Location: between the northeastern shores of Asia and the northwestern shores of North America.
Area: 595 thousand sq. km.
Average depth: 71 m.
Greatest depth: 1,256 m.
Bottom topography: predominantly flat, the Chukchi Sea is located within the shelf, which is crossed by the Herald and Barrow canyons.
Salinity: 24-32 ‰.
Current: cold Chukotka, warm current coming from the Bering Strait.
Inhabitants: char, cod, walrus, seal, seal, whales, grayling, navaga,
Additional information: the rivers Amguema, Kobuk, Noatak flow into the Chukchi Sea; Most of the year the sea is covered with ice.
Location: between the Scandinavian Peninsula, the islands of Iceland and Jan Mayen.
Area: 1.4 million sq. km.
Average depth: 1,700 m.
Greatest depth: 3,970 m.
Bottom topography: The Norwegian Sea is separated from the Atlantic Ocean by an underwater ridge.
Salinity: 35 ‰.
Current: warm Norwegian.
Inhabitants: cod, herring.
Additional information: thanks to the warm Norwegian Current, which is a side branch of the Gulf Stream, the Norwegian Sea does not freeze.
Location: between the Taimyr peninsulas, the Severnaya Zemlya islands and the New Siberian Islands.
Area: 662 thousand sq. km.
Average depth: 50 m.
Greatest depth: 3,385 m.
Bottom topography: the Laptev Sea is located within the continental shallows, which in the north abruptly ends to the ocean floor.
Average water temperatures: below 0ºС all year round.
Salinity: 10-34‰.
Inhabitants: walrus, sea hare, seal, char, muksun, nelma, taimen, perch, sturgeon, sterlet.
Additional information: the sea is named after the Russian explorers brothers D.Ya. and H.P. Laptev; The Laptev Sea is one of the harshest Arctic seas, it is covered with ice almost all year round, the polar day and night last for 5 months.
Location: off the coast of Asia, between the archipelagos of Franz Josef Land, Novaya Zemlya and Severnaya Zemlya.
Area: 883 thousand sq. km.
Average depth: 65 m.
Greatest depth: about 620 m.
Bottom topography: mostly flat, with many islands.
Average water temperatures: about 0ºС all year round (ice lasts 8-9 months).
Salinity: 12-33 ‰.
Inhabitants: salmon, sturgeon, whitefish, cod, char, flounder and others.
Additional information: most of the year the sea is covered with drifting ice; The Ob and Yenisei rivers flow into the Kara Sea.
Location: between the islands of Greenland, Iceland, Spitsbergen, Jan Mayen.
Area: 1,195 thousand sq. km.
Average depth: 1,641 m.
Greatest depth: 5,527 m.
Bottom topography: a huge basin, bounded by the underwater ridges of Mon and Knipovich, the Greenland-Iceland threshold.
Salinity: 32-34‰.
Currents: cold East Greenland, warm Spitsbergen.
Inhabitants: several species of whales, dolphins, harp seals, cod, herring, sea bass, black halibut.
Additional information: Floating ice is common in the Greenland Sea.
Location: between the New Siberian Islands and the Wrangel Islands.
Area: 913 thousand sq. km.
Average depth: 54 m.
Greatest depth: 915 m.
Bottom topography: mostly flat, with small trenches in the southern part.
Salinity: 10-30 ‰.
The currents form a cyclonic circulation; in the north the currents go from east to west, in the south - from west to east.
Inhabitants: muksun, char, nelma, perch, whitefish, navaga, flounder, walruses, seals.
Additional information: the rivers Indirka, Alazeya, Kolyma, and Bolshaya Chukochia flow into the East Siberian Sea.
Location: off the coast of North America, between Cape Barrow and the western shores of the Canadian Arctic Archipelago.
Area: 476 thousand sq. km.
Average depth: 1,004 m.
Greatest depth: 4,683 m.
Relief: predominantly flat, the sea is located on the continental shallows.
Salinity: 28-32‰.
The currents form a cyclonic gyre.
Additional information: the sea is named after the English admiral F. Beaufort; The sea is covered with ice all year round.
Location: northern shores of Europe.
Area: 90 thousand sq. km.
Average depth: 100 m.
Maximum depth: 330 m.
Bottom topography: highly dissected; Kandalaksha depression, numerous hills, sand ridges,
Average water temperatures: below 1ºС in February (water freezes for 6 months or more), 6-15ºС in August.
Salinity: 24-30 ‰.
Currents: weak, speed less than 1 km/h.
Inhabitants: about 50 species of fish (herring, cod, smelt, navaga, flounder, brown trout, salmon and others), harp seals, ringed seals, beluga whales.
Additional information: the rivers Northern Dvina, Onega, Mezen and others flow into the White Sea.
In terms of the number of islands and archipelagos, the Arctic Ocean ranks second after the Pacific Ocean. This ocean contains such large islands and archipelagos as Greenland, Franz Josef Land, Novaya Zemlya, Severnaya Zemlya, Wrangel Island, the New Siberian Islands, and the Canadian Arctic Archipelago.
The Arctic Ocean is divided into three large water areas:
- Arctic Basin; The center of the ocean, its deepest section reaches 4 km.
- North European Basin; It includes the Greenland Sea, the Norwegian Sea, the Barents Sea and the White Sea.
- Mainland Shoal; Includes the seas that wash the continents: the Kara Sea, the Laptev Sea, the East Siberian Sea, the Chukchi Sea, the Beaufort Sea and the Baffin Sea. These seas account for more than 1/3 of the total ocean area.
It is quite simple to imagine the topography of the ocean floor in a simplified manner. The continental shelf (maximum width 1300 km) ends with a sharp decrease in depth to 2-3 km, forming a kind of step that surrounds the central deep-sea part of the ocean.
This natural bowl is more than 4 km deep in the center. dotted with many underwater ridges. In the 50s of the 20th century, bottom echolocation showed that the Arctic Ocean is dissected by three trans-oceanic ridges: Mendeleev, Lomonosov and Gakkel.
The waters of the Arctic Ocean are fresher than other oceans. This is explained by the fact that large rivers of Siberia flow into it, thereby desalinating it.
Climate
From January to April, there is an area of high pressure in the center of the ocean, better known as the Arctic High. In the summer months, on the contrary, lower pressure prevails in the Arctic basin. The pressure difference constantly brings cyclones, precipitation and winds of up to 20 m/s to the Arctic Ocean from the Atlantic. On their way to the center of the ocean, a huge number of cyclones pass through the North European basin, causing sudden changes in weather, heavy rainfall and fog.
The air temperature ranges from -20 to -40 degrees. In winter, when 9/10 of the ocean area is covered with drifting ice, the water temperature does not rise above 0 degrees Celsius, dropping to -4. The thickness of the drifting ice floes is 4-5 meters. Icebergs are constantly found in the seas surrounding Greenland (Baffin Sea and Greenland Sea). By the end of winter, the ice area reaches 11 million square meters. km. Only the Norwegian, Barents and Greenland Seas remain ice-free. The warm waters of the North Atlantic Current flow into these seas.
In the Arctic basin, ice islands drift, the ice thickness of which is 30-35 meters. The “lifetime” of such islands exceeds 6 years and they are often used to operate drifting stations.
By the way, Russia is the first and only country that uses drifting polar stations. Such a station consists of several buildings where expedition members live and a set of necessary equipment is located. The first such station appeared in 1937 and was called “North Pole”. The scientist who proposed this method of exploring the Arctic is Vladimir Wiese.
Fauna of the Arctic Ocean
Until the 20th century, the Arctic Ocean was a “dead zone”; research was not carried out there due to very harsh conditions. Therefore, knowledge about the animal world is very scarce.
The number of species decreases as you approach the center of the ocean in the Arctic basin, but phytoplankton develops everywhere, including under drifting ice. This is where feeding fields for various minke whales are located.
The colder areas of the Arctic Ocean are favored by animals that can easily withstand harsh climatic conditions: narwhal, beluga whale, polar bear, walrus, seal.
In the more favorable waters of the North European basin, the fauna is more diverse due to fish: herring, cod, sea bass. The habitat of the now almost exterminated bowhead whale is also located there.
The fauna of the ocean is gigantic. Giant mussels, giant cyanide jellyfish, and sea spider live here. The slow progression of life processes endowed the inhabitants of the Arctic Ocean with longevity. Recall that the bowhead whale is the longest-living vertebrate on Earth.
The flora of the Arctic Ocean is unusually sparse, because... drifting ice does not allow the sun's rays to pass through. With the exception of the Barents and White Seas, the organic world is represented by unpretentious algae, which predominate in the continental shallows. But in terms of the amount of phytoplankton, the seas of the Arctic Ocean can easily compete with more southern seas. There are more than 200 species of phytoplakton in the ocean, almost half of them are diatoms. Some of them have adapted to live on the very surface of the ice and during the flowering period they cover it with a brown-yellow film, which, by absorbing more light, causes the ice to melt faster.
The smallest representative of the earth's oceans is the Arctic Ocean. It covers the territory of the North Pole and is bordered on different sides by continents. The average depth of the Arctic Ocean is 1225 meters. It is the shallowest ocean of all.
Position
A reservoir of cold water and ice that does not extend beyond the Arctic Circle washes the shores of the continents of the hemisphere and Greenland from the north. The average depth of the Arctic Ocean is quite shallow, but its waters are the coldest. Surface area - 14,750,000 square kilometers, volume - 18,070,000 cubic kilometers. The average depth of the Arctic Ocean in meters is 1225, while the deepest point is located 5527 meters below the surface. This point belongs to the pool
Bottom relief
Scientists learned quite a long time ago about the average and greatest depth of the Arctic Ocean, but almost nothing was known about the bottom topography until the war of 1939-1945. Over the past decades, a wide variety of information has been collected through submarine and icebreaker expeditions. In the structure of the bottom there is a central basin, around which the marginal seas are located.
Almost half of the ocean area is occupied by the shelf. In Russian territory it stretches up to 1300 km from the earth. Near the European coasts, the shelf is much deeper and highly indented. There are suggestions that this happened under the influence of Pleistocene glaciers. The center is an oval basin of the greatest depth, which is divided by the Lomonosov Ridge, discovered and partially studied in the post-war years. Between the Eurasian shelf and the indicated ridge there is a basin, the depth of which ranges from 4 to 6 km. On the other side of the ridge there is a second basin, the depth of which is 3400 m.
The Arctic Ocean is connected to the Pacific Ocean by the Bering Strait; the border with the Atlantic runs through. The structure of the bottom is due to the widespread development of the shelf and underwater continental region. This explains the extremely low average depth of the Arctic Ocean - more than 40% of the total area is no deeper than 200 m. The rest is occupied by the shelf.
Natural conditions
The climate of the ocean is determined by its position. The severity of the climate is aggravated by the gigantic amount of ice - in the central part of the basin the thick layer never melts.
Cyclones develop over the Arctic all year round. The anticyclone is active mainly in winter, while in summer it moves to the junction with the Pacific Ocean. Cyclones are rampant in the area in summer. Thanks to such changes, the variation of atmospheric pressure over the polar ice is clearly visible. Winter lasts from November to April, summer - from June to August. In addition to cyclones originating over the ocean, cyclones that come from outside often roam here.
The wind regime at the pole is heterogeneous, but speeds above 15 m/s are practically never encountered. Winds over the Arctic Ocean predominantly have a speed of 3-7 m/s.
The average temperature in winter is from +4 to -40, in summer - from 0 to +10 degrees Celsius.
Low cloudiness has a certain periodicity throughout the year. In summer, the probability of low clouds reaching 90-95%, in winter - 40-50%. Clear skies are more typical for the cold season. In summer there are frequent fogs, sometimes they do not rise for up to a week.
Precipitation typical for this area is snow. It practically never rains, and if it does, it usually comes with snow. Every year, 80-250 mm falls in the Arctic basin, and a little more in the northern European region. The snow thickness is thin and unevenly distributed. In the warm months, the snow actively melts, sometimes disappearing completely.
In the central region, the climate is milder than on the outskirts (near the coasts of the Asian part of Eurasia and North America). The Atlantic Ocean penetrates the water area and forms the atmosphere over the entire ocean area.
Flora and fauna
The average depth of the Arctic Ocean is sufficient for the appearance of a large number of different organisms in its thickness. In the Atlantic part you can find a varied number of fish, such as cod, sea bass, herring, haddock, and pollock. The ocean is home to whales, mainly bowhead and minke whales.
Most of the Arctic is treeless, although spruce, pine and even birch trees grow in northern Russia and the Scandinavian Peninsula. Tundra vegetation is represented by cereals, lichens, several varieties of birch, sedge, and dwarf willows. Summer is short, but in winter there is a huge flow of solar radiation, stimulating the active growth and development of flora. The soil can warm up in the upper layers by up to 20 degrees, increasing the temperature of the lower air layers.
A feature of the Arctic fauna is the limited number of species with an abundance of representatives of each of them. The Arctic is home to polar bears, arctic foxes, snowy owls, hares, crows, tundra partridges and lemmings. Herds of walruses, narwhals, seals and beluga whales splash in the seas.
Not only the average and maximum depth of the Arctic Ocean determines the number of animals and plants, but towards the center of the ocean the density and abundance of species inhabiting the territory decreases.
The Arctic Ocean is the smallest ocean on Earth by area, located entirely in the northern hemisphere, between Eurasia and North America.
The ocean area is 14.75 million km², the volume of water is 18.07 million km³. The average depth is 1225 m, the greatest depth is 5527 m in the Greenland Sea. Most of the bottom relief of the Arctic Ocean is occupied by the shelf (more than 45% of the ocean floor) and the underwater margins of continents (up to 70% of the bottom area). The Arctic Ocean is usually divided into 3 vast water areas: the Arctic Basin, the North European Basin and the Canadian Basin. Due to the polar geographical position, the ice cover in the central part of the ocean remains throughout the year, although it is in a mobile state.
The territories of Denmark (Greenland), Iceland, Canada, Norway, Russia and the United States of America adjoin the Arctic Ocean. The legal status of the ocean is not directly regulated at the international level. It is fragmentarily determined by the national legislation of the Arctic countries and international legal agreements. During much of the year, the Arctic Ocean is used for shipping by Russia via the Northern Sea Route and the United States and Canada via the Northwest Passage.
The ocean was identified as an independent ocean by the geographer Varenius in 1650 under the name Hyperborean Ocean - “Ocean in the extreme north” (ancient Greek Βορέας - the mythical god of the north wind or in other words North, ancient Greek ὑπερ - - prefix, indicating an excess of something). Foreign sources of that time also used the names: Oceanus Septentrionalis - “Northern Ocean” (Latin Septentrio - north), Oceanus Scythicus - “Scythian Ocean” (Latin Scythae - Scythians), Oceanes Tartaricus - “Tartar Ocean”, Μare Glaciale - “Arctic Sea” (lat. Glacies - ice). On Russian maps of the 17th - 18th centuries the names are used: Sea Ocean, Sea Ocean Arctic, Arctic Sea, Northern Ocean, Northern or Arctic Sea, Arctic Ocean, Northern Polar Sea, and the Russian navigator Admiral F. P. Litke in the 20s of the XIX century centuries called it the Arctic Ocean. In other countries the English name is widely used. Arctic Ocean - "Arctic Ocean", which was given to the ocean by the London Geographical Society in 1845.
General information
The Arctic Ocean is located between Eurasia and North America. The border with the Atlantic Ocean runs along the eastern entrance of the Hudson Strait, then through the Davis Strait and along the coast of Greenland to Cape Brewster, through the Denmark Strait to Cape Reydinupur on the island of Iceland, along its coast to Cape Gerpir, then to the Faroe Islands, then to the Shetland Islands and along 61° north latitude to the coast of the Scandinavian Peninsula. In the terminology of the International Hydrographic Organization, the boundary of the Arctic Ocean runs from Greenland through Iceland, then to Spitsbergen, then through Bear Island and to the coast of Norway, which includes the Norwegian Sea in the Atlantic Ocean. The border with the Pacific Ocean is a line in the Bering Strait from Cape Dezhnev to Cape Prince of Wales. In the terminology of the International Hydrographic Organization, the border runs along the Arctic Circle between Alaska and Siberia, which separates the Chukchi and Bering seas. However, some oceanographers classify the Bering Sea as the Arctic Ocean.
The Arctic Ocean is the smallest of the oceans. Depending on the method of defining the boundaries of the ocean, its area ranges from 14.056 to 15.558 million km², that is, about 4% of the total area of the World Ocean. The volume of water is 18.07 million km³. Some oceanographers view it as an inland sea of the Atlantic Ocean. The Arctic Ocean is the shallowest of all oceans, with an average depth of 1225 m (the greatest depth is 5527 m in the Greenland Sea). The length of the coastline is 45,389 km.
Seas
The area of the seas, bays and straits of the Arctic Ocean is 10.28 million km² (70% of the total ocean area), the volume is 6.63 million km³ (37%).
Marginal seas (from west to east): Barents Sea, Kara Sea, Laptev Sea, East Siberian Sea, Chukchi Sea, Beaufort Sea, Lincoln Sea, Greenland Sea, Norwegian Sea. Inland seas: White Sea, Baffin Sea. The largest bay is Hudson Bay.
Islands
In terms of the number of islands, the Arctic Ocean ranks second after the Pacific Ocean. In the ocean is the largest island on Earth, Greenland (2175.6 thousand km²) and the second largest archipelago: the Canadian Arctic Archipelago (1372.6 thousand km², including the largest islands: Baffin Island, Ellesmere, Victoria, Banks, Devon, Melville , Axel-Heiberg, Southampton, Prince of Wales, Somerset, Prince Patrick, Bathurst, King William, Bylot, Ellef-Ringnes). The largest islands and archipelagos: Novaya Zemlya (North and South Islands), Spitsbergen (islands: Western Spitsbergen, North-Eastern Land), New Siberian Islands (Kotelny Island), Severnaya Zemlya (islands: October Revolution, Bolshevik, Komsomolets), Franz Land Joseph, Kong Oscar Islands, Wrangel Island, Kolguev Island, Milna Land, Vaygach Island.
Shores
The land relief along the North American ocean coasts is predominantly hilly with low denudation plains and low mountains. Accumulative plains with frozen landforms are typical for the northwestern trough. The large islands of the northern Canadian archipelago, as well as the northern part of Baffin Island, have a mountainous glacial topography with ice sheets and rocky peaks and ridges protruding above their surface, which form the Arctic Cordillera. The maximum height on Ellesmere Earth reaches 2616 m (Barbot Peak). 80% of Greenland's area is occupied by an extensive ice sheet up to 3000 m thick, rising to an elevation of 3231 m. The coastal strip of land (ranging from 5 to 120 km wide) along almost the entire coastline is free of ice and is characterized by mountainous terrain with trough valleys and glacial cirques and Carlings. In many places, this strip of land is cut through by valleys of outlet glaciers, along which glacial discharge occurs into the ocean, where icebergs form. The main features of the surface relief of the island of Iceland are determined by volcanic forms - there are more than 30 active volcanoes. The highest areas of the basalt plateau are occupied by cover-type glaciers. From the southwest to the northeast, a rift zone runs through all of Iceland (part of the Mid-Atlantic Ridge, to which most volcanoes and earthquake epicenters are confined.
The coasts in western Eurasia are predominantly high, dissected by fjords, the top surfaces of which are often covered with ice. In the coastal zone, sheepsheads, drumlins, kamas, and edge formations are widespread. The northern part of the Scandinavian Peninsula is represented by the Finnmark lowlands, the main elements here are also created by the glacier. The same coastal topography is characteristic of the Kola Peninsula. The Karelian coast of the White Sea is deeply dissected by glacial valleys. The relief of the opposite coast is represented by surface plains descending from the south to the White Sea. Here the low-mountain Timan Ridge and the Pechora Lowland come ashore. Further to the east is the mountain belt of the Urals and Novaya Zemlya. The southern island of Novaya Zemlya is free of ice cover, but bears traces of recent glaciation. In the north of the South Island and the North Island there are powerful glaciers (except for the narrow coastal strip). The islands are dominated by mountain-glacial terrain, a significant area of which is covered with glaciers descending to the sea and giving rise to icebergs. 85% of Franz Josef Land is covered by glaciers, under which there is a basalt plateau. The southern coast of the Kara Sea forms
The West Siberian Plain, which is a young platform, composed of Quaternary sediments on top. The Taimyr Peninsula in its northern part is occupied by the Byrranga highlands, consisting of ridges and plateau-like massifs. Permafrost landforms are widespread. About half the area of Severnaya Zemlya is covered by ice sheets and domes. The lower reaches of the valleys are flooded by the sea and form fjords. The coasts of the East Siberian and Chukchi Seas are located within the Verkhoyansk-Chukchi folded country. The Lena River forms a vast delta, complex in structure and origin. To the east of it, to the mouth of the Kolyma River, stretches the Primorskaya Plain, composed of Quaternary sediments with permafrost, cut through the valleys of numerous rivers.
Geological structure and bottom topography
Most of the bottom relief of the Arctic Ocean is occupied by the shelf (more than 45% of the ocean floor) and the underwater continental margins (up to 70% of the bottom area). This is what explains the small average depth of the ocean - about 40% of its area has depths of less than 200 m. The Arctic Ocean is bordered and partially continues under its waters by continental tectonic structures: the North American ancient platform; Icelandic-Faroe protrusion of the Caledonian Eurasian platform; The East European ancient platform with the Baltic shield and the Barents Sea ancient platform lying almost completely under water; Ural-Novozemelskoye mining structure; West Siberian young platform and Khatanga trough; Siberian ancient platform; Verkhoyansk-Chukotka folded country. In Russian science, the ocean is usually divided into 3 vast water areas: the Arctic basin, which includes the deep-water central part of the ocean; North European basin, including the continental slope of the Barents Sea up to the 80th parallel in the section between Spitsbergen and Greenland; The Canadian basin, which includes the waters of the straits of the Canadian Archipelago, Hudson Bay and the Baffin Sea.
North European Basin
The basis of the bottom topography of the North European basin is a system of mid-ocean ridges, which are a continuation of the Mid-Atlantic Ridge. On the continuation of the Reykjanes ridge is the Icelandic rift zone. This rift zone is characterized by active volcanism and intense hydrothermal activity. In the north, in the ocean, it continues with the Kolbeinsey rift ridge with a well-defined rift valley and transverse faults cutting the ridge. At 72°N latitude, the ridge is crossed by the large Jan Mayen fault zone. North of the intersection of the ridge with this fault, the mountain structure experienced a displacement of several hundred kilometers to the east. The displaced segment of the mid-ocean ridge has a sublatitudinal strike and is called the Mona Ridge. The ridge retains a northeastern strike until it intersects with 74° north latitude, after which the strike changes to meridional, where it is called the Knipovich Ridge. The western part of the ridge is a high monolithic ridge, the eastern part is relatively low and merges with the continental foot, under the sediments of which this part of the ridge is largely buried.
From the island of Jan Mayen in the south to the Faroe-Iceland threshold stretches the Jan Mayen Ridge, which is an ancient mid-ocean ridge. The bottom of the basin formed between it and the Kolbeinsey ridge is composed of erupted basalts. Due to the erupted basalt, the surface of this section of the bottom is leveled and raised above the ocean bed adjacent to the east, forming the underwater Icelandic plateau. An element of the submarine margin of the European subcontinent off the coast of the Scandinavian Peninsula is the Våring Plateau protruding far to the west. It divides the Norwegian Sea into two basins - Norwegian and Lofoten with maximum depths of up to 3970 meters. The bottom of the Norwegian Basin has hilly and low-mountain terrain. The basin is divided into two parts by the Norwegian Range - a chain of low mountains stretching from the Faroe Islands to the Våring Plateau. To the west of the mid-ocean ridges is the Greenland Basin, which is dominated by flat abyssal plains. The maximum depth of the Greenland Sea, which is also the maximum depth of the Arctic Ocean, is 5527 m.
On the underwater continental margin, continental-type crust is widespread with a crystalline basement occurring very close to the surface within the shelf. The bottom topography of the Greenland and Norwegian shelves is characterized by exaration forms of glacial relief.
Canadian Basin
Most of the Canadian Basin consists of the straits of the Canadian Arctic Archipelago, which are also called the Northwest Passage. The bottom of most straits is over-deepened, the maximum depths exceed 500 m. The bottom topography is characterized by the widespread distribution of relict glacial relief and the great complexity of the outlines of the islands and straits of the Canadian archipelago. This indicates the tectonic predetermination of the relief, as well as the recent glaciation of this part of the ocean floor. On many islands of the archipelago, vast areas are still occupied by glaciers. The width of the shelf is 50-90 km, according to other sources - up to 200 km.
Glacial landforms are characteristic of the bottom of Hudson Bay, which, unlike the straits, is generally shallow. The Baffin Sea has a great depth of up to 2141 m. It occupies a large and deep basin with a clearly defined continental slope and a wide shelf, most of which lies deeper than 500 m. The shelf is characterized by submerged landforms of glacial origin. The bottom is covered with terrigenous sediments with a large proportion of iceberg material.
Arctic Basin
The main part of the Arctic Ocean is the Arctic Basin. More than half of the basin is occupied by a shelf, the width of which is 450-1700 km, with an average of 800 km. According to the names of the marginal Arctic seas, it is divided into the Barents Sea, Kara Sea, Laptev Sea and East Siberian-Chukchi Sea (a significant part is adjacent to the shores of North America).
The Barents Sea shelf, structurally and geologically, is a Precambrian platform with a thick cover of sedimentary rocks of the Paleozoic and Mesozoic, its depth is 100-350 m. On the outskirts of the Barents Sea, the bottom is composed of ancient folded complexes of various ages (near the Kola Peninsula and north-west of Spitsbergen - Archean-Proterozoic, off the coast of Novaya Zemlya - Hercynian and Caledonian). The most significant depressions and troughs of the sea: the Medvezhinsky Trench in the west, the Franz Victoria and St. Anna trenches in the north, the Samoilov Trench in the central part of the Barents Sea, large hills - the Medvezhinsky Plateau, the Nordkinskaya and Demidov Banks, the Central Plateau, the Perseus Rise, the Admiralty Rise. The bottom of the White Sea in the northern and western parts is composed of the Baltic shield, in the eastern part - the Russian platform. The bottom of the Barents Sea is characterized by dense dissection of glacial and river valleys flooded by the sea.
The southern part of the Kara Sea shelf is mainly a continuation of the West Siberian Hercynian platform. In the northern part, the shelf crosses the submerged part of the Ural-Novaya Zemlya meganticlinorium, the structures of which continue in northern Taimyr and the Severnaya Zemlya archipelago. To the north are the Novaya Zemlya Trench, the Voronin Trench and the Central Kara Upland. The bottom of the Kara Sea is crossed by clearly defined extensions of the Ob and Yenisei valleys. Near Novaya Zemlya, Severnaya Zemlya, and Taimyr, exaration and accumulative relict glacial landforms are common at the bottom. The shelf depth is on average 100 m.
The predominant type of relief on the shelf of the Laptev Sea, the depth of which is 10-40 m, is a marine accumulative plain, along the coasts, and on individual banks - abrasive-accumulative plains. This same leveled relief continues on the bottom of the East Siberian Sea; in some places on the sea bottom (near the New Siberian Islands and north-west of the Bear Islands) a ridge relief is clearly expressed. The bottom of the Chukchi Sea is dominated by flooded denudation plains. The southern part of the sea is a deep structural depression filled with loose sediments and Meso-Cenozoic volcanic rocks. The shelf depth in the Chukchi Sea is 20-60 m.
The continental slope of the Arctic basin is dissected by large, wide submarine canyons. Cones of turbidity flows form an accumulative shelf - the continental foot. A large alluvial fan forms the submarine Mackenzie Canyon in the southern part of the Canada Basin. The abyssal part of the Arctic basin is occupied by the mid-ocean Gakkel Ridge and the ocean floor. The Gakkel Ridge (with depths of 2500 m above sea level) starts from the Lena Valley, then extends parallel to the Eurasian submarine margin and adjoins the continental slope in the Laptev Sea. Numerous earthquake epicenters are located along the rift zone of the ridge. From the underwater edge of northern Greenland to the continental slope of the Laptev Sea, the Lomonosov Ridge stretches - this is a monolithic mountain structure in the form of a continuous shaft with depths of 850-1600 m below sea level. Beneath the Lomonosov Ridge lies a continental-type crust. The Mendeleev Ridge (1200-1600 m below sea level) stretches from the underwater margin of the East Siberian Sea north of Wrangel Island to Ellesmere Island in the Canadian archipelago. It has a blocky structure and is composed of rocks typical of oceanic crust. There are also two marginal plateaus in the Arctic basin - Ermak, north of Spitsbergen, and Chukotka, north of the Chukchi Sea. Both of them are formed by continental-type earth crust.
Between the underwater part of Eurasia and the Gakkel Ridge lies the Nansen Basin with a maximum depth of 3975 m. Its bottom is occupied by flat abyssal plains. The Amundsen Basin is located between the Haeckel and Lomonosov ridges. The bottom of the basin is a vast flat abyssal plain with a maximum depth of 4485 m. The North Pole is located in this basin. Between the Lomonosov and Mendeleev ridges there is the Makarov Basin with maximum depths of more than 4510 m. The southern, relatively shallow (with a maximum depth of 2793 m) part of the basin is distinguished separately as the Podvodnikov Basin. The bottom of the Makarov Basin is formed by flat and undulating abyssal plains, the bottom of the Podvodnikov Basin is an inclined accumulative plain. The Canadian Basin, located south of the Mendeleev Ridge and east of the Chukotka Plateau, is the largest basin in area with a maximum depth of 3909 m. Its bottom is mainly a flat abyssal plain. Under all basins the earth's crust does not have a granite layer. The thickness of the crust here is up to 10 km due to a significant increase in the thickness of the sedimentary layer.
Bottom sediments of the Arctic basin are exclusively of terrigenous origin. Sediments of fine mechanical composition predominate. In the south of the Barents Sea and in the coastal strip of the White and Kara Seas, sandy deposits are widely represented. Iron-manganese nodules are widespread, but mainly on the shelf of the Barents and Kara seas. The thickness of bottom sediments in the Arctic Ocean reaches 2-3 km in the American part and 6 km in the Eurasian part, which is explained by the wide distribution of flat abyssal plains. The large thickness of bottom sediments is determined by the high amount of sedimentary material entering the ocean, annually about 2 billion tons or about 8% of the total amount entering the World Ocean.
to be continued
Before talking about the mythology of the Arctic Ocean, we must first study the subject itself.
Area 14.75 million square meters. km, average depth 1225 m, greatest depth 5527 m in the Greenland Sea. The volume of water is 18.07 million km³.
The shores in the west of Eurasia are predominantly high, fjord, in the east - delta-shaped and lagoonal, in the Canadian Arctic Archipelago - mostly low, flat. The shores of Eurasia are washed by the seas: Norwegian, Barents, White, Kara, Laptev, East Siberian and Chukotka; North America - Greenland, Beaufort, Baffin, Hudson Bay, bays and straits of the Canadian Arctic Archipelago.
In terms of the number of islands, the Arctic Ocean ranks second after the Pacific Ocean. The largest islands and archipelagos of continental origin: Canadian Arctic Archipelago, Greenland, Spitsbergen, Franz Josef Land, Novaya Zemlya, Severnaya Zemlya, New Siberian Islands, Wrangel Island.
The Arctic Ocean is usually divided into 3 vast water areas: the Arctic basin, including the deep-water central part of the ocean, the North European basin (Greenland, Norwegian, Barents and White seas) and the seas located within the continental shallows (Kara, Laptev Sea, East Siberian , Chukotka, Beaufort, Baffin), occupying more than 1/3 of the ocean area.
The width of the continental shelf in the Barents Sea reaches 1300 km. Behind the continental shoal, the bottom drops sharply, forming a step with a depth at the foot of up to 2000-2800 m, bordering the central deep-sea part of the ocean - the Arctic basin, which is divided by the underwater Gakkel, Lomonosov and Mendeleev ridges into a number of deep-sea basins: Nansen, Amundsen, Makarov, Canadian, Podvodnikov and others.
The Fram Strait between the islands of Greenland and Spitsbergen of the Arctic Basin connects with the North European Basin, which in the Norwegian and Greenland Seas is intersected from north to south by the Icelandic, Mona and Knipovich underwater ridges, which together with the Gakkel Ridge constitute the northernmost segment of the world system of mid-ocean ridges.
In winter, 9/10 of the area of the Arctic Ocean is covered with drifting ice, mainly multi-year ice (about 4.5 m thick), and fast ice (in the coastal zone). The total volume of ice is about 26 thousand km3. Icebergs are common in the Baffin and Greenland seas. In the Arctic basin, the so-called ice islands, formed from the ice shelves of the Canadian Arctic Archipelago, drift (for 6 or more years); their thickness reaches 30-35 m, as a result of which they are convenient to use for the operation of long-term drifting stations.
The flora and fauna of the Arctic Ocean are represented by Arctic and Atlantic forms. The number of species and individuals of organisms decreases towards the pole. However, phytoplankton is developing intensively throughout the Arctic Ocean, including among the ice of the Arctic basin. The fauna is more diverse in the North European basin, mainly fish: herring, cod, sea bass, haddock; in the Arctic basin - polar bear, walrus, seal, narwhal, beluga whale, etc.
For 3-5 months, the Arctic Ocean is used for maritime transport, which is carried out by Russia along the Northern Sea Route, the USA and Canada along the Northwest Passage.
The most important ports: Churchill (Canada); Tromsø, Trondheim (Norway); Arkhangelsk, Belomorsk, Dikson, Murmansk, Pevek, Tiksi (Russia).
