Ancient glaciation of Eurasia. The role of ancient glaciation in the formation of the relief of Eurasia

The retreat of the fourth and last Wurm glaciation in the history of the Earth began in the 18th millennium BC. e. However, Northern Europe for another ten thousand years remained bound by an ice shell, the thickness of which reached two kilometers. The frozen sea of blue ice rested against the northern spurs of the Alps and the Carpathians.

slopes Ural Range a powerful tongue of ice reached the heart of the Eurasian Plain. Mountain peaks of the Pyrenees, Apennines, Balkans, Caucasus, Central Asia were covered in huge ice caps that sent chilling torrents of ice and snow down into the deep valleys that surrounded them. From Middle England to the Middle Dnieper and further to the Pacific Ocean, the Eurasian continent encircled a wide belt of tundra. The arctic cold with a piercing cold burned the waters and shores of the Mediterranean, the Black and Caspian Seas. And in Southern Europe, in Asia Minor, on boundless expanses Central Asia and Siberia, with evergreen needles, the ocean of taiga is spread.

TO XIV thousand. BC e. from under the ice cover, the lands of modern Denmark, Germany, Poland, South Lithuania, part Northern Russia and Siberia. The glacier retreating into the Arctic left everywhere huge lakes and scattered piles of huge boulders everywhere. Contours emerged from under the ice northern seas. Following the receding glacier, mammoths, woolly rhinos, and reindeer moved north. To the south of them, in the boundless Eurasian expanses, herds of wild horses, bulls, deer, bison grazed. They were constantly hunted by hyenas, bears, cave lions. The mammoths and woolly rhinoceroses that reached the north of the continent soon died and now remind of themselves only as fossilized, frozen remains preserved by permafrost.

In the XIV-XI millennium BC. e. the final, Gothic, phase of the last (Wurm) glaciation of the Earth has passed. From century to century, the rocks of Northern Britain and Scandinavia, polished by ice and cold, became clearer and clearer. The sun rescued them from the ice captivity, which lasted nearly a hundred thousand years. Following the receding glacier, the tundra, scorched by the arctic cold, was lined with a boundless green carpet. And in pursuit of her, the taiga stepped over the Carpathian and Alpine barriers. From year to year it pushed further and further north, towards the steaming cold Arctic, pushing out dwarf birch trees torn by prickly winds and shapeless, spreading pine trees, clinging to death in the thawing earth with light yellow crooked trunks. Following the persistent green dwarfs, the seas of coniferous forests were advancing to the north by living waves.

For ten thousand years, a giant ice sheet has been sliding meter by meter from Europe.

The planet thawed, the climate softened. The continent was covered with mixed forest. Its fragrant, delicate green canopy hid the land from the cold currents of air from the north. Glacial lakes filled with life, their swampy banks overgrown with juicy herbs. Silent involuntary wanderers, eternal companions of the glacier - boulders, fragments of distant northern rocks, gloomy uninvited guests in Europe - dressed in moss and grew into the turf. In northern Eurasia, warmed by the sun, oak groves, spreading lindens, and elms were added from century to century.

But in the IX millennium BC. e. Europe still fully felt the cold of the leaving Arctic ice. The precipitous cliffs of Britain and Scandinavia, polished almost to a mirror shine by the salty waves of the Atlantic, blue ice floes and cruel winds, endlessly said goodbye to the boundless sparkling ice field creeping north.

During the IX-VI millennium BC. e. forest-tundra Northern Europe overgrown with mixed forest. The canopy of the forests was filled with many red deer, wild boars, fur-bearing animals, and a rich feathered world. Europe was turning into a hunting paradise. The climate became milder from century to century.

Freed from the ice captivity, the Baltic took on a modern shape. Water Lake Ladoga made their way to Gulf of Finland and formed a new river - the Neva. The land that existed between Britain and the Continent gradually sank more and more into the depths of the sea. The resulting English Channel separated the islands of the British Archipelago from Europe. The Black Sea for a long time remained a lake connected with the Caspian, but its breakthrough by the waters of the Bosphorus Isthmus was nearing, and around the 5th millennium BC. e. this event happened. Europe took on a modern shape.

One of the mysteries of the Earth, along with the emergence of Life on it and the extinction of dinosaurs at the end of the Cretaceous period, is - Great Glaciations.

It is believed that glaciations are repeated on Earth regularly every 180-200 million years. Traces of glaciation are known in deposits that are billions and hundreds of millions of years ago - in the Cambrian, in the Carboniferous, in the Triassic-Permian. The fact that they could be, "say" the so-called tillites, breeds very similar to moraine last one, to be exact. last glaciations. These are the remains of ancient deposits of glaciers, consisting of a clay mass with inclusions of large and small boulders scratched during movement (hatched).

Separate layers tillites, found even in equatorial Africa, can reach power of tens and even hundreds of meters!

Signs of glaciation have been found on different continents - in australia, South America, Africa and India which is used by scientists to reconstruction of paleocontinents and are often cited as evidence theories of plate tectonics.

Traces of ancient glaciations indicate that continental-scale glaciations- this is not at all a random phenomenon, it is a natural phenomenon that occurs under certain conditions.

The last of the ice ages began almost a million years ago, in the Quaternary time, or the Quaternary period, the Pleistocene was marked by the extensive distribution of glaciers - Great Glaciation of the Earth.

Under the powerful, many kilometers of ice covers were Northern part North American continent - the North American ice sheet, reaching a thickness of up to 3.5 km and extending to about 38 ° north latitude and a significant part of Europe, on which (ice cover up to 2.5-3 km thick). On the territory of Russia, the glacier descended in two huge tongues along the ancient valleys of the Dnieper and Don.

Partially glaciation also covered Siberia - there was mainly the so-called "mountain-valley glaciation", when glaciers did not cover the entire space with a powerful cover, but were only in the mountains and foothill valleys, which is associated with a sharply continental climate and low temperatures in Eastern Siberia. But almost all Western Siberia, due to the fact that the damming of the rivers took place, and their flow into the Arctic Ocean stopped, it turned out to be under water, and was a huge sea-lake.

In the Southern Hemisphere, under the ice, as now, was the entire Antarctic continent.

During the period of maximum distribution of Quaternary glaciation, glaciers covered over 40 million km 2–about a quarter of the entire surface of the continents.

Having reached the greatest development about 250 thousand years ago, the Quaternary glaciers of the Northern Hemisphere began to gradually decrease, as the glacial period was not continuous throughout the Quaternary period.

There are geological, paleobotanical and other evidence that glaciers disappeared several times, replaced by epochs. interglacial when the climate was even warmer than today. However, the warm epochs were replaced by cold spells, and the glaciers spread again.

Now we live, apparently, at the end of the fourth epoch of the Quaternary glaciation.

But in Antarctica, glaciation arose millions of years before the time when glaciers appeared in North America and Europe. In addition to climatic conditions, this was facilitated by the long-standing high mainland. By the way, now, due to the fact that the thickness of the glacier of Antarctica is huge, the continental bed of the "ice continent" is in some places below sea level ...

Unlike the ancient ice sheets of the Northern Hemisphere, which disappeared and reappeared, the Antarctic ice sheet has changed little in its size. The maximum glaciation of Antarctica was only one and a half times greater than the modern one in terms of volume, and not much more in area.

Now about the hypotheses ... There are hundreds, if not thousands, of hypotheses why glaciations occur, and whether they were at all!

Usually put forward the following main scientific hypotheses:

Volcanic eruptions, leading to a decrease in the transparency of the atmosphere and cooling throughout the Earth;
Epochs of orogeny (mountain building);
Quantity reduction carbon dioxide in the atmosphere, which reduces the "greenhouse effect" and leads to cooling;
The cyclical activity of the Sun;
Changes in the position of the Earth relative to the Sun.

But, nevertheless, the causes of glaciation have not been finally clarified!

It is assumed, for example, that glaciation begins when, with an increase in the distance between the Earth and the Sun, around which it rotates in a slightly elongated orbit, the amount of solar heat received by our planet decreases, i.e. Glaciation occurs when the Earth passes the point in its orbit that is farthest from the Sun.

However, astronomers believe that changes in the amount of solar radiation hitting the Earth alone are not enough to start an ice age. Apparently, fluctuations in the activity of the Sun itself also matter, which is a periodic, cyclic process, and changes every 11-12 years, with a cycle of 2-3 years and 5-6 years. And the largest cycles of activity, as established by the Soviet geographer A.V. Shnitnikov - approximately 1800-2000 years.

There is also a hypothesis that the emergence of glaciers is associated with certain parts of the Universe through which our solar system passes, moving with the entire Galaxy, either filled with gas, or “clouds” of cosmic dust. And it is likely that the "cosmic winter" on Earth comes when Earth is located at the point farthest from the center of our Galaxy, where there are accumulations of "cosmic dust" and gas.

It should be noted that usually periods of warming always “go” before cooling epochs, and there is, for example, a hypothesis that the Arctic Ocean, due to warming, is sometimes completely freed from ice (by the way, this is happening now), increased evaporation from the surface of the ocean , currents of humid air are directed to the polar regions of America and Eurasia, and snow falls over the cold surface of the Earth, which does not have time to melt in a short and cold summer. This is how ice sheets form on the continents.

But when, as a result of the transformation of part of the water into ice, the level of the World Ocean drops by tens of meters, warm Atlantic Ocean ceases to communicate with the Arctic Ocean, and it is again gradually covered with ice, evaporation from its surface abruptly stops, less and less snow falls on the continents, the “feeding” of glaciers is deteriorating, and the ice sheets begin to melt, and the level of the World Ocean rises again. And again the Arctic Ocean connects with the Atlantic, and again the ice cover began to gradually disappear, i.e. the cycle of development of the next glaciation begins anew.

Yes, all these hypotheses quite possible, but so far none of them can be confirmed by serious scientific facts.

Therefore, one of the main, fundamental hypotheses is climate change on the Earth itself, which is associated with the above hypotheses.

But it is quite possible that the processes of glaciation are associated with the combined impact of various natural factors, which could act jointly and replace each other, and it is important that, having begun, glaciations, like “wound clocks”, are already developing independently, according to their own laws, sometimes even “ignoring” some climatic conditions and patterns.

And the ice age that began in the Northern Hemisphere about 1 million years back, not finished yet, and we, as already mentioned, live in a warmer period of time, in interglacial.

Throughout the epoch of the Great Glaciations of the Earth, the ice either receded or advanced again. On the territory of both America and Europe, there were, apparently, four global ice ages, between which there were relatively warm periods.

But the complete retreat of the ice occurred only about 20 - 25 thousand years ago, but in some areas the ice lingered even longer. The glacier retreated from the area of modern St. Petersburg only 16 thousand years ago, and in some places in the North small remnants of the ancient glaciation have survived to this day.

Note that modern glaciers cannot be compared with the ancient glaciation of our planet - they occupy only about 15 million square meters. km, i.e. less than one-thirtieth of the earth's surface.

How can you determine whether there was a glaciation in a given place on the Earth or not? This is usually fairly easy to determine by peculiar shapes. geographical relief and rocks.

Large accumulations of huge boulders, pebbles, boulders, sands and clays are often found in the fields and forests of Russia. They usually lie directly on the surface, but they can also be seen in the cliffs of ravines and in the slopes of river valleys.

By the way, one of the first who tried to explain how these deposits were formed was the outstanding geographer and anarchist theorist, Prince Peter Alekseevich Kropotkin. In his work "Investigations on the Ice Age" (1876), he argued that the territory of Russia was once covered by huge ice fields.

If we look at the physical map European Russia, then in the location of hills, hills, basins and valleys major rivers some patterns can be seen. So, for example, Leningrad and Novgorod region from the south and east, as it were, limited Valdai Upland, which has the form of an arc. This is exactly the line where, in the distant past, a huge glacier, advancing from the north, stopped.

To the southeast of the Valdai Upland is the slightly winding Smolensk-Moscow Upland, stretching from Smolensk to Pereslavl-Zalessky. This is another of the boundaries of the distribution of sheet glaciers.

Numerous hilly winding uplands are also visible on the West Siberian Plain - "manes", also evidence of the activity of ancient glaciers, more precisely glacial waters. Many traces of stops of moving glaciers flowing down the mountain slopes into large basins have been found in Central and Eastern Siberia.

It is difficult to imagine ice several kilometers thick on the site of the current cities, rivers and lakes, but, nevertheless, the glacial plateaus were not inferior in height to the Urals, the Carpathians or the Scandinavian mountains. These gigantic and, moreover, mobile masses of ice influenced the entire natural environment- relief, landscapes, river runoff, soils, vegetation and wildlife.

It should be noted that in Europe and the European part of Russia, practically no rocks have survived from the geological epochs preceding the Quaternary period - the Paleogene (66-25 million years) and the Neogene (25-1.8 million years), they were completely eroded and redeposited during the Quaternary, or as it is often called, Pleistocene.

Glaciers originated and moved from Scandinavia, Kola Peninsula, the Polar Urals (Pai-Khoi) and the Northern Islands Arctic Ocean. And almost all the geological deposits that we see on the territory of Moscow are moraine, more precisely moraine loams, sands of various origins (water-glacial, lake, river), huge boulders, as well as cover loams - all this is evidence of the powerful impact of the glacier.

On the territory of Moscow, traces of three glaciations can be distinguished (although there are many more of them - different researchers distinguish from 5 to several dozen periods of advances and retreats of ice):

Okskoe (about 1 million years ago),
Dnieper (about 300 thousand years ago),
Moscow (about 150 thousand years ago).

Valdai the glacier (disappeared only 10 - 12 thousand years ago) "did not reach Moscow", and the deposits of this period are characterized by water-glacial (fluvio-glacial) deposits - mainly the sands of the Meshchera lowland.

And the names of the glaciers themselves correspond to the names of those places to which the glaciers reached - to the Oka, the Dnieper and the Don, the Moscow River, Valdai, etc.

Since the thickness of the glaciers reached almost 3 km, one can imagine what a colossal work he did! Some elevations and hills on the territory of Moscow and the Moscow region are powerful (up to 100 meters!) Deposits that the glacier “brought”.

The best known, for example Klinsko-Dmitrovskaya moraine ridge, separate hills on the territory of Moscow ( Vorobyovy Gory and Teplostan Upland). Huge boulders weighing up to several tons (for example, the Maiden's Stone in Kolomenskoye) are also the result of the work of the glacier.

Glaciers smoothed out uneven terrain: they destroyed hills and ridges, and the resulting rock fragments filled depressions - river valleys and lake basins, transferring huge masses of stone fragments over a distance of more than 2 thousand km.

However, huge masses of ice (considering its colossal thickness) pressed so hard on the underlying rocks that even the strongest of them could not withstand and collapsed.

Their fragments were frozen into the body of a moving glacier and, like emery, scratched rocks composed of granites, gneisses, sandstones and other rocks for tens of thousands of years, developing depressions in them. Until now, numerous glacial furrows, "scars" and glacial polishing on granite rocks, as well as long hollows in the earth's crust, subsequently occupied by lakes and swamps, have been preserved. An example is the countless depressions of the lakes of Karelia and the Kola Peninsula.

But glaciers did not plow out all the rocks on their way. The destruction was mainly those areas where the ice sheets originated, grew, reached a thickness of more than 3 km and from where they began their movement. The main center of glaciation in Europe was Fennoscandia, which includes scandinavian mountains, the plateaus of the Kola Peninsula, as well as the plateaus and plains of Finland and Karelia.

Along the way, the ice was saturated with fragments of destroyed rocks, and they gradually accumulated both inside the glacier and under it. When the ice melted, masses of debris, sand and clay remained on the surface. This process was especially active when the movement of the glacier stopped and the melting of its fragments began.

At the edge of glaciers, as a rule, water flows arose, moving along the surface of the ice, in the body of the glacier and under the ice layer. Gradually, they merged, forming whole rivers, which, over thousands of years, formed narrow valleys and washed away a lot of clastic material.

As already mentioned, the forms of glacial relief are very diverse. For moraine plains many ridges and ridges are characteristic, indicating the stops of moving ice and the main form of relief among them are shafts of terminal moraines, usually these are low arched ridges composed of sand and clay with an admixture of boulders and pebbles. The depressions between the ridges are often occupied by lakes. Sometimes among the moraine plains one can see outcasts- blocks hundreds of meters in size and weighing tens of tons, giant pieces of the glacier bed, transferred by it over great distances.

Glaciers often blocked the flow of rivers and near such "dams" huge lakes arose, filling the depressions of river valleys and depressions, which often changed the direction of river flow. And although such lakes existed for a relatively short time (from a thousand to three thousand years), they managed to accumulate on their bottom lake clays, layered precipitation, counting the layers of which, one can clearly distinguish the periods of winter and summer, as well as how many years these precipitations accumulated.

In the era of the last Valdai glaciation arose Upper Volga glacial lakes(Mologo-Sheksninskoe, Tverskoe, Verkhne-Molozhskoe, etc.). At first, their waters had a flow to the southwest, but with the retreat of the glacier, they were able to flow to the north. Traces of the Mologo-Sheksninskoe Lake remained in the form of terraces and coastlines at an altitude of about 100 m.

There are very numerous traces of ancient glaciers in the mountains of Siberia, the Urals, Far East. As a result of ancient glaciation, 135-280 thousand years ago, sharp peaks of mountains appeared - "gendarmes" in Altai, in the Sayans, the Baikal and Transbaikalia, in the Stanovoy Highlands. The so-called "reticulate type of glaciation" prevailed here, i.e. if one could look from a bird's eye view, one could see how ice-free plateaus and mountain peaks rise against the background of glaciers.

It should be noted that during the periods of glacial epochs, rather large ice massifs were located on part of the territory of Siberia, for example, on archipelago Severnaya Zemlya, in the Byrranga mountains (Taimyr Peninsula), as well as on the Putorana Plateau in northern Siberia.

Extensive mountain-valley glaciation was 270-310 thousand years ago Verkhoyansk Range, Okhotsk-Kolyma Highlands and in the mountains of Chukotka. These areas are considered glaciation centers of Siberia.

Traces of these glaciations are numerous bowl-shaped depressions of mountain peaks - circuses or karts, huge moraine shafts and lake plains in place of melted ice.

In the mountains, as well as on the plains, lakes arose near ice dams, periodically the lakes overflowed, and giant masses of water rushed at incredible speed through low watersheds into neighboring valleys, crashing into them and forming huge canyons and gorges. For example, in Altai, in the Chuya-Kurai depression, “giant ripples”, “drilling boilers”, gorges and canyons, huge outcropping blocks, “dry waterfalls” and other traces of water streams escaping from ancient lakes “only - just "12-14 thousand years ago.

"Intruding" from the north on the plains of Northern Eurasia, the ice sheets either penetrated far to the south along the depressions of the relief, or stopped at some obstacles, for example, hills.

Probably, it is not yet possible to determine exactly which of the glaciations was the “greatest”, however, it is known, for example, that the Valdai glacier was sharply inferior in area to the Dnieper glacier.

The landscapes at the borders of the sheet glaciers also differed. So, in the Oka epoch of glaciation (500-400 thousand years ago), to the south of them there was a strip of Arctic deserts about 700 km wide - from the Carpathians in the west to the Verkhoyansk Range in the east. Even further, 400-450 km to the south, stretched cold forest-steppe, where only such unpretentious trees as larches, birches and pines could grow. And only at the latitude of the Northern Black Sea region and Eastern Kazakhstan did comparatively warm steppes and semi-deserts begin.

In the era of the Dnieper glaciation, the glaciers were much larger. Tundra-steppe (dry tundra) with a very harsh climate stretched along the edge of the ice cover. The average annual temperature approached minus 6°C (for comparison: in the Moscow region mean annual temperature currently around +2.5°C).

The open space of the tundra, where there was little snow in winter and very coldy, cracked, forming the so-called "permafrost polygons", which in plan resemble a wedge in shape. They are called "ice wedges", and in Siberia they often reach a height of ten meters! Traces of these "ice wedges" in ancient glacial deposits "speak" of the harsh climate. Traces of permafrost, or cryogenic impact, are also visible in the sands, these are often disturbed, as if “torn” layers, often with a high content of iron minerals.

Water-glacial deposits with traces of cryogenic impact

The last "Great Glaciation" has been studied for over 100 years. Many decades of hard work of outstanding researchers were spent on collecting data on its distribution on the plains and in the mountains, on mapping terminal moraine complexes and traces of glacier-dammed lakes, glacial scars, drumlins, and areas of “hilly moraine”.

True, there are researchers who generally deny the ancient glaciations, and believe glacial theory erroneous. In their opinion, there was no glaciation at all, but there was “a cold sea on which icebergs floated”, and all glacial deposits are just bottom sediments of this shallow sea!

Other researchers, "recognizing the general validity of the theory of glaciations", however, doubt the correctness of the conclusion about the grandiose scales of the glaciations of the past, and the conclusion about the ice sheets that leaned on the polar continental shelves is especially strong distrust, they believe that there were "small ice caps of the Arctic archipelagos”, “bare tundra” or “cold seas”, and in North America, where the largest “Laurentian ice sheet” in the Northern Hemisphere has long been restored, there were only “groups of glaciers merged at the bases of domes”.

For Northern Eurasia, these researchers recognize only the Scandinavian ice sheet and isolated "ice caps" of the Polar Urals, Taimyr and the Putorana Plateau, and in the mountains of temperate latitudes and Siberia - only valley glaciers.

And some scientists, on the contrary, “reconstruct” “giant ice sheets” in Siberia, which are not inferior in size and structure to the Antarctic.

As we have already noted, in the Southern Hemisphere, the Antarctic ice sheet extended to the entire continent, including its underwater margins, in particular, the regions of the Ross and Weddell seas.

The maximum height of the Antarctic ice sheet was 4 km, i.e. was close to modern (now about 3.5 km), the area of ice increased to almost 17 million square kilometers, and the total volume of ice reached 35-36 million cubic kilometers.

Two more large ice sheets were in South America and New Zealand.

The Patagonian Ice Sheet was located in the Patagonian Andes, their foothills and on the neighboring continental shelf. Today it is reminded of by the picturesque fjord relief of the Chilean coast and the residual ice sheets of the Andes.

"South Alpine Complex" New Zealand- was a reduced copy of the Patagonian. It had the same shape and also advanced to the shelf, on the coast it developed a system of similar fjords.

In the Northern Hemisphere, during periods of maximum glaciation, we would see huge arctic ice sheet resulting from the union North American and Eurasian covers into a single glacial system, and an important role was played by floating ice shelves, especially the Central Arctic ice shelf, which covered the entire deep-water part of the Arctic Ocean.

The largest elements of the Arctic ice sheet were the Laurentian Shield of North America and the Kara Shield of Arctic Eurasia, they had the form of giant plano-convex domes. The center of the first of them was located over the southwestern part of the Hudson Bay, the top rose to a height of more than 3 km, and its eastern edge extended to the outer edge of the continental shelf.

The Kara ice sheet occupied the entire area of the modern Barents and Kara seas, its center lay above by the Kara Sea, and the southern marginal zone covered the entire north of the Russian Plain, Western and Central Siberia.

From other elements of the Arctic cover special attention deserves East Siberian Ice Sheet which spread on the shelves of the Laptev, East Siberian and Chukchi seas and was larger than the Greenland ice sheet. He left traces in the form of large glaciodislocations New Siberian Islands and Tiksi area, are also associated with grandiose glacial-erosion forms of Wrangel Island and the Chukotka Peninsula.

So, the last ice sheet of the Northern Hemisphere consisted of more than a dozen large ice sheets and many smaller ones, as well as from the ice shelves that united them, floating in the deep ocean.

The periods of time in which glaciers disappeared, or were reduced by 80-90%, are called interglacials. The landscapes freed from ice in the conditions of a relatively warm climate were transformed: the tundra receded to north coast Eurasia, and taiga and broad-leaved forests, forest-steppes and steppes occupied a position close to the modern one.

Thus, over the past million years, the nature of Northern Eurasia and North America has repeatedly changed its appearance.

Boulders, crushed stone and sand, frozen into the bottom layers of a moving glacier, acting as a giant “file”, smoothed, polished, scratched granites and gneisses, and peculiar strata of boulder loams and sands formed under the ice, characterized by high density associated with the impact of glacial load - the main, or bottom moraine.

Since the dimensions of the glacier are determined balance between the amount of snow that falls on it annually, which turns into firn, and then into ice, and what does not have time to melt and evaporate during the warm seasons, then as the climate warms, the edges of the glaciers recede to new, “equilibrium boundaries”. The end parts of the glacial tongues stop moving and gradually melt, and the boulders, sand and loam included in the ice are released, forming a shaft that repeats the outlines of the glacier - terminal moraine; the other part of the clastic material (mainly sand and clay particles) is carried out by melt water flows and is deposited around in the form fluvioglacial sand plains (zandrov).

Similar flows also act in the depths of glaciers, filling cracks and intraglacial caverns with fluvioglacial material. After the melting of glacial tongues with such filled voids on the earth's surface, chaotic heaps of hills of various shapes and compositions remain on top of the melted bottom moraine: ovoid (when viewed from above) drumlins, elongated like railway embankments (along the axis of the glacier and perpendicular to the terminal moraines) ozes and irregular shape kamy.

All these forms of the glacial landscape are very clearly represented in North America: the boundary of ancient glaciation is marked here by a terminal moraine ridge with heights of up to fifty meters, stretching across the entire continent from its eastern coast to its western one. To the north of this "Great Ice Wall" glacial deposits are represented mainly by moraine, and to the south of it - by a "cloak" of fluvioglacial sands and pebbles.

As for the territory of the European part of Russia, four epochs of glaciation have been identified, and for Central Europe, four glacial epochs have also been identified, named after the corresponding alpine rivers - gunz, mindel, riss and wurm, and in North America Nebraska, Kansas, Illinois and Wisconsin glaciations.

Climate periglacial(surrounding the glacier) territories was cold and dry, which is fully confirmed by paleontological data. In these landscapes, a very specific fauna appears with a combination of cryophilic (cold-loving) and xerophilic (dry-loving) plants – tundra-steppe.

Now similar natural zones, similar to periglacial ones, have been preserved in the form of so-called relic steppes- islands among the taiga and forest-tundra landscape, for example, the so-called alasy Yakutia, the southern slopes of the mountains of northeastern Siberia and Alaska, as well as the cold, arid highlands of Central Asia.

tundrosteppe differed in that it the herbaceous layer was formed mainly not by mosses (as in the tundra), but by grasses, and it was here that formed cryophilic version herbaceous vegetation with a very high biomass of grazing ungulates and predators - the so-called "mammoth fauna".

In its composition, various types of animals were fancifully mixed, both characteristic of tundra – reindeer, caribou, musk ox, lemmings, For steppes - saiga, horse, camel, bison, ground squirrels, and mammoths and woolly rhinos, saber-toothed tiger - smilodon, and giant hyena.

It should be noted that many climatic changes were repeated as if "in miniature" in the memory of mankind. These are the so-called "Little Ice Ages" and "Interglacials".

For example, during the so-called "Little Ice Age" from 1450 to 1850, glaciers advanced everywhere, and their size exceeded modern ones (snow cover appeared, for example, in the mountains of Ethiopia, where it is not now).

And in the preceding "Little Ice Age" Atlantic optimum(900-1300) glaciers, on the contrary, decreased, and the climate was noticeably milder than the current one. Recall that it was at that time that the Vikings called Greenland the “Green Land”, and even settled it, and also reached the coast of North America and the island of Newfoundland on their boats. And the Novgorod merchants-ushkuyniki passed through the "Northern by sea” to the Gulf of Ob, having founded the city of Mangazeya there.

And the last retreat of the glaciers, which began over 10 thousand years ago, is well remembered by people, hence the legends about the Flood, so a huge amount of melt water rushed down to the south, rains and floods became frequent.

In the distant past, the growth of glaciers occurred in epochs with low air temperature and increased humidity, the same conditions developed in the last centuries of the last era, and in the middle of the last millennium.

And about 2.5 thousand years ago, a significant cooling of the climate began, the Arctic islands were covered with glaciers, in the countries of the Mediterranean and the Black Sea at the turn of the eras, the climate was colder and more humid than now.

In the Alps in the 1st millennium BC. e. glaciers moved to lower levels, cluttered mountain passes ice and destroyed some high-lying villages. It was during this era that glaciers in the Caucasus became sharply activated and grew.

But by the end of the 1st millennium, climate warming began again, mountain glaciers retreated in the Alps, the Caucasus, Scandinavia and Iceland.

The climate began to seriously change again only in the 14th century, glaciers began to grow rapidly in Greenland, the summer thawing of the soil became more and more short-lived, and by the end of the century permafrost was firmly established here.

From the end of the 15th century, the growth of glaciers began in many mountainous countries and polar regions, and after the relatively warm 16th century, severe centuries came, and were called the Little Ice Age. In the south of Europe, severe and long winters often repeated, in 1621 and 1669 the Bosporus froze, and in 1709 the Adriatic Sea froze off the coast. But the "Little Ice Age" ended in the second half of the 19th century and a relatively warm era began, which continues to this day.

Note that the warming of the 20th century is especially pronounced in the polar latitudes of the Northern Hemisphere, and fluctuations in glacial systems are characterized by the percentage of advancing, stationary and retreating glaciers.

For example, for the Alps there are data covering the entire past century. If the proportion of advancing alpine glaciers in the 40-50s of the XX century was close to zero, then in the mid-60s of the XX century, about 30% of the surveyed glaciers advanced here, and in the late 70s of the XX century - 65-70%.

Their similar state indicates that the anthropogenic (technogenic) increase in the content of carbon dioxide, methane and other gases and aerosols in the atmosphere in the 20th century did not affect the normal course of global atmospheric and glacial processes. However, at the end of the last, twentieth century, glaciers began to retreat everywhere in the mountains, and the ice of Greenland began to melt, which is associated with climate warming, and which especially intensified in the 1990s.

It is known that the increased amount of technogenic emissions of carbon dioxide, methane, freon and various aerosols into the atmosphere seems to be helping to reduce solar radiation. In this regard, “voices” appeared, first of journalists, then of politicians, and then of scientists about the beginning of a “new ice age”. Ecologists "sounded the alarm", fearing "the coming anthropogenic warming" due to the constant growth of carbon dioxide and other impurities in the atmosphere.

Yes, it is well known that an increase in CO 2 leads to an increase in the amount of retained heat and thereby increases the air temperature near the Earth's surface, forming the notorious "greenhouse effect".

Some other gases of technogenic origin have the same effect: freons, nitrogen oxides and sulfur oxides, methane, ammonia. But, nevertheless, far from all carbon dioxide remains in the atmosphere: 50-60% of industrial CO 2 emissions end up in the ocean, where they are quickly assimilated by animals (corals in the first place), and of course, assimilated by plants–remember the process of photosynthesis: plants absorb carbon dioxide and release oxygen! Those. the more carbon dioxide - the better, the higher the percentage of oxygen in the atmosphere! By the way, this has already happened in the history of the Earth, in the Carboniferous period ... Therefore, even a multiple increase in the concentration of CO 2 in the atmosphere cannot lead to the same multiple increase in temperature, since there is a certain natural control mechanism that sharply slows down the greenhouse effect at high concentrations of CO 2.

So all the numerous "scientific hypotheses" about the "greenhouse effect", "rise in the level of the World Ocean", "changes in the course of the Gulf Stream", and naturally "the coming Apocalypse" for the most part imposed on us "from above", by politicians, incompetent scientists, illiterate journalists, or simply swindlers from science. The more you intimidate the population, the easier it is to sell goods and manage ...

But in fact, a normal natural process is taking place - one stage, one climatic epoch is replaced by another, and there is nothing strange in this ... And the fact that natural disasters occur, and that there are supposedly more of them - tornadoes, floods, etc. - so another 100-200 years ago, vast areas of the Earth were simply uninhabited! And now there are more than 7 billion people, and they often live where exactly floods and tornadoes are possible - along the banks of rivers and oceans, in the deserts of America! Moreover, remember that natural disasters have always been, and even ruined entire civilizations!

As for the opinions of scientists, which both politicians and journalists like to refer to so much ... Back in 1983, American sociologists Randall Collins and Sal Restivo wrote in plain text in their famous article “Pirates and Politicians in Mathematics”: “... There is no fixed set of norms that guide the behavior of scientists. Only the activity of scientists (and other types of intellectuals related to them) is unchanged, aimed at acquiring wealth and fame, as well as gaining the opportunity to control the flow of ideas and impose their own ideas others… The ideals of science do not predetermine scientific behavior, but arise from the struggle for individual success in various conditions competitions …".

And a little more about science ... Various large companies often provide grants for so-called "research" in certain areas, but the question arises - how competent is the person conducting the research in this area? Why was he chosen out of hundreds of scientists?

And if a certain scientist, a “certain organization” orders, for example, “some research on the safety of nuclear energy”, then it goes without saying that this scientist will be forced to “listen” to the customer, since he has “quite certain interests”, and it’s understandable that he, most likely, will “adjust” “his conclusions” for the customer, since the main question is already not a question of scientific research–what does the customer want to get, what result. And if the result of the customer not satisfied, then this scientist will no longer be invited, and not in any "serious project", i.e. "monetary", he will no longer participate, as they will invite another scientist, more "compliant" ... Much, of course, depends on citizenship, and professionalism, and reputation as a scientist ... But let's not forget how much they "receive" in Russia scientists... Yes, in the world, in Europe and in the USA, a scientist lives mainly on grants... And any scientist also "wants to eat."

In addition, the data and opinions of one scientist, albeit a major specialist in his field, are not a fact! But if the research is confirmed by some scientific groups, institutes, laboratories, t only then can research be worthy of serious attention.

Unless of course these "groups", "institutes" or "laboratories" were not funded by the customer of this study or project ...

A.A. Kazdym,
candidate of geological and mineralogical sciences, member of MOIP

Most of the pre-existing mammals died out. According to many scientists, the ice age is not over yet, but we live in a relatively warmer, interglacial era. Studying the traces left by glaciers, one can trace their role step by step. The last ice age of the Earth was named by the English naturalist C. Lyell back in 1832. This was the last stage in the Quaternary period of the Cenozoic era.

Although the Pleistocene glaciation was not a catastrophe, since there were ice ages in other geological periods, it was an extremely important event in the history of the development of the Earth's surface. This glaciation embraced and. The centers of glaciation here were: in North America - the Labrador Peninsula and areas west of Hudson Bay; in Eurasia, ice moved from the Polar Urals and from the Taimyr Peninsula. In general, Pleistocene ice covered about 38 million km2, that is, 26% of modern land (now 11%). Thus, the ancient glaciation was 2.5 times larger than the modern one. And it was located differently: at present, there are 7 times more ice in the Southern Hemisphere than in the Northern, and in the Pleistocene, the glaciation of the Northern Hemisphere was twice as large as the Southern.

With the accumulation of ice and an increase in thickness, it increases to the lower layers, and they become plastic, acquiring mobility. The greater the mass of ice in the body of the glacier, the more mobile it is.

Huge masses of ice, moving for several tens of thousands of years and geologically only recently liberated the territory, were a powerful factor influencing, transforming it. Moving ice carried out three main types of work:,. The erosional work of the glacier consisted of the following: all loose crust was removed from the glaciation centers, and a crystalline foundation comes to the surface, forming shields;

the crystalline foundation was broken by cracks, and blocks of massive crystalline rocks were frozen into the ice and moved along with it. This led to the fact that they were streaked with strokes and furrows, which were made by blocks frozen into the ice and moving with it; low rocks and hills made of crystalline rocks were smoothed and polished by ice, which led to the formation of special landforms called "ram's foreheads". The accumulation of "ram's foreheads" forms a relief of curly rocks, well expressed, for example, on, in, in;

the areas of glacier erosion are characterized by an abundance of lake basins plowed by the glacier.

Blocks of destroyed rocks were transported by the glacier to areas that are no longer characterized by erosion, but by accumulative work of the glacier.

In more southern regions, where the ice melted, the glacier performed accumulative work. Here the brought material settled -. It consists of mixed sand, clay, large (boulders) and small rock fragments. On the surface, the moraine forms a hilly moraine. In the zone of glacial accumulation, the formation of lake basins also took place, but they differed in depth, shape, and rocks that make up their walls from lake basins formed in the erosion zone of the glacier. In the pre-glacial regions, vast sandy plains - sandra - formed.

The landforms created by ancient glaciation are most pronounced where the thickness of the glacier, and therefore its relief-forming role, is greatest. Here, during the period of maximum glaciation, the glacier reached 48-50° north latitude. The glacier was able to move south only to 60 ° north latitude (slightly south of the latitudinal segment). Both the thickness of the glacier and its mobility were the least.

Over the past 100 years, several dozen hypotheses have been put forward to explain the causes of a significant cooling on Earth that caused glaciation. It is possible that the reason for it is complex. It is assumed that the distribution of ice increases when the period of greatest distance of the axis of the Solar System from the center of the Galaxy coincides with the moment of a significant decrease in solar activity. And on Earth at the same time, the content of carbon dioxide rises after powerful eruptions.

One of the latest hypotheses considers the flourishing of life forms in a warm climate to be the cause of glaciation. The organic world accumulates a huge amount of carbon dioxide, removing it from the atmosphere, as a result of which it becomes more transparent and the heat transfer of the earth's surface increases, and this leads to a general cooling on the Earth. Subsequently, with a decrease in air, the volume of absorbed carbon dioxide decreases, and the gas content in the air is restored, but glaciers, having arisen, acquire a certain stability and the ability to influence the climate.

Quite recently (in geological time) man spontaneously intervened in the natural system Earth-glaciation. He prevented, without suspecting it, the onset of a new extensive glaciation, or rather, a new phase of it. Man-made industry not only compensated for the decrease in carbon dioxide in the atmosphere, but also began to constantly saturate it with carbon dioxide. Above the ice on Earth, a threat loomed. It is reinforced by the ever-increasing artificial energy production. But the destruction of glaciers can cause catastrophic changes on Earth: a rise in the level and flooding of the land, an increase in the number, an increase in snowfall and in the mountains.

At one time it was believed that it would be better to get rid of glaciers, returning the Earth to a mild and warm climate. However, now the huge role that glaciation plays on the globe is becoming more and more clear.

Glaciers accumulate a cold reserve three times the amount of solar energy absorbed by our Earth in a year. These are natural refrigerators that save the planet from overheating. Their value especially increases, since there arose real threat overheating of our planet as a result of the increasing industrial activity of mankind.

Glaciation creates contrasts on the earth's surface and thereby enhances the masses above the Earth, increases the diversity of climates, conditions and the forms of life themselves.

Glaciers are huge reserves of clean fresh water.

Dnieper glaciation
was maximum in the middle Pleistocene (250-170 or 110 thousand years ago). It consisted of two or three stages.

Sometimes the last stage of the Dnieper glaciation is distinguished into an independent Moscow glaciation (170-125 or 110 thousand years ago), and the period of relatively warm time separating them is considered as the Odintsovo interglacial.

At the maximum stage of this glaciation, a significant part of the Russian Plain was occupied by an ice sheet, which, in a narrow tongue along the Dnieper valley, penetrated south to the mouth of the river. Aurélie. Permafrost existed in most of this territory, and the average annual air temperature was then no higher than -5-6°C.
In the southeast of the Russian Plain, in the middle Pleistocene, the so-called "early Khazar" rise in the level of the Caspian Sea by 40-50 m occurred, which consisted of several phases. Their exact dating is unknown.

Mikulin interglacial
Following the Dnieper glaciation followed (125 or 110-70 thousand years ago). At this time in central regions The winter of the Russian Plain was much milder than now. If at present the average January temperatures are close to -10°С, then during the Mikulin interglacial they did not fall below -3°С.
Mikulin time corresponded to the so-called "Late Khazar" rise in the level of the Caspian Sea. In the north of the Russian Plain, a synchronous rise in the level of the Baltic Sea was noted, which then connected with the Ladoga and Onega lakes and, possibly, the White Sea, as well as the Arctic Ocean. The general fluctuation of the level of the world ocean between the epochs of glaciation and melting of ice was 130-150 m.

Valdai glaciation
After the Mikulin interglacial, consisting of the Early Valdai or Tver (70-55 thousand years ago) and Late Valdai or Ostashkov (24-12:-10 thousand years ago) glaciations, separated by the Middle Valdai period of repeated (up to 5) temperature fluctuations, during which the climate was much colder modern (55-24 thousand years ago).
In the south of the Russian platform, the early Valdai corresponds to a significant "Attelian" lowering - by 100-120 meters - of the level of the Caspian Sea. It was followed by the "early Khvalynian" rise in sea level by about 200 m (80 m above the initial level). According to A.P. Chepalyga (Chepalyga, t1984), the influx of moisture into the Caspian basin of the Upper Khvalynian time exceeded its losses by approximately 12 cubic meters. km per year.
After the "Early Khvalynian" rise in sea level, the "Enotaevsk" lowering of the sea level followed, and then again the "Late Khvalynian" rise in sea level by about 30 m relative to its initial position. According to G.I. Rychagov, at the end of the Late Pleistocene (16 thousand years ago). The late Khvalynian basin was characterized by water column temperatures somewhat lower than modern ones.
The new lowering of the sea level occurred rather quickly. It reached its maximum (50 m) at the very beginning of the Holocene (0.01-0 million years ago), about 10 thousand years ago, and was replaced by the last - the “Novo-Caspian” sea level rise by about 70 m about 8 thousand years ago.
Approximately the same fluctuations in the water surface occurred in the Baltic Sea and the Arctic Ocean. The general fluctuation of the level of the world ocean between the epochs of glaciation and melting of ice was then 80-100 m.

According to radioisotope analyzes of more than 500 different geological and biological samples taken in southern Chile, the mid-latitudes in the western Southern Hemisphere experienced warming and cooling events at the same time as the mid-latitudes in the western Northern Hemisphere.

Chapter " The world in the Pleistocene. Great glaciations and exodus from Hyperborea" / Eleven glaciations of the Quaternaryperiod and nuclear wars

One of the mysteries of the Earth, along with the emergence of Life on it and the extinction of dinosaurs at the end of the Cretaceous period, is - Great Glaciations.

Separate layers tillites, found even in equatorial Africa, can reach power of tens and even hundreds of meters!

Signs of glaciation have been found on different continents - in Australia, South America, Africa and India which is used by scientists to reconstruction of paleocontinents and are often cited as evidence theories of plate tectonics.

Traces of ancient glaciations indicate that continental-scale glaciations- this is not at all a random phenomenon, it is a natural phenomenon that occurs under certain conditions.

The northern part of the North American continent, the North American ice sheet, which reached a thickness of up to 3.5 km and extended to about 38 ° north latitude, and a significant part of Europe, were under thick, many kilometers of ice covers, on which (ice cover up to 2.5-3 km thick) . On the territory of Russia, the glacier descended in two huge tongues along the ancient valleys of the Dnieper and Don.

Partially glaciation also covered Siberia - there was mainly the so-called "mountain-valley glaciation", when glaciers did not cover the entire space with a powerful cover, but were only in the mountains and foothill valleys, which is associated with a sharply continental climate and low temperatures in Eastern Siberia . But almost all of Western Siberia, due to the fact that the rivers were springing up and their flow into the Arctic Ocean stopped, turned out to be under water, and was a huge sea-lake.

In the Southern Hemisphere, under the ice, as now, was the entire Antarctic continent.

During the period of maximum distribution of Quaternary glaciation, glaciers covered over 40 million km 2–about a quarter of the entire surface of the continents.

Now we live, apparently, at the end of the fourth epoch of the Quaternary glaciation.

But in Antarctica, glaciation arose millions of years before the time when glaciers appeared in North America and Europe. In addition to climatic conditions, this was facilitated by the high mainland that existed here for a long time. By the way, now, due to the fact that the thickness of the glacier of Antarctica is huge, the continental bed of the "ice continent" is in some places below sea level ...

Now about the hypotheses ... There are hundreds, if not thousands, of hypotheses why glaciations occur, and whether they were at all!

Usually put forward the following main scientific hypotheses:

Volcanic eruptions, leading to a decrease in the transparency of the atmosphere and cooling throughout the Earth;
Epochs of orogeny (mountain building);
Reducing the amount of carbon dioxide in the atmosphere, which reduces the "greenhouse effect" and leads to cooling;
The cyclical activity of the Sun;
Changes in the position of the Earth relative to the Sun.

But, nevertheless, the causes of glaciation have not been finally clarified!

There is also a hypothesis that the emergence of glaciers is associated with certain parts of the Universe through which our solar system passes, moving with the entire Galaxy, either filled with gas, or “clouds” of cosmic dust. And it is likely that "space winter" on Earth occurs when the globe is at the point furthest from the center of our Galaxy, where there are accumulations of "cosmic dust" and gas.

But when, as a result of the transformation of part of the water into ice, the level of the World Ocean drops by tens of meters, the warm Atlantic Ocean ceases to communicate with the Arctic Ocean, and it gradually becomes covered with ice again, evaporation from its surface stops abruptly, less and less snow falls on the continents and less, the "feeding" of glaciers is deteriorating, and the ice sheets begin to melt, and the level of the World Ocean rises again. And again the Arctic Ocean connects with the Atlantic, and again the ice cover began to gradually disappear, i.e. the cycle of development of the next glaciation begins anew.

Yes, all these hypotheses quite possible, but so far none of them can be confirmed by serious scientific facts.

Therefore, one of the main, fundamental hypotheses is climate change on the Earth itself, which is associated with the above hypotheses.

And the ice age that began in the Northern Hemisphere about 1 million years back, not finished yet, and we, as already mentioned, live in a warmer period of time, in interglacial.

Note that modern glaciers cannot be compared with the ancient glaciation of our planet - they occupy only about 15 million square meters. km, i.e. less than one-thirtieth of the earth's surface.

How can you determine whether there was a glaciation in a given place on the Earth or not? This is usually quite easy to determine by the peculiar forms of geographical relief and rocks.

If we look at the physical and geographical map of European Russia, then in the location of hills, hills, basins and valleys of large rivers, we can notice some patterns. So, for example, the Leningrad and Novgorod regions from the south and east are, as it were, limited Valdai Upland, which has the form of an arc. This is exactly the line where, in the distant past, a huge glacier, advancing from the north, stopped.

It is difficult to imagine ice several kilometers thick on the site of the current cities, rivers and lakes, but, nevertheless, the glacial plateaus were not inferior in height to the Urals, the Carpathians or the Scandinavian mountains. These gigantic and, moreover, mobile masses of ice influenced the entire natural environment - relief, landscapes, river flow, soils, vegetation and wildlife.

Glaciers originated and moved from Scandinavia, the Kola Peninsula, the Polar Urals (Pai-Khoi) and the islands of the Arctic Ocean. And almost all the geological deposits that we see on the territory of Moscow are moraine, more precisely moraine loams, sands of various origins (water-glacial, lake, river), huge boulders, as well as cover loams - all this is evidence of the powerful impact of the glacier.

Okskoe (about 1 million years ago),
Dnieper (about 300 thousand years ago),
Moscow (about 150 thousand years ago).

Valdai the glacier (disappeared only 10-12 thousand years ago) “did not reach Moscow”, and the deposits of this period are characterized by water-glacial (fluvio-glacial) deposits - mainly the sands of the Meshcherskaya lowland.

And the names of the glaciers themselves correspond to the names of those places to which the glaciers reached - to the Oka, the Dnieper and the Don, the Moskva River, Valdai, etc.

However, huge masses of ice (considering its colossal thickness) pressed so hard on the underlying rocks that even the strongest of them could not withstand and collapsed.

But glaciers did not plow out all the rocks on their way. The destruction was mainly those areas where the ice sheets originated, grew, reached a thickness of more than 3 km and from where they began their movement. The main center of glaciation in Europe was Fennoscandia, which included the Scandinavian mountains, the plateaus of the Kola Peninsula, as well as the plateaus and plains of Finland and Karelia.

In the era of the last Valdai glaciation arose Upper Volga glacial lakes(Mologo-Sheksninskoe, Tverskoe, Verkhne-Molozhskoe, etc.). At first, their waters had a flow to the southwest, but with the retreat of the glacier, they were able to flow to the north. Traces of the Mologo-Sheksninskoye Lake remained in the form of terraces and coastlines at an altitude of about 100 m.

There are very numerous traces of ancient glaciers in the mountains of Siberia, the Urals, and the Far East. As a result of ancient glaciation, 135-280 thousand years ago, sharp peaks of mountains appeared - "gendarmes" in Altai, in the Sayans, the Baikal and Transbaikalia, in the Stanovoy Upland. The so-called "reticulate type of glaciation" prevailed here, i.e. if one could look from a bird's eye view, one could see how ice-free plateaus and mountain peaks rise against the background of glaciers.

It should be noted that during the periods of glacial epochs, rather large ice massifs were located on part of the territory of Siberia, for example, on Severnaya Zemlya archipelago, in the Byrranga mountains (Taimyr Peninsula), as well as on the Putorana Plateau in northern Siberia.

Traces of these glaciations are numerous bowl-shaped depressions of mountain peaks - circuses or karts, huge moraine shafts and lake plains in place of melted ice.

"Intruding" from the north on the plains of Northern Eurasia, the ice sheets either penetrated far to the south along the depressions of the relief, or stopped at some obstacles, for example, hills.

In the era of the Dnieper glaciation, the glaciers were much larger. Tundra-steppe (dry tundra) with a very harsh climate stretched along the edge of the ice cover. The average annual temperature approached minus 6°C (for comparison: in the Moscow region, the average annual temperature is currently about +2.5°C).

The open space of the tundra, where in winter there was little snow and severe frosts, cracked, forming the so-called "permafrost polygons", which in plan resemble a wedge in shape. They are called "ice wedges", and in Siberia they often reach a height of ten meters! Traces of these "ice wedges" in ancient glacial deposits "speak" of the harsh climate. Traces of permafrost, or cryogenic impact, are also visible in the sands, these are often disturbed, as if “torn” layers, often with a high content of iron minerals.

Water-glacial deposits with traces of cryogenic impact

True, there are researchers who generally deny the ancient glaciations, and consider the glacial theory to be erroneous. In their opinion, there was no glaciation at all, but there was “a cold sea on which icebergs floated”, and all glacial deposits are just bottom sediments of this shallow sea!

And some scientists, on the contrary, “reconstruct” “giant ice sheets” in Siberia, which are not inferior in size and structure to the Antarctic.

Two more large ice sheets were in South America and New Zealand.

"South Alpine Complex" New Zealand- was a reduced copy of the Patagonian. It had the same shape and also advanced to the shelf, on the coast it developed a system of similar fjords.

The largest elements of the Arctic ice sheet were the Laurentian Shield of North America and the Kara Shield of Arctic Eurasia, they had the form of giant plano-convex domes. The center of the first of them was located over the southwestern part of the Hudson Bay, the peak rose to a height of more than 3 km, and its eastern edge extended to the outer edge of the continental shelf.

The Kara ice sheet occupied the entire area of the modern Barents and Kara Seas, its center lay over the Kara Sea, and the southern marginal zone covered the entire north of the Russian Plain, Western and Central Siberia.

Of the other elements of the Arctic cover, the East Siberian Ice Sheet which spread on the shelves of the Laptev, East Siberian and Chukchi seas and was larger than the Greenland ice sheet. He left traces in the form of large glaciodislocations New Siberian Islands and the Tiksi region, are also associated with grandiose glacial-erosion forms of Wrangel Island and the Chukotka Peninsula.

So, the last ice sheet of the Northern Hemisphere consisted of more than a dozen large ice sheets and many smaller ones, as well as from the ice shelves that united them, floating in the deep ocean.

The periods of time in which glaciers disappeared, or were reduced by 80-90%, are called interglacials. The landscapes freed from ice in a relatively warm climate were transformed: the tundra retreated to the northern coast of Eurasia, and the taiga and broad-leaved forests, forest-steppe and steppe occupied a position close to the present.

Thus, over the past million years, the nature of Northern Eurasia and North America has repeatedly changed its appearance.

It should be noted that many climatic changes were repeated as if "in miniature" in the memory of mankind. These are the so-called "Little Ice Ages" and "Interglacials".

And in the preceding "Little Ice Age" Atlantic optimum(900-1300) glaciers, on the contrary, decreased, and the climate was noticeably milder than the current one. Recall that it was at that time that the Vikings called Greenland the “Green Land”, and even settled it, and also reached the coast of North America and the island of Newfoundland on their boats. And the Novgorod merchants-Ushkuiniki passed through the "Northern Sea Route" to the Gulf of Ob, founding the city of Mangazeya there.

In the Alps in the 1st millennium BC. e. glaciers moved to lower levels, cluttered mountain passes with ice and destroyed some high-lying villages. It was during this era that glaciers in the Caucasus became sharply activated and grew.

But by the end of the 1st millennium, climate warming began again, mountain glaciers retreated in the Alps, the Caucasus, Scandinavia and Iceland.

So all the numerous “scientific hypotheses” about the “greenhouse effect”, “rising the level of the World Ocean”, “changes in the course of the Gulf Stream”, and of course the “coming Apocalypse” are mostly imposed on us “from above”, by politicians, incompetent scientists, illiterate journalists, or simply science swindlers. The more you intimidate the population, the easier it is to sell goods and manage ...

As for the opinions of scientists, which both politicians and journalists like to refer to so much ... Back in 1983, American sociologists Randall Collins and Sal Restivo wrote in plain text in their famous article “Pirates and Politicians in Mathematics”: “... There is no fixed set of norms that guide the behavior of scientists. Only the activities of scientists (and other types of intellectuals related to them) are unchanged, aimed at acquiring wealth and fame, as well as gaining the opportunity to control the flow of ideas and impose their own ideas on others ... The ideals of science do not predetermine scientific behavior, but arise from the struggle for individual success in various conditions of competition ... ".

Unless of course these "groups", "institutes" or "laboratories" were not funded by the customer of this study or project ...

A.A. Kazdym,
candidate of geological and mineralogical sciences, member of MOIP