Siberian platform

6.1. general characteristics

The Siberian Platform is another ancient platform in Russia. It covers an area of ​​4.4 million square meters. km, which is 26% of the territory of the Russian Federation.

The platform is located between the Yenisei rivers - in the west and Lena - in the east.

Unlike the East European, the Siberian platform has a predominantly mid-mountain relief with absolute elevations of 1,000-1,500 m. In the central part of the platform, there is the Central Siberian plateau, in the southeastern part of the Aldan highland, the Stanovoy and Dzhugdzhur ridges. On the territory of the Siberian platform, in addition to the named ones, there are the rivers Nizhnaya and Podkamennaya Tunguska, Angara, Vitim, Olekma, Aldan, belonging to the basin of the Arctic Ocean.

The boundaries of the platform are: in the west and south - the structures of the Ural-Mongolian belt, in the east - the structures of the Pacific belt, in the north - the Yenisei-Khatanga trough separating the Siberian platform from the folded structures of Taimyr.

6.2. Basic structural elements

The Siberian platform has a two-tiered structure.

The lower stage is the Archean-Early Proterozoic basement, the upper stage is the cover. In contrast to the East European Platform, where the cover began to form in the Early Riphean, on the Siberian Platform the cover complex began to form in the second half of the Early Proterozoic. The development areas of the platform cover meet Central Siberian (Leno-Yeniseiskaya) plate.

The foundation on the Siberian platform lies at depths from 0 to (according to geophysical data) 10-12 km.

The exits of the foundation to the surface are answered by shields.

There are two shields on the platform: in its northern part - Anabar Shield and Olenek uplift, in the southeastern part - Aldan (Aldano-Stanovoy) shield.

The following structures are located within the Central Siberian (Leno-Yenisei) plate.

On the frame of the Anabar shield and the Olenek uplift is located Anabar anteclise, on the frame of the Aldan shield - Aldan Anteclise; in the western part of the platform is Yenisei anteclise, in the southwest - Angara-Lena Anteclise... Anteclises are composed mainly of Riphean and Early Paleozoic complexes.

Between Anabar and Yenisei anteclises the Tunguska syneclise is located composed of Late Paleozoic-Mesozoic formations, including Permian-Triassic trap complexes that are unique in terms of distribution area and volume. Between Anabar and Aldan anteclises is located Leno-Vilyui syneclise, made mainly of Mesozoic sedimentary strata. In the northeastern part of the platform is located Predverkhoyansk trough, also composed of Mesozoic sedimentary strata and occupying a transitional position to the Verkhoyansk-Chukotka fold area of ​​the Pacific belt.

A diagram of the main structures of the Siberian platform is shown in Fig. 5.

Rice. 5. Diagram of the main structures of the Siberian platform

1. Late Jurassic-Early Cretaceous foredeep. 2. Jurassic-Cretaceous syneclises and superimposed depressions. 3. Permian-Triassic trap complexes. 4. Early Paleozoic anteclises. 5. The protrusions of the crystalline basement. 6. The boundaries of the main structures. 7. Local grabens and horsts.

8. Astroblems. 9. Folded framing of the platform. 10. Faults. Roman numerals indicate: I - Aldan shield (Ia - Aldan block, Ib - Stanovoy block), II - Aldan anteclise, III - Angara-Lena anteclise, IV - Yenisei anteclise, V - Anabar anteclise, VI - Anabar shield, VII - Olenek uplift, VIII - Tunguska syneclise, IX - Lena-Vilyui syneclise, X - Predverkhoyansk trough.

6.3. Foundation structure

The platform foundation is formed by Archean and Early Proterozoic complexes of deeply metamorphosed rocks, and it is represented on the Aldan (Aldan-Stanovoy), Anabar shields and Olenek uplift.

Aldan (Aldan-Stanovoy) shield... It is located in the southeastern part of the platform, where it has tectonic conjugations with the structures of the Ural-Mongolian belt.

The Aldan (Aldan-Stanovoy) shield, according to the features of its geological structure, is divided into two blocks: the northern - Aldan and southern - Stanovoi, separated by a large fault. The differences between these two blocks are that Paleozoic and Mesozoic granitoids are widespread in the Stanovoy block, reflecting its tectonic-magmatic activation, coupled with magmatism that accompanied the formation of the Pacific belt.

Archaea(AR). Metamorphic formations of the Archean Aldan block ( Aldan complex) are conventionally divided into three parts. The lower part contains ferruginous quartzites, high-alumina crystalline schists, biotite-garnet and garnet-sillimanite granulites. Within this part of the section, there are bodies of crystal-bearing pegmatites, as well as iron ore deposits of the formation of ferruginous quartzites. In the middle part - amphibole, biotite-amphibole, hypersthene gneisses, marble; in the upper part, biotite, hypersthene, and garnet-biotite gneisses. The Aldan complex contains two groups of different age intrusive rocks: 1) Archean granite-gneisses, forming large conformable bodies with gradual transitions to the host rocks; 2) Early Proterozoic leucocratic granites, represented by small bodies with tearing contacts.

In the Stan block, Archean formations ( dead series) are represented by biotite, two-mica, epidote-biotite, amphibole gneisses, and amphibolites. These formations are broken through by a large number of granites of Archean, Early Proterozoic, as well as Paleozoic and Mesozoic ages.

general power Archean metamorphic formations not less than 10 km.

Early Proterozoic (PR 1). The Early Proterozoic formations include garnet-hypersthene, hypersthene-amphibole-diopside, biotite, garnet-biotite, etc. gneisses, crystalline schists, marble, calciphyres. The thickness of these formations is estimated to be no less than 12 9 km. There are large massifs of anorthosites and gabbro-anorthosites of the same age.

Anabar shield and Olenek uplift... In these structures, located in the northern part of the platform, archean(AR) metamorphic rocks are arranged as follows. Their lower part contains two-pyroxene, amphibole-pyroxene plagiogneisses, amphibolites, quartzites; higher there are leucocratic hypersthene gneisses and biotite gneisses; even higher - garnet and garnet-biotite gneisses, calciphyres, diopside rocks; the section ends with biotite-amphibole gneisses, amphibolites, and quartzites. Archean and Early Proterozoic intrusive massifs of charnockites (hypersthene granites), granodiorites, alaskites, migmatites occur in the fields of development of these formations.

6.4. Cover structure

As noted above, the beginning of the formation of the platform cover on the Siberian Platform refers to second half of the early Proterozoic.

Education dates back to this time Udokan series, which is a protoplatform cover in the western part of the Aldan Shield. The Udokan Series, about 12 km thick, has a three-membered structure. Its lower part contains biotite-graphite schists, carbonaceous phyllites, and quartzites, in the middle part - marbleized dolomites and dolomitized limestones, in the upper part - red-colored cross-bedded sandstones, to which the unique Udokan copper sandstone deposit is confined.

On the Central Siberian Plate, seven structural-stratigraphic complexes (from bottom to top) are distinguished in the structure of the platform cover: Riphean, Vendian-Cambrian, Ordovician-Silurian, Devonian-Early Carboniferous, Middle Carboniferous-Triassic, Jurassic-Cretaceous, and Cenozoic.

An important feature The structure of the cover of the Siberian platform, which distinguishes it from the East European, is the wide participation of different-age igneous complexes in it (Fig. 6).

Rice. 6. Layout of uneven-aged igneous complexes

on the Siberian platform

1-2 - Jurassic-Cretaceous: 1 - granitoids and syenites ( a), felsic and intermediate volcanics ( b),

2 - alkaline gabbroids and syenites; 3-6 - Late Paleozoic-Triassic: 3 - alkaline-ultrabasic formation (a- kimberlite pipes, b- massifs of alkaline-ultrabasic composition); 4-6 - trap formation (4 - intrusions, 5 - lavas, 6 - tuffs); 7-8 - Middle Paleozoic: 7 - trap formation ( a- intrusions, b- volcanic rocks), 8 - alkaline-ultrabasic formation, kimberlites; 9 - Late Proterozoic-Early Cambrian traps, intrusions of ultrabasic and alkaline rocks; 10 - platform boundaries.

Riphean complex

Distributed on the frames of the Aldan, Anabar shields and the Olenek uplift.

Early Riphean(RF 1). The sediments of this age are based on gray and red-colored quartz and quartz-feldspar sandstones, sometimes containing glauconite, and gravelstones. Dolomites lie higher. The total thickness is about 1.5 km.

Middle Riphean(RF 2). It is represented by threefold repeating rhythms, in the lower parts of which there are quartz-glauconite sandstones, siltstones and mudstones, and in upper parts- limestones and dolomites. The total thickness is about 3 km.

Late Riphean(RF 3). It is represented mainly by a stratum of dolomites with a thickness of about 700 m.

Sedimentation on the platform was accompanied by intrusion of trap-type gabbrodolerites, dikes, sills, and stocks, as well as small intrusions of alkaline-ultrabasic composition.

Occupies the middle part of North Asia. This is one of the large, relatively stable ancient blocks of the continental crust of the Earth, belonging to the number of ancient (pre-Riphean) platforms. Its foundation was formed in the Archean; subsequently, it was repeatedly covered by seas, in which a powerful sedimentary cover was formed. Several stages of intraplate magmatism occurred on the platform, the largest of which was the formation of Siberian traps at the Permian-Triassic boundary. Before and after the intrusion of the traps, there were sporadic outbreaks of kimberlite magmatism that formed large diamond deposits.

The Siberian platform is limited by zones of deep faults - marginal seams, well-defined gravity steps, and has polygonal outlines. The modern boundaries of the platform took shape in the Mesozoic and Cenozoic and are well expressed in the relief. The western border of the platform coincides with the valley of the Yenisei River, the northern one - with the southern edge of the Byrranga Mountains, the eastern one - with the lower reaches of the Lena River (Priverkhoyanskiy foredeep), in the southeast - with the southern end of the Dzhugdzhur ridge; in the south, the border runs along the faults along the southern edge of the Stanovoy and Yablonovy ridges; then, skirting from the north to complex system the faults of the Transbaikal and Baikal regions, descending to the southern end of Lake Baikal; the southwestern boundary of the platform extends along the Main East Sayan Fault.

The platform is distinguished by the Early Precambrian, mainly Archean, basement and platform cover (Riphean-Anthropogen). Among the main structural elements platforms are distinguished: the Aldan shield and the Lena-Yenisei plate, within which the basement is exposed on the Anabar massif, Olenek and Sharyzhalgai uplifts. The western part of the plate is occupied by the Tunguska, and the eastern - by the Vilyui syneclise. In the south, there is the Angara-Lensky trough, separated from the Nyuisk depression by the Peleduy uplift.

Geological history

1. In the Archean and early Proterozoic, most of the basement of the East Siberian Platform was formed.
2. At the end of the Proterozoic (Vend) and the beginning of the Paleozoic, the platform was periodically covered by a shallow sea, as a result of which a thick sedimentary cover was formed.
3. At the end of the Paleozoic, the Paleoural Ocean closed, the crust of the West Siberian Plain was consolidated, and it, together with the East Siberian and East European platforms, formed a single continent.
4. An outbreak of kimberlite magmatism in the Devonian.
5. On the border of the Permian and Triassic, there was powerful flash trap magmatism.
6. In the Mesozoic, some parts of the platform were covered by epicontinental seas.
7. On the Cretaceous-Paleogene boundary, rifting and a new outbreak of magmatism, including carbonatite and kimberlite, occurred on the platform.

The typical cover of the platform begins to form in the Riphean time and includes seven complexes. The Riphean complex is represented by carbonate-terrigenous, red-variegated rocks 4000-5000 m thick, filling aulacogens and gentle depressions. The Vendian-Cambrian complex is composed of shallow-water terrigenous and terrigenous-carbonate deposits, and in the Angara-Lena trough - and saline (lower - middle Cambrian) strata, 3000 m. The Ordovician-Silurian complex is represented by variegated terrigenous rocks, as well as limestones and dolomites, 1000- 1500 m. Devonian-Lower Carboniferous complex is distributed to a limited extent; in the south, the Devonian is represented by continental red-colored strata with traps, in the north - by variegated carbonate-terrigenous deposits; in the Vilyui syneclise - a thick trap stratum and saline deposits, 5000-6000 m. The Middle Carboniferous - Middle Triassic complex is developed in the Tunguska syneclise and is represented by a coal-bearing stratum of the Middle Carboniferous - Permian up to 1000 m thick and a Triassic volcanogenic stratum (3000-4000 m), subdivided into lower - tuff and upper - lava parts (undifferentiated tholeiitic basalts); all deposits are broken by dikes, stocks and sills of basalts; in the Devonian, Triassic and Cretaceous in the northeast of the platform, kimberlite pipes of the explosion are formed. Upper Triassic - Cretaceous complex is composed of continental and less often marine sandy-clayey coal-bearing deposits, 4500 m, widespread only on the outskirts of the platform. The Cenozoic complex is developed locally and is represented by continental sediments, weathering crusts and glacial formations. The Paleogene Popigai astrobleme is known on the Anabar massif.

Minerals

The East Siberian platform is rich in various minerals.

Large deposits of iron ores are located on the Aldan shield, in the Angara-Ilim iron ore basin. Copper-nickel sulfide deposits are associated with traps in the Norilsk ore region, and cuprous sandstones are developed in the Udokan series on the Aldan shield. Diamonds are confined to kimberlite pipes.

There are several large coal basins: large deposits of coal are known on the Siberian platform (Lensky coal basin, Tunguska coal basin, Irkutsk coal basin, Kansk-Achinsk coal basin, South Yakutsk coal basin). Deposits of rock and potassium salt were discovered,

The Siberian platform is limited by zones of deep faults - marginal seams, well-defined gravity steps, and has polygonal outlines. The modern boundaries of the platform took shape in the Mesozoic and Cenozoic and are well expressed in the relief. The western border of the platform coincides with the valley of the Yenisei River, the northern one - with the southern edge of the Byrranga Mountains, the eastern one - with the lower reaches of the Lena River (Priverkhoyanskiy foredeep), in the southeast - with the southern end of the Dzhugdzhur ridge; in the south, the border runs along the faults along the southern edge of the Stanovoy and Yablonovy ridges; then, skirting from the north along a complex system of faults in Transbaikalia and the Baikal region, it descends to the southern tip of Lake Baikal; the southwestern boundary of the platform extends along the Main East Sayan Fault.

Basically, the foundation and the platform cover (-) stand out on the platform. The main structural elements of the platform are: the Aldan shield and the Lena-Yenisei plate, within which the basement is exposed on the Anabar massif, Olenek and Sharyzhalgai uplifts. The western part of the plate is occupied by the Tunguska, and the eastern - by the Vilyui syneclise. In the south, there is the Angara-Lensky trough, separated from the Nyuisk depression by the Peleduy uplift.

The basement of the platform is sharply dissected and composed of strongly metamorphosed Archean rocks, in the western half of the latitudinal, and in the east - north-north-western strikes. Weakly metamorphosed strata of the Lower Proterozoic (Udokan Series) are preserved in separate depressions and grabens, lie flat and are formations of a protoplatform cover.

The typical cover of the platform begins to form in the Riphean time and includes seven complexes. The Riphean complex is represented by carbonate-terrigenous, red-variegated rocks 4000-5000 m thick, filling aulacogens and gentle depressions. The Vendian-Cambrian complex is composed of shallow-water terrigenous and terrigenous-carbonate deposits, and in the Angara-Lena trough - and saline (lower - middle Cambrian) strata, 3000 m. The Ordovician-Silurian complex is represented by variegated terrigenous rocks, as well as limestones and dolomites, 1000- 1500 m. Devonian-Lower Carboniferous complex is distributed to a limited extent; in the south, the Devonian is represented by continental red-colored strata with traps, in the north - by variegated carbonate-terrigenous deposits; in the Vilyui syneclise - a thick trap stratum and saline deposits, 5000-6000 m. The Middle Carboniferous - Middle Triassic complex is developed in the Tunguska syneclise and is represented by a coal-bearing stratum of the Middle Carboniferous - Permian up to 1000 m thick and a Triassic volcanogenic stratum (3000-4000 m), subdivided into the lower - tuff and upper - lava parts (undifferentiated tholeiitic basalts); all deposits are broken by dikes, stocks and sills of basalts; in the Devonian, Triassic and Cretaceous in the northeast of the platform, kimberlite pipes of the explosion are formed. Upper Triassic - Cretaceous complex is composed of continental and less often marine sandy-clayey coal-bearing deposits, 4500 m, widespread only on the outskirts of the platform. The Cenozoic complex is developed locally and is represented by continental sediments, weathering crusts and glacial formations. The Paleogene Popigai astrobleme is known on the Anabar massif.

The Siberian platform is characterized by intense magmatism, which manifested itself in the Early Proterozoic, Riphean - Early Cambrian, Middle, Upper Paleozoic - Triassic and Late. Trap magmatism is absolutely dominant in volume (more than 1 million km 3).

The Siberian platform is rich

Land masses appeared, the formation of which continued in the Proterozoic. As a result, the vast Precambrian Siberian Platform was formed. During the period of Baikal folding, the Yenisei ridge arose, the Turukhansk uplift and the formation of the folded basement ended throughout the entire territory. Two shields, Anabar and Aldan, were separated by a deep trough formed in the eastern part of the platform. In the Cambrian period - this is the beginning of the Paleozoic era, the existing land was submerged and covered by the waters of the seas. At the bottom of the seas, marine sedimentary strata accumulated. On the platform margins, the accumulation of salts, gypsum, or, in other words, the formation of the platform cover took place.

During the Caledonian orogeny, the Siberian platform was still covered by the sea, and new folded structures were being formed to the north of it. Their formation took place on the Severnaya Zemlya archipelago and in the north of the Taimyr Peninsula. The slow retreat of the sea, characteristic of the Devonian, is associated with the general rise of the territory. A continental regime is established and a dense network of rivers and lakes is formed. The platform, or rather its north-western part, is undergoing immersion, resulting in the formation of the Tunguska syneclise.

With the manifestation of Hercynian folding, the platform base disintegrates. Volcanic activity begins with maximum tension in the Triassic. The outpouring of lavas forms trap sheets, i.e. erupted rocks, represented by andesites, dolerites, basalts. Their manifestation is clearly visible in the Tunguska syneclise. Depressions and troughs are filled with lacustrine, river, delta sediments. Into the Hercynian time is running active folding, the Byrranga mountains and the North Siberian lowland are formed. In the Middle Era - Mesozoic - active tectonic activity manifests itself only on the outskirts of the plain.

The geological structure of the territory is represented by 2 large structures:

1. Siberian platform;
2. Taimyr-Khatanga fold area.

The oldest Siberian platform retains its plain appearance for more than $ 600 million years. The platform has two floors - a folded crystalline basement composed of gneisses, marble, quartzites, i.e. metamorphosed rocks and a loose cover, composed of marine and continental rocks of the Paleozoic and Mesozoic. In the basement of the platform, a $ 2 $ shield and $ 2 $ large protrusions were formed - the Aldan and Anabar shields, the Yenisei ledge and the Turukhansk uplift. Deep depressions separate the basement uplifts, among which the Angara-Lensky trough, the Tunguska syneclise, and the Vilyui syneclise stand out.

Taimyr-Khatangskaya fold area represented by the folded area of ​​Taimyr and Severnaya Zemlya. The northern part of the region is Caledonian, while the central and southern parts are Hercynids. The Khatanga depression is the basis of the North Siberian lowland.

Relief of Central Siberia

The events of the Alpine folding played an important role in the formation of the modern relief of Central Siberia. Such mountain rises as the Anabar massif, the Yenisei ridge, the Aldan highlands, the Byrranga mountains will correspond to the protrusions of the folded basement. The depressions are associated with the Leno-Vilyui and North Siberian lowlands. The inversion forms include the Tunguska syneclise and the Angara-Lensk trough. The lithological composition of rocks of different ages also had a big influence for relief formation. The territory of Central Siberia is mainly occupied by high plateaus and plateaus, a smaller part is accounted for by mountains and low-lying plains.

The mountains Byrranga belong to the Taimyr-Khatanga folded area and are flat low mountains, with a height of $ 800 - $ 900 m and small foci of modern glaciation. It is a system of parallel ridges that descend to the west and north. The base of the mountains is of Caledonian and Hercynian age. The mountains experienced numerous secondary uplifts and dislocations.

They stretch for $ 1100 km with a width of more than $ 200 $ km and are divided by the valleys of the Pyasina and Taimyra rivers into $ 3 parts:

1. The western lowest part has heights of $ 250 - $ 320 m;
2. Middle part with a height of $ 400 $ - $ 600 m;
3. Eastern part - $ 600 - $ 1000 m.

The southernmost of the ridges, the Glavnaya Ridge, is the highest. Byrranga is the world's northernmost continental mountain system.

For $ 1000 $ km stretched North Siberian Plain occupying the Pre-Taimyr trough. It has heights in the range of $ 100 m and is composed of Quaternary sediments. The plain is swampy and has many lakes of tectonic and glacial origin. The relief of the plain was formed by Quaternary glaciations and marine transgressions. In general, it has a hilly-ridge and hilly-ridged appearance with alluvial depressions and flat accumulative plains. In the east of the North Siberian Lowland there are $ 2 $ ridge - Pronchishchev and Chekanovsky.

In modern relief-forming exogenous processes great importance have:

1. Erosion;
2. Physical weathering caused by the sharp continentality of the climate;
3. Permafrost processes and its widespread distribution;
4. Karst phenomena caused by the distribution of carbonate rocks. There are areas of limestone, gypsum, salt karst.

Remark 1

It must be said that permafrost slows down modern erosion processes and hinders the development of karst, and this suggests that karst landforms in Central Siberia are not widespread.

The main part of Central Siberia is occupied Central Siberian plateau, which is based on the Siberian platform. It is characterized by a combination of flat and gently undulating stepped relief. The heights of the plateau are gradually decreasing to the east, towards the Central Yakut Plain.

The plateau includes:

1. Putorana plateau;
2. Syverma plateau;
3. Yenisei ridge;
4. Irkutsk plain;
5. Prilenskoe plateau;
6. Central Yakut Plain;
7. Vilyui plateau;
8. Anabar plateau;
9. Central Siberia;
10. Anabar-Olenek plain;
11. Central Tunguska plateau.

The Central Siberian Plateau is characterized by the elevation and contrast of the relief, which is its main feature. The plateau has significant fluctuations in altitude from $ 150 to $ 2200 m, with an average altitude of $ 500 - $ 700 m. The highest altitude is the Aldan Highlands - $ 2306 m above sea level. The Anabar plateau, the Aldan Upland, the Yenisei Ridge correspond to the protrusions of the platform basement. In those places where the depressions were located, there are morphostructures prevailing on the plateau - the Central Yakutsk Lowland, the Irkutsk-Cheremkhovskaya Plain, reflecting the connection of the relief with the ancient structures of the basement. But, there are also opposite examples, when the deflections of the foundation correspond to hills and plateaus. For example, the Putorana plateau and Syverma plateau are associated with the Tunguska syneclise. The Angara-Lena trough corresponds to the Angara-Lena plateau.

Mineral resources of Central Siberia

The bowels of Central Siberia are exceptionally rich in various minerals.

Iron ore... Different genesis of ores is found both in the basement and in the cover of the platform. Magnetites of the South Aldan basin, Angara-Pit iron ore basin of the Yenisei ridge. The large synclinorium is associated with iron ores of sedimentary origin - the Vilyui and Cannes depressions. Copper-nickel ores, the formation of which is associated with basic-hyperbasic intrusions, intruded into the trap series - Norilkoye, Talnakhskoye deposits.

Aldan deposits gold associated with Mesozoic alkaline magmatism. Platinum- the southern part of the Aldan shield. There are placer deposits of platinum along the river valleys. Maymecha-Kotuyskoye deposit of rare metals.

Nonmetallic minerals:

Indigenous diamond deposits occurring in the basins of the Vilyui, Olenek, Muna rivers. The main diamond deposits are associated with "explosion tubes" - diatremes. They are filled with kimberlites - this is a brecciated rock, consisting of yellow and bluish clays, including large fragments of volcanic rocks.

Kureyskoye, Noginskoye fields graphite... These deposits were formed as a result of thermal metamorphism. coal... Graphites are of high quality.

Huge reserves rock salt concentrated in the Usolye-Sibirskoye field. This is the Berezovsky trough in the central part of the Tunguska syneclise. In the northern part of the platform, the Nordwick salt domes of the Early Devonian age are known. The Kempendyai salt domes are associated with the Vilyui syneclise.

Two levels are presented in the territory of Central Siberia bituminous and brown coals... These are the Tunguska coal basin and the Irkutsk-Cheremkhovsky and Cannes basins. In the Vilyui syneclise and the Predverkhoyansk foothill trough, there is a huge Lensky coal basin in terms of reserves. There are coal deposits on the Taimyr Peninsula. Middle Paleozoic deposits of the Tunguska syneclise are considered promising hydrocarbon deposits.

Deposits of refractory rocks are associated with marine sedimentary rocks. clay and limestone.

Page 1

The Siberian platform, occupying the entire Central Siberian Plateau, is located in the interfluve of the Yenisei and Lena rivers from Taimyr in the north to the Baikal Upland and the Eastern Sayan Mountains in the south. The Siberian platform is composed of the Archean - Early Proterozoic basement and sedimentary cover, where the main role is played by the ubiquitous Paleozoic and Precambrian deposits. In contrast to the East European, the Siberian platform is characterized by a more complex geological structure associated with a wide distribution of faults, the presence of powerful trap intrusions and a pronounced lithological-facies heterogeneity of the Lower Paleozoic, Vendian and Riphean deposits.

The Siberian platform possesses Ar-Heian-Early Proterozoic crystalline. The section of the Upper Proterozoic-Phanerozoic cover contains shallow-water marine terrigenous and carbonate deposits, rock and potassium salts, continental coal-bearing series, and a trap complex. A strip of kimberlite pipes stretches in the center of the platform, plutons of basic and alkaline rocks are developed in the north and southeast. The foundation of the Sino-Korean Platform (Sino-Korean) is formed by the Ar-Hey and Lower Proterozoic complexes.

The Siberian platform has a two-tiered structure. The lower structural stage is composed of complex and highly metamorphosed formations of the Archean and Early Proterozoic ages, which form the basement of the platform. They come to the surface on the Aldan and Anabar shields and in the Angara-Kan part of the Yenisei ridge. The upper structural layer is composed of rocks from the Late Proterozoic to the Quaternary age. It is divided into a number of floors corresponding to certain stages of sedimentation and the formation of tectonic structures.

The Siberian platform occupies a vast territory in area, and the permafrost conditions are diverse here. In general, for the territory, the average annual temperature of rocks is natural conditions and when they are violated, it changes from 4 in the southwest to - 9 in the northeast. Kheta) under natural conditions, the mean annual temperature of rocks varies from - 6 5 for areas with moss cover and minimal snow accumulation to - 4 for areas with sod cover and maximum snow accumulation. The destruction of the moss-peat cover leads to an increase in the average annual temperature of the rocks from –2 with maximum snow accumulation to –6 when the snow cover is compacted. Violation of surface conditions increases the range of changes in the average annual temperature of rocks.

The Siberian platform belongs to the type of ancient platforms. Formations of all geological systems are involved in its structure. Strongly metamorphosed rocks of the Archean n of the Lower Proterozoic form a crystalline basement, which is exposed on the surface on the Anabar and Aldan shields, and in internal field the platform is buried under a cover of sediments having a thickness in the blue -: ah up to 10 - 20 km.

The Precambrian Siberian Platform occupies the space between the Yenisei and Lena rivers. Its boundaries are deep faults separating the platform in the west from the Hercynian West Siberian plate, in the east - from the mesozoids of the Northeast of Eurasia, in the south - from the activated regions of the Mongol-Okhotsk belt. In the north, the border is conventionally drawn within the shelf north of the islands archipelago Severnaya Zemlya.

Siberian platform, since the volume of drilling and seismic exploration here was insignificant, and other research methods are ineffective due to the complex geological structure due to the presence of a thick trap cover, evaporites and a developed network of faults. A fundamental assessment of the possible commercial oil and gas content of the Lower Paleozoic and Precambrian deposits became possible thanks to the discovery in 1973 of the first in the Kuyumbinsky basin, the oil and gas field, which is now being explored.

The Siberian platform, the Cambrian-Ordovician-Silurian deposits are characterized by a predominantly carbonate composition. Considering the ubiquitous cracking of basement deposits (G.P. Sverchkov, V.L.Dsdoev, G.B. formation of accumulations of oil and gas.

Siberian platform and is confined to the step of the same name.

The Siberian platform, complicating the Sobinsko-Tete, is the Rinsky mega-shaft of the Katangsky saddle, which divides the Baikit and Nepa-Botuobinsky anteclises.

С-3 of the Siberian platform - Dokl.

The territory of the Siberian platform is rich in hydropower resources, the development of which predetermined the development of hydraulic engineering construction in the east of the country from this region. Here in the 60s were built: Irkutsk hydroelectric power station - the firstborn of the Angara-Yenisei cascade; the world's largest Bratsk hydroelectric power station, which has created the largest reservoir with a capacity of 169 billion m3; first on The far north high rock-fill dam of the Vilyui hydroelectric power station; Mamakanskaya HPP, and in 1970 the first units of the northernmost Ust-Khantayskaya HPP were launched.

Considering the Siberian platform, one cannot fail to name also the explosion tubes - peculiar structures formed as a result of the breakthrough of magmatic melts onto the surface. Primary diamond deposits, as well as small occurrences of oil, gas, semi-liquid and solid bitumen, are associated with the explosion pipes.

In the Siberian platform, the East Siberian megaprovince is distinguished, which includes the Leno-Tunguska, Leno-Vi-lyui and Yenisei-Anabar oil and gas provinces.