What is a geological structure. The USSR
This section describes the geological structure (stratigraphy, tectonics, history of geological development, commercial oil and gas potential) of the Luginets field.
Stratigraphy
The geological section of the Luginets deposit is represented by a thick layer of terrigenous rocks of various lithofacies composition of the Mesozoic-Cenozoic age, lying on the eroded surface of the Paleozoic deposits of the intermediate complex. The stratigraphic subdivision of the section was carried out according to data from deep wells on the basis of correlation schemes approved by the Interdepartmental Stratigraphic Committee in 1968 and refined and supplemented in subsequent years (Tyumen in 1991). The general scheme of stratified formations may look like this:
Paleozoic erathema - RJ
Mesozoic erathema - MF
Jurassic - J
Lower-mid section - J 1-2
Tyumen Formation - J 1-2 tm
Upper section - J 3
Vasyugan Formation - J 3 vs
Georgievskaya suite - J 3 gr
Bazhenov Formation - J 3 bg
Cretaceous system - K
Lower section - K 1
Kulomzinskaya suite - K 1 kl
Tara Formation - K 1 tr
Kiyalinskaya suite - K 1 kl
Lower-upper section - K 1-2
Pokur suite - K 1-2 pk
Upper section - K 2
Kuznetsov suite - K 2 kz
Ipatovskaya suite - K 2 ip
Slavgorod suite - K 2 sl
Gankinskaya suite - K 2 gn
Cenozoic erathema - KZ
Paleogene system - R
Paleocene - P 1
Lower section - R 1
Talitskaya suite - Р 1 tl
Eocene - R 2
Middle department - R 2
Lyulinvor suite - P 2 ll
Middle-upper section - R 2-3
Chegan Formation - P 2-3 cg
Oligocene - P 3
Quaternary - Q
Paleozoic erathema - RJ
According to drilling data, the basement rocks in the study area are mainly represented by formations of an intermediate complex - limestones with interlayers of terrigenous and effusive rocks of various thicknesses. Deposits of the intermediate complex were discovered by ten wells: six exploration and four production wells. The most complete section of the intermediate complex (thickness 1525 m) was uncovered in well No. 170.
Mesozoic erathema - MF
Jurassic - J
The Jurassic deposits in the area described are represented by sediments of different facies of the Middle and Upper Jurassic. They are subdivided into three suites - Tyumen, Vasyugan and Bazhenov.
Lower-mid section - J 1-2
Tyumen Formation - J 1-2 tm
The suite is named after the city of Tyumen, Western Siberia. Allocated by Rostovtsev N.N. in 1954. Its thickness is up to 1000-1500 m. It contains: Clathropteris obovata Oishi, Coniopteris hymenophyloides (Bron gn.) Sew., Phoenicopsis angustifolia Heer.
The deposits of the Tyumen Formation lie on the eroded surface of the Jurassic intermediate complex. The productive horizon Yu 2 lies at the top of this suite.
The formation is composed of continental sediments - mudstones, siltstones, sandstones, carbonaceous mudstones and coals with a predominance of clayey-siltstone rocks in the section. Sand layers, due to their continental origin, are characterized by sharp facies-lithological variability.
Upper section - J 3
The Upper Jurassic deposits are mainly represented by rocks of transitional genesis from marine to continental. Represented by the Vasyugan, Georgievskaya and Bazhenov suites.
Vasyugan Formation - J 3 vs
The suite is named after the Vasyugan River, West Siberian Lowland. I singled out Sherikhod V.Ya. in 1961. Its thickness is 40-110 m. The suite contains: Quenstedtoceras and assemblages of foraminifers with Recurvoides scherkalyemis Lev. and Trochammina oxfordiana Schar. Part of the noon series.
The deposits of the Vasyugan Formation conformably overlie the deposits of the Tyumen Formation. The deposits are composed of sandstones and siltstones interbedded with mudstones, carbonaceous mudstones, and occasional interlayers of coals. According to the generally accepted division of the section of the Vasyugan suite, the main productive horizon Yu 1, identified in the section of the suite, is everywhere divided into three strata: sub-coal, inter-coal and supra-coal. The lower sub-coal strata includes sandy formations Yu 1 4 and Yu 1 3 of coastal-marine genesis, which are quite consistent in area, the deposits of which contain the bulk of the oil and gas reserves of the Luginets field. The intercoal sequence is represented by mudstones and interlayers of coals and carbonaceous mudstones, rare lenses of sandstones and siltstones of continental origin. The upper - supercoal strata is composed of layers of sandstones and siltstones Yu 1 2 and Yu 1 1 that are not sustained in area and section. Sandy-silty layer Yu 1 0 included in the composition of the productive horizon Yu 1, because it forms a single massive reservoir with the productive strata of the Vasyugan suite, stratigraphically belongs to the Georgievskaya suite, the deposits of which are absent in significant areas of the Luginets field.
Georgievskaya suite - J 3 gr
Name of the formation after the village of Georgievskoe, Olkhovaya river basin, Donbass. Allocated: Blank M. Ya., Gorbenko V. F. in 1965. Stratotype on the left bank of the Olkhovaya River near the village of Georgievskoye. Its thickness is 40 m. It contains: Belemnitella Langei Langei Schatsk., Bostrychoceras polyplocum Roem., Pachydiscus wittekindi Schlut.
The rocks of the Vasyugan Formation are overlain by deep sea clays of the Georgievskaya Formation. Within the described zone, the thickness of the suite is insignificant.
Bazhenov Formation - J 3 bg
The suite is named after the village of Bazhenovo, Sargatsky district, Omsk region, Western Siberia. Highlighted Gurari F.G. in 1959 Its thickness is 15-80 m. Stratotype - according to one of the wells of the Sargat area. It contains: numerous remains of fish, crushed by shells of Dorsoplanitinaeu, rarely buchy.
The Bazhenov Formation is ubiquitous and is composed of deep sea bituminous mudstones, which are a reliable cover for the oil and gas deposits of the Vasyugan Formation. Its thickness is up to 40m.
The marine sediments of the Bazhenov Formation are characterized by a consistent lithological composition and areal distribution, and a clear stratigraphic reference. These factors, as well as a clear appearance on the well logs, make the formation a regional benchmark.
Cretaceous system - K
Lower section - K 1
Kulomzinskaya suite - K 1 kl
The retinue is distributed in the southern and central regions of the West Siberian Plain. Highlighted by: Aleskerova Z.T., Osechko T.I. in 1957. Its thickness is 100-250 m. It contains Buchia cf. volgensis Lah., Surites sp., Tollia sp., Neotollia sibirica Klim., Temnoptychites sp. The retinue is included in the Poludinskaya series.
The formation is composed of marine, predominantly argillaceous deposits, which overlap the Upper Jurassic. These are mainly gray, dark gray mudstones, compact, strong, silty, with thin interlayers of siltstone. In the upper part of the suite, a group of sandy beds B 12-13 is distinguished, and in the lower part, the Achimov unit is distinguished, composed mainly of compacted sandstones and siltstones with mudstone interbeds.
Tara Formation - K 1 tr
The suite is distributed in the southern and central regions of the West Siberian Lowland. Identified by a reference well in the area of the city of Tara, Omsk region, Western Siberia, by Rostovtsev N.N. in 1955. Its thickness is 70-180 m. Contains: Temnoptycnites spp. The Tara Formation is included in the Poludinskaya Group.
The deposits of the suite conformably rest on the rocks of the Kulomzinskaya suite and are sandy deposits of the final stage of the Upper Jurassic-Valanginian transgression of the sea. The main composition of the suite is a series of sand beds of the B 7 - B 10 group with subordinate interlayers of siltstones and mudstones.
Kiyalinskaya suite - K 1 kl
The suite is distributed in the south of the West Siberian Plain. It was identified by a well near the Kiyaly station, Kokchetav region, Central Kazakhstan by Bogdanovich A.K. in 1944 Its thickness is up to 600 m. Contains: Carinocyrena uvatica Mart. etvelikr., Corbicula dorsata Dunk., Gleichenites sp., Sphenopteris sp., Podozamites lanceolatus (L. et H.) Shimp., P. reinii Geyl., Pitiophyllum nordenskiodii (Heer) Nath.
The Kiyalinskaya Formation is composed of continental deposits, which overlap the deposits of the Tara Formation and is represented by unevenly interbedded clays, siltstones, and sandstones, with the former predominating in the section. Sand layers in the suite belong to the group of layers B 0 -B 6 and A.
Lower-upper section - K 1-2
Pokur suite - K 1-2 pk
The Lower-Upper Cretaceous deposits in the Aptalb-Cenomanian are combined into the Pokur suite, which is the most thick. The retinue is distributed on the territory of the West Siberian Lowland. The formation was named after a reference well near the village of Pokurka on the Ob River, Khanty-Mansiysk Autonomous Okrug. The formation was identified by N.N. Rostovtsev. in 1956. It lies according to the Sargat series, overlaps with a break of the Derbyshinsky
The suite is composed of continental deposits, represented by intercalation of clays, siltstones and sandstones. The clays are gray, brownish-gray, greenish-gray, in some places silty, lumpy, cross-bedded.
The sand beds of the Pokur Formation are uneven along strike, their thickness varies from a few meters to 20 m. The lower part of the formation is more sandy.
Upper section - K 2
The Upper Cretaceous deposits are represented by a sequence of marine, predominantly clayey rocks, which, according to those lying on the Lower Cretaceous deposits, are divided into four formations: Kuznetsovskaya (Turonian), Ipatovskaya (Upper Turonian + Coniacian + Lower Santonian), Slavgorodskaya (Upper Santonian + Campanian) and Gankinskaya (Maastrichtian + Denmark).
Kuznetsov suite - K 2 kz
The formation was identified by the Kuznetsovo well, the Tavda River, Sverdlovsk region Rostovtsev N.N. in 1955. Its thickness is up to 65 m. Contains: Baculites romanovskii Arkh., Inoceramus ef. labiatus Schloth. and foraminifera with Gaudryina filiformis Berth
The formation is composed of gray, dark gray, dense, foliated, sometimes calcareous or silty and micaceous clays.
Ipatovskaya suite - K 2 ip
The formation was identified from a well in the village of Ipatovo, Novosibirsk region by N.N. Rostovtsev. in 1955. Its thickness is up to 100 m. It contains: a complex of foraminifers with large Lagenidae; Clavulina hasts Cushm. and Cibicides westsibirieus Balakhm.
The suite is distributed in the southern and central parts of the West Siberian Lowland. Included in the Derbyshinsky series, divided into a number of packs.
The deposits of the suite are represented by intercalation of siltstones, opoka-like clays and opoka. Siltstones are gray, dark gray, weakly cemented, sometimes glauconite, layered in places; opoka-like clays are gray, light gray and bluish-gray, silty; the flasks are light gray, horizontally and undulating, with conchoidal fracture.
Slavgorod suite - K 2 sl
The formation was identified by the reference well - the city of Slavgorod, Altai Territory by Rostovtsev N.N. in 1954. The suite is up to 177 m thick, contains: foraminifera and radiolarians, is included in the Derbyshinsky series, is distributed in the southern and central parts of the West Siberian Lowland.
The Slavgorod Formation is composed mainly of gray, greenish-gray clays, homogeneous, greasy to the touch, plastic, sometimes with rare thin layers of sandstones and siltstones, with inclusions of glauconite and pyrite.
Gankinskaya suite - K 2 gn
The suite is distributed in the West Siberian Lowland and the eastern slope of the Urals. Identified by a well in the village of Gankino, Northern Kazakhstan, by Bogdanovich A.K. in 1944. The thickness of the formation is up to 250 m. It contains: Baculites anceps leopoliensis Nowak., B. nitidus Clasun., Belemnitella lancealata Schloth., assemblages of foraminifers with Gaudryina rugosa spinulosa Orb., Spiroplectammina variabilis Neckaja, Sp. kasanzevi Dain, Brotzenella praenacuta Vass.
The Ganka Formation is included in the Derbyshinsky Group and is subdivided into a number of members.
The suite is composed of gray, greenish-gray, siliceous, unstratified marls, and gray clays, in areas calcareous or silty, with thin layers of silt and sand.
Paleogene system - R
The Paleogene system includes marine, mainly clay deposits of the Talitsky (Paleocene), Lyulinvor (Eocene), Chegan (Upper Eocene - Lower Oligocene) formations and continental deposits of the Nekrasovskaya series (Middle - Upper Oligocene), which according to lie on the Cretaceous deposits.
Lower section - R 1
Talitskaya suite - Р 1 tl
The formation is distributed in the West Siberian lowland and the eastern slope of the Urals, named after the village of Talitsa, Sverdlovsk region, distinguished by Alekserova Z.T., Osyko T.I. in 1956. The thickness of the suite is up to 180 m. It contains: assemblages of foraminifers from the Ammoscalaria inculta zones, spores and pollen from Trudopollis menneri (Mart.) Zakl., Quercus sparsa Mart., Normapolles, Postnor mapolles, radiolarians and ostracods, Nuculana biarata Koen., Tellina edwardsi Koen ., Athleta elevate Sow., Fusus speciosus Desh., Cylichna discifera Koen., Paleohupotodus rutoti Winkl., Squatina prima Winkl.
The Talitskaya suite is composed of dark gray to black clays, dense, viscous in places, greasy to the touch, sometimes silty, with interlayers and powders of silt and fine-grained, quartz-feldspar-glauconite sands, with pyrite inclusions.
Middle department - R 2
Lyulinvor suite - P 2 ll
Suite, distributed in the West Siberian Plain. The name is given for the Lumin-Vor hill, the Sosva river basin, Ural Lee P.F. in 1956. The thickness of the suite is up to 255 m. It is divided into three subformations (the boundary between the subformations is conventional). The suite contains: a complex of diatoms, a spore-pollen complex with Triporopollenites robustus Pfl. and with Triporopollenites excelsus (R. Pot) Pfl., a radiolarian complex with Ellipsoxiphus ckapakovi Lipm. and with Heliodiscus Lentis Lipm.
The suite is composed of greenish-gray, yellow-green, oily to the touch clays, in the lower part - flask-like, sometimes turning into flasks. Clays contain interlayers of gray micaceous silts and inequigranular quartz-glauconite sands and weakly cemented sandstones.
Middle-upper section - R 2-3
Chegan Formation - P 2-3 cg
The retinue is distributed in Ustyurt, the northern Aral Sea region, on the Turgai Plain and in the south of the West Siberian Plain. Named after the Chegan River, Aral Sea, Kazakhstan Vyalov O.S. in 1930. Its thickness is up to 400 m. It contains: assemblages of juveniles with Turritella, with Pinna Lebedevi Alex., Glossus abichiana Rom., assemblages of foraminifers with Brotzenella munda N. Buk. and with Cibicides macrurus N. Buk., ostracod assemblages with Trachyleberis Spongiosa Liep., spore and pollen assemblages with Qulreus gracilis Boitz. The formation is divided into two subformations.
The Chegan Formation is represented by bluish-green, greenish-gray, dense clays, with nests, powders and lenticular interlayers of gray quartz and quartz-feldspar, inequigranular and silt sands.
Quaternary - Q
Sediments of the Quaternary system are represented by gray, dark gray, fine-medium-grained sands, less often coarse-grained, sometimes clayey, loams, brownish-gray clays, with interlayers of lignite and a soil-vegetative layer.
Geological structure
Territory Russian Federation occupied mainly by platforms - ancient and young. The ancient East European and Siberian platforms (cratons) have an Early Precambrian crystalline basement and a Late Precambrian-Phanerozoic sedimentary cover. They are separated by the Late Proterozoic-Paleozoic-Mesozoic Ural-Okhotsk mobile belt(or Ural-Mongolian), which also borders Siberian platform from the south (see tectonic map). southern framing East European Platform is the Mediterranean (Alpine-Himalayan) late Proterozoic-Phanerozoic mobile belt, which retains high mobility. To the east of the Siberian platform and the Precambrian massifs - Bureya and Khanka - stretches the marginal continental Western Pacific Mobile Belt separating Eurasia from the depression Pacific Ocean. This belt has not finished its development yet. The folded structures of the Ural-Okhotsk and Mediterranean mobile belts are partially overlain by the Phanerozoic sedimentary cover of young platforms (Barents-Pechora, West Siberian and Scythian). Some sections of ancient platforms and mobile belts that entered into platform development were involved in repeated mountain building in the course of further evolution. Repeatedly manifested epiplatform orogeny in the south of Siberia (Altai, Sayan, Baikal, Transbaikalia) led to the formation of the Central Asian inland mountain belt. On South Eastern Siberia located Baikal rift system .
The northern periphery of Russia, covering a wide Arctic shelf, is a passive margin of the Arctic Ocean. At the bottom of the shelf seas, the structural elements of the land continue. The eastern periphery is the active margin of the Pacific Ocean with all its characteristic elements: marginal seas (Bering, Okhotsk, the northern part of Japan), volcanic arcs (Kuril, Kamchatka, the western end of the Aleutian-Komandorskaya) and deep-water trenches.
East European Platform
Takes up almost all European part territory of Russia, with the exception of the Timan Ridge, the Pechora Lowland, the western slope of the Ural Mountains, Ciscaucasia, the northern slope of the Greater Caucasus, and is represented by its northern, central, eastern and southeastern parts. The largest building blocks East European platform are Baltic shield and Russian stove .
Baltic shield covers the Kola Peninsula and Karelia, is composed of outcropping and exposed Kola superdeep well rocks of the crystalline basement, whose age is from 1.7 to 3.2 billion years, i.e., Early Proterozoic and Archean. The Kola, Karelian, and White Sea megablocks stand out in the structure of the shield. Within the Kola and Karelian megablocks, Archean formations predominate, represented by gneisses, granitoids, crystalline schists, and amphibolites, among which greenstone belts composed of basic and ultrabasic volcanic rocks, metamorphosed mainly in greenschist facies, stand out. The belts are associated with ferruginous quartzites Olenegorsk group of deposits(Kola Peninsula) and Kostomuksha field(Karelia) iron ores. In the southern part of the Kola megablock, the Pechenga-Imandra-Varzug rift structure extends, filled with a thick volcanic-sedimentary series of the Lower Proterozoic. The Pechenga deposit of copper-nickel ores is associated with ultrabasic igneous rocks that make up bedded intrusions. Within the Karelian megablock, Lower Proterozoic terrigenous flyschoid formations are developed along its western periphery (marginal part of the Svecofene belt). To the east, strike-slip depressions are common - grabens filled with volcanic-sedimentary rocks of the Lower and clastic strata of the Middle Proterozoic. The Archean-Early Proterozoic complexes of Karelia are cut through by intrusions of Middle Proterozoic rapakivi granites. The Kola and Karelian megablocks are separated by the Belomorian megablock, an Archean-Early Proterozoic granulite-gneiss belt, characterized by a higher degree of metamorphism and a very complex structure.
Within Russian plate the foundation is covered by a sedimentary cover and occurs at depths of 0–2 km in domes anteclise(Voronezh, Volga-Ural) up to, as a rule, 3-5 km in the central parts syneclise(v Caspian syneclise up to 20 km or more). The basement of the Voronezh anteclise, which comes to the surface in the upper reaches of the Don and in quarries Kursk magnetic anomaly(KMA), is composed of Archean blocks separated by a narrow, elongated in the meridional direction, band of terrigenous rocks and ferruginous quartzites of the Lower Proterozoic, to which large deposits of iron ore (KMA) are confined. Internal structure The Archean and partially Early Proterozoic basement of the Volga-Ural anteclise is characterized by great complexity and has a scaly-thrust character. Ancient continental rifts are buried under the sedimentary cover of the Russian Plate - aulacogens, dissecting the foundation of the East European Platform. These include the Central Russian rift system, its southeastern (Pachelma) and northern branches, the Dnieper-Donetsk, Kamsko-Belsky, Vyatsky, Dono-Medveditsky, and other aulacogenes. These structures are mainly confined to the base of the syneclise, over some of them there are deformation zones of the sedimentary cover, swells. The aulacogenes are made up of a complex of Riphean and Lower Vendian rocks: continental clastic, partly shallow-marine carbonate deposits hosting mafic volcanic rocks. Some structures also contain Devonian terrigenous and volcanogenic formations. The sedimentary cover is composed of Upper Vendian and entire Phanerozoic rocks; its section reaches its greatest thickness and fullness in syneclises - Moscow, Mezen, Caspian and the youngest Ulyanovsk-Saratov. Shallow-marine terrigenous-carbonate, partly continental gray- and red-colored, sometimes lagoonal gypsum-saline deposits predominate; bauxites and phosphorites are also present. In the Caspian syneclise, the thickness of the cover exceeds 20 km; the basement lacks the granite metamorphic layer characteristic of the continental crust. A distinctive feature of its sedimentary occurrence is the presence in the section of deep-sea deposits of the upper part of the Devonian - lower part of the Permian, overlain by a thick layer of salts of the Kungurian stage of the Lower Permian, which is associated with the occurrence salt tectonics. Oil and natural combustible gas deposits are confined to the sedimentary cover of the East European Platform ( Volga-Ural oil and gas province and Caspian oil and gas province), coal ( Moscow region coal basin), aluminum ores represented by bauxites (Tikhvinskoye, Severoonezhskoye deposits), phosphate ores represented by phosphorites (Vyatsko-Kamskoye, Egoryevskoye deposits), stone ( Baskunchak) and potassium ( Verkhnekamskoye field) salts, writing chalk, refractory clays and building stone.
Platform magmatism on the East European Platform is manifested in aulacogenes formed and revived in the Paleozoic (Dnieper-Donetsk, Vyatka), in the northern part of the Baltic Shield (Khibiny ring pluton of alkaline-ultrabasic rocks of Devonian age, containing deposits of apatite-nepheline ores; Lovozero pluton, with associated with deposits of rare earth ores). On the northern slope of the Mezen syneclise, there are kimberlite pipes, to which primary diamond deposits are confined. Arkhangelsk diamondiferous region(pipes "Arkhangelskaya", named after Lomonosov, "Pionerskaya", named after Karpinsky-1, named after Karpinsky-2, "Pomorskaya" and named after V. Grib).
Siberian platform
It is located in Central and Eastern Siberia, between the Yenisei and Lena. The foundation of the Siberian Platform protrudes to the surface within Aldano-Stanovoi shield(in the southeast) Anabar Shield(in the north), and is also exposed in a small area in the extreme northeast of the platform - at the top of the Olenyok arch. It is composed of Early Precambrian, mainly Archean, formations, partially reworked in the Early Proterozoic.
In the building Aldano-Stanovoi shield the Aldan (northern) and Stanovoi (southern) megablocks stand out. The Aldan megablock, composed mainly of Archean rocks, is divided by submeridional thrust faults into 3 blocks: Olekma (western), Batomg (eastern) - granite-greenstone, and Central Aldan - granulite-gneiss. Deposits of ferruginous quartzites (Tarynnakh and Gorkit deposits of magnetite ores) are confined to the greenstone belts of the late Archean and, probably, early Proterozoic. In the southwestern part of the Aldan megablock, the Early Proterozoic Udokan rift basin is located, filled with a thick sequence of continental clastic rocks hosting cupriferous sandstones, with which the largest Udokan field copper ores. The Stanovoi megablock, which experienced intensive tectonothermal reworking in the Early Proterozoic, is pushed over the Aldan megablock. Archean rock complexes are zoned metamorphosed and intruded by large layered plutons of gabbro-anorthosites and granite intrusions of high alkalinity of the late Early Proterozoic. During the period of the Mesozoic activation of the Stanovoy zone, the formation of Late Jurassic-Early Cretaceous batholiths of granitoids took place. Deposits of ores of gold (Kuranakhskoe ore field), iron (Taiga, Chineyskoe), rare earth elements and apatite (Seligdarskoe) are associated with igneous rocks of epochs of tectonomagmatic activation of the shield. From the south, the Stanovoi megablock is bounded by the North Tukuringra Fault, along which the Aldan-Stanovoi Shield is pushed over the folded structures of the Ural-Okhotsk mobile belt. On the newest stage The Stanovaya zone was involved in intensive uplift and became part of the Central Asian belt of revived mountains.
Anabar Shield composed mainly of Archean rocks metamorphosed in granulite facies. In its southeastern part, Early Proterozoic primary sedimentary and volcanogenic formations are common, which also protrude to the surface at the top of the Olenyok arch. In the northern marginal part of the Anabar shield is the Popigai astrobleme with the unique shock-metamorphic deposits of industrial diamonds Skalnoye and Udarnoye confined to it.
The basement rock complex includes the Early Proterozoic formations of the Akitkan volcanoplutonic belt, which extends along the northwestern shore of Lake Baikal and plunges in a northeastern direction under the sedimentary cover.
Foundation Lena-Yenisei plate, which is the area of distribution of the platform cover, is dissected by a series of differently oriented aulacogens (Kotuisky, Udzhinsky, Olenyoksky, Turukhano-Norilsky, Irkineevsky, Urinsky, Vilyui system of paleorifts), filled with Riphean shallow-marine terrigenous-carbonate and partly continental clastic deposits, including volcanics. During the Paleozoic, some aulacogenes experienced inversion or regeneration. In the section of the revived aulacogens (Vilyui paleorift, etc.), there are Middle Upper Devonian volcanic rocks overlain by the Upper Devonian saliferous sequence, which is associated with the manifestation of salt-dome tectonics in the upper horizons of the platform cover. In the structure of the Lena-Yenisei Plate, syneclises are distinguished: Prisayansko-Yenisei, Tungusskaya, Vilyuiskaya, within which the thickness of the sedimentary cover is 3–7 km (in the north of the Tunguska syneclise, 12 km). These structures are separated and framed by anteclises (the largest are Anabar-Olenyok, Aldan and Nepa-Botuobinsk). At their tops, the foundation lies at depths of 0–2 km. The platform cover is composed of shallow-marine and continental rocks of the Middle - Upper Riphean and Vendian - Phanerozoic. In the Sayan-Yenisei syneclise, filled with deposits of the Cambrian, Ordovician and Silurian, there is a thick sequence of stone and potassium salts of the Cambrian age (Bratskoye, Usolskoye deposits). The southern part of the syneclise, sandwiched between the folded structures of the Eastern Sayan and the Baikal-Patom highlands, forms the so-called. Irkutsk amphitheater. To the northeast of it, between the marginal part of the Nepa-Botuoba anteclise and the thrust front of the Baikal-Patom folded region, there are the Pre-Patom trough and the Angara-Lena dislocation zone, where the Cambrian-Silurian deposits are torn from the basement and crushed into a system of folds of northeast strike . It is confined to the Nepa dislocation zone within the Nepa-Botuoba anteclise Nepa-Gazhensky potassium-bearing basin. Within the Tunguska syneclise, the Middle Carboniferous-Permian coal-bearing series is widespread ( Tunguska coal basin), overlain by the Upper Permian–Lower Triassic trap complex. As a result of the metamorphism of coals of the Tunguska series under the contact action of intrusions of the basic composition, graphite deposits arose (Noginskoye, Kureyskoye). Rich sulfide copper-nickel ores with cobalt and platinoids ( Norilsk group of fields). To the northeast of the Tunguska syneclise is the Maimecha-Kotui trough, notable for its Triassic alkaline-ultrabasic formation with large ring plutons (Gulinsky), which are associated with deposits of titanomagnetite, apatite, nepheline, and rare earth ores. The western limit of the Tunguska syneclise is the Turukhano-Norilsk dislocation zone, the southwestern limit is the small Baikit anteclise, within which oil deposits have been identified in the Riphean carbonate rocks (oil and gas bearing area). The Upper Riphean and Vendian-Lower Cambrian deposits of the Nepa-Botuobinsk anteclise, which separates the Tunguska syneclise from the Vilyui syneclise, contain oil and gas deposits (the Nepa-Botuobinsk region Lena-Tunguska oil and gas province). The Vilyui syneclise is located above the Vilyui paleorift system and is made up of Jurassic-Cretaceous shallow-marine and continental coal-bearing deposits ( Lena coal basin). Its eastern marginal part is superimposed by the shallow Lower Aldan Basin, within which continental terrigenous sediments of the Paleogene and Neogene are developed. To the north of the syneclise in the direction of the Anabar massif, a strip of kimberlite pipes extends, with which primary diamond deposits are associated. Yakutsk diamond province(Udachnaya, Yubileinaya, Mir, International, Zarnitsa, Aikhal, Krasnopresnenskaya pipes) and diamond placers. In the southern half of the Siberian Platform, small superimposed depressions are developed, filled with Jurassic continental coal-bearing deposits: the Kansko-Taseevskaya, superimposed on the northern part of the Sayan-Yenisei syneclise; Irkutsk, located in the western part of the "amphitheater" (brown coal basins); a chain of rift depressions - grabens along the overthrust of the Stanovoi megablock of the Aldan-Stanovoi Shield (Chulmanskaya, Tokinskaya, etc. - South Yakutsk coal basin).
Ural-Okhotsk (Ural-Mongolian) mobile belt
The belt stretches across Eurasia from the Barents Sea to Sea of Okhotsk and consists of two segments. The northern (Ural-Siberian) segment separates the East European and Siberian platforms. Southern (Central Asian) separates the Siberian platform from the Sino-Korean one. In the structure of the belt, folded systems of different ages (from Baikalides to mesozoids) are distinguished, formed within Paleoasian ocean, partially covered by covers of the West Siberian and Barents-Pechora young platforms.
South Barents-Timan fold system of Baikal age, the formations of which underlie the sedimentary cover of the Barents-Pechora Plate and come to the surface on the Rybachy and Kanin peninsulas and in the Timan Ridge, is located in the northwest of the mobile belt. Its outer (southwestern) zone is composed of Riphean terrigenous deposits of the continental slope and foot of the ancient East European continent (Baltic). To the east, igneous rocks, probably of island-arc origin, play a significant role. In Pai-Khoi and the Polar Urals, the Baikalid system is sharply unconformably overlain by Hercynian structures.
Ural fold-thrust system Hercynian age extends along the eastern edge of the ancient East European platform and is separated from it by a chain edge deflections. The system is separated by the Main Ural Fault - a gently sloping overthrust– into two longitudinal megazones: the western and eastern slopes. The megazone of the western slope is underlain by the submerged foundation of the East European Platform and is composed of formations of its Paleozoic passive margin - shelf terrigenous and carbonate rocks of the Ordovician - Lower Carboniferous. The deposits are crumpled into folds, disturbed by overthrusts, sometimes covered with plates ophiolites transferred from the eastern slope megazone. The latter has a more complex structure, which includes ophiolites, which are relic oceanic crust of marginal (back-arc) and interarc seas, complexes of volcanic arcs of the Late Ordovician - Early Carboniferous, Late Devonian-Early Carboniferous flysch. Sedimentary-volcanogenic complexes of the eastern slope megazone are intruded by Late Paleozoic granitoids, with which skarn-magnetite ores are associated (Goroblagodatskoye deposit, Vysokogorskaya group), and earlier gabbro-peridotites of the Platinum-bearing belt of the Urals (titanomagnetite vanadium-bearing deposits of Gusevogorskoye, Kachkanarskoye with platinoids). Numerous deposits of copper-pyrite-polymetallic ores (Gaiskoye, Sibayskoye, Blyavinskoye, Uchalinskoye, etc.) are associated with island-arc volcanic rocks. The folded formations of the system are thrust in the west over the foredeeps filled with Upper Paleozoic-Triassic deposits. The structure of the eastern slope of the Urals is complicated by rift grabens filled with the coal-bearing formation of the Upper Triassic - Lower Jurassic (Chelyabinsk lignite basin).
In the north, the structures of the Urals are butt-jointed with Pai-Khoi-Novaya Zemlya folded system early Mesozoic age. The Paleozoic formations composing it have a certain similarity with the deposits of the megazone of the western slope of the Urals. On the island of the Northern archipelago New Earth Paleozoic deposits of a platform nature are conformably underlain by Upper Proterozoic rocks, which sharply unconformably overlap the metamorphic basement of the Middle Proterozoic age. Similar relationships give grounds to single out here the epigrenville platform massif - Svalbard (Barents), which limits the South Barents structures of Baikal age from the north. The Kara astrobleme is superimposed on the Pai-Khoi segment of the system.
In the east, the folded formations of the Urals are covered by a sedimentary cover. West Siberian platform(slabs), along the eastern edge of which intensely deformed rocks are exposed folded system of the Yenisei Ridge Baikal age. The Riphean formations of the Yenisei Ridge are represented by terrigenous and terrigenous-carbonate flyschoid deposits of the continental slope and foot of the ancient Siberian continent (Siberia). Black shales contain the bodies of gold ores of the giant Olimpiada deposit. In the northwest of the fold system, there are ophiolites and island-arc volcanic rocks of the Riphean age, which formed in an active continental margin setting.
North of the Siberian platform is located Taimyr fold system, separated from it by a deep (over 14 km) Yenisei-Khatanga trough. There are three zones within the system. The central one has a complex fold-thrust structure; among thrust scales there are plates composed of island-arc volcanic rocks and ophiolites of the Riphean. In the northern zone and on the islands of the Severnaya Zemlya archipelago, terrigenous deposits of the Upper Riphean appear, which are sediments of the foot and slope of the Precambrian continental block, similar to the Svalbard one and, possibly, constituting its eastern continuation. The southern zone is superimposed on the submerged edge of the Siberian Platform; it was formed by the Lower-Middle Paleozoic shelf carbonate rocks of the underwater margin of the ancient Siberian continent. The section of deposits of the Upper Paleozoic and the beginning of the Mesozoic resembles the sedimentary cover of an ancient platform. The thick sequences that form the southern zone of the Taimyr fold system are intensively dislocated and disturbed by overthrusts facing the platform. Deformations in this area date back to the end of the Triassic - Jurassic - beginning of the Cretaceous.
Salairo-Caledonian-Hercynian Altai-Sayan folded region located in the south of Western and Central Siberia. In the northeast, it adjoins the Siberian Platform. The region has a very complex structure and consists of differently oriented folded zones of different ages: Salair structures of the Eastern Sayan, Kuznetsk Alatau and Mountain Shoria, Eastern Tuva, Dzhida zone; Caledonian structures of the Western Sayan, Gorny Altai; Hercynian structures of Rudny Altai, Salair Ridge. Within its limits, a number of median arrays ( microcontinents), for example, the Gargano-Khamar-Dabansky with an Early Proterozoic basement and an Upper Riphean-Lower Cambrian cover. In the structure of folded zones, an important role is played by island-arc volcanic-sedimentary rocks and ophiolites (East Sayan-Kuznetsk and Dzhida zones, Eastern Tuva and the Salair ridge), terrigenous flyschoid formations (West Sayan and Gorno-Altai zones). Within Rudny Altai, rocks of the Middle Devonian–Early Carboniferous volcanoplutonic association are widespread. The intermountain Middle-Late Paleozoic Minusinsk depression is filled in the lower part with volcanogenic and clastic molasses Devonian, and then coal-bearing strata of the Upper Paleozoic and Jurassic ( Minusinsk coal basin). Within the intermountain Kuznetsk trough, the Devonian-Early Carboniferous marine terrigenous-carbonate formation is widespread, which is overlain by the Upper Paleozoic coal-bearing series ( Kuznetsk coal basin- one of the largest in the world, the largest in Russia in terms of coking coal reserves), Triassic traps and Jurassic continental deposits with coals.
To the west of the Altai-Sayan region is located Irtysh-Zaisanskaya fold-integument system late Hercynian age, occupying an axial position in the structure of the Ural-Okhotsk belt. In its central part, in the fault zone, Ordovician-Early Devonian ophiolites are developed, olistostromes, metamorphic complexes. The Irtysh-Zaisan system extends into Russia from Kazakhstan. To the north, the folded formations submerge under the cover of the West Siberian young platform, being exposed on the right bank of the Ob to Novosibirsk and Tomsk (Tom-Kolyvan zone); to the north, the structure of the system was traced by drilling to the latitude of Norilsk.
In the east, the Altai-Sayan region merges with structures Baikal-Patom folded region, composed of Riphean terrigenous-carbonate deposits of the paleomargin of the Siberian Platform, island-arc complexes of the Late Proterozoic and Cambrian ages. Within its limits, relics of the oceanic crust of the marginal seas of the same age, represented by ophiolites, have been established. Huge areas are occupied by the Middle Paleozoic Angara-Vitim granite batholith. In the north of the region, in the black shale strata of the Upper Proterozoic, the largest gold ore deposit in Russia was discovered Dry Log .
The Hercynian-Mesozoic Mongolian-Okhotsk fold-integument system. From the south, it is limited by the Priargunsky and Bureya massifs with a Precambrian basement, and in the east it articulates with the northern end of the Sikhote-Alin fold system. The Mongolian-Okhotsk system arose on the site of the basin, which in the Late Paleozoic and Mesozoic was the bay of the Pacific Ocean. Deformations in this area are dated in the west by the Late Paleozoic, in the east by the Mesozoic (late Jurassic).
Significant areas in the north of the Ural-Okhotsk belt are covered by a sedimentary cover, which belongs to the young Barents-Pechora and West Siberian platforms, separated by the Ural-Novaya Zemlya fold system. Foundation Barents-Pechora platform - Baikal, in the north of the Barents Sea - Grenville. In the southern part of the platform (on land), the cover is composed of Paleozoic shallow-water and partly continental deposits; to the north, within the Barents Sea, powerful complexes of the Mesozoic also take part in its structure. Oil and gas fields are associated with the sedimentary cover of the platform ( Timan-Pechora oil and gas province and East Barents Province) and coal ( Pechora coal basin).
West Siberian platform(megasyneclise), which continues in the southern part of the Kara Sea, has a folded Paleozoic and partly Precambrian basement, broken by a network of rift depressions, which are filled with Triassic clastic strata containing basalts. Salairids and hercynides of the Altai-Sayan region, the Irtysh-Zaisan system, the Caledonides of the Kazakh uplands, and the Central Kazakhstan massif (microcontinent) are traced under the cover of Meso-Cenozoic sediments. The sedimentary cover is represented by continental and shallow-marine terrigenous rocks of the Jurassic - Cenozoic (in some places in the section there is a Paleozoic complex), which are associated with oil and gas fields ( West Siberian oil and gas province). The northeastern branch of the West Siberian platform is the Yenisei-Khatanga trough, at the base of which a Triassic (possibly older) rift extends. The trough is filled with oil and gas bearing Jurassic and younger sediments. It separates the ancient Siberian platform from the southern zone of the Taimyr fold system and, like it, is superimposed on the northern margin of the platform.
Western Pacific Mobile Belt
The belt covers the North-East and the Far East of Russia. It is located to the east of the Siberian platform, Bureya and Khanka Precambrian massifs and consists of several folded areas. In the north is the Late Mesozoic Verkhoyansk-Chukotka fold-cover region, within which the Verkhoyansk-Kolyma (in the west) and Novosibirsk-Chukotka (in the east) fold systems are distinguished. The Verkhoyansk-Kolyma system over most of its area is underlain by the submerged basement of the Siberian Platform and is composed of Riphean-Jurassic carbonate and terrigenous deposits of its passive paleomargin, folded into large linear folds. In the central part of the system, there is the Kolyma-Omolon massif (microcontinent) with an Early Precambrian basement and a gently deformed Riphean-Mesozoic cover. To the west of it, in accordance with folded structures, there is a chain of late Jurassic granite plutons with gold and tin mineralization (the Deputatskoye, Odinokoye, etc. deposits). In the Chersky Ridge, ophiolites have been identified that mark the boundary between the ancient Siberian continent and the basin with oceanic crust that separated the Kolyma-Omolon microcontinent from it in the Early Paleozoic. The Verkhoyansk-Kolyma system is thrust in the west onto the Cis-Verkhoyansk marginal trough, which extends along the eastern periphery of the Siberian Platform and is filled with Cretaceous and partially Cenozoic coal-bearing molasses.
The Novosibirsk-Chukotka fold system covers the Novosibirsk archipelago (partially), the southern parts of the East Siberian and Chukchi seas, and the northern coast of Chukotka. Paleozoic and Mesozoic terrigenous-carbonate deposits of the passive margin of the hypothetical Hyperborean platform, which is the northern limit of the system, take part in its structure. In the south, island-arc volcanic rocks have been identified. The Novosibirsk-Chukotka and Verkhoyansk-Kolyma fold systems are separated by the South Anyui suture zone, which has a very complex fold-thrust structure and is marked by Jurassic ophiolites and Late Jurassic-Early Cretaceous granite intrusions. In the west, the Novosibirsk link of the Novosibirsk-Chukotka system is separated from Taimyr by a young rift basin of the Laptev Sea that emerged at the end of the Early Cretaceous. Along the southern part of this sea and its coast, the Lena-Anabar zone of the Verkhoyansk-Kolyma system extends to the west, adjoining the southern zone of the Taimyr fold system and together with it pushing over the Siberian platform. To the east of the Novosibirsk archipelago, there are rift troughs of the East Siberian and Chukchi seas, formed in the middle of the Cretaceous and superimposed on the southern part of the Hyperborean platform and the northern part of the Novosibirsk-Chukotka system.
In the southeast, the Verkhoyansk-Chukotka folded region is limited Okhotsk-Chukotka volcano-plutonic belt the middle of the Cretaceous, superimposed on a folded and metamorphic base of different ages. The belt is composed of terrestrial volcanic rocks of basic, intermediate, and felsic composition, which are closely related to intrusive massifs of gabbro, diorites, granodiorites, and granites. Adjacent to it is the Late Mesozoic-Cenozoic Koryak-Kamchatka folded area, which is a complex accretionary complex, which includes island-arc formations of the Paleozoic, Mesozoic and Paleogene. The youngest element of the area is the Miocene-modern volcanic arc of Eastern Kamchatka (Shiveluch, Klyuchevskaya Sopka, Tolbachik volcanoes, etc.) and the Kuril Islands, which limits the Sea of Okhotsk depression from the southeast. The shallow-water part of the sea is considered by some scientists as a block with an ancient continental crust (microcontinent), and by others as a Miocene oceanic plateau included in the accretionary complex. The deep-water South Okhotsk (Kuril) basin, located in the rear of the Kuril volcanic arc, is a captured section of the oceanic plate or, according to other researchers, back-arc basin .
From the west, the Sea of Okhotsk depression is limited by the Cenozoic Sakhalin fold-cover system. In its structure, two megazones are distinguished, separated by a steep fault - a shift. In the eastern megazone, island-arc complexes are developed, the upper age limit of which corresponds to the end of the Miocene. The western megazone is composed of a thick layer of Upper Cretaceous–Paleogene terrigenous deposits accumulated in a deep-water trench, which adjoined the East Sikhote-Alin volcano-plutonic belt of the corresponding age from the east. The western megazone of the Sakhalin system is separated from the named belt by the latest rift graben of the Tatar Strait, which arose in the Miocene and opens in the south into the newly formed basin of the Sea of Japan. The fold-and-thrust structures of the system are superimposed by a large depression filled with Pliocene molasse, to which the North-East Sakhalin region is confined. Okhotsk oil and gas province, continuing on the eastern shelf of the island.
Late Mesozoic Sikhote-Alin fold-cover system It is located on the mainland and adjoins the ancient Bureya and Khanka massifs from the east. It extends to the mouth of the Amur, where it merges with the Mongol-Okhotsk fold system. The Sikhote-Alin system is divided by the NE-trending Central Sikhote-Alin strike-slip into two megazones. The western one is a complex accretionary complex formed at the beginning of the Cretaceous. Olystostromes play an important role in its structure. melange, which include Paleozoic, Triassic and Jurassic ophiolites and limestones. The formations of the complex are intruded by Early Cretaceous granites and overlain by Lower Cretaceous flysch. Repeated deformations with the introduction of granite intrusions occurred in the middle of the Cretaceous. The eastern megazone is composed of Upper Cretaceous–Paleogene volcanic rocks of the marginal volcanoplutonic belt.
Mediterranean (Alpine-Himalayan) mobile belt
The belt covers the extreme south of the European part of Russia. It includes the Crimean peninsula, the Ciscaucasia, the northwestern subsidence and the northern slope of the Greater Caucasus. The flat part of the Crimean peninsula and Ciscaucasia in tectonic terms correspond to the young Scythian platform(plate) with a Paleozoic (mainly) folded base, unconformably overlain by a Permian-Lower Triassic molasse and a cover of Middle Jurassic and younger terrigenous and carbonate sediments. In the eastern part of the platform, under a slightly deformed cover, Upper Triassic felsic volcanic rocks occur, and Jurassic rocks are present in the section of the cover. evaporites(large Gremyachinskoe deposit of potassium salts). Oil and natural combustible gas deposits are confined to the Scythian Plate and the forward troughs of the Greater Caucasus ( North Caucasian oil and gas province). Between the Scythian and East European platforms there is a narrow folded zone of the Karpinsky Ridge(Donetsk-Caspian) of Paleozoic age, which arose as a result of inversion of the eastern link of the Dnieper-Donetsk rift system. Folded Devonian-Carboniferous-Lower Permian and Triassic formations of the zone are overlain by Jurassic-Cenozoic platform deposits.
In the south, the Scythian platform is separated by a discontinuous strip of foredeeps (West-Kuban, or Indolo-Kuban; East Kuban, Terek-Caspian) from the cover-folded mountain structures of the Mountainous Crimea and the Greater Caucasus, which are part of the Dobrudzhan-Crimean-Caucasian-Kopetdag branch of the Alpine - The Himalayan belt, the folded systems of which were formed in the Cenozoic within the Mesozoic-Cenozoic Neotethys ocean (see Art. Tethys). At the base of the incision mountain-folded structure of the Crimean Mountains overlie: intensely deformed sandy-argillaceous flysch of the Upper Triassic - Lower Jurassic, Middle Jurassic island-arc volcanics and volcanogenic-sedimentary strata, which are overlain by Upper Jurassic reef limestones (in the southwest - conglomerates, in the eastern part - flysch), Lower Cretaceous terrigenous-carbonate rocks and monoclinally overlying Upper Cretaceous - Eocene marl-carbonate deposits. The southern flank of the orogen is lowered along faults below the level of the Black Sea within the limits of the underwater margin of the Crimean Peninsula. There are chains of Middle Jurassic hypabyssal intrusions of gabbro, diorites, and plagiogranites (Ayudag, Plaka, Kastel, etc. massifs along the southern slope of the Crimean Mountains).
north slope mountain-fold structure of the Greater Caucasus is a gently sloping monocline composed of shelf sediments of the Upper Jurassic - Paleogene. This structure was formed due to the tectonic uplift of the southern edge of the Scythian platform. In the Rocky, Peredovy, and Glavny (Vodorazdelny) ranges of the Central Caucasus, fold-cover complexes of the Baikal and Hercynian ages, including the Lower Paleozoic ophiolites, protrude from under the obliquely deposited Mesozoic deposits. The Upper Proterozoic and Lower Middle Paleozoic formations are intruded by Late Paleozoic, Mesozoic and Cenozoic granite intrusions. The skarn marbles in the contact zone of the young intrusion are dated Tyrnyauz field complex tungsten-molybdenum ores. In the Eastern Caucasus, the Paleozoic complex plunges under a thick lower and middle Jurassic black shale sequence accumulated in the axial part of the marginal basin of the Neotethys ocean. The foredeeps are filled with thick Oligocene-Neogene molasses. In the axial zone of the Terek-Caspian trough, the Tersky and Sunzha swells are localized, containing large oil deposits (fields in Dagestan, Chechnya and Ingushetia). The foredeeps are separated by the transverse Mineralovodsko-Stavropol uplift, within which manifestations of Neogene-Quaternary magmatic activity are known, including the Elbrus and Kazbek volcanoes in the Greater Caucasus, dissected by erosion laccoliths Caucasian Mineral Waters. Between the folded structures of the Mountainous Crimea and the Greater Caucasus is located Kerch-Taman transverse trough, composed of a thick layer of dislocated deposits of the Oligocene - Neogene, incl. clayey Maikop series, which is associated with the manifestation of clay diapirism and mud volcanism on the Kerch and Taman peninsulas.
Geological structure planets is directly related to the formation of the earth's crust. The geology of the planet began with the formation of the crust. Scientists, after analyzing ancient rocks, came to the conclusion that the age of the Earth's lithosphere is 3.5 billion years. The key types of tectonic structures on land are geosynclines and platforms. They are seriously different from each other.
Platforms are large and stable patches of the earth's crust that are made up of crystalline substrate and relatively young rocks.
In most cases, there are no rock formations and active volcanoes on the platforms. Earthquakes are not often seen here, and vertical movements cannot develop high speed. The crystalline base of the Russian platform was formed in the Proterozoic and Archean eras, that is, two billion years ago. During this era, the planet underwent serious transformations, and the mountains became their logical outcome.
Crystal schists, quartzites, gneisses and other ancient rocks have turned them into folds. During the Paleozoic era, the mountains became smoother, their surfaces slowly oscillated.
When the surface was below the boundary of the ancient ocean, the process of marine transgression and the accumulation of marine sediments began. Sedimentary rocks such as clay, salt, limestone accumulated intensively. When the land was freed from water, red-colored sands accumulated. If sedimentary material accumulated in shallow lagoons, brown coal and salt were also concentrated here.
During the Paleozoic and Mesozoic epochs, crystalline rocks were overlain by a thick sedimentary cover. For detailed analysis of these rocks, it is necessary to drill wells to extract the core. Specialists can conduct a thorough study of the geological structure, studying the natural outcrop of rocks.
Along with classical geological research, modern science actively uses aerospace and geophysical research methods. Promotion and demotion Russian territory, the creation of continental conditions is provoked by tectonic movements, the nature of which has not yet been explained. But the connection of tectonic processes with those that occur in the bowels of the planet is beyond doubt.
Geology distinguishes several types of tectonic processes:
- Ancient. Movements of the Earth's crust that occurred during the Paleozoic era.
- New. Movements of the Earth's crust that occurred during the Mesozoic and Cenozoic eras.
- Newest. Movements of the earth's crust over the past few million years.
The latest tectonic processes have played a key role in the formation of the modern relief.
Relief features in Russia
The relief is the totality of all the irregularities that are on the surface of the earth. This should also include the seas and oceans.
The relief plays an important role in the formation of climatic conditions, the distribution of certain groups of animals and plants, and strongly affects the economic activity of people. According to geographers, relief is the framework of nature. The relief on the territory of Russia surprises with the diversity and complexity of its structure. Endless plains here are replaced by mountain chains, intermountain basins and volcanic cones.
Pictures from space and physical map countries allow us to determine some regularities of the orographic pattern of the territory of the state. Orography - the relative position of the relief in relation to each other.
Features of the orography of Russia:
- The territory is 60 percent plains.
- The west and center of the country are lower than the other parts. The border between the parts runs along the Yenisei.
- Mountains are located on the outskirts of the country.
- The territory leans towards the Arctic Ocean. This is evidenced by the course of the Northern Dvina, Ob, Yenisei and other large rivers.
On Russian territory there are plains that are considered the largest on the planet - Russian and West Siberian.
The Russian Plain is characterized by a hilly relief, an alternation of uplands and lowlands. The northeast of the plain is higher than the rest of its parts. The plain rises above the ocean level in this part by more than 400 meters. In the south of the plain is the Caspian lowland. This is the lowest part of the plain, rising only 28 meters above the ocean level. The average height is 170 meters.
The relief of the West Siberian Plain does not impress with its diversity. The main part of the lowland is located below the World Ocean by 100 meters. The average height of the plain is 120 meters. The maximum height indicators are observed in the northwestern part of the plain. Here is the North Sovinskaya Upland, thanks to which the plain rises 200 meters above the ocean.
The Ural Range acts as a watershed between these plains. The ridge does not differ in high height and width. Its width is no more than 150 kilometers. The peak of the Urals is Narodnaya Gora - its height is 1895 kilometers. The total length of the Ural Mountains in the southern direction is about 2 thousand kilometers.
The Central Siberian Plateau ranks third in terms of area among the plains in Russia. The object is located between the Yenisei and Lena. The average height of the plateau is 480 meters above the ocean. The highest point of the plain is in the zone of the Putorana Plateau. It is located 1700 meters above the ocean.
The plateau in the eastern part smoothly passes into the Central Yakut lowland, and in the north - into the North Siberian Plain. The outskirts of the country in the South-East are occupied by mountainous regions.
The highest mountains of the country are located between the Caspian and Black Seas, in a southwestern direction from the Russian Plain. Here is also the highest point in the whole country. This is Mount Elbrus. Its height reaches 5642 meters.
The Sayan Mountains and the Altai Mountains pass along the southern outskirts of the country in an easterly direction. The top of the Sayans is Munku-Sardyk, and the top of the Altai Mountains is Belukha. Smoothly these mountains pass into the Cis-Baikal and Trans-Baikal ranges.
The Stanovoi range connects them with the northeastern and eastern ranges. Ranges of small and medium height are found here - Suntar-Khayata, Verkhoyansky, Chersky, Dzhugdzhur. In addition to them, there are highlands here - Kolyma, Koryak, Yano-Oymyakon, Chukchi. On the south side Far East they are connected with the average height of the Amur and coastal ridges. For example, this is Sikhote-Alin.
In the extreme East of Russia, you can see the Kuril and Kamchatka mountains. All active volcanoes in Russia are concentrated in these places. The highest of the currently active volcanoes is Klyuchevskaya Sopka. A tenth of the entire territory of Russia is occupied by mountains.
Mineral Russian minerals
Russia is the world leader in mineral reserves among all the states of the planet. To date, 200 deposits have been discovered. The total value of the deposits is about 300 trillion dollars.
Russian minerals in relation to the world reserve:
- oil, 12 percent;
- natural gas - 30 percent;
- coal - 30 percent;
- potassium salts - 31 percent;
- cobalt - 21 percent;
- iron ore - 25 percent;
- nickel - 15 percent.
In the bowels of the Russian land there are ore, non-metallic and combustible minerals.
The fossil fuel group includes coal, oil, natural gas, oil shale and peat. The largest deposits are in Siberia, the Volga region, the Baltic region, the Caucasus, the Yamal Peninsula.
The group of ore minerals includes iron, manganese, aluminum ores, as well as non-ferrous metal ores. The largest deposits are located in Siberia, Gornaya Shoria, the Kola Peninsula, the Far East, Taimyr and the Urals.
Russia ranks second in the world in diamond mining after South Africa. V in large numbers on the territory of the Russian Federation, a variety of gems, minerals, building minerals.
The Prikazansky District is located in the east of the Russian Platform. The Precambrian crystalline basement, exposed by boreholes at a depth of about 1800 m, is overlain by a thick layer of sedimentary rocks of the Paleozoic group. It includes deposits of the Devonian, Carboniferous, Permian systems. Only rocks of the Upper Permian, Neogene and Quaternary system emerge on the day surface, which make up the modern relief of the region.
The Upper Permian includes deposits of the Kazan and Tatar stages, which lie on the eroded, heavily karstized surface of gypsum and anhydrite of the Lower Permian. The total thickness of Upper Permian deposits is about 250 m. They are exposed in numerous outcrops in the valleys of the Volga and its tributaries, in gullies and ravines, and also a large number boreholes.
The formations of the Kazanian stage are represented by two substages, the lower and the upper, which differ sharply from each other lithologically and faunistically. Sandstones, sandy limestones, clays and marls with a total thickness of 30–35 m are involved in the formation of the Lower Kazan substage. (Scientific guide to Kazan and its environs, 1990)
The Kazanian Stage is represented in the west mainly by marine formations and is characterized by a diverse fauna of foraminifers, brachiopods, pelecypods, gastropods, bryozoans, corals, nautiloids, and conodonts. To the east, there is a depletion of the marine fauna and its gradual replacement by brackish and continental ones. From east to west, the layer thickness decreases from 190–200 m to 15–20 m.
The Upper Kazanian substage is widespread. Four strata (layers) are distinguished in its composition: Prikazanskaya, Pechishchinskaya, Upper Uslonskaya and Morkvashinsky. The structure of the Upper Kazanian substage is characterized by significant facies variability and distinct rhythm. In the west, types of sections are developed, entirely represented by marine formations with a corresponding complex of faunal remains. In the east, the sections of the substage consist of formations of continental facies with freshwater shell fauna, bones of terrestrial vertebrates, and rich plant complexes. Between the two extreme types of sections there is a fairly wide (50-100 km) transition zone, within which marine layers alternate with continental red-colored deposits.
Urzhum deposits are widespread in the territory of the Republic of Tatarstan, composing many watershed and watershed spaces. In its western part, they are developed almost everywhere. The lower boundary of the stage is clearly marked here by the change in the section of gray-colored carbonate-argillaceous rocks with the remains of the marine fauna of the Kazan Age. In the eastern part, the Urzhum deposits compose the tops of the watersheds, the lower boundary of the stage is drawn along the sole of alluvial sandstones and conglomerates, which are eroded on lacustrine clayey-siltstone rocks containing a complex of pelecypods and ostracods characteristic of the Upper Kazanian substage. In the rest of the territories, the Urzhum deposits were exposed by boreholes under the overlying Upper Permian, Cretaceous, Jurassic, Neogene and Quaternary formations.
The deposits of the upper (Tatar) division (P 3) are represented by the Severodvinsk and Vyatka stages. In the most complete sections, their thickness reaches 150-200 m.
Sediments of the Severodvinian stage are relatively widespread in the western part of the Republic of Tatarstan, where they form the watersheds of the Volga and Sviyaga, Maly Cheremshan and Bolshaya Sulcha rivers and their tributaries. They also come to the surface in the cliffs of the right slope of the Volga valley and in the valleys of its right-bank tributaries. In the eastern part of the territory of the republic, Serodvinian deposits form the watersheds of the Sheshma and Zai, Zai and Ik, Dymka and Bolshoi Kandyz rivers. The lower boundary of the stage is clearly marked by the change of pale-colored carbonate-argillaceous rocks with pelecypods and otstracods of the Urzhum Age by bright-colored sandy-siltstone-argillaceous rocks of the Severodvinsk Age, containing the Late Permian faunistic complex.
Neogene deposits (N) within the territory of the Republic of Tatarstan are represented by formations of alluvial, less often alluvial-lacustrine and lacustrine-marsh origin, which formed in the late Neogene (Pliocene).
Formations of the Quaternary period (Q) are ubiquitous in the territory of the Republic of Tatarstan, absent only on the steep slopes of river valleys. Quaternary formations cover Permian, Mesozoic, Neogene deposits and are characterized by a significant diversity, complexity of structure, great diversity of facies and lithological composition, and variability of thicknesses. The formation of Quaternary formations was determined by the structure of the relief, the composition of the underlying rocks, the nature of the latest tectonic movements, as well as climatic features.
Modern (Holocene, Q IV) alluvial deposits compose floodplain terraces and channels of most of the rivers of the Republic of Tatarstan. Floodplain deposits are mainly represented by quartz sands, cross-layered with interlayers of sandy loams, loams; interlayers of coarser sands and pebbles with pebbles of local rocks appear in the lower horizons. The total thickness of the Holocene (modern) alluvium is 25-30 m. organic matter. The thickness of these deposits is from 1-2 to 10-12 m. Modern biogenic (marsh) deposits are represented by peat, clays, loams up to 1-2 m thick. Man-made deposits associated with human activities are distributed mainly in cities and other settlements , in places of mining, along the lines of railways and highways. (Geological monuments of nature of the Republic of Tatarstan, 2007)
Bedrock layers generally lie quietly, forming 4 brachyanticlinal folds with an amplitude of about 40-60 m, related to the southern tip of the Vyatka swell (Verkhneuslonskaya, Kamskoustinskaya, Kazanskaya and Kinderskaya).
The upper terraces are separated from the lower ones by a well-defined ledge 29-50 m high. They have a complex geological and geomorphological structure. Directly near the ledge there is a Middle Pleistocene terrace, the absolute height of which varies from 80 to 140 m (30-90 m above the level of the reservoir)
The alluvium composing the high Middle Pleistocene terrace has a two-membered structure. The lower suite (35-40 m) is represented by “normal” (humid) alluvium with a distinct division into channel and floodplain facies. The upper suite is periglacial alluvium, represented mainly by sands. It can be assumed that the anomalously high sections of this terrace (120-140m) are partly formed by blown sands. The Early Pleistocene terrace is a basement one - it is composed of “normal” alluvium, the base of which lies 10-30 m above the low water of the old Volga.
The most ancient element of the valley of the entire Volga is a deep (up to minus 100-200 m) erosion incision made by alluvial and lacustrine deposits of the Akchagyl stage of the Upper Pliocene. These deposits also go beyond the incision and in some places form a late Pliocene accumulative plain, strongly reworked by erosion in the Quaternary. In some places they underlie the alluvium of the Middle Pleistocene terrace or form the basement of the Early Pleistocene alluvium. Less distinctly under the alluvium of the Holocene, late and middle Pleistocene, the alluvium of a less deep (up to minus 10-20 m) erosion cut, called G.I. Goretsky Vedensky, can be traced. It is of Early Pleistocene age and is younger than the alluvium of the Early Pleistocene basement terrace.
The wide distribution of carbonate and sulphate rocks of the Lower Permian and the Kazanian stage led to the intensive development of karst processes. In the Prikazansky region, karst is developed everywhere, but the intensity of its development is not the same and is controlled by relief, tectonics, and rock composition.
Karst phenomena are confined primarily to river valleys, because the watershed spaces are composed of non-karst rocks of the Tatar stage. The karsting sequence of the Kazanian stage is most highly elevated in the vaults of the brachyanticlines, which creates favorable conditions for karsting.
Basically, karst is associated with vertical and horizontal circulation of groundwater in the thickness of the Upper Kazanian substage, which lies above the level of rivers, i.e. with processes in the zone of active karst. These are non-pressure descending type bicarbonate-calcium waters.
The historical and administrative center of Kazan is located on the left bank of the Kazanka. This is primarily the Kremlin, built on a cape-like ledge of a high Middle Pleistocene terrace. A ledge of high terraces divides the city into two parts - upper and lower. A similar division is more clearly visible in the old left-bank part of the city.
Middle Permian (Biarmian) deposits (P 2) occupy more than 2/3 of the territory of the Republic of Tatarstan under Quaternary formations. The deposits form the surface of the pre-Quaternary relief; in the southwest they are overlain by Mesozoic rocks, and in the valleys of large rivers - by Neogene formations. Absent only in some parts of paleorivers. The middle section includes deposits of the Kazan and Urzhum stages. Their total thickness reaches 300 m. (Scientific guide to Kazan and its environs, 1990)
Kabirova Kamila
Chugunova Valeria
Relief
The Prikazansky district is located in the east of the Russian platform. (Scientific guide to Kazan and its environs, 1990) Kazan, the oldest city in the Middle Volga region, is located on the left bank of the Volga in the lower reaches of its small, 112 km long tributary of the Kazanka. In this section, the Volga, crossing the southern part of the Vyatka swell, is cut into limestones and dolomites of the Kazanian stage of the Upper Permian. Rounding the Verkhneuslonskaya brachianticline, the Volga abruptly changes the direction of the current from east to south. The width of its ancient valley decreases to 10 km, but a pronounced asymmetry of the slope remains. The steep and high right slope is composed of bedrock, the left one is formed by a series of Quaternary alluvial terraces, on which the city lies.
After the construction of the Kuibyshev hydroelectric complex in 1957, a reservoir was formed that flooded the floodplain near Kazan and partially the first floodplain terraces. The lower reaches of the Kazanka turned into a bay. The Volga came close to the walls of the Kremlin. Small areas of the first terrace above the floodplain and the high floodplain that are not flooded by the reservoir are protected by a dam. The width of the reservoir near Kazan varies from 3 to 7 km.
The main part of the city is located on two terraced levels, separated by a well-marked ledge 20-25 m high, dividing the city into upper and lower parts. This division has not only geomorphological significance, but also socio-economic. The upper part of the city is in all respects more comfortable and environmentally friendly. The lower part was inhabited by ordinary working people.
The lower part of the city is located on the second Late Pleistocene terrace above the floodplain, which is more early work called first. Its surface lies at a height of 15-18 m above the low water level of the old Volga and 4-7 m above the level of the reservoir. In the rear part of the terrace, swampy depressions were traced, most of which were filled up.
In the southern part of the city, near the foot of the ledge of high terraces, there is a system of interconnected Kaban lakes: Lower (or Near), Middle (or Far) and Upper. Their areas are respectively 0.6; 1.2; 0.25 km2. These are Late Pleistocene oxbow lakes of the Volga, heavily complicated by karst. The deepest is the Middle Boar - about 25m.
The upper part of the city is located on high Middle and Early Pleistocene terraces, morphologically almost indistinguishable. Their absolute heights fluctuate within 80-120 m, relative under the low water of the Volga - 40-80 m, above the level of the reservoir - 30-70 m.
Before filling the Kuibyshev reservoir in the floodplain of the Volga, adjacent to the city from the west, large areas were washed, the surface of which merged with the surface of the second terrace above the floodplain. Port facilities, a stadium and other buildings were placed on these sites. To protect them from flooding, embankment dams were built.
The spread of the ledge separating the upper and lower terraces largely determined the direction of the streets and the general layout of the historical part of the city. Along the ledge on the lower terrace, Sverdlov, Pavlyukhin, Orenburg tract streets also stretch.
The ledge and the surface of the upper terraces are cut by deep gullies and young ravines, longer (up to 3 km) on the slopes to the Volga and shorter (up to 1 km) on the slopes to the Kazanka and its right tributary the Knox. The formation of the vast majority of ravines is due to human activity - the reduction of forests, plowing of land, the extraction of pottery and brick loam, the laying of roads and streets descending the ledge. In recent years, after the construction and streamlining of storm sewers, the growth of ravines has stopped. Many short ravines in the central part of the city have been filled in. (Middle Voga, 1991)
Ravines also develop more intensively on the right bank, where their average density is 0.5 - 1.0 km/km 2 . On the left bank, ravines dissect the ledge of high terraces and the slopes of the valleys of small rivers, their average density does not exceed 0.1 km / km 2. The development of ravine erosion is due to human activity - deforestation, plowing of land - which began in the time of the Bulgar state, but proceeded especially intensively in the 19th century. In forested areas, ravines sometimes appear only on slopes along roads after heavy rains. The densest ravine network develops in loams, the less dense one develops in the clay-marl stratum of the Tatarian stage. Such are the differences in the rate of growth of ravines. Along with primary ravines, secondary ravines cut into the bottoms of Pleistocene gullies are widespread. There are especially many such ravines on the right slope of the Volga valley. Their formation was facilitated by the intensive erosion of the right slope by the Volga, due to which many beams became "hanging". Stationary observations in various regions of the Middle Volga region show that 2/3 of the growth of ravines in length occurs due to the runoff of melt water. (Scientific guide, 1990)
On the right bank of the Kazanka, a near-terrass depression of a low floodplain terrace was occupied by a peat bog (Kizichesky swamp). Currently, intensive residential development is being carried out here on the poured soils.
Gilmanova Aigul
Climate
Republic of Tatarstan
The territory of the Republic of Tatarstan is characterized by a moderately continental type of climate in the middle latitudes with warm summers and moderately cold winters.
Climate formation is significantly affected by the predominance of western air transport in the troposphere in the lower stratosphere. Air masses moving from the Atlantic Ocean soften and moisten the local climate, despite the considerable distance from the ocean. At the same time, air masses also come here from other, including sharply continental regions, such as Siberia and Kazakhstan. (Scientific guide to Kazan and surroundings, 1990).
Kazan
Due to the fairly frequent entry of air masses from the west, Kazan has a rather high relative humidity: in the cold half-year (November-March) about 80-85%, in the warm half-year (April-October) about 60-80%, the average annual 76%. The annual amount of precipitation is about 500 mm, in the warm period about 340 mm falls, in the cold about 160 mm. In the annual course, the maximum amount of precipitation occurs in the summer months. February and March are the least irrigated in terms of precipitation. Prevailing winds: south, west, southeast and southwest. In summer, the frequency of northern and northwestern winds increases.
Despite the great distance from the oceans and seas, the climate of Kazan is characterized by a high frequency of significant and continuous cloudiness. From September to May inclusive, the frequency of cloudy sky conditions is over 50%, and in the autumn-winter months it is over 70%. In autumn and winter, cloud systems are more often observed, extending into the hundreds and thousands. These are altostratus, nimbostratus and stratus clouds, usually covering the entire sky. In summer, on the contrary, altocumulus, cumulus, cumulonimbus and stratocumulus clouds have a greater frequency.
Accumulations of products of condensation and sublimation of water vapor in the surface layer of the atmosphere impair visibility. Depending on the degree of turbidity, fog or haze occurs. In the cold season, with heavy snowfall combined with strong winds throughout the territory of the Republic, in particular in the city of Kazan and its environs, blizzards are observed, which are classified as dangerous phenomena. Heavy rain, hail, thunderstorms are also included here.
The main features of the climate of Kazan and its environs in terms of climatic indicators are as follows: the annual value of the total radiation is about 3500 mJ / m 2, its maximum in June is about 610 mJ / m 2, the minimum in December is about 30 mJ / m 2, mean annual temperature about +3.7◦С, the warmest month is July with an average monthly air temperature of about +20◦С, the coldest month is January with an average monthly temperature of about -13◦С.
The absolute maximum air temperature in July reached 38◦С, in January -4◦С, on the contrary, the absolute minimum dropped in January to -47◦С, in July to -3◦С. According to the absolute minimum air temperature in Kazan, there are only two months without negative temperatures - July and August, and according to the absolute minimum temperature on the soil surface, only one - July. Thus, fluctuations in air temperature and soil surface in Kazan and its environs are very large.
The annual course of temperature parameters is simple, solar-conditioned. The maximum radiation balance and turbulent heat transfer falls in June, the maximum air temperature in July (July 20-25). On average, about 13 days this month have an average daily temperature in the range of 20-25◦С, about 12 days with an average daily temperature of 15-20◦С. There are about four hot days with an average daily temperature of 25-30◦С.
In winter, in January, on average, there are about 14 days with an average daily temperature ranging from -5 to -15◦С. There are six days with an average daily temperature from -15 to -20◦С, five to six days from -20 to -30◦С. Hard frosts with an average daily temperature below -30◦С do not occur annually.
Climatic characteristics of the seasons.
The calendar seasons - spring, summer, autumn, winter - do not coincide with the climatic and phenological seasons in duration and dates of beginning and end.
The beginning of spring is conditionally taken as the date of a stable transition of the average daily air temperature through 0ºС and the date of destruction of the stable snow cover. For the Kazan region, these are March 31 - April 3 and April 9-11, respectively. The date of transition of the average daily air temperature through 15 ºС, observed on May 26-30, is taken as the end of spring.
Spring is characterized by a rapid increase in temperature due to an increase in the influx of solar radiation and a decrease in cloudiness. In spring, the conditions of atmospheric circulation change: the western transport from the Atlantic Ocean, which is especially intense in winter, weakens in spring, and the meridional circulation intensifies, which is associated with intrusions of warm air masses from the south and intrusions of cold air masses from the Arctic. Sharp drops in temperature, accompanied by precipitation, occur during the rapid movement of Arctic air masses to the south in the rear of cyclones.
In March, in the last winter month, the average monthly air temperature in Kazan is 4.7-5.8 ºС, in April 4.2-5.1 ºС, the average May temperature is 12.6-13.3 ºС.
Early spring is characterized by late frosts. The amount of precipitation is increasing. Precipitation falls mainly in the form of rain; snowfalls are observed only in the first half of April. In April and May, the number of hours of sunshine noticeably increases due to an increase in the length of the day and a decrease in cloudiness. Days with partly cloudy prevail. The wind regime changes due to the seasonal restructuring of the air pressure field.
In late May - early June, warm, often hot weather sets in in the Kazan region. The end of spring - the beginning of summer, conventionally taken as the date of the transition of the average daily air temperature through 15 ºС, for the end of summer - the transition of the average daily temperature through 10 ºС downwards, which is celebrated in Kazan on September 19-22.
During the summer period, various types of weather are observed: warm and humid, hot with short-term heavy rainfall, climatically hot dry and windy weather, cool rainy and cool dry.
The climatic and weather conditions of summer in the Kazan region are formed mainly under the influence of the transformation of relatively cold air masses entering here. The average number of hours of sunshine in four summer months outside the city is 1003. Temperature regime summer in Kazan is quite homogeneous. On the outskirts of the city, temperatures are approximately 1ºC lower. In summer, due to the increase in the absolute moisture content of air masses and the frequency of cyclonic processes, the moisture circulation increases. Therefore, heavy precipitation falls during the summer months. During the entire summer season, a semi-clear sky condition prevails. The prevailing wind directions in summer are western, northwestern and northeastern. The frequency of southwestern and northeastern winds is noticeably less.
Unfavorable weather phenomena in the summer season for the climate of Tatarstan and the Kazan region are showers, thunderstorms, hail, dry winds, and droughts. The onset of autumn in the Kazan region is characterized by a relatively sharp decrease in air and soil temperatures, an increase in the number of cloudy and rainy days, increased winds, and an increase in relative air humidity. Specified conditions weather usually coincide with the end of the frost-free period and the transition of the average daily air temperature through 10 ºС downwards. In Kazan given transition falls on September 19-22. From August to September, the amount of precipitation decreases by approximately 10 mm. The partial pressure of water vapor decreases by an average of 4-5 hPa. In autumn, cloudiness increases, the number of cloudy days increases. The frequency of winds of the southwestern and southern directions increases, the frequency of winds of the northern half of the horizon decreases. Autumn is characterized by an increased frequency of fogs, which is extremely unfavorable for the operation of various modes of transport.
With the transition of the average daily air temperature through 0ºС downwards (30.10-2.11) and the appearance of snow cover (27.10-1.11), winter sets in. But since for some time the air temperature either rises or falls, and as a result of which the snow cover melts during this period, which lasts for three weeks, it is called pre-winter. Winter is established from the moment when the air temperature passes through -5ºС with the formation of a stable snow cover. Winter with pre-winter lasts five months - from November to March. The winter period is characterized by higher wind speeds, which cause snow, low and general blizzards. There are few days with high rainfall in winter. Precipitation, which usually falls in solid form, forms a snow cover. In protected areas (forests, city parks, buildings), the depth of snow cover is noticeably greater. Blizzards are unfavorable weather phenomena. Along with strong winds, hard frosts, ice, hoarfrost, fogs should be included here. In Kazan and its environs, there are on average about 10 days with ice and more than 20 days with frost a year. An unfavorable manifestation of the climate in the winter period can be attributed to relatively long periods of time with very low temperatures. Strong prolonged frosts were observed in January and February 2006.
The relief, hydrography, vegetation, soil and snow cover cause territorial diversity in the distribution of individual climatic indicators. However, these climatic differences fit within the framework of a larger zone, whose climate features are determined by radiation and circulation factors. The influence of relief on a number of climate indicators can be traced quite clearly. And in this regard, of paramount importance are such aspects of the relief as its absolute height, the prevailing slopes, their orientation in relation to the prevailing air currents, as well as dissection, the impact of which is manifested primarily in the creation of microclimatic differences. (The climate of Kazan and its changes in the modern period, 2007)
Geologically, the territory of Russia consists of a complex mosaic of blocks formed by various rocks that arose over 3.5–4 billion years.
There are large lithospheric plates 100–200 km thick, which experience slow horizontal movements at a rate of about 1 cm/year due to convection (substance flow) in the deep layers of the Earth's mantle. When moving apart, deep cracks are formed - rifts, and later appear during spreading. The heavy oceanic lithosphere, when changing the movement of plates, sinks under the continental plates in subduction zones, along which oceanic trenches and island volcanic arcs are formed, or at the edges of the continents. When continental plates collide, a collision occurs with the formation of folded belts. In the collision of oceanic and continental plates, an important role is played by accretion - the attachment of alien blocks of the crust, which can be brought thousands of kilometers away during the sinking and absorption of the oceanic in the process of subduction.
At present, most of the territory of Russia is located within the Eurasian lithospheric plate. Only the folded region of the Caucasus is part of the Alpine-Himalayan collision belt. In the extreme east is an oceanic plate. It plunges under the Eurasian Plate along the subduction zone expressed by the Kuril-Kamchatka deep-water trench and the volcanic arcs of the Kuril Islands and Kamchatka. Within the Eurasian Plate, splits along the Baikal and Momsky rifts are manifested, expressed by the depression of the lake. Baikal and large fault zones in . The boundaries of the plates are highlighted with increased .
In the geological past, as a result of displacement, the East European and Siberian platforms were formed. The East European Platform includes a shield, where Precambrian metamorphic and igneous rocks are developed on the surface, and the Russian Plate, where the crystalline basement is covered by a sedimentary rock cover. Accordingly, within the Siberian platforms, the Aldan and Anabar shields are distinguished, formed in the Early Precambrian, as well as vast spaces covered by sedimentary and volcanic rocks, which are considered as the Central Siberian Plate.
The Quaternary system (quaternary) is manifested almost everywhere, but the thickness of the deposits rarely exceeds a few tens of meters. A significant role is played by boulder loams, traces of ancient ice sheets.
Intrusive formations of various ages and compositions are widespread on shields and in folded belts. The most ancient Archean complexes on the shields are represented by orthoamphibolites and other ultrabasic and basic rocks. Younger Archean granitoids compose complexes with an age of 3.2–2.6 Ga. Large massifs form alkaline granites and syenites of the Proterozoic with a radiological age of 2.6–1.9 Ga. In the marginal part of the Baltic Shield, rapakivi granites with an age of 1.7–1.6 Ga are common. Intrusions of alkaline syenites of Carboniferous age - 290 Ma are distinguished in the northern part of the shield. In the Tunguska syneclise, along with volcanics, bedded intrusions - dolerite sills - are widespread. In the volcanic belts of the Far East, large intrusions of granitoids are developed, which together with volcanic rocks form volcano-plutonic complexes.
In recent decades, extensive work has been carried out to study the adjacent water areas, including offshore geophysical work and well drilling. They were sent to search for hydrocarbon deposits on the shelf, which led to the discovery of a number of unique fields. As a result, it became possible to show the structure of water areas on a geological map, although in the eastern seas of the Russian sector of the Arctic, the map remains largely schematic. Due to insufficient study, it was necessary to show undivided deposits in some places. The marine basins are filled with thick Mesozoic and Cenozoic sedimentary rocks with separate outcrops of Paleozoic and granitoids of different ages on uplifts.
In the basin, on the Precambrian basement, a cover of sedimentary rocks is developed with outcrops of the Triassic and Jurassic along its sides, and in the center - with a wide distribution of the Upper Cretaceous - Paleocene. Under the bottom, a continuation of the West Siberian plate with a Cretaceous and Paleogene cover is traced. In the eastern sector of the Arctic, significant parts of the water area are covered by Neogene sediments. Volcanic rocks are developed in the Gakkel mid-ocean ridge and near the De Long Islands. Near the islands, continuations of outcrops of Mesozoic and Paleozoic rocks can be traced.
In Okhotsk, and from under a continuous cover of Neogene deposits, older sedimentary rocks, volcanics and granitoids, forming relics of microcontinents, protrude in places.
