The geographical position of Antarctica is unique - there is no other continent on Earth that is entirely located in the polar region of the planet. This arrangement led to the emergence of permanent glaciation on the continent and very difficult climatic conditions. The area of Antarctica is 14 million km2. Due to the peculiarities of the location, there is no need to talk about the length from north to south and from west to east, however, the maximum distance between two opposite points of the coast is about 5700 km. In the very north, the continent is crossed in several places by the Antarctic Circle.
Of the extreme points of the continent, only the northern one can be named: Cape Sifre (63°12" 48" S, 57°18" 8" E) on the Antarctic Peninsula.
The continent is located in the sub-Antarctic and Antarctic climate zones of the Earth.
Antarctica is washed by the Southern Ocean. Otherwise, if this ocean is not considered, it is washed by the waters of the Atlantic, Indian and Pacific Oceans.
The continent occupies the extreme southern position, is not connected to any of the other continents, and is also farthest away from the rest.
Antarctica is a territory that includes the mainland of Antarctica and adjacent Antarctic waters (southern margins of the Pacific, Atlantic and Indian oceans) with islands up to 48-60° south. w.
Antarctica is icy, deserted and the most... cold continent. It is located in the southern polar region of the Earth, so all its shores are northern. Most of the territory lies in the Eastern Hemisphere. Antarctica is significantly removed from inhabited land. The distance to the nearest continent - South America is more than 900 km (Drake Passage). The coastline of Antarctica is formed mainly by the edges of a glacier, which ends in a wall of several tens of meters into the ocean. Only one peninsula stands out - the Antarctic.
Natural conditions and resources. Relief and minerals. From space, Antarctica resembles a plain. But this is an unusual "plain" on Earth. Its average height above sea level is 2040 m, which is almost three times the average height of all continents. A special feature of this “plain” is that its surface is covered with a thick layer of compressed ice, which reaches 4000 m in the central part, forming a kind of dome. Its ice spreads from the center of the continent to the edges, forming icebergs. Antarctica's glaciers contain 80% fresh water Earth.
The ice shell hides complex structures, plains and deep depressions. The continent is based on the ancient Antarctic platform, which was part of Gondwana - this is the Eastern part of Antarctica; The western (folded) region includes the Transantarctic Mountains - a continuation of the Andes. In some places they protrude to the surface. The highest point of the mainland is Mount Vinson (5140 m). On the seashore of Rossa there is active volcano Erebus.
Deposits of coal and iron ore have been discovered in the depths of Antarctica, and signs of deposits of gold, uranium, copper, nickel, lead, and silver have also been established.
Climate. The peculiarities of the geographical location and ice cover determined the formation of a harsh climate, the coldest on Earth. Polar explorers at the Vostok station noted the lowest temperature -89.2°C. Cold and dry Antarctic air masses form over the continent. Constant katabatic winds blow from the high ice dome, reaching hurricane speeds of up to 80 m/s. Winters are especially harsh in Antarctica. The average temperature in winter is -70° C. Summer temperatures in the interior regions rarely rise above -36° C. Precipitation in the central part of the continent falls less than 100 mm, and it falls only in a solid state. The climate of the coastal part is different. Strong winds are frequent here, the amount of precipitation increases (up to 300 mm), summer temperatures are higher (-1.0 ° C), and there are rains. There are two climatic zones on the mainland: Antarctic and subantarctic.
The organic world is poor compared to other continents. The mainland's vegetation includes mosses, lichens, algae, and microscopic fungi.
The centers of life in the icy desert of the mainland are oases (places free of ice). The animal world is richer and more diverse than the plant world. The life of most animals is connected with the ocean; there are few land animals. There is a lot of plankton in coastal waters, which fish, whales, and seals feed on. The most typical birds of Antarctica are penguins. Even far from the coast, in the mountains, you can find nesting places of birds (petrels, skuas, gray gulls).
Natural resources: iron ore, chromium, copper, gold, nickel, platinum and other minerals; small reserves of coal and hydrocarbons have been discovered (not currently being developed); krill, fish and crabs are industrial fisheries
Definition: This indicator contains information about natural resources, reserves of minerals, raw materials, energy, fisheries and forest resources.
Antarctica is a southern polar continent occupying the central part of the southern polar region of Antarctica. Almost all of the continent's landmass is located south of the Antarctic Circle. The coastline (more than 30 thousand km long) is slightly indented; almost along its entire length it consists of glacial cliffs, up to several tens of meters high.
The area of Antarctica is twice the size of Australia and, including islands and ice shelves, is about 13.2 million km2. About 97% of its territory is covered with ice. This is the only continent located near the pole, within the Antarctic Circle. The area in the center of which is Antarctica, along with the adjacent areas of the Atlantic, Pacific and islands, is called Antarctica. The Antarctic border lies within 50-60o S. w.
According to scientists, in ice at a depth of more than 1000 m, conditions with elevated temperatures and colossal pressure are created, where ice melting is possible. This probably leads to the formation of subglacial ice, the accumulation of water in depressions of the relief. A consequence of its existence are also modern glacial lakes in the coastal zone of the mainland, which periodically instantly descend.
High pressure at the depth of the ice sheet, its movement, as well as processes associated with melting at depth indicate its mobility and unstable state. These factors, according to scientists, can create conditions for the formation of deposits on the Antarctic shelf. Antarctica is likely to contain large deposits of iron, copper, deposits of rare earth, radioactive and trace elements, as well as non-metallic minerals such as rock crystal, mica, phosphorus, etc.
According to geologists, the depths of Antarctica contain oil, gas, coal, lead, zinc, gold, silver, molybdenum, etc. According to scientists, oil and gas deposits on the deserted continent are one and a half times greater than the volume of deposits. According to the US Geological Survey, Antarctica's potential oil reserves are estimated at 6.5 billion tons, and more than 4 trillion cubic meters.
Almost all of Antarctica lies within the Antarctic Circle. Due to its inaccessible position, Antarctica was discovered by Russian navigators F.F. Bellingshausen and M.P. Lazarev later than other continents.
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Lesson type: Learning new material.
Wall map of the hemispheres, Wall map of Antarctica, video, atlas for 7th grade, educational supplies, lesson presentation. (Presentation 1)
During the classes
Teacher's words:
The epigraph for our lesson will be a line from the poem by the famous English poet Alfred Tennyson “Fight and seek, find and not give up.” How do you understand it?
“And this unknown land of snow and ice lies beyond the southern polar circle, shining dazzlingly in the rays of the sun on a polar day or shrouded in clouds and whirlwinds of a blizzard in the darkness polar night. This region is beautiful in its own way, and anyone who has been there once will always remember the great silence of the icy desert.”
What continent do you think will be discussed in this lesson?
We wrote down the topic of the lesson in printed notebooks. (Annex 1)
The word Antarctica is translated as “anti” against, and “Arctic” is the northern polar region of the Earth. That is, against the Arctic.
- What do you already know about Antarctica?
- Why does Antarctica have such features?
Geographical location of Antarctica.
In printed notebooks, the first paragraph provides a plan for describing the geographical location of the continent.
After reading each point, one student comes to the board and answers on the wall map of the hemispheres and Antarctica, and everyone else follows the answer using atlases, and so we will work with each point of the plan.
Let's read it out first point– Determine where the continent is located relative to the equator? – look and answer.
Answer: located further south, meaning in the southern hemisphere.
Regarding the tropics?
Answer: Not intersected by the tropics.
Almost the entire territory of the mainland is within the southern polar circle.
The position of the continent relative to the prime meridian?
Answer: intersected by the prime meridian in the west.
Yes, indeed, most of the continent, more than 70% lies east of the zero hemisphere, that is, in the eastern hemisphere, and only less than 30% lies in the western hemisphere.
We can conclude that the continent is unique, as it lies in three hemispheres. Remember which ones?
Answer: in the south, east and west. Let's mark the southern polar circle and the prime meridian on the outline map in a printed notebook.
Reading second point.
Find extreme points mainland.
Due to its geographical location, Antarctica has only one extreme point. Open the atlas “ Physical card Antarctica” and find it (Cape Sifre). We independently determined the coordinates. Mark the cape on the outline map in your printable notebook.
Reading third point plan.
What oceans and seas wash the continent?
Independently determined from atlases and signed them on contour maps in a printed notebook in blue.
Reading fourth point plan.
How is the continent located relative to other continents?
Answer: far from other continents, the southern part of South America and Australia are closest to it.
Yes, Antarctica is indeed separated from other continents by vast oceanic expanses.
The position of the continent near the pole led to the formation of a thick ice cover, the average thickness of which is about 2 thousand meters. Due to the thickness of the ice, Antarctica turned out to be the highest continent on Earth. Due to its geographical location, as well as its icy shell, Antarctica is the world's pole of cold, where the most recorded low temperature Earth. Open your textbook to page 39 and tell me what temperature it is and where it was recorded?
Answer: At Vostok station, - 89.2? C.
We have given a description of the geographical location of the continent, studied its main features, and now we will get acquainted with the history of the discovery of the continent.
History of the discovery of Antarctica.
Under point 2 in the printed workbooks “History of Discovery”, there is a table that we will fill out. There are four columns in the table, look at their names.
Teacher's words:
Antarctica was discovered much later than other continents. Although even ancient scientists expressed the idea of the existence of a continent in the high latitudes of the southern hemisphere.
In the second half of the 18th century, an English expedition led by the navigator James Cook set off in search of the southern continent. He searched for Antarctica for more than three years, crossing the southern polar circle more than once, but he was never able to break through the ice to the mainland. Returning, Cook declared: “There is no southern continent! And not a single person will ever dare to penetrate further south than I did...”
Therefore, after Cook's voyage, for 50 years not a single ship set off for those waters where giant impenetrable ice protected the distant approaches to the south pole. Let's write it down in the table under the number 1.
The Russians put an end to a long break in the exploration of southern latitudes.
On the morning of July 5, 1819, the first Russian expedition set off for the southern polar waters on the ships Mirny and Vostok. They were led by sailors Thaddeus Faddeevich Bellingshausen, who was the head of the expedition, and Mikhail Petrovich Lazarev, look at their portraits. They walked around the mainland and discovered many islands.
January 28, when the expedition reached the shores of the mainland, is considered the day of the discovery of Antarctica. We write it down in the table under number 2:
Do you know who was the first to reach the south pole?
Answer: Amudsen.
Let's look at the fragment. (Presentation slide 6)
How did you feel while watching?
On December 14, 1911, the South Pole was reached by Roald Amudsen, and a month later by Robert Scott.
This was the greatest geographical discovery. They received the first information about the interior of the continent. Let's write it down in the table under number 3:
And under the number 4:
Checking the table:
| Traveler, explorer | Country, homeland of the traveler | opening date | Discoveries and achievements |
| 1. James Cook | Great Britain | 1773-1775 | First crossing of the Antarctic Circle |
| 2.F.F. Bellingshausen and M.P. Lazarev | Russia | 1820 | Discovery of the mainland |
| 3. Raoul Amudsen | Norway | 14.12.1911 | First achievement of the South Pole |
| 4. Robert Scott | Great Britain | 18.01.1912 | Second achievement of the South Pole |
But these achievements came at a high price. Robert Scott's group died on the way back, just a few kilometers short of reaching the base where there were food and fuel. Eight months later, a tent was found, half covered with snow.
At the site of Scott's first wintering place, a cross made of Australian redwood was erected with the names of the five victims, and words were carved into the cross. What do you think? - a catchphrase, which was the epigraph to the lesson, from the novel “Two Captains” by Veniamin Kaverin.
“Fight and search, find and not give up.”
These people are remembered by expressing their feelings in poetry, “In Memory of Captain Scott”:
Square iceberg. Black water.
And white penguins in black tailcoats.
A gloomy bastion of sparkling ice.
And the plains leading to death.
And it’s not the masts of ships that seem strange,
Captivated by presumptuous hope -
Break through the clutches of sparkling fields
To the ground, hidden by armored clothing,
I see a bony hand,
Frozen above the persistent and harsh,
The last, unborn word
The last entry of a stingy diary.
Land and people 1962
Throughout the journey, Scott kept a diary where he recorded all his thoughts and feelings. His last words were: “For God’s sake, don’t leave our loved ones.”
And after people died, did they forget about Antarctica? Or, remembering the difficulties, were you preparing for new expeditions?
Exploration of Antarctica.
Report from one of the students. Approximate content: In the 20th century, active exploration of Antarctica began.
During all this time, a large number of stations were opened. Open the atlas and look.
Find the Vostok station, this station was opened in 1957. You and I already know that the lowest temperature of the earth was recorded at this station. Remember which one?
Answer: - 89.2?С
At this temperature, iron also freezes. If you leave two axes on the street overnight, then in the morning, when you hit them against each other, they will break.
In 1957-1958, with the vision of the International Geophysical Year, 12 countries of the world decided to jointly study the continent.
In difficult climatic conditions, several scientific stations were built in a short period of time. Look at the screen and find them - Mirny, Novolazarevskaya, Vostok, Molodezhnaya. They are located not only on the coast, but also in the interior, hard-to-reach parts of Antarctica.
The main and largest station at this time is Molodezhnaya - find it on the atlas map. The Antarctic Aerometeorological Center is located here.
Antarctica does not belong to any state. There is no permanent population on the mainland due to the harsh natural conditions. Any weapons tests or nuclear explosions are prohibited on its territory.
Antarctica is called the continent of science and peace.
Consolidation of the studied material.
- A crossword puzzle will help you consolidate what you have learned. (Appendix 2)
- Checking the crossword (Presentation, slide 10-17)
Homework.
- Find an explanation for the expression “Antarctica is the icy heart of the planet!”
Relief and ice cover
Antarctica is the highest continent on Earth; the average height of the continent's surface above sea level is more than 2000 m, and in the center of the continent it reaches 4000 meters. Most of this height is made up of a permanent ice cover of the continent, under which the continental relief is hidden and only ~5% of its area is free of ice - mainly in West Antarctica and the Transantarctic Mountains: islands, sections of the coast, the so-called. “dry valleys” and individual ridges and mountain peaks (nunataks) rising above the icy surface. The Transantarctic Mountains, crossing almost the entire continent, divide Antarctica into two parts - West Antarctica and East Antarctica, which have different origins and geological structures. In the east there is a high (highest elevation of the ice surface ~4100 m above sea level) ice-covered plateau. The western part consists of a group of mountainous islands connected by ice. On the Pacific coast are the Antarctic Andes, whose altitude exceeds 4000 m; the highest point of the continent - 4892 m above sea level - the Vinson Massif of the Sentinel Ridge. In West Antarctica there is also the deepest depression of the continent - the Bentley Trench, probably of rift origin. The depth of the ice-filled Bentley Trench reaches 2555 m below sea level.
The Antarctic ice sheet is the largest on our planet and is approximately 10 times larger in area than the next largest, the Greenland Ice Sheet. It contains ~30 million km³ of ice, that is, 90% of all land ice. It has a dome shape with the surface increasing in steepness towards the coast, where it is framed in many places ice shelves. The average thickness of the ice layer is 2500-2800 m, reaching a maximum value in some areas of East Antarctica - 4800 m. The accumulation of ice on the ice sheet leads, as in the case of other glaciers, to the flow of ice into the ablation (destruction) zone, which acts as coast of the continent (see Fig. 3); the ice breaks off in the form of icebergs. The annual volume of ablation is estimated at 2500 km³.
A special feature of Antarctica is the large area of ice shelves (low (blue) areas of West Antarctica), amounting to ~10% of the area above sea level; these glaciers are the source of icebergs of record sizes, significantly exceeding the size of the icebergs of the outlet glaciers of Greenland; for example, in 2000, the largest known ice cap broke off from the Ross Ice Shelf. this moment(2005) iceberg B-15 with an area of over 10,000 km². In winter (summer in the northern hemisphere) the area sea ice around Antarctica it increases to 18 million km², and in summer it decreases to 3-4 million km².
The Antarctic ice sheet formed about 14 million years ago, apparently facilitated by the rupture of the bridge connecting South America and the Antarctic Peninsula, which led, in turn, to the formation of the Antarctic circumpolar current (Western Wind Current) and the isolation of Antarctic waters from the World Ocean - these waters make up the so-called Southern Ocean.
Seismic activity
Antarctica is a tectonically calm continent with little seismic activity; manifestations of volcanism are concentrated in Western Antarctica and are associated with the Antarctic Peninsula, which arose during the Andean period of mountain building. Some of the volcanoes, especially island volcanoes, have erupted in the last 200 years. The most active volcano in Antarctica is Erebus. It is called “the volcano guarding the path to South Pole».
Climate
Antarctica has an extremely harsh cold climate. The absolute pole of cold is located in East Antarctica, where temperatures down to −89.2 °C were recorded (the area of the Vostok station).
Another feature of the meteorology of East Antarctica is katabatic winds, caused by its dome-shaped topography. These stable southerly winds arise on fairly steep slopes of the ice sheet due to the cooling of the air layer near the ice surface, the density of the near-surface layer increases, and it flows down the slope under the influence of gravity. The thickness of the air flow layer is usually 200-300 m; because of large quantity icy dust carried by the wind, horizontal visibility in such winds is very low. The strength of the katabatic wind is proportional to the steepness of the slope and greatest strength reaches in coastal areas with a high slope towards the sea. Maximum strength katabatic winds reach the Antarctic winter - from April to November they blow almost continuously around the clock, from November to March - at night or when the Sun is low above the horizon. In summer, during the daytime, due to the heating of the surface layer of air by the sun, katabatic winds along the coast cease.
Data on temperature changes from 1981 to 2007 show that the temperature background in Antarctica changed unevenly. For West Antarctica as a whole, an increase in temperature has been observed, while for East Antarctica no warming has been detected, and even some negative trend has been noted. It is unlikely that the melting process in Antarctica will increase significantly in the 21st century. On the contrary, as temperatures rise, the amount of snow falling on the Antarctic ice sheet is expected to increase. However, due to warming, more intense destruction of ice shelves and acceleration of the movement of Antarctica's outlet glaciers, throwing ice into the World Ocean, is possible.
Inland waters
Due to the fact that not only the average annual, but also in most areas, even summer temperatures in Antarctica do not exceed zero degrees, precipitation there falls only in the form of snow (rain is extremely a rare event). It forms a glacial cover (snow is compressed under its own weight) with a thickness of more than 1700 m, in some places reaching 4300 m. Antarctic ice Contains up to 90% of all fresh water on Earth.
In the 90s of the 20th century, Russian scientists discovered the subglacial non-freezing Lake Vostok - the largest of the Antarctic lakes, having a length of 250 km and a width of 50 km; the lake holds about 5,400 thousand km³ of water.
In January 2006, geophysicists Robin Bell and Michael Studinger from the American Lamont-Doherty Geophysical Observatory discovered the second and third largest subglacial lakes, with an area of 2000 km² and 1600 km² respectively, located at a depth of about 3 km from the surface of the continent. They reported that this could have been done earlier if the data from the 1958-1959 Soviet expedition had been analyzed more thoroughly. In addition to these data, satellite data, radar readings and measurements of the force of gravity on the surface of the continent were used.
In total, as of 2007, more than 140 subglacial lakes were discovered in Antarctica.
Biosphere
The biosphere in Antarctica is represented in four “arenas of life”: coastal islands and ice, coastal oases on the mainland (for example, the “Banger Oasis”), the nunataks arena (Mount Amundsen near Mirny, Mount Nansen on Victoria Land, etc.) and the ice sheet arena .
Plants and animals are most common in the coastal zone. Terrestrial vegetation in areas deprived of ice exists mainly in the form of various types of mosses and lichens and does not form a closed cover (Antarctic moss-lichen deserts).
Antarctic animals are completely dependent on the coastal ecosystem of the Southern Ocean: due to the paucity of vegetation, all food chains coastal ecosystems begin in the waters surrounding Antarctica. Antarctic waters are especially rich in zooplankton, primarily krill. Krill directly or indirectly form the basis of the food chain of many species of fish, cetaceans, squid, seals, penguins and other animals; There are no completely land mammals in Antarctica; invertebrates are represented by approximately 70 species of arthropods (insects and arachnids) and nematodes living in soils.
Terrestrial animals include seals (Weddell, crabeater seals, leopard seals, Ross seals, elephant seals) and birds (several species of petrels, two species of skuas, Adélie penguins and emperor penguins).
In the freshwater lakes of continental coastal oases - “dry valleys” - there are oligotrophic ecosystems inhabited by blue-green algae, roundworms, copepods (cyclops) and daphnia, while birds (petrels and skuas) fly here occasionally.
Nunataks are characterized only by bacteria, algae, lichens and severely suppressed mosses; only skuas, following people, occasionally fly onto the ice sheet.
There is an assumption about the presence in subglacial lakes of Antarctica, such as Lake Vostok, of extremely oligotrophic ecosystems, practically isolated from the outside world.
In 1994, scientists reported a rapid increase in the number of plants in Antarctica, which seems to confirm the hypothesis of global warming of the planet.
The Antarctic Peninsula and its surrounding islands have the most favorable conditions on the mainland climatic conditions. It is here that the only flowering plants in the region grow - Antarctic meadowsweet and Quito colobanthus.
Exploring Antarctica
The first ship to cross the Antarctic Circle belonged to the Dutch; it was commanded by Dirk Geeritz, who sailed in the squadron of Jacob Magyu. In 1559, in the Strait of Magellan, Geeritz's ship lost sight of the squadron after a storm and went south. When it dropped to 64° S. sh., was found there high ground. In 1671 La Roche discovered South Georgia; Bouvet Island was discovered in 1739; in 1772 Indian Ocean Yves-Joseph Kerglen, a French naval officer, discovered the island named after him.
Almost simultaneously with Kerglen’s voyage, James Cook set off from England on his first voyage to the southern hemisphere, and already in January 1773 his ships “Adventure” and “Resolution” crossed the Antarctic Circle at the meridian 37°33′E. d. After a difficult struggle with ice, he reached 67°15′ S. sh., where he was forced to turn north. In December 1773, Cook again set off for the southern ocean, crossing it on December 8 and at parallel 67°5′ S. w. was covered in ice. Having freed himself, Cook went further south and at the end of January 1774 reached 71°15′ S. sh., southwest of Tierra del Fuego. Here an impenetrable wall of ice prevented him from going further. Cook was one of the first to reach the south polar seas and, having encountered solid ice in several places, declared that it could not be penetrated further. They believed him, and for 45 years polar expeditions did not undertake.
In 1819, Russian sailors F.F. Bellingshausen and M.P. Lazarev, on the sloops of war "Vostok" and "Mirny", visited South Georgia and tried to penetrate deep into the Arctic Ocean. For the first time, in January 1820, almost on the Greenwich meridian, they reached 69°21′ S. sh.; then, leaving the Arctic Circle, Bellingshausen walked along it east to 19° east. d., where he crossed it again and reached in February 1820 again almost the same latitude (69°6′). Further east, he rose only to the 62° parallel and continued his path along the outskirts of the floating ice. Then, on the meridian of the Balleny Islands, Bellingshausen reached 64°55′, and in December 1820 reached 161°w. d., passed the southern polar circle and reached 67°15′ S. latitude, and in January 1821 reached 69°53′ S. w. Almost at the 81° meridian, he discovered the high coast of the island of Peter I, and having gone further east, inside the southern polar circle, the coast of Alexander I Land. Thus, Bellingshausen was the first to complete a complete voyage around Antarctica at latitudes from 60° to 70°.
After this, the study of the coast of the continent and its interior began. Numerous studies were carried out by English expeditions led by Ernest Shackleton (he wrote the book “The Most Terrible Campaign” about them). In 1911-1912, a real race to conquer the South Pole began between the expeditions of the Norwegian explorer Roald Amundsen and the Englishman Robert Scott. Amundsen was the first to reach the South Pole; a month after him, Robert Scott's party arrived at the cherished point and died on the way back.
From the middle of the 20th century, the study of Antarctica began on an industrial basis. On the continent, various countries are creating numerous permanent bases that conduct meteorological, glaciological and geological research all year round. On December 14, 1958, the third Soviet Antarctic expedition, led by Evgeniy Tolstikov, reached the South Pole of Inaccessibility and established a temporary station there, the Pole of Inaccessibility.
Population
Due to the severity of the climate, Antarctica has no permanent population. However, there are scientific stations located there. The temporary population of Antarctica ranges from 4,000 people in summer (about 150 Russians) to 1,000 people in winter (about 100 Russians).
Antarctica has been assigned the top-level Internet domain .aq and the telephone prefix +672.
Geographical location, size of territory and nature of the coastline. Geographers distinguish between the concepts “Antarctica” and “Antarctica”. The name “Antarctica” comes from the Greek words “anti” - against, “arktikos” - northern, i.e. lying opposite the northern polar region of the Earth - the Arctic. Antarctica includes the continent of Antarctica with its adjacent islands and the southern polar waters of the Atlantic, Indian and Pacific oceans to the zone of the so-called Antarctic convergence, where cold Antarctic waters meet the relatively warm waters of temperate latitudes. This zone occupies an intermediate position between the northern limit of the appearance of icebergs and the edge of sea ice during their period. maximum spread. On average it lies about 53?05" S.
The area of Antarctica within these limits, including the continent of Antarctica, is approximately 52.5 million km2.
Antarctica is a continent located almost entirely within the Antarctic Circle. Its area is about 14 million km2, which is approximately twice the area of Australia. The geometric center of the continent, called the Pole of Relative Inaccessibility, is located at 84? S. latitude, in comparative proximity to the South Pole.
The coastline, which is over 30 thousand km long, is poorly indented. Almost the entire coastline of the continent consists of glacial cliffs up to several tens of meters high. From the Quiet and Atlantic Oceans The marginal seas of Wedell, Bellingshausen, Amundsen, and Ross jut into the coast of the mainland. Large areas of marginal seas are covered with ice shelves, which are a continuation of the continental ice shell. The narrow Antarctic Peninsula extends towards South America, protruding several degrees north of the Antarctic Circle.
Brief information from the history of discovery and research. The hypothesis about the existence of Antarctica is associated with the name of the ancient Greek geographer and astronomer C. Ptolemy, who lived in the 1st-2nd centuries. ad. Then the assumption was born that the ratio of land and sea areas in the Northern and Southern Hemispheres should be approximately the same. For many centuries this hypothesis was not confirmed.
In 1774-1775 English navigator James Cook, making round the world expedition, penetrated into Antarctic waters much further south than its predecessors. But he was never able to break through the cold and ice to the mainland. J. Cook's journey ended the first period in the history of the discovery and exploration of Antarctica - the period of speculation about the existence of Antarctica.
The second period ended with the discovery of Antarctica. The honor of discovering the continent belongs to Russian sailors - the first Russian Antarctic expedition of 1819-1821. On the sloops “Vostok” and “Mirny” under the command of F.F. Bellingshausen and M.P. Lazarev. The immediate discovery of the coast of Antarctica occurred on January 28, 1820.
The third period begins with the study of Antarctic waters and coasts. For many decades, ships of researchers from a number of countries have been heading to the shores of Antarctica. In 1882-1883 For the first time, research was carried out in Antarctica under the agreed program of the first International Polar Year.
The fourth period of study of Antarctica begins with the first winter on the mainland of the Norwegian K. Borchgrevink in 1898 on the shore of Robertson Bay near Cape Adare. This stage ended with the conquest of the South Pole in 1911-1912. The expedition of the Englishman Robert Scott went to the Pole from the western edge of the Ross Sea - from McMurdo Bay - on Scottish ponies and skis. The expedition, led by experienced polar explorer Roald Amundsen, set off on dog sleds from the eastern edge of the Ross Sea - from Whale Bay. The Norwegian expedition was the first to reach the South Pole on December 14, 1911, and its participants successfully returned to the coast and sailed to their homeland. R. Scott came to the South Pole with four comrades on skis 35 days later - January 16, 1912. On the way back, R. Scott and his companions died from exhaustion and cold... History has reconciled rivals in a special way in the tragic race to the South Pole: The American scientific station “Amundsen-Scott” now constantly operates there.
Among the Antarctic researchers, one should also mention the Australian D. Mawson and the Englishman E. Shelkton, as well as American expeditions 1928-1930, 1933-1936, 1939-1941 under the leadership of R. Baird. After the Second World War begins modern stage research of Antarctica within the framework of the International Geophysical Year program (1957-1958). Under this program, our country was assigned to explore East Antarctica - the most inaccessible and unexplored part of the continent. The first comprehensive Antarctic expedition of the USSR (1955-1956), headed by M.M. Somov, left the Kaliningrad port on the diesel-electric ship Ob and founded the Mirny scientific station on the coast of Antarctica. In subsequent years, other stations were created inside the continent and in coastal areas: “Vostok”, “Pole of Inaccessibility”, “Pionerskaya” and others. The center of Soviet Antarctic research was moved to the Molodezhnaya station, where natural conditions are less harsh than in the Mirny area.
In 1959, 12 states, including Argentina, Australia, the USSR, the USA, Japan and others, concluded the International Treaty on Antarctica, which prohibits the use of the continent for military purposes, provides for freedom of scientific research and the exchange of information on the results of the work of scientific stations and expeditions. Until now, this Treaty has been respected, and Antarctica is figuratively called the “continent of science and peace.”
Based on the results of research by domestic and foreign scientists, we now have an accurate understanding of the characteristics of the nature of Antarctica.
Geological structure and relief. Minerals. In the light of modern ideas (the first geological map of the continent was published in 1978 based on materials from domestic and foreign expeditions), the basis of the continent is the ancient Antarctic platform. Its area exceeds 11 million km2. The Antarctic platform has a complex geological history development as part of Gondwana, a characteristic three-tier structure. Coal-bearing strata were found in the upper structural layer, or cover of the platform. They contain plant remains of tree ferns, coniferous trees and southern beech trees, similar to those now growing in the forests of Patagonia. Scientists suggest that in the Paleogene period glaciation had not yet touched Antarctica; a temperate climate prevailed there. Glaciation of the continent began only in the Neogene.
In West Antarctica, during the period of Alpine folding, mountain systems- continuation of the Andes of South America. Here the Vinson massif rises 5140 m above sea level.
The solid surface of Antarctica is covered with a powerful ice sheet, the average thickness of which is about 2000 m, and the maximum reaches more than 4000 m. If we take the ice sheet as the relief surface of the continent, then we can assume that Antarctica is the highest continent on Earth. However, a significant part of the “stony” Antarctica (about 1/3) lies below ocean level. Some areas are lowered 2-2.5 km below sea level.
A variety of minerals have been discovered in the depths of Antarctica: ores of ferrous and non-ferrous metals, large reserves of mica and graphite, uranium, gold and diamonds are known. The coal-bearing area in the Transantarctic Mountains alone is estimated at more than 1 million km2. Geologists suggest that the huge depression between the Ross and Wedell seas stores large reserves of oil and gas. But all these mineral reserves are still considered potential, since their modern extraction in the harsh conditions of Antarctica is associated with great difficulties and is not economically profitable.
Climate. Antarctica is the coldest continent on the planet. In the conditions of the polar night in winter there is a strong cooling of it. And in summer, the ice and snow cover of Antarctica reflects almost 90% solar radiation. In inland areas, even in summer, average daily temperatures remain within -30? C, and in winter they reach -70? C. The Vostok station recorded the lowest temperature on our planet (-89.2? C). On the coast of the mainland it is much warmer: in summer the air temperature is about 0? C, and in winter there are moderate frosts - up to -10... -25? C.
As a result of strong cooling, a baric maximum is formed in the center of the continent - an area of high atmospheric pressure, from which constant katabatic winds blow towards the oceans. They are especially strong in a strip 600-800 km wide when moving away from the coast.
The ice cover in Antarctica is constantly replenished due to snowfall and its subsequent crystallization on the ice surface. On average there is about 200 mm of precipitation per year. And in the central regions of the mainland their number is several tens of millimeters.
From the inner regions of the ice dome, the ice gradually spreads to the outskirts. In summer, huge blocks of ice break off from the edge of the ice sheet in the form of tabletop and pyramidal icebergs and slide into the water, and then are carried away by currents into the ocean.
Vegetation and animal world. The main part of the territory of Antarctica belongs to the zone of Antarctic deserts, which is practically devoid of vegetation and wildlife. The oases of Antarctica can be considered as centers of life on an icy continent. The modern vegetation of the continent is represented by lower plants: mosses - 80 species, lichens - 800 species, as well as microscopic algae. And in the region of the Pole of Cold, bacteria were found in the snow.
The fauna of Antarctica is connected with the oceanic waters washing the continent. In summer, dozens of bird species nest on the coast and on coastal cliffs - petrels, albatrosses, skua gulls and penguins. Among the latter, the most typical are Adélie penguins, which make long journeys into the interior of the continent, and large emperor penguins. The coastal waters are home to whales, sperm whales, killer whales, and various types of seals. There is a lot of plankton in coastal waters, especially small crustaceans (krill). Fish, whales, pinnipeds, and birds feed on it.
Antarctic waters are a catchment area for cetaceans, pinnipeds, nototheniids, and krill. But to date, the marine resources of Antarctica have been greatly depleted and many species of animals, such as whales, are under protection.
There is no permanent population in Antarctica. Its international status is such that it does not belong to any state. Only scientists from all countries of the world can study on the continent scientific research, and some tourist and sports expeditions break the icy silence of the vast expanses of the mainland.
