-Dzhagdy ridge, in the northern part of the Bureya ridge and, possibly, in the Badzhal ridge, where later it was replaced by a valley one. In the Sikhote-Alin system, glaciation was crustal. The results of the ice work were reflected in the relief in the form of mountain troughs, circuses, carts, grinding and polishing of mountain peaks and slopes, and also affected the change in the hydrographic network caused by the local intensified glacial accumulation.
At present, the question of the type of ancient glaciation of the Upper Zeya Plain is still unclear. Located 300-400 m above sea level, this plain is hypsometrically higher than most of the other plains of the Amur basin and islands. Its western end is 600 km away from the sea coast, and its eastern end is 350 km away. However, through valleys in the headwaters of the Arga connect it with the Uda River basin and open the way for the influence of the Pacific Ocean. These features of its geographic location influenced the nature of the Quaternary glaciation within its boundaries.
In the formation of the relief of the Upper Zeya Plain, glaciers apparently descended from the surrounding mountain ranges: the Stanovoy Range, Tukuringra-Dzhagdy and Dzhugdyr.
Glaciation on the Sikhote-Alin and on the ridges of Sakhalin was very insignificant and did not affect the low mountains, as well as the Amur and other plains.
The climatic conditions of the time of maximum glaciation in the non-glacial regions of the south of the Far East can be easily visualized from the results of the analysis of pollen from the strata of the second above-floodplain terrace of Ussuri at st. Vyazemskaya, there were found the bones of a huge forest-steppe animal - a trogontery elephant (Earlier, in 1948, part of the bones was delivered to A.F. Baranov and was mistaken for mammoth bones).
Granite massif Tarbaganakh ...
This elephant, a typical animal of the Lower-Middle Quaternary, lived in the harsh conditions of the cold forest-steppe (Nikolskaya, 1951).
Accumulations of loose moraine and fluvioglacial deposits are observed in valleys and intermontane basins. Sections of the valleys turned out to be buried under glacial deposits, which is of particular importance for gold-bearing regions, where traces of glaciation deserve special study in order to explore buried placers.
In some places, after the melting of the ice sheet, glacioisostasis manifested itself (Glacioisostasis is the phenomenon of subsidence of a section of the earth's surface under the load of a glacier and a compensatory rise in its body at the end of glaciation), as a result of which erosion intensified, which led to the formation of break valleys, giving new features to the structure of the hydrographic network.
The post-glacial uplift of the entire territory of the Far East led to a general increase in deep erosion (erosion stage). Enlivened by the general rise of the territory, the tributaries of the main rivers flowing across large geological structures, which used the main direction of geological structures for their valleys, cut into the depths of the ridges, cut the anticlinoria and, joining the upper reaches, gave a new direction to the main river; as a result, the structure of the hydrographic network acquires, in general terms, a modern look.
The subsidence that followed the rise was uneven (much stronger in tectonic depressions). The sinking amplitude increased from west to east and towards the sea coast. This time was characterized by the predominance of lateral erosion, and the erosion of the overlying terraces took place. The process of ‘redeposition of loose formations and the accumulation of peat bogs on the coasts, in river valleys and lacustrine depressions’ went on intensively. This stage can be called erosion-accumulative. For a number of areas of the sea coast, diving continues at the present time.
Interesting data on the subsidence of the coastal parts of the Far East are given in the works of G.U. unified system of Pra-Amur. Communication was disrupted due to the immersion of part of the territory below sea level.
The flooded submarine valleys were discovered by bathymetric studies, and an underwater depression with a depth of 2-3 km was formed over a large area. G.U. Lindberg attributes this expansion of the deep-water basins of the Sea of Okhotsk and Japan to the post-glacial time.
The sinking was followed by a second rise in the central parts of the mainland and insular Far East, and the outlines of the surface "took on a modern look.
In the history of the continental development of the relief of the southern half of the Far East, five stages can be distinguished:
I. A very long stage, covering a huge segment of the Cretaceous and the beginning of the Tertiary period. At this time, the territory was leveled by denudation of mountains and filling of depressions in the Lower Amur zone and on the island. Sakhalin. At this stage, folding and uplift occurs.
II. The second half of the Tertiary and the beginning of the Quaternary were marked by tectonic dissection of the territory in the western half of the Far East and the emergence of new mountain structures, the formation of islands and peninsulas in the eastern half. The northern half of the territory was predominantly an area of demolition, in the south there were extensive areas of accumulation.
III. The middle of the Quaternary period is remarkable for glaciation (to one degree or another), which covered all mountain systems and spread to the northern plains. It coincided with the regression of the seas. For the southern, extra-glacial part of the Far East, this stage was characterized by the development of many lacustrine reservoirs.
IV. Upper Quaternary time is characterized by the revival of erosion in the conditions of the general uplift of the territory. There is a sub-stage of subsidence characterized by the predominance of lateral erosion and redeposition of loose strata.
V. Modern period of action of various zonal physical and geographical processes in sharply different tectonic conditions: calm in the west and intensively continuing mountain building and volcanism in the east; characterized by human impact on nature.
Option 1
° WITH; precipitation over 600 mm.
C) Kamchatka Peninsula D) Primorye
Test on the topic "Large natural regions of Russia"
Option 2
5. Correlate which parts of the Russian Plain are characterized by the following descriptions of natural components?
A) European North B) Central Russia C) European South
Answers.
Option 1
Option 2
Preview:
Test on the topic "Large natural regions of Russia"
Option 1
1. Which of the mountain systems belongs to the area of alpine folding?
A) Caucasus B) Ural C) Khibiny D) Altai
2. Indicate where the combination of the PZ of the West Siberian Lowland is correctly indicated:
A) tundra - forest-tundra - taiga - mixed forests - deciduous forests
B) forest-tundra - taiga - deciduous forests - steppe
C) tundra - forest-tundra - taiga - forest-steppe - steppe
D) taiga - forest-tundra - forest-steppe - steppe
3. Determine which of the lakes is located on the Caspian lowland:
A) Vats B) Khanka C) Sarez D) Elton
4. The smallest amount of precipitation in the territory of the East European Plain falls on ...
A) northwest B) northeast C) southeast D) southwest
5. Correlate which parts of the Russian Plain are characterized by the following descriptions of natural components?
1) in summer, the sun almost never sets, and in winter - the kingdom of snow;
2) the relief is flat; salt lakes formed in shallow depressions; precipitation falls 5-6 times less than it can evaporate;
3) summer is neither cold nor sultry; the average July temperature is 17 - 20° WITH; precipitation over 600 mm.
A) European North B) Central Russia C) European South
6. Stone birch forests with tall grass meadows grow in the Far East in the region
A) Chukotka Peninsula B) Sakhalin Island
C) Kamchatka Peninsula D) Primorye
7. In what sequence do the altitudinal belts replace each other in the mountains of North-Eastern Siberia from the foothills to the peaks?
A) forests, mountain tundra, dwarf cedar thickets, cold deserts and glaciers;
B) mountain tundra, cold deserts, eternal snows and glaciers;
C) forests, thickets of dwarf cedar, mountain tundra;
D) forests, mountain tundra, cold desert
8. In which part of the Urals there are many shallow lakes occupying karst basins?
A) in the Cis-Urals B) in the Subpolar Urals
C) in the Trans-Urals D) at the eastern foot of the Middle Urals
9. What adverse natural phenomena are most likely to threaten the residents of Yuzhno-Sakhalinsk?
A) earthquakes B) droughts C) surge floods D) typhoons
10. What natural complexes are represented in the mountain basins of Southern Siberia?
A) deciduous forests B) steppes C) deserts D) monsoon forests
Test on the topic "Large natural regions of Russia"
Option 2
1. Which of the mountain systems belongs to the area of the Hercynian folding?
A) Caucasus B) Ural C) Khibiny D) Byrranga
2. The territory of the Far East is characterized by high tectonic activity. This is due to:
A) the coastal position of the region;
B) the large extent of the territory from north to south;
C) the Far East is predominantly mountainous;
D) the position of the territory at the junction of the largest lithospheric plates.
3. Northern Uvaly is a watershed of river basins ...
A) Northern Dvina and Volga B) Dnieper and Pechora C) Volga and Ob D) Yenisei and Lena
4. Select an area for which nature is the most typical forest swamp complexes:
A) Central Russia B) Western Siberia
C) North-East of Siberia D) Far East
5. Correlate which parts of the Russian Plain are characterized by the following descriptions of natural components?
1) among the picturesque hills and ridges, there are many lakes with bizarre outlines; moraine hills and ridges are covered with spruce and spruce-deciduous forests; pine forests grow on sandy hills;
2) this is the territory poorest by rivers; rivers are mainly fed by snow; they are meandering, with a slow current, with an abundance of old women; rivers grow shallow in summer;
3) rivers are characterized by an abundance of rapids and waterfalls; they are abundant in water, have a fast flow and a short length; many rivers flow through lakes, creating a single water system.
A) European North B) Central Russia C) European South
6. The Far Eastern multi-tiered forest with cedars, firs, spruces, yews, maples, wild apple trees and pears is widespread in (on)
A) Kamchatka B) the coast of the Sea of Okhotsk
C) Kuril Islands D) Primorye
7. In what sequence do the altitudinal belts replace each other in the Caucasus from the foothills to the peaks?
A) forest belt, forest-steppe belt, subalpine belt, alpine belt, snow and glacier belt;
B) forest-steppe belt, forest belt, subalpine belt, alpine belt, snow and glacier belt;
C) forest-steppe belt, forest belt, alpine belt, subalpine belt, snow and glacier belt;
D) forest-steppe belt, forest belt, subalpine belt, snow and glacier belt;
8. The main salt deposits of Western Siberia are located in the natural zone
A) tundra B) taiga C) mixed forests D) steppe
9. Select the features of nature typical for the Ural Mountains:
A) the western slopes receive more precipitation than the eastern;
B) the height of the mountains increases from north to south;
C) steppe and forest natural complexes are most typical;
D) are the watershed between the basins of the Pacific and Arctic oceans.
10. What mountain systems do not belong to the mountain belt of Southern Siberia?
A) Altai B) Apple ridge C) Verkhoyansk ridge D) Western Sayan
Answers.
Option 1
1 - А 2 - В 3 - Г 4 - В 5 - 1-А, 2-В, 3-B
6 - C 7 - C 8 - A 9 - A, D 10.B
Option 2
1 - B 2 - G 3 - A 4 - B 5 - 1-B, 2-C, 3-A
6 - G 7 - B 8 - G 9 - A, C 10. C
The Far East it is customary to call the territory of Russia located off the coast of the Pacific Ocean. This territory also includes the Kuril archipelago located directly in the Pacific Ocean, over which the dispute has been going on for many years. The Far East consists of mainland, peninsular and insular parts. In addition to the Kuril Islands, it also includes the Kamchatka Peninsula, the island, and other (smaller) solitary ones located at the eastern borders of Russia.
The length of the Far East from the northeast (from) to the southwest (to the borders of Korea and) is quite large and amounts to 4.5 thousand kilometers. Its northern part is located beyond the Arctic Circle, so there is snow here almost all year round, and the seas washing the coast are not completely cleared of ice even in summer. The land in the northern part of the Far East is shackled. It reigns here. In the southern part of the Far East, conditions are much milder. One of the unusual indicators of this part is that the trees characteristic of the north are adjacent to the plants more often found in the subtropics. Thus, the climatic conditions at different points of this territory are quite different from each other. This is especially true of the temperature regime, but everywhere it is increased. Proximity also has a great influence on the climate of the entire Far East.
Far Eastern cedar cones
Only a quarter of the territory of the Far East is occupied. They are mainly located in those parts of the coast where tectonic activity is low (West Kamchatka, North Sakhalin), as well as in intermontane depressions (Sredneamurskaya, Anadyr, Central Kamchatka), so their area is relatively small. The relief of the Far East was formed mainly in the Mesozoic and Cenozoic periods. It was then that folded zones and intermontane depressions appeared. The ocean had some influence on the formation of the relief. So, for example, the entire modern and eastern slope at that time was under water. Only later did these areas appear on the surface, where they are still located.
From west to east, the character of the Far East changes from more ancient to younger, and from folded-block to folded and block-folded. The highest parts of the mountains (the Dzhagdy, Bureinsky, Badjalsky, Sikhote-Alin ranges and others) were occupied in ancient times. Traces of this have been preserved in our time in the idea of various small forms of relief (hills, cars and trogs).
Thus, as a result of various internal (tectonic) and external (glaciation, ocean waters), various types of relief were formed:
- - denudation middle mountains and low mountains with areas of glacial landforms on Paleozoic and Mesozoic block-folded structures
- erosion-denudation low mountains of Sikhote-Alin and Sakhalin on Mesozoic and Cenozoic folded-block and folded structures with lava plateaus
- denudation-erosional stratal plains of intermontane depressions
- plains of intermontane depressions on Mesozoic and Cenozoic folded structures.
Ussuri taiga
Depending on the nature of tectonic processes, they also change on the surface. So, for example, on the Kuril Islands, under which the thickness reaches 15-20 kilometers, mainly three elements of tectonic structure are developed. These are island arcs and deep-sea depressions. Their formation was carried out sequentially. At the first stage, a deep-sea trench was formed at the point of contact between the oceanic and continental plates. At the second stage, a marginal sea is formed, and then a rift depression near the islands.
The relief of the Kamchatka Peninsula and the mainland of the country is a reflection of a more ancient period. It is dominated by continental and transitional (from oceanic to continental) crust, block-folded structures, longitudinal-transverse troughs. In the relief of this territory, these features are expressed by lowlands and volcanic forms. Here, for example, is the intermountain Anadyr-Penzhinskaya plain.
The structure of Kamchatka and the Kuril Islands is mainly composed of Cretaceous and sedimentary. Loose Neogene sediments are also present in the places of troughs. Modern processes of relief formation in the Far East are determined by tectonic processes and permafrost (in the northern part).
Active tectonic processes currently taking place in the Far East are the cause of various. There are several active volcanoes and geysers in this area. Quite often, strong (up to 10 points) and seaquakes occur in this part of the planet. The latter are the cause of the emergence - huge ocean waves. All these cataclysms lead to significant destruction and even human casualties. Therefore, this part of Russia is the most unfavorable from the point of view of the presence of dangerous natural phenomena.
The territory of the Far East zonally belongs to the area of the Late Cenozoic folding and is part of the Pacific belt. The Russian Pacific coast is part of two converging continental plates - Asian and American. The plate contact zone is determined by the characteristic "depression" of the ocean floor.
Typical signs of counter movement of plates and activity of the crust are deep depressions and noticeable mountain building processes, accompanied by earthquakes and volcanic activity. In fact, geosynclines, the active zones of the earth's crust, form a contracting ring around the Pacific Ocean.
Scientists confirm the fact that the total area of the ocean is shrinking, a vivid evidence of this is the so-called Pacific volcano belt - a chain of high mountain ranges. The rise of the ocean floor is also characteristic of the Russian territory of the Far East. A sign of the geological youth of the region and tectonic activity is the high concentration of active and dormant volcanoes.
The Kamchatka Peninsula is known for 29 active volcanoes, while the total number of them in the region is about 180 units. Another evidence of activity is the Kuril Islands, built by a chain of volcanoes, in addition, a deep (9.7 km) Kuril-Kamchatka trench is found near the islands. Most scientists are confident that such troughs can be considered the entry point of the oceanic crust under the mainland.
The northern part of the Far East is considered to be superior in age, having a more complex geological and tectonic structure than in the zone of the Kuriles and Kamchatka, characterized by high mobility and seismological activity, which are characteristic of modern geosynclines.
Among the elements of the mainland Far East there are:
- Edge arrays;
- Folding systems;
- Structured platform range.
The marginal part, located in the southeast of the region under consideration, is notable for the presence of narrow deep-water depressions passing at the junction of the oceanic and continental crust. Geologist L.I. Red, depending on the location, highlights the group of megablocks and their constituent elements:
- Okhotsk Sea - Koni-Taigonos belt of volcanoes, Kuril-Kamchatka arc (islands), Okhotsk Sea depression (southern) and massif, East Shalinskaya and Hokaido-Sakhalin fold systems;
- Kolymsky - Okhotsk and Omolonsky massifs, Okhotsk-Chukotka belt of volcanoes, South Anyui and Verkhoyansk-Chukotka folding regions;
- Aldano-Stanovoy - the southeastern section of the vast Siberian plate, the uplifting Aldan-Stanovoy shield with characteristic crystalline complexes indicating an ancient age of formation;
- Bering Sea - adjoining parts of the geosynclinal-folded Koryak system (south), Kuril-Kamchatka arc (north) and Aleutian-Alaska system (west);
- Amur - Sikhote-Alin volcano belt and folded system, Khanka and Bureinsky massifs of intergeosynclinal type, Amur-Okhotsk folded system.
The relief of the Far East
The predominant type of relief in the Far East is mountainous, this is due to the peculiarities of the tectonic structure. The dominance of uplands determines the secondary importance of the plains and their coastal and intermountain localization. The largest plains are located within: Central Kamchatka depression, Anadyr and Penzhin lowlands, Parapolsky dol.
The predominant number of ridges located in the north of the Far East are characterized as horst massifs and anticlinal uplifts. Synclinal troughs are found in zones of depression. The Chukotka ridges are composed of Verkhoyansk rocks and have the age of Mesozoic folding.
In the localized area of the Okhotsk-Chukotka belt of volcanoes, ridges are formed that protrude on the northern Okhotsk coast, the south of the Chukotka upland, the western section of the Anadyr-Penzhinsky depression and the ridges of the Anadyr plateau. These elements have a varied structure and are composed of structures of different ages, including the Quaternary, Paleogene and Upper Cretaceous.
Present in the area of the structure of the Cenozoic period. The folded zone of this time includes: Kuriles, Kamchatka, Koryak highlands. A characteristic feature of all these elements is their localization in the zone of high volcanic activity and a young geosyncline. The highest point of the region is located at an altitude of 4.75 km - Klyuchevskaya Sopka, the average height of the mountain peaks is 2-3 km.
In addition to tectonic processes, rivers, the ocean and the climate took an active part in the formation of the region's relief. Erosional factors in the relief are traced throughout the entire Far East. Also significant factors include: physical weathering, solutification and periodic glaciation.
The characteristic and typical relief of the Far East is mid-mountain and low-mountain massifs. There is a pronounced network of deep valleys, dissecting most of the massifs, and mountains with flat tops are also found in large numbers. The height of the region ranges from 0.5 to 1.7 km. The most elevated zones of Kamchatka, the Koryak and Chukotka highlands have a varied, with a predominance of alpine, relief. Most of the relief forms are glacial; the share of lava plateaus is also significant.
Mineral resources of the Far East
The wealth of the subsoil of the Russian Far East is a proven fact. The total amount of deposits makes the region a world leader in this indicator. There are minerals such as oil, gas, metals of various categories and classes, etc. The region can develop silver deposits, bauxite, tin, titanium and other chemical elements whose characteristics correspond to world standards. There are areas in the Far East, the development of which does not require large investments, all of them can be developed within a short period of time.
The mining process in the region is difficult for the following reasons:
- Lack of exploration data;
- Lack of infrastructure;
- High transport and logistics costs;
- Shallow depth of occurrence of fossils.
Regardless of the complexity of the conditions, there is a noticeable increase in the role of the Far East in the economic development of the country. In the future, the region will be used to develop the latest technologies for geological exploration and mining. In general, the potential of the region is assessed as very high.
Geological structure of the Far East
The Far East is an area of the new Cenozoic folding, part of the Pacific fold belt. The Pacific Ocean, washing the shores of the Russian Far East, is the remnant of a single World Ocean. On it from two sides the land "comes" in the form of America and Asia. In the contact zone, the continental plates "crush" the oceanic crust. The result is the formation of deep oceanic trenches, and volcanism and earthquakes accompany the most active mountain-building processes. It turns out that the belt of moving parts of the earth's crust - geosynclines - surrounds the Pacific Ocean and "compresses" the ring around it.
Experts note that the area of the Pacific is shrinking. A chain of mountain ranges has formed around it, which is called the Pacific volcanic belt. "Land attack on the sea" and active mountain-building processes are also characteristic of the Russian Far East. The large number of volcanoes in this area is a consequence of geological youth and a characteristic feature of tectonics. The Kamchatka Peninsula is distinguished by an abundance of volcanoes, here they are known for $ 180, including $ 29 active. The Kuril Islands are also a chain of volcanic mountains.
Near the Kuriles is the deep-water Kuril-Kamchatka trench, the depth of which reaches $ 9,700 m. Not all scientists, but a number of them, believe that in such troughs, according to the theory of lithospheric plates, the oceanic crust sinks under the mainland. A complex tectonic structure is noted in the northern part of the Far East, which is more ancient. Kamchatka and the Kuril Islands are mobile parts of the Pacific belt, characterized by active volcanic activity and are located in the zone of the modern geosyncline.
In the tectonic structure of the mainland of the Far East, there are:
- Platform-row structures;
- Folded systems;
- Border arrays.
The southeastern marginal part of the Far East has narrow deep-water depressions that run along the border of the oceanic crust. According to L.I. Red, a well-known geologist, in the Far East, a number of large megablocks of the earth's crust can be distinguished.
These include:
- Aldano-Stanovoy megablock;
- Amur megablock;
- Kolyma megablock;
- Okhotsk Sea megablock;
- Bering Sea megablock.
Within Aldano-Stanovoy the megablock contains such structural elements as the Aldan-Stanovoy shield and the southeastern part of the Siberian platform. A feature of the shield is its tendency to uplift, as a result of which the most ancient crystalline complexes appeared on the surface.
The main structural elements of the Amur megablock are:
- Quite large intergeosynclinal massifs - Bureinsky, Khankaisky;
- Amur-Okhotsk and Sikhote-Alin geosynclinal-fold systems;
- East Sikhote-Alin volcanic belt.
The Kolyma megablock is characterized by:
- Verkhoyansk-Chukotka fold area;
- Omolon and Okhotsk massifs;
- South Anyui fold zone;
- Okhotsk-Chukotka volcanic belt.
In the Okhotsk Sea megablock, the following stands out:
- Island Kuril-Kamchatka arc;
- Koni-Taigonos volcanic belt;
- Two geosynclinal fold systems - Hokkaido-Sakhalin and East Sakhalin;
- Okhotsk massif;
- Deep-water South Sea of Okhotsk depression.
The Bering Sea megablock includes:
- Southern part of the Koryakskaya geosynclinal-fold system;
- Northern part of the Kuril-Kamchatka island arc;
- Western part of the Aleutian-Alaska system.
The relief of the Far East
The predominance of mountainous relief is associated with the complex tectonic structure of the northern part of the Far East. The plains occupy a subordinate position and are located on the shores of sea bays protruding into the land or in intermontane depressions - Anadyr lowland, Penzhin lowland, Parapolsky dol, Central Kamchatka depression. Most of the northern mountain ranges of the Far East are anticlinal uplifts or block horst massifs. Depressions are confined to synclinal troughs. The ridges of the Chukotka Upland make up the rocks of the Verkhoyansk complex and belong to the Mesozoic folding.
Within the Okhotsk-Chukotka volcanic belt, the southern ridges of the Chukotka Upland, the Anadyr Plateau, the western part of the Anadyr-Penzhinsky Depression and the ridges of the northern coast of the Sea of Okhotsk were formed. They are composed of volcanic terrestrial formations that are of Upper Cretaceous, Paleogene and Quaternary ages. The Cenozoic fold zone includes the eastern regions of the Far East - the Koryak Highlands, Kamchatka, and the Kuril Islands. They are located in the zone of the modern geosyncline and active volcanic activity. The highest mountains, the height of which is $ 2000 - $ 3000 m, are associated with this part of the territory. The highest point is the active Klyuchevskaya Sopka volcano - $ 4750 $ m. Not only tectonic processes took part in the formation of the modern relief of the Far East. A large role is given to the intensive erosional activity of rivers, due to the humid climate, the close location of the sea shores, and the density of erosional dissection.
The following took part in the formation of the relief:
- Double Quaternary glaciation;
- Physical weathering;
- Deluvial flush;
- Permafrost relief formation, especially solifluction.
Remark 1
In general, for the Far East, the characteristic types of relief are low-mountain and mid-mountain massifs. Some of them are dissected by a network of deep valleys, others are massive with flat tops. Average heights vary from $ 500 - $ 600 m to $ 1500 - $ 1700 m. The highest ridges of the Chukotka, Koryak highlands and Kamchatka have a high-mountainous, often alpine relief, which is characterized by various forms created by both modern and Quaternary glaciers. Lava plateaus play a significant role in the relief of the Far East.
Mineral resources of the Far East
The Russian Far East is rich in a variety of minerals, the reserves of which it is the leader not only in Russia, but also in the world. The subsoil of the region contains hydrocarbons, apatites, rare earth metals, rare metals, silver, polymetallic ores, manganese ores, titanomagnetite ores, copper and iron ores. It is planned to develop coal, bauxite, tin, the chemical characteristics of which meet world standards. In the Far East, there are such fields, the development of which does not require large expenditures, so it will not take a long time to develop them.
The mineral deposits of the Far East are insufficiently studied and have a number of characteristic features:
- The infrastructure required for development is missing;
- Terrain inaccessible for reconnaissance;
- Transportation for ore processing is very expensive;
- Insufficient depth to extract raw materials.
