For what reasons a glacier formed in Antarctica. Melting of glaciers - Actual environmental problem

The ice of the Arctic and Antarctic are not at all eternal. Nowadays, due to the impending global warming caused by the environmental crisis of thermal and chemical pollution The atmosphere, the mighty shields of the water with frost are pushed. It threatens a great disaster for a huge area of \u200b\u200bthe territory, which includes the lowland seaside lands of different countries, first of all, European (for example, Holland).

But since the glacial panel of the poles can disappear, it means that it once originated in the process of the development of the planet. "White hats" appeared - for a very long time - within some limited interval geological history Earth. Glaciers can not be considered an integral property of our planet as a cosmic body.

Comprehensive (geophysical, climatological, glaciological and geological) studies of the southern mainland and many other areas of the planet convincingly proved that Antarctica ice cover arose relatively recently. Similar conclusions were made in relation to the Arctic.

First, the data of glaciology (science of glaciers) indicate a gradual increase in ice cover over the past millennia. For example, a glacier covering the Sea of \u200b\u200bRoss, only 5,000 years ago was much less than the square than now. It is assumed that then he served only half of the current territory covered by him. Until now, as some experts believe, the slow intention of this Giant Ice Language continues.

Drilling wells in the thicker mainland ice gave unexpected results. The cores clearly showed how to share the next layers of ice during the last 10-15 millennia. In different layers found spores of bacteria and vegetable pollen. Consequently, the Ice Schit continent Ros and actively developed during the last millennium. The climatic and other factors affected this process, since the rate of formation of layers of ice varies.

Some of bacteria antarctic ice frozen in the thicker (up to 12 thousand years old) managed to revive and explore the microscope. Along the way, a study of air bubbles, closed in these huge layers of frozen water was organized. Work in this area is not completed, but it is clear that in the hands of scientists was evidence of the composition of the atmosphere in the distant past.

Geological studies confirmed that the glaciation is a short-term natural phenomenon. The oldest of open scientists of global glaciation happened over 2000 million years ago. Then these colossal catastrophes repeated quite often. Ordovician glaciation falls on an era, remote from our time for 440 million years. During this climatic cataclysm, a great many marine invertebrates died. Other animals at that time did not yet exist. They appeared much later to become victims of the next seizures of freezing, covering almost all continents.

The last glaciation, apparently, has not yet ended, but for a while retreated. The great depths of the ice occurred about 10 thousand years ago. Since then, powerful ice shells, once covered Europe, a significant part of Asia and North America, remained only in Antarctica, on the Arctic Islands and over the water of the Arctic Ocean. Modern mankind lives in the period of the so-called. Internias, which will have to change the new onset of ice. Unless, of course, before they do not melt finally.

Geologists received a lot interesting facts About Antarctica itself. The great white mainland, apparently, was once completely free from ice and was distinguished by a smooth and warm climate. Two million years ago, dense forests grew on his coasts, like Taiga. At the open ice, the spaces are able to systematically find fossils of a later, social time - the prints of leaves and twigs of ancient thermal-loving plants.

Then, more than 10 million years ago, despite the cooling started on the continent, the local expanses occupied extensive groves of laurels, chestnodes, lavrius, beaks and other subtropical plants. It can be assumed that these groves inhabited animals characteristic for the pore - Mastodonts, sabersubes, hipparones, etc. But much more striking the oldest finds in Antarctica.

In the central part of Antarctica found, for example, the skeleton of the fossil lizard of the lorezaurus - not far from the southern pole, in the outcrops mountain breeds. Large reptile two-meter length differed on rarity terrible appearance. The age of the find is 230 million years.

Lorezavra were, like other beasts, typical representatives of the thermal-loving fauna. They inhabited hot swampy shorts, abundantly overgrown with vegetation. Scientists have discovered a whole belt in geological sediments South Africa, crowded with bones of these animals, which received the name of the limit zone. Something similar was found at the South American Continent, as well as in India. Obviously, in the early Triassic period, 230 million years ago, the climate of Antarctica, Industan, South Africa and South America was similar, since there could still have the same animals.

Scientists are looking for an answer to the riddle of the birth of glaciers - what global processes that are invisible in our era of Ingreland, 10 Millennies ago were a huge part of the land and the world's ocean under the hardened water shell? What caused such a sharp climate change. None of the hypotheses is convincing so much to become generally accepted. Nevertheless, it is worth remembering the most popular. Among the hypotheses can be distinguished by three, conditionally referred to as space, planetary climatic and geophysical. Each of them prefers a certain group of factors or one decisive factor that served as the root cause for the cataclysm.

The cosmic hypothesis is based on the data of geological surveys and astrophysical observations. When setting the age of sea and other breeds caused by ancient glaciers, it turned out that climatic catastrophes happened with strict periodicity. The Earth frozen at the time interval, as if specifically for this allotted. Each great cooling is separated from other periods, approximately 200 million years. So, after every 200 million years of the domination of the warm climate on the planet, a tightening winter was reappeared, a powerful ice caps were formed. Climatologists appealed to materials accumulated by astrophysics: what can be connected so incredibly a long time between several iterative (regularly manifested) events in the atmosphere and the hydrosphere of the space object? Perhaps with comparable on scale and temporary frameworks by space events?

Calculations of astrophysics are called as such an event - the turnover of the Sun around the galactic nucleus. The size of the galaxy is extremely large. The diameter of this space disk reaches the size of about 1000 trillion km. The sun is located from the galactic nucleus at a distance of 300 trillion km, so the full turn of our star around the center of the system is delayed on such a colossal period of time. Apparently, in its path, the solar system crosses some kind of area in the galaxy, under the influence of which another glaciation occurs on Earth.

This hypothesis is not adopted in the scientific world, although it seems convincing to many. However, the facts on the basis of which it could be proved or at least convincingly confirm, scientists do not have. Facts confirming the galactic influence on a million-week fluctuations in the climate of the planet are absent, except for the strange coincidence of numbers there is nothing. Astrophysics did not find the mysterious area in the galaxy, where the earth begins to freeze. The type of external influence is not found, because of which something like that can happen. Someone involves a decrease in solar activity. It seems to be a "cold zone" reduced the intensity of the stream solar radiationAnd as a result, the Earth began to get less heat. But it is only assumptions.

Proponents of the original version came up with the name for the imaginary processes occurring in the star system. Full turn Solar system Around the galactic nucleus was called the Galactic year, and a small interval during which the Earth remains in a dysfunctional "cold zone", - cosmic winter.

Some supporters of extraterrestrial origin of glaciers are looking for climate change factors not in the far galaxy, but within the solar system. For the first time, such an assumption sounded in 1920, his author was the Yugoslav scientist M. Milankovich. He took into account the slope of the Earth to the plane of the ecliptic and the slope itself of the ecliptic to the solar axis. According to Milankovich, the unpoled of great glaciation should be found here.

The fact is that, depending on these slopes, the amount of radiant energy of the Sun, reaching ground surface. In particular, different latitudes receive different amounts of rays. Changing over time, the interpretation of the axes of the Sun and the Earth causes oscillations in the amount of solar radiation in different parts of the planet and at some coincidence the circumstances leads to the staging of the change of warm and cold phases.

In the 90s. XX century This hypothesis has been carefully checked using computer models. Numerous external influences on the location of the planet regarding the sun - the orbit of the Earth were slowly evolved under the influence of gravitational fields of neighboring planets, the trajectory of the earth's movement was gradually transformed.

French Geophysic A. Berger compared the obtained figures with geological data, with the results of radioisotope analysis of marine deposits, showing changes in temperature over millions of years. Temperature oscillations oceanic water Fully coincided with the dynamics of the process of transformation of the earth orbit. Consequently, the space factor could well provoke the start of the climate and global glaciation.

At the moment, it is impossible to argue that Milankovich's hypothesis is proved. First, it requires additional long-term checks. Secondly, scientists tend to adhere to the opinion that global processes could not be caused by the action of only one factor, especially if he is external. Most likely, the action of various action was synchronized natural phenomena, and a decisive role in this amount belonged to the elements of the Earth.

The planetary-climatic hypothesis is repelled precisely from this position. The planet is a huge climate machine that guides the movement of air flows, cyclones and typhoons. The inclined position in relation to the plane of the ecliptic determines the inhomogeneous heating of its surface. In a sense, the planet itself is a powerful climate regulation device. And its inner forces are the reasons for its metamorphosis.

These internal forces include mantle currents, or so-called. Convection flows in the layers of the molten magmatic substance, the mantle layer underlying the ground crown. The movements of these currents from the core of the planet to the surface generate earthquakes and eruption of volcanoes, formation processes. The same flows cause the occurrence of deep splits in the earth's crust, carrying the name of rhythic zones (valleys), or rhyps.

Rift valleys are numerous on the ocean day, where the bark is very thin and easily breaks under the pressure of convection flows. In these areas, volcanic activity is extremely high. Here is constantly poured out of the depths of the mantle substance. According to the planetary climatic hypothesis, it is the outpacing of magma that play a crucial role in the oscillatory process of the historical conversion of the weather mode.

Rift faults on the ocean day during periods of the greatest activity are highlighted enough heat to cause intensive evaporation of sea water. From this, a lot of moisture accumulates in the atmosphere, which then falls on the surface of the Earth. In cold latitudes, precipitation falls in the form of snow. But since their loss is too intense and quantity is large, the snow cover becomes more powerful than this happens.

The snow cap is extremely slow, for a long time the arrival of precipitation exceeds their flow rate - melting. As a result, it begins to grow and converted to the glacier. The climate on the planet is also gradually changing, since it is formed a steady area of \u200b\u200bhaving ice. After some time, the glacier begins to expand, since the dynamic system of uneven arrival-flow can not be in equilibrium, and ice increases to incredible sizes and roll almost the entire planet.

However, the maximum of glaciation becomes at the same time the beginning of its degradation. Having achieved a critical mark, extremum, ice growth stops, having met the stubborn resistance of other natural factors. The dynamics acquired inverse nature, the rise was replaced by a decline. However, the victory of "summer" over the "winter" comes not immediately. Originally begins a protracted "spring" for several millennia. This is a change of short seizures of glaciation with warm membranes.

Earth civilization was formed in the epoch of the so-called. Holocene passionflash. It began about 10,000 years ago, and it will end, if you believe mathematical models, at the end of III thousand AD, i.e. About 3000 g. From this point on, the next cooling will begin, which will reach apogee after 8000 of our summer.

The main argument of the planetary-climatic hypothesis is the fact of a periodic change of tectonic activity in rift valleys. Convection currents in the depths of the Earth exchanging the earth's bark with a different force, this leads to the existence of such epochs. Geologists have materials convincingly proving that climatic oscillations are chronologically linked to the periods of the greatest tectonic activity of the subsoil.

Mountain deposits show that the next cooling climate comes in time to significant movements of powerful blocks earth crustwho were accompanied by the emergence of new faults and the rapid release of hot magma from both new and old rifts. However, the same argument is used by supporters of other hypotheses to confirm its rightness.

These hypotheses can be considered as a species of a single geophysical hypothesis, since it relies on the data on the planet's geophysics, namely, it is entirely relying in its calculations on paleogeography and tectonics. Tectonics examines the geology and physics of the process of movement of the bark blocks, and Paleogeography studies the consequences of such a movement.

As a result of multi-billion coolation displacements solid On the earth's surface, the outlines of continents were significantly changed, as well as relief. The fact that there are powerful strata nanos or bottom crashes on land, directly indicates advantage of the bark blocks accompanied by its bending or lifting in this region. For example, the Moscow region is composed in large quantities Limestones, replete residues of marine lilies and corals, as well as clay rocks containing ammonite pearl sinks. It follows from this that the territory of Moscow and its surroundings at least twice flooded with marine waters - 300 and 180 million years ago.

Whenever due to the displacement of the huge bark blocks, or lowering, or raising its particular site. In case of lowering, the ocean waters invaded the continent, the onset of the seas, transgression occurred. When lifting the sea, they retired (regression), the surface of the sushi grew, and the mountain ridges rushed at the site of the former salt pool.

The ocean is a powerful regulator and even the Earth's Climate Generator due to its enormous heat capacity and other unique physicochemical properties. This water tank controls the most important air flows, air composition, precipitation and temperature in extensive sushi areas. Naturally, an increase or decrease in its surface area affects the nature of global climatic processes.

Each transgression significantly increased the area of \u200b\u200bsaline, while the regression of the seas significantly reduced this area. Accordingly, climate oscillations occurred. Scientists have established that periodic non-plaque cooling roughly coincided in time with regression periods, while the offensive of the seas to land was invariably accompanied by the warming of the climate. It would seem that another mechanism of global glaciation, which, possibly, is the most important thing, if not exceptional. Nevertheless, there is another climate-forming factor accompanying tectonic progress - in-formation.

The offensive and retreat of ocean waters passively accompanied the growth or destruction of the mountain ranges. The earth's crust under the influence of convection fluxes was wrinkled by chains of the highest peaks, then there. Therefore, an exceptional role in long-period climatic fluctuations is still to retrieve the process of the pea formation (orogenesis). Not only the surface area of \u200b\u200bthe ocean, but also the direction of air flows depended on it.

If the mountain range disappeared or a new one occurred, then the movement of large air masses changed sharply. Following this, the many years of weather in a given location was transformed. So, due to the property, local climates changed along the entire planet, which led to the general reincarnation of the land climate. As a result, the emerging tendency to global cooling only dial the pace.

The last glaciation is tied to the era of the Alpine Gorons ending in our eyes. The result of this orogenesis was the Caucasus, Himalayas, Pamir and many other high mountain systems of the planet. The eruption of Santorin volcanoes, Vesuvius, Unnamed and others provoked by this particular process. It can be said that today this hypothesis dominates in modern scienceAlthough it is not completely proven.

The hypothesis has received unexpected development, and Antarctica is in an annex to climatology. The ice mainland acquired its current appearance completely due to the tectonics, only the crucial role has not played regression and not a change of air flows (these factors are counted in the secondary). The main on the influence of the factor should be called water cooling. Nature froze Atlantis exactly the same technique, which person cools the nuclear reactor.

The "nuclear" version of the geophysical hypothesis is based on the theory of drift of continents and paleontological finds. Modern scientists do not question the existence of continental plates. Since due to the convection of the mantle, the blocks of the earth's crust are movable, then this mobility is accompanied by a horizontal displacement of the continents themselves. They slowly, at a speed of 1-2 cm per year crawled along the molten mantle layer.

The mutual location of the continents changed over time, which was affected by the climate of the Earth, since the air and ocean flows depended. Lestosauri's fossil bones in Antarctica and extremely numerous similar finds in Africa, South America and India confirm the suggestion of scientists that all these southern lands are once, including Australia, were combined into one super magician.

The unified southern continent of Gondwan existed over 200 million: from 240 to 35 million years ago. About 35 million years ago, tectonic movements of the cortex finally split it on the current "pieces", one of which was Antarctica. The split adversely affected her climate because it was insulation.

Previously, the Antarctic coast was washed only two cold flows, the action of which was compensated to the total ocean flows, coming from Australia docked with Antarctic. After all the slices of supermaster were messed up in different directions and left Antarctica alone in the midst of the ocean, it began to actively wash with many currents formed with the time a solid flow - so-called Circumpolar flow.

It surrounded Antarctica and gained strength as the growth and deepening of the "fifth ocean" - the southern waters of the Antarctic region. Every second flow passes more water than all the planet rivers, which is not surprising if we take into account the middle depth " southern Ocean"Aqualued 3 km. The flow covers all water layers to the bottom, being the greatest climatic barrier. This fantastic barrier absorbs all heat, which is only supplied to the white mainland from the outside.

It turned out to be sufficiently lowering the air temperature in the Antarctic region only 3 ° C so that the barrier began to act like a refrigerator. Now the rise of the snow-ice cover was inevitable even while maintaining relatively warm regime on the continent. The glacier gradually, in the process of growth, displaced heat to the outskirts, where it was absorbed by the circumpolar flow.

If the climate on the planet has been significantly warmed by the climate on the planet, then due to the glacial periods caused by the extensive raising of sushi, he gradually approached modern state. The climatic zonality began to be traced increasingly clearly. Because of the gradual cooling, the thermal-loving flora gradually retreated to the south, alternating in a temperate zone with deciduous and coniferous forests. The last glacial period in Cenozoic ended about 10-12 thousand years ago. The epochs of the cooling contributed to the formation of mountain glaciers on the planet and an increase in the scale of the olelion of Antarctica.
How did the unique continent of Antarctica appear? This is not only the highest mainland, but also the region of the biggest oscale land. Distinctive features Antarctica is the powerful cover of the mainland ice and the severity of natural conditions, which are determined by the position of the mainland around the southern pole, as well as the ratio of sushi and the sea in high southern latitudes.
Antarctica ice shell power is 2 thousand meters, but in some areas it reaches a height of four kilometers. According to the estimated estimates, the total volume of mainland ice is 22 million km3 here, that is, 87% of the volume of ice ice is concentrated in Antarctica.
Nowhere on our planet is observed as low temperatures throughout the year, as on Antarctic mainland. In particular, the average annual air temperature in its central areas reaches a mark of 55-57 ° C below zero. Antarctica is the greatest source in our planet. Her ice shell has a huge ability to reflect the sun's rays. In such conditions, the air conditioner would be inappropriate, but it is necessary for us today in summer, when the thermometer indicators reach 30-40 degrees of heat. Modern equipment plays a big role in our life. It helps to get out of difficult situations. During the choice of technology, you need to pay attention to quality.

According to modern scientific researchFor a long polar day, the total radiation over Antarctic is approaching equatorial, but about 90% of this solar radiation is reflected back to the atmosphere. The formation of ice cover occurred 25-30 million years ago, as evidenced by the data of the study of precipitation of the World Ocean. Back at the beginning cenozoic era Moderate cool climate has retained in Antarctica.
With cooling on the planet, there were initially small glaciers in the mountains of Hambursv in Eastern Antarctica, but gradually, getting abundant food in the form of snow, they descended from the mountains to the plain. The massive ice cover began to form. For a long time, Australia has been connected with Antarctic, but approximately 35 million years ago she broke off.
In the deepened and expanding strait between Australia and Antarctica, the water was poured cold flow, the most powerful in the modern ocean system. It sweels twice as much as in all combined rivers of our planet. As a result, a natural natural barrier was formed, which prevented any heat penetration into the Antarctic region.
The barrier of the circumpolar flow and today retains the giant ice shell of Antarctica from the destruction. In addition, the neighborhood of a huge ice array with rather warm ocean basins provides in the southern hemisphere of our planet conditions for enhanced atmospheric circulation throughout the year.
The distribution of pressure in the upper layers of the atmosphere determines the inflow relative to warm and wet air from the ocean to Antarctica, which causes precipitation that feeds the glaciation. Nowadays, the Ice Cap Antarctica plays an important role in the system of global circulation of the atmosphere on the planet. The disappearance of a huge ice shell would contribute to a decrease in the contrast of the temperature, weakening the interconnecting air flows and the actual erosion of the geographical boundaries and climatic zones. This, in turn, would lead to less contrast natural conditions and a sharp reduction in the wide variety of life on our planet.

Were great catastrophes.
Primitive organisms became more complicated while, through a long string of ancestors, there were finally a person. Grades were gradually filled in the geological chronicle, and the slim picture of the development of the Earth was already close to completion. It seemed that the founder of the founder of the scientific geology of Charles Lileel was coming true, made back in 1830: "Order in nature, from the most early periods, was monotonous in the sense, in which we consider it to be monotonous and now, and we hope that it will remain as such and for the future. "
And yet the catastrophe was!
signs of sharp changes were noted simultaneously within the entire land. Over the last billion years the greatest value There were four great catastrophes - 650, 230, 65 and 35 million years ago.
The first of them was associated with the largest in the history of the earth byolenion. His traces were found on all the continents, except Antarctica, which is now covered with glaciers and therefore poorly studied. There are signs of glaciation and in equatorial areas. They may argue - the continents move, and those areas that are currently at the equator have once been near Poles. But now learned to determine the latter of ancient continents. It turned out that Scotland and Belarus, where ice sediments were found with about 650 million years old, at that time were at the equator. So, the glaciers then reached the equator. Prior to that, the sun gave heat a few percent less than now. But in the atmosphere there were much more carbon dioxide, and the greenhouse effect warmed the ground. In the oceans, plants appeared (blue-green, and then "real" algae), they consumed and decomposed carbon dioxide gas, and "by eating their own blanket", brought the earth to almost complete glaciation. As a result, many algae extinct, and the "blanket" gradually recovered.
The second catastrophe occurred 230 million years ago, shortly after another major glaciation. It was not worldwide and covered only polar and part of the temperate latitudes of the southern hemisphere. With glaciation, as has been proven, climate aridness is associated. The water of the oceans entered the huge bays surrounded by deserts, and evaporated in them. Salts fell away. One of these bays was in the east of the East European Plain. Salt left the ocean, the water during his great cycle returned to it. As a result, the salinity of the water of the ocean has greatly decreased. Not all maritime organisms were able to survive it. According to some data, 97 percent of the organisms who lived before in the seas and the oceans died out. Ground fauna and catastrophe flora did not touch.
Sixty-five million years ago, the most mysterious event in geological history occurred. Dinosaurs and other giant reptiles that prevail to it more than one hundred million years have become extinct dinosaurs and other gigantic reptiles. Together with them extinct weathered Sea Ammonites, Belemnites and many types of microscopic organisms. Dozens of hypotheses are proposed explaining the extinction, but among them there is not one that would be convincing, from the point of view of all or at least most researchers. The theory of extinction of dinosaurs still have to be created.
In the mesozoic, when dinosaurs lived, the warm climate dominated all the land. Water on the surface of the oceans in the polar regions had a temperature of 15, and sometimes 18 degrees. Approximately the same conditions dominated at the beginning of the Cenozoic - the "century of mammals" - up to 35 million years ago. But then very quickly, almost instantly (on the scale of geological time it "Moment" lasted about a hundred thousand years) The temperature everywhere decreased by several degrees. In the tropics it became colder than now, and in moderate and polar latitudes after cooling, the temperature was still much higher than modern.

Causes of cooling
Until recently, the temperature changes were tried mainly on the remnants of animals and plants. On the cooling indicated the extinction of thermal-loving species. But it was always possible to say that in the past, organisms lived in different conditions than now, and the extinction is not connected with cooling, but with something else. Thermometers are now found, which allow you to more objectively judge the conditions of the past. The isotopic composition of oxygen, which is part of an ancient organisms is determined. In addition to the most common isotope with atomic weight 16, there is still an isotope with atomic weight 18 - the so-called heavy oxygen. But in the remnants of ancient organisms, the content of severe oxygen changes depending on the temperature of the water in which they dwell. The oxygen thermometer showed that about 35 million years ago, it was the cooling, and not any other than a doubt change in the habitat.
What was the reason for cooling? There are many hypotheses. The first of them is a hypothesis of reducing the luminosity of the Sun. But astrophysics against - neither the sun, no stars like it can change the luminosity sharply. It does not decrease, but very slowly and gradually grows - about one percentage of 100 million years. Some botany suggested that the slope of the earth's axis suddenly changed. Specialists in heavenly mechanics refuse to even discuss such a hypothesis, it seems completely ridiculous.
Is it possible to explain the cooling of the fact that "the blanket" was told "the earth - decreased by the greenhouse effect of its atmosphere? To do this, it should reduce the content of carbon dioxide. It depends on how quickly consume carbon dioxide plants. Than magnificent vegetation, the higher the photosynthesis and those less content CO in the atmosphere. But when cooling, vegetation becomes less lush, and the content of carbon dioxide in the air is growing. Greenhouse effect Holds back the cooling caused by other reasons.
Maybe the earth "changed out" to another, brighter clothes? After all, we, to escape from the heat, we move into white. White surfaces reflect the sun's rays. So that the Earth acquires a big whiteness, extensive glaciers should appear, sea ice And snowy fields. They appear only at low temperatures. An increase in albedo (reflective, ability) can support cooling, but it cannot be caused.
Up to 35 million years ago, snow and ice was probably not anywhere else, except for high mountains. But polar latitudes received as much solar heat as they receive it now. Where did the extra warmth come from? In winter, ice are in the Sea of \u200b\u200bAzov, but the southwestern part of the Barents Sea never freezes. This is explained by the fact that the northern shores of Europe is suitable for the warm current. Maybe 40-50 million years ago it was more powerful? Alas, and this explanation is not suitable. Once there was no sea between Scandinavia and Greenland. Fifty-five million years ago, they began to move slowly from each other, and only about 30 million years ago, a deep-sea message was established between Norwegian-Greenland and Poland. The sea, through which an ancient Gulf Stream could have been leaked!
Oceans and the atmosphere of the Earth form a single climate machine. The location of the continent of the northern hemisphere did not create conditions for the warm climate of the Arctic. But the situation saved the southern hemisphere. Australia then was much south and formed a single mainland with Antarctica. South America has connected with him - the drill strait was not. In such conditions, warm currents caused by the eastern winds in subtropical latitudes were rotated south along the eastern shores of South America and Australia and reached Antarctica. Within its limits, a pretty warm climate was dominated and the forests of southern beech grew. It is through Antarctica from America in Australia, a sample, many representatives penetrated vegetable world And even freshwater crustaceans. Two huge whirlpools in the southern hemisphere - one in a quiet, and the other in the Atlantic and Indian Oceans - a moderate and polar latitudes were insulated. The heat was so much that it was enough for heating the northern hemisphere.
55 million years ago Australia became slowly moving away to the north. But between her and Antarctica, there was still a long time, and then the strait was narrow and shallow. Only 35 million years ago, South Australia arose powerful oceanic currentCustomized by Western winds. This radically changed the climatic conditions of the whole land. Two southern hemisphere whispering was merged into one. Now from the southeastern shores of South America (still connected with Antarctic) ocean water made almost trip around the world Near the coast of Antarctica, the south-western banks of South America and turned north. Further, along the equator, their challenges are already eastern winds. Through a wide and deep shed between Australia (although she moved away from Antarctica, but was much south who now) and Southeast Asia the flow penetrated into Indian Ocean, then rotated south and ... the cycle was repeated.

Glaciers cover Antarctia
On distant and cold south during long Path Water managed to cool very much. Then cooled water penetrated tropical latitudes and also cooled them. The cooling caused the growth of glaciers in East Antarctica. The names of Eastern and Western Antarctic are conditional. In essence, any part of this mainland will be Northern in relation to the southern pole. But European travelers usually walked to Antarctica through Atlantic Ocean. For them, its more rugged part adjacent to South America was in the West, and the main, more massive part - in the east. If we mentally remove the modern ice cover, then Western Antarctica will turn into the Islands Archipelago, the Eastern will still remain in the mainland.
For the growth of glaciers, it is necessary that the snow falling for the winter does not have time to melt in the summer. Snow is becoming more and more, gradually he under the severity of the overlying layers turns into ice. Cashing large masses, the ice begins to flow, like lava (but much slower). In the mountain valleys, ice flows are moving, huge glacial shields and dome with relatively steep edges and a flat middle, similar to Karavai are formed on the plain. This analogy is not accidental - after all, the dough acquires the form of punishing the same hydromechanical laws for which the ice acquires the form of the dome. Both the dough and ice can be viewed as very viscous fluids.
In the center of East Antarctica are mountains of Hamburg. Now they are buried under the ice. Mountains managed to detect, measuring the thickness of the glacier.
At the tops of the mountains of Hambursva, the glaciers could arise before the start of the cooling. When the temperature declined, the glaciers took the entire mountain range. A cold air mass that cooled the surrounding area was formed above it. The more glaciers became, the better the conditions for their further growth. Very quickly (of course, in a geological sense), just a few tens of thousands of years, the glaciers took all Eastern Antarctica and reached her shores. But they were almost anywhere went down to the sea and almost did not give rise to icebergs.
The appearance of a glacial shield with an area of \u200b\u200b10 million square kilometers had a huge impact on the climate and the initial cooling was repeated many times. Ice was covered by seven percent of the entire surface of the sushi. He began to fall out, sea ice appeared. Huge white surfaces reflected the sun's rays. As a result, it became colder throughout the land - not only in the southern, but also in the northern hemisphere. The cooling was accompanied by an enhancement of aridness - it was at this time that the sugar desert was formed.
The growth of glaciers also caused a decrease in the ocean level. From its surface, water is constantly evaporated, but it is just as constantly returning back - the moisture that is transferred to the air flows to the land, then the rivers flow into the ocean again. But when glaciers grow, the snow falling on them is not returning to the ocean, but goes to the construction of glaciers: the volume of water connected in glaciers, as if deducted from the ocean volume. 35 million years ago, the ocean level fell about sixty meters. As a result, extensive shallow water turned into a land. The sea went with most of the Eastern European Plain and from Western Siberia.
The vegetation has changed dramatically. Before the start of the cooling of the palm trees grew up to the coast of the Kara and Okhotsk seas. When it became colder, they were preserved only in the southern part of the Eastern European Plain, in Central Asia and in the region of Vladivostok.
But the most important changes have undergone animal world. Up to 35 million years ago, multiparty - minor animals were widespread, similar to rodents, but had a completely different internal structure. They died out, and rodents came to replace them. Ancient predators and ancient ungulates were extinct, instead, the development of modern predators and hoofs began. Changes in the detachment of primates are of great importance. Up to 35 million years ago, only lemurs were distributed and long ads - lower primates. Now Lemurs are found in Madagascar, in the rest of the tropical zone most of them extinted with the beginning of the cooling. Monkeys came to the change of lemraram.
So, the main features of the environment of us were 35 million years ago as a result of the beginning of the olelion of East Antarctica. The glaciation was the reason, but there was no root cause. All as we already know, began with the separation of Australia and Antarctica and the movement of Australia to the north.

Long path of nature land
35 million years ago there were only the main features of modern nature, but she was still not very similar to what we see today. The ground was to have a long and difficult path. Australia's movement to the north continued; About 20 million years ago, a deep-water strait was closed, separating it from South-East Asia (shallow straits there exist now). Equatorial for the Pacific, before that, penetrating into the Indian Ocean, turned to the south along the shores of Australia and began to heat the temperate latitudes of the southern hemisphere. In the north, finally there was a deep-water message between the Norwegian-Greenland and the polar pool, and warm water penetrated it. And in the north, warming happened in the extreme south.
Alas, it was short. 25 million years ago, South America began to move away from Antarctica. 12-14 million years ago, the shed between them became wide enough and deep. Through the Strait, the Drake began to pass the southern circular flow, encircling Antarctica. The water exchange between the tropical and moderate latitudes of the southern hemisphere has sharply decreased dramatically. In the polar latitudes it was cold, in the tropics it became warmer - there no longer got cold water from the south. It was then that modern climatic contrasts arose when they suffer from heat in some places, and in others - from the cold. Antarctic glaciers increased - they also occupied Western Antarctica.
Cooling in moderate latitudes caused dryness enhancement. It was then, about 12 million years ago, a steppe emerged in the south of East European Plain. In the steppes, Eurasia and the Savannes of Africa wandered the herd of hypartarions - three-plated kin relatives that moved from America along the land "bridge", which existed on the site of modern Bering Strait. In the south of Asia and Africa spread ramapitecia, which can be considered our right ancestors. Their growth was small - approximately meter, but they have already walked on two legs.
About three million years ago, glacial shields appeared in the northern hemisphere. They covered Greenland, Iceland and land, which was on the site of the Barents Sea. The appearance of new birth of animals - elephants, bulls and horses is connected with the new cooling and enhancement of aridness. IN East Africa Australopiteki (descendants of ramapitecov) began to hunt, applying the first stone implements - they turned into people.
About a million years ago, the oledenation covered the moderate latitude of the northern hemisphere. The edge of the glacier dominated the very cold and dry steppes, mammoths and hairy rhinos were grazed. Glaciers then fell, then retreated again. For one of the periods of the smallest development of glaciers, our time falls.
Will the recognition of sharp changes to any incorrect conclusions? After all, B. early XIX. A century some believed that after each catastrophe, a new "act of divine creation" should be followed. The author of the "catastrophe theory" of Georges Kuvier did not write anything like that. In his opinion, the empty mainland settled animals that came from other places. How they appeared there, Kuvye did not specify. About the "Divine Creation" wrote some students of Kuvye, who sought to agree on his views with religious ideology.
How is the case today, when no one in the justice of evolutionary theory is in doubt? Now it is proved that many organisms suddenly appeared after the catastrophe actually existed before it, but were very rare or found only in separate limited areas. When the "Mountains of the Earth" died, the former Paria went on an external geological history. They quickly multiplied, widespread and became new owners of the Earth. At first there were no organisms that could master all the conditions suitable for living. This gave impetus to quick evolution.
Monkeys, for example, existed to the last catastrophe, but were much less common than lemurs. It is possible that if the warm and wet climate is preserved, Lemur would dominate and now. On one of the reports made by me in Moscow, the question was asked: "If the antening of Antarctica did not begin, then we would live among subtropical forests?" I had to give such an answer: "There would really be subtropical forests here, but they would not live in them, and lemurs with huge eyes." The cooling has many times increased the rate of evolution. Great catastrophes are in the essence of the revolution in the development of the organic world. Without them, he would develop much slower.
In this regard, the words of the great English natural scientist of the XVII century Villama Gareva are remembered: "Do not praise, not to blame - everything worked well." Once Supporters of George Kuvier and Charles Lileel fiercely argued with each other. Now it is clear that they were right and others. And slow and gradual development, and disasters are explained by natural reasons.
The last great "catastrophe" is associated with the beginning of the beolation of Antarctica. Will the new catastrophe case happen if the warming caused by the human activity will lead to the melting of glaciers and the rise in the ocean level of 70 meters? A look in the past shows that the "World Flood" will not be. After all, 20-30 million years ago, the volume of glaciers was already close to modern. At that time, a rather warm climate dominated in moderate and polar latitudes. The ice shield of Eastern Antarctica fell on the edges, but did not decrease in size - much more snow fell on its surface than now.
In my opinion, the upcoming warming will also lead to heavy snowfall. The largest glacier shields may even increase their thickness as a result. They will give less icebergs and told a little along the edges, but will not decrease in volume until the amount of melting exceeds the volume of snow water, annually obtained by glaciers. So that it happens, you need warming by 10-12 degrees. Only after this, Antarctician glaciers will begin to fall apart, and the ocean level to grow. But about such warming in the foreseeable future, speech does not go. With a smaller warming, the ocean level may even decrease as a result of an increase in the thickness of Antarctic glaciers.
From monkeys, widely spreading 35 million years ago, Homo Sapiens occurred, a reasonable man. If humanity justifies this high title and will act reasonably, the last great "catastrophe" will not turn, indeed, in a catastrophe.

D. Kvasov, Doctor of Geographical Sciences

Still after the death of the famous researchers Captain Robert Scott and Sir Ernest Sheklton helped scientists learn more about Antarctica. The data recorded in the ship journals of expedition members has shown that the area covering the end of the ice has not changed.

The study, published in the European Journal of Sciences on Earth, suggests that Antarctic sea ice is much less sensitive to climate change than the Arctic, which for the 20th century is pretty strengthened - from the end of the 1970s the Arctic lost an average of 53,900 square meters. KM Ice per year.

According to the climatologists of the Reding University,

the volume of antarctic ice during the summer decreased by only 14% compared with the 1900s.

As Robert Bindshadler explains, a researcher from the center of Space Flights of Goddard and one of the authors of the study, from the results obtained "it follows that the starting of the glacier can continue decades. Maybe,

changes that today occur with Pine Island have actually begun in the 1940s. "

Understanding what causes current changes in glaciers is a significant step in finding ways to combat global warming and its consequences.

Specialists of the US National Agency for Air Space and Space Studies (NASA) have found the cause of the melting of Antarctic ice, writes The Independent. Researchers are considered a source of heat that melts the ice shell in the southern pole of the Earth can be hiding under ice mantle plume (hot lava stream capable of breaking the earth's bark and break out to the surface by forming a volcano - editor). The temperature of the earth's crust over it increases, which leads to melting, cracking and destruction of glaciers.

About 30 years ago, the hypothesis about the existence of such a plum under the region, Mary Bard in Western Antarctica, a scientist deposited from the University of Colorado. But only recently managed to find confirmation of his assumption. NASA specialists were able to make sure the veracity of this theory.

For this, experts have developed a special mathematical model. Calculations have shown how many geothermal energy is required for the processes occurring in the land of Mary Bard, including for the emergence of existing underground rivers and lakes. Comparing the theoretical model with the data obtained during the Antarctic expeditions, scientists came to the conclusion that under the surface there is indeed a mantle plume, which was formed another 50-110 million years ago - long before the formation on the continent of the ice shield.

As wrote a "new day", the cause of the melting of glaciers in Greenland is also a mantle plum. The study was conducted by an international group of scientists, with the direct participation of employees of the Novosibirsk State University (NSU) and the Institute of Oil and Genology and Geophysics () SB RAS. Scientists tied up now the decrease in the volume of ice cover with the events of 80-35-million limitations, when sushi began to rise above the ocean, later the name of Greenland. It was then that the so-called ancient mantine plume originated.

Scientists have discovered melting water under Greenland glaciers. It was previously believed that the glaciers were taped only in the coastal part of the island, but in 2001, in his depths between the stone rock and ice, they found a layer of liquid water. Due to the fact that here the thickness of the glaciers reaches 3 thousand meters, and the plus temperatures are not at all, melt water, which forms treated rivers and lakes, should not be.

Researchers are confident that the melting of ice contributes to plume, the main part of which is now under Iceland, and it is called "Icelandic". He is well known to geologists and, as it turned out, tens of millions of years ago, Greenland sailed over him. After calculating the theoretical heat flux, which can cause plume, it turned out that it is quite enough to melt the lower part of the glacier.

"This work presented geophysical evidence that the Icelandic plume left a trace in the lithosphere of the island. Thus, not only fast climate variations on Earth affect the mass of Greenland glaciers, but also the echoes of large-scale events that took place tens of millions of years ago, "said one of the research participants, head of NSU laboratories and, Professor Ivan Kulakova. The results of the study were published in the prestigious magazine Nature Geoscience.

As Lenta.Ru reminds, in October from one of the two largest ISLAND Glaciers Pine Island surfed with an area of \u200b\u200ban area, four times the island of Manhattan. According to the forecast made on the basis of the satellite images of glaciers, in the future the process of melting of ice will accelerate another two or three times, increasing the level of the world's ocean. In July, one of the largest registered icebergs broke out in Antarctica in Antarctica. Its area was 5800 square kilometers.

Washington, Ivan Gridin