How many years was the ice age. Last glacial period
In the history of the Earth, there were long periods when the entire planet was warm - from the equator to the poles. But there were so cold times that glaciation achieved those regions that are currently related to moderate zones. Most likely, the change of these periods was cyclical. At warm times, ice could be relatively small, and it was only in the polar regions or on the tops of the mountains. An important feature of the glacial periods is that they change the nature of the earth's surface: every glaciation affects appearance Earth. By themselves, these changes may be small and insignificant, but they are constant.
History of glacial periods
We do not know exactly how many glacial periods were throughout the history of the Earth. We know at least five, perhaps seven glacial periods, starting with Precambriansky, in particular: 700 million years ago, 450 million years ago (Ordovica period), 300 million years ago - Permo-carboxyloy, one of the largest glacial periods, affected southern continents. Under the south continents, the so-called Gondwana is meant - an ancient supercontinent, which included Antarctica, Australia, South America, India and Africa.
The most recent glaciation refers to the period in which we live. The Quaternary period of the Cenozoic era began about 2.5 million years ago, when the northern hemispheric glaciers reached the sea. But the first signs of this glaciation date back to 50 million years ago in Antarctica.
The structure of each glacial period is periodic: there are relatively short warm epochs, and there are longer periods of icing. Naturally, cold periods are not a consequence of glaciation alone. The glaciation is the most visual consequence of cold periods. However, there are quite long intervals that are very cold, despite the lack of glaciation. Today, examples of such regions are Alaska or Siberia, where it is very cold in winter, but there is no glaciation, since there is not enough precipitation capable of providing a sufficient amount of water to form glaciers.
Opening of glacial periods
It is known from the middle of the XIX century on Earth. Among the many names associated with the discovery of this phenomenon, the first is usually called the name of Louis Agassis, a Swiss geologist who lived in the middle of the XIX century. He studied the Alps glaciers and realized that once they were much more extensive than today. It noticed not only he. In particular, Jean de Charpete, another Swiss, also noted this fact.
It is not surprising that these discoveries were made mainly in Switzerland, since the glaciers still exist in the Alps, even though they are fast enough. It is easy to see that once the glaciers were much more - just look at the Swiss landscape, the triggers (Ice Valleys) and so on. However, it was Agassis first that he put forward this theory in 1840, posing it in the book "Étude Sur Les Glaciers", and later, in 1844, he developed this idea in the book "Système Glaciare". Despite the initial skepticism, over time, people began to understand that it is really true.
With the advent of geological mapping, especially in Northern Europe, it became clear that earlier the glaciers had a huge scale. Then there were extensive discussions on how this information correlates with the World Floral, because the conflict arose between the geological evidence and biblical teachings. Initially, glacial deposits were called deluel, because they were considered evidence of a worldwide flood. Only then it became known that such an explanation does not fit: these deposits were proof of cold climate and extensive glaciation. By the beginning of the twentieth century it became clear that the glaciation was many, and not one, and from the moment this region of science began to develop.
Studies of glacial periods
Known geological confirmation of glacial periods. The main evidence of glaciation occurs from characteristic deposits formed by the glaciers. They persist in a geological cut in the shape of thick ordered layers of special injuries (sediments) - diamine. These are simply ice accumulations, but they include not only the deposition of the glacier, but also the malcasses formed by its flows, glacial lakes or glaciers moving towards the sea.
There are several forms of glacial lakes. Their main difference lies in the fact that they are aquatic body fenced with ice. For example, if we have a glacier who rises to the valley of the river, then it blocks the valley as a plug in a bottle. Naturally, when the ice blocks the valley, the river will still flow, and the water level will increase until it flows across the edges. In this way, ice Lake Forms through direct contact with ice. There are certain deposits that are contained in such lakes and which we can reveal.
Due to how the glaciers are melted, which depends on seasonal changes in temperature, the annual yield occurs. This leads to the annual increase in minor deposits falling from ice into the lake. If we then look at the lake, we will see there a layered (rhythmic layered precipitation), which are also known under the Swedish name "Varva" (VARVE), which means "annual accumulations". Thus, we can really see the annual lamination in glacial lakes. We can even count these preventive and find out how long this lake existed. In general, with this material, we can get a lot of information.
In Antarctica, we can see the huge size of the shelf glaciers who go out of the ground in the sea. And naturally, ice float, so it keeps on the water. As he floats, he carries with him pebbles and minor deposits. Because of the thermal exposure to water, ice melts and resets this material. This leads to the formation of the process of so-called rafting rocks that go into the ocean. When we see fossil sediments of this period, we can find out where there was a glacier, how far he stretched and so on.
Causes of glaciation
The researchers believe that the glacial periods arise because the land climate depends on the uneven warm-up of its surface of the sun. For example, the equatorial regions, where the sun is almost vertically above the head, are the warmest zones, and the polar regions, where it is at a large angle to the surface, the coolest. This means that the difference in heating of different parts of the Earth's surface controls the ocean-atmospheric machine, which is constantly trying to transfer heat from the equatorial regions to the poles.
If the Earth was an ordinary ball, this transfer would be very effective, and the contrast between the equator and the poles is very small. So it was in the past. But since now there are continents, they become on the path of this circulation, and its streams becomes very complex. Simple streams are constrained and changed - largely due to the mountains, which leads to the circulation schemes that we see today and which are managed by trade winds and oceanic currents. For example, one of theories about why the Ice Age began 2.5 million years ago, binds this phenomenon with the emergence of the Himalayan mountains. Himalayas are still growing very quickly, and it turns out that the existence of these mountains in a very warm part of the Earth manages such things as the monsoon system. The beginning of the Quaternary Ice Age is also associated with the closure of the Panama Isthmus, which connects the north and south of America, which prevented the transfer of heat from the Equatorial Pacific Zone to the Atlantic.
If the location of the continents relative to each other and relative to the equator allowed the circulation to work effectively, it would be warm on the poles, and relatively warm conditions It would be preserved throughout the earth's surface. The amount of heat obtained by the Earth would be constantly and only varied a bit. But since our continents create serious circulation barriers between the North and South, we have pronounced pronounced climatic zones. This means that the pole is relatively cold, and the equatorial regions are warm. When everything happens as now, the earth may vary under the influence of variations in the amount of solar heat that it gets.
These variations are almost completely constant. The reason for this is that over time the earth's axis changes, as the earth orbit changes. Taking into account such complex climatic zoning, the change in the orbit may contribute to long-term changes in the climate, which leads to climate fluctuations. Because of this, we have no solid icing, and periods of icing interrupted by warm periods. This happens under the influence of orbital changes. Recent orbital changes are treated as three separate phenomena: one 20 thousand years long, the second is 40 thousand years old, and the third is 100 thousand years.
This led to deviations in the circuit of cyclic climate change during the ice age. The icing, most likely, arose during this cyclical period of 100 thousand years. The last intersection era, which was the same warm as the current, lasted about 125 thousand years, and then there was a long glacier epoch, which took about 100 thousand years. Now we live in another interglacial era. This period will not last forever, so the next glacier era is waiting for us in the future.
Why the glacial periods are completed
Orbital changes change the climate, and it turns out that the glacial periods are characterized by alternating cold periods that can last up to 100 thousand years, and warm periods. We call them glacial (glyhal) and interglacial (interpretor) by epochs. The interledstial era is usually characterized by approximately the conditions that we see today: high level seas, limited objects of icing and so on. Naturally, and now there are glaciation in Antarctica, Greenland and other similar places. But in general climatic conditions relatively warm. In this, the essence of the interviewology: high sea level, warm temperature conditions and the generally smooth climate as a whole.
But during the Ice Epoch, the average annual temperature varies significantly, the vegetative belts are forced to shift to the north or south depending on the hemisphere. Regions like Moscow or Cambridge become uninhabited, at least in winter. Although they can be inhabited in summer because of a very pronounced contrast between the seasons. But what actually happens: cold zones are significantly expanding, the average annual temperature is reduced, and general climatic conditions become very cold. While the greatest glacial events are relatively limited in time (perhaps about 10 thousand years), the entire long cold period can last 100 thousand years or even more. This looks like an interledeter cyclicity.
Due to the duration of each period, it is difficult to say when we leave the current era. This is due to the tactonics of the plates, the location of the continents on the surface of the Earth. Currently North Pole And the South Pole Isolated: Antarctic is located on the South Pole, and the North Arctic Ocean in the north. Because of this, there is a problem with heat circulation. Until the location of the continents change, this ice age will continue. In accordance with long-term tectonic changes, it can be assumed that it will take another 50 million years in the future until significant changes occur, which will allow land to leave the glacial period.
Geological consequences
It releases the huge sections of the continental shelf, which today are flooded. This will mean, for example, that one day you can walk from Britain to France, from New Guinea in Southeast Asia. One of the most critical places is Bering Strait, connecting Alaska with Eastern Siberia. It is fine enough, about 40 meters, so if the sea level drops to one hundred meters, then this area will become land. This is also important because plants and animals will be able to migrate through these places and get into the regions where today they cannot get. Thus, the colonization of North America depends on the so-called berygia.
Animals and glacial
It is important to remember that we ourselves are "products" of the glacial period: we evolved during it, so we can survive it. However, it's not a matter of individual individuals - this is a matter of the whole population. The problem today is that we are too much and our activity has significantly changed natural conditions. IN natural conditions Many animals and plants we see today have a long story and perfectly experience the ice age, although there are those that evolve slightly. They migrate, adapt. There are zones in which animals and plants survived the ice age. These so-called refugiums were located on the north or south of their place today.
But as a result of human activity, some of the species died or extinct. It happened on all continents, it is possible, with the exception of Africa. A huge number of large vertebrates, namely mammals, as well as the silent in Australia, was exterminated by a person. This was caused either directly by our activities, such as hunting, or indirectly - the destruction of their habitat. Animals living in northern latitudes today, in the past lived in the Mediterranean. We destroyed this region so much that these animals and plants will most likely be very difficult to colonize it again.
The consequences of global warming
Under normal conditions, on geological standards, we would soon be returned to the glacial period. But due to global warming, which is the consequence of human activity, we displays it. We will not be able to prevent it at all, since the reasons that caused him in the past exist now. Human activity, unintended nature element, affects atmospheric warming, which may already cause a delay in the next glant.
Today, climate change is a very relevant and exciting issue. If the Greenland ice shield melts, the sea level will rise six meters. In the past, during the previous intergarent era, which was about 125 thousand years ago, the Greenland ice shield richly melted, and the sea level was 4-6 meters above today. This, of course, is not the end of the world, but not temporary complexity. In the end, the Earth was recovered from the catastrophe before, she will be able to survive this.
The long-term forecast for the planet is not bad, but for people this is another question. The more research we conduct research, the better we understand how the Earth changes and what it leads, the better we understand the planet on which we live. This is important because people finally began to think about changing the sea level, global warming and the effect of all these things on agriculture and population. Much of this is associated with the study of the glacial periods. With the help of these studies, we recognize the mechanisms of glaciation, and we can use this knowledge with the absorption, trying to soften some of these changes that they themselves call. This is one of the main results and one of the objectives of the study of the glacial periods.
Of course, the main consequence of the glacial period is huge glacial shields. Where does the water come from? Of course, from the oceans. What happens during the glacial periods? Glaciers are formed as a result of precipitation on land. Due to the fact that the water does not return to the ocean, the sea level falls. In the times of the strongest glaciation, the sea level may fall more than one hundred meters.
In the history of the Earth, there were long periods when the entire planet was warm - from the equator to the poles. But there were so cold times that glaciation achieved those regions that are currently related to moderate zones. Most likely, the change of these periods was cyclical. At warm times, ice could be relatively small, and it was only in the polar regions or on the tops of the mountains. An important feature of the glacial periods is that they change the nature of the earth's surface: each glaciation affects the appearance of the Earth. By themselves, these changes may be small and insignificant, but they are constant.
History of glacial periods
We do not know exactly how many glacial periods were throughout the history of the Earth. We know at least five, perhaps seven glacial periods, starting with Precambriansky, in particular: 700 million years ago, 450 million years ago (Ordovica period), 300 million years ago - Permo-carboxyloy, one of the largest glacial periods, affected southern continents. Under the south continents, the so-called Gondwana is meant - an ancient supercontinent, which included Antarctica, Australia, South America, India and Africa.
The most recent glaciation refers to the period in which we live. The Quaternary period of the Cenozoic era began about 2.5 million years ago, when the northern hemispheric glaciers reached the sea. But the first signs of this glaciation date back to 50 million years ago in Antarctica.
The structure of each glacial period is periodic: there are relatively short warm epochs, and there are longer periods of icing. Naturally, cold periods are not a consequence of glaciation alone. The glaciation is the most visual consequence of cold periods. However, there are quite long intervals that are very cold, despite the lack of glaciation. Today, examples of such regions are Alaska or Siberia, where it is very cold in winter, but there is no glaciation, since there is not enough precipitation capable of providing a sufficient amount of water to form glaciers.
Opening of glacial periods
It is known from the middle of the XIX century on Earth. Among the many names associated with the discovery of this phenomenon, the first is usually called the name of Louis Agassis, a Swiss geologist who lived in the middle of the XIX century. He studied the Alps glaciers and realized that once they were much more extensive than today. It noticed not only he. In particular, Jean de Charpete, another Swiss, also noted this fact.
It is not surprising that these discoveries were made mainly in Switzerland, since the glaciers still exist in the Alps, even though they are fast enough. It is easy to see that once the glaciers were much more - just look at the Swiss landscape, the triggers (Ice Valleys) and so on. However, it was Agassis first that he put forward this theory in 1840, posing it in the book "Étude Sur Les Glaciers", and later, in 1844, he developed this idea in the book "Système Glaciare". Despite the initial skepticism, over time, people began to understand that it is really true.
With the advent of geological mapping, especially in Northern Europe, it became clear that earlier the glaciers had a huge scale. Then there were extensive discussions on how this information correlates with the World Floral, because the conflict arose between the geological evidence and biblical teachings. Initially, glacial deposits were called deluel, because they were considered evidence of a worldwide flood. Only then it became known that such an explanation does not fit: these deposits were proof of cold climate and extensive glaciation. By the beginning of the twentieth century it became clear that the glaciation was many, and not one, and from the moment this region of science began to develop.
Studies of glacial periods
Known geological confirmation of glacial periods. The main evidence of glaciation occurs from characteristic deposits formed by the glaciers. They persist in a geological cut in the shape of thick ordered layers of special injuries (sediments) - diamine. These are simply ice accumulations, but they include not only the deposition of the glacier, but also the malcasses formed by its flows, glacial lakes or glaciers moving towards the sea.
There are several forms of glacial lakes. Their main difference lies in the fact that they are aquatic body fenced with ice. For example, if we have a glacier who rises to the valley of the river, then it blocks the valley as a plug in a bottle. Naturally, when the ice blocks the valley, the river will still flow, and the water level will increase until it flows across the edges. Thus, the glacial lake is formed through direct contact with ice. There are certain deposits that are contained in such lakes and which we can reveal.
Due to how the glaciers are melted, which depends on seasonal changes in temperature, the annual yield occurs. This leads to the annual increase in minor deposits falling from ice into the lake. If we then look at the lake, we will see there lamps (rhythmic layered precipitation), which are also known under the Swedish name "Verva" ( varve.) What does "annual accumulations" mean. Thus, we can really see the annual lamination in glacial lakes. We can even count these preventive and find out how long this lake existed. In general, with this material, we can get a lot of information.
In Antarctica, we can see the huge size of the shelf glaciers who go out of the ground in the sea. And naturally, ice float, so it keeps on the water. As he floats, he carries with him pebbles and minor deposits. Because of the thermal exposure to water, ice melts and resets this material. This leads to the formation of the process of so-called rafting rocks that go into the ocean. When we see fossil sediments of this period, we can find out where there was a glacier, how far he stretched and so on.
Causes of glaciation
The researchers believe that the glacial periods arise because the land climate depends on the uneven warm-up of its surface of the sun. For example, the equatorial regions, where the sun is almost vertically above the head, are the warmest zones, and the polar regions, where it is at a large angle to the surface, the coolest. This means that the difference in heating of different parts of the Earth's surface controls the ocean-atmospheric machine, which is constantly trying to transfer heat from the equatorial regions to the poles.
If the Earth was an ordinary ball, this transfer would be very effective, and the contrast between the equator and the poles is very small. So it was in the past. But since now there are continents, they become on the path of this circulation, and its streams becomes very complex. Simple streams are constrained and changed - largely due to the mountains, which leads to the circulation schemes that we see today and which are managed by trade winds and oceanic currents. For example, one of theories about why the Ice Age began 2.5 million years ago, binds this phenomenon with the emergence of the Himalayan mountains. Himalayas are still growing very quickly, and it turns out that the existence of these mountains in a very warm part of the Earth manages such things as the monsoon system. The beginning of the Quaternary Ice Age is also associated with the closure of the Panama Isthmus, which connects the north and south of America, which prevented the transfer of heat from the Equatorial Pacific Zone to the Atlantic.
If the location of the continents relative to each other and relative to the equator allowed the circulation to work effectively, it would be warm on the poles, and relatively warm conditions would be preserved throughout the earth's surface. The amount of heat obtained by the Earth would be constantly and only varied a bit. But since our continents create serious corporate barriers between the North and South, we have pronounced climatic zones. This means that the pole is relatively cold, and the equatorial regions are warm. When everything happens as now, the earth may vary under the influence of variations in the amount of solar heat that it gets.
These variations are almost completely constant. The reason for this is that over time the earth's axis changes, as the earth orbit changes. Taking into account such complex climatic zoning, the change in the orbit may contribute to long-term changes in the climate, which leads to climate fluctuations. Because of this, we have no solid icing, and periods of icing interrupted by warm periods. This happens under the influence of orbital changes. Recent orbital changes are treated as three separate phenomena: one 20 thousand years long, the second is 40 thousand years old, and the third is 100 thousand years.
This led to deviations in the circuit of cyclic climate change during the ice age. The icing, most likely, arose during this cyclical period of 100 thousand years. The last intersection era, which was the same warm as the current, lasted about 125 thousand years, and then there was a long glacier epoch, which took about 100 thousand years. Now we live in another interglacial era. This period will not last forever, so the next glacier era is waiting for us in the future.
Why the glacial periods are completed
Orbital changes change the climate, and it turns out that the glacial periods are characterized by alternating cold periods that can last up to 100 thousand years, and warm periods. We call them glacial (glyhal) and interglacial (interpretor) by epochs. The interledstial era is usually characterized by approximately the conditions that we see today: high sea levels, limited objects of icing and so on. Naturally, and now there are glaciation in Antarctica, Greenland and other similar places. But in general, climatic conditions are relatively warm. In this, the essence of the interviewology: high sea level, warm temperature conditions and the generally smooth climate as a whole.
But during the Ice Epoch, the average annual temperature varies significantly, the vegetative belts are forced to shift to the north or south depending on the hemisphere. Regions like Moscow or Cambridge become uninhabited, at least in winter. Although they can be inhabited in summer because of a very pronounced contrast between the seasons. But what actually happens: cold zones are significantly expanding, the average annual temperature is reduced, and general climatic conditions become very cold. While the greatest glacial events are relatively limited in time (perhaps about 10 thousand years), the entire long cold period can last 100 thousand years or even more. This looks like an interledeter cyclicity.
Due to the duration of each period, it is difficult to say when we leave the current era. This is due to the tactonics of the plates, the location of the continents on the surface of the Earth. Currently, the North Pole and the South Pole are isolated: Antarctic is located on the South Pole, and the Arctic Ocean in the north. Because of this, there is a problem with heat circulation. Until the location of the continents change, this ice age will continue. In accordance with long-term tectonic changes, it can be assumed that it will take another 50 million years in the future until significant changes occur, which will allow land to leave the glacial period.
Geological consequences
Of course, the main consequence of the glacial period is huge glacial shields. Where does the water come from? Of course, from the oceans. What happens during the glacial periods? Glaciers are formed as a result of precipitation on land. Due to the fact that the water does not return to the ocean, the sea level falls. In the times of the strongest glaciation, the sea level may fall more than one hundred meters.
It releases the huge sections of the continental shelf, which today are flooded. This will mean, for example, that one day it will be possible to walk from Britain to France, from New Guinea to Southeast Asia. One of the most critical places is Bering Strait, connecting Alaska with Eastern Siberia. It is fine enough, about 40 meters, so if the sea level drops to one hundred meters, then this area will become land. This is also important because plants and animals will be able to migrate through these places and get into the regions where today they cannot get. Thus, the colonization of North America depends on the so-called berygia.
Animals and glacial
It is important to remember that we ourselves are "products" of the glacial period: we evolved during it, so we can survive it. However, it's not a matter of individual individuals - this is a matter of the whole population. The problem today is that we are too much and our activity has significantly changed natural conditions. In natural conditions, many animals and plants we see today have a long story and perfectly experience the ice age, although there are those that evolve insignificantly. They migrate, adapt. There are zones in which animals and plants survived the ice age. These so-called refugiums were located on the north or south of their place today.
But as a result of human activity, some of the species died or extinct. It happened on all continents, it is possible, with the exception of Africa. A huge number of large vertebrates, namely mammals, as well as the silent in Australia, was exterminated by a person. This was caused either directly by our activities, such as hunting, or indirectly - the destruction of their habitat. Animals living in northern latitudes today, in the past lived in the Mediterranean. We destroyed this region so much that these animals and plants will most likely be very difficult to colonize it again.
The consequences of global warming
Under normal conditions, on geological standards, we would soon be returned to the glacial period. But due to global warming, which is the consequence of human activity, we displays it. We will not be able to prevent it at all, since the reasons that caused him in the past exist now. Human activity, unintended nature element, affects atmospheric warming, which may already cause a delay in the next glant.
Today, climate change is a very relevant and exciting issue. If the Greenland ice shield melts, the sea level will rise six meters. In the past, during the previous intergarent era, which was about 125 thousand years ago, the Greenland ice shield richly melted, and the sea level was 4-6 meters above today. This, of course, is not the end of the world, but not temporary complexity. In the end, the Earth was recovered from the catastrophe before, she will be able to survive this.
The long-term forecast for the planet is not bad, but for people this is another question. The more research we conduct research, the better we understand how the Earth changes and what it leads, the better we understand the planet on which we live. This is important because people finally began to think about changing the level of sea, global warming and the influence of all these things on agriculture and the population. Much of this is associated with the study of the glacial periods. With the help of these studies, we recognize the mechanisms of glaciation, and we can use this knowledge with the absorption, trying to soften some of these changes that they themselves call. This is one of the main results and one of the objectives of the study of the glacial periods.
This is the transfer of the article of our English-language publication Serious Science. You can read the original version of the text by reference.
The last glacial period led to the appearance of a woolly mammoth and the huge growth of the area of \u200b\u200bglaciers.
But he was only one of many, which was cooled by the Earth throughout 4.5 billion years of its history.
Consequences of warming
The last glacial period led to the appearance of a woolly mammoth and the huge growth of the area of \u200b\u200bglaciers. But he was only one of many, which was cooled by the Earth throughout 4.5 billion years of its history.
So, how often the planet covers the glacial periods and when should we expect the next?
The main periods of glaciation in the history of the planet
The answer to the first question depends on whether you mean large glaciation or small, which occur during these long periods. Throughout history, the Earth survived five large periods of glaciation, and some of them lasted for hundreds of millions of years. In fact, even now the Earth is experiencing a long period of glaciation, and this explains why it has polar ice.
Five main ice ages are Huronsky (2.4-2.1 billion years ago), cryogenic glaciation (720-635 million years ago), Andasca-Sugar (450-420 million years ago), late Paleozoicoye (335-260 Million years ago) and quaternary (2.7 million years ago to the present).
These large periods of glaciation can alternate smaller glacial periods and warm periods (inteludes). At the beginning of Quaternary glaciation (2.7-1 million years ago), these cold glacial periods took place every 41 thousand years. Nevertheless, in the last 800 thousand years, essential glacial periods appeared less often - approximately every 100 thousand years.
How does the 100,000-year-old cycle work?
Ice shields grow for approximately 90 thousand years, and then begin to melt for 10 thousand years of the warm period. Then the process is repeated.
Given that the last Ice Age ended about 11,700 years ago, perhaps time came to start one more?
Scientists believe that we would have to experience the next glacial period right now. However, there are two factors associated with the Earth's orbit, which affect the formation of warm and cold periods. Considering how many carbon dioxide we throw into the atmosphere, the next ice age will not begin at least 100 thousand years.
What causes the glacial period?
The hypothesis put forward by Serbian astronomer Milyutin Milankovich explains why there are cycles of glacial and intergreic periods on Earth.
Since the planet rotates around the Sun, the amount of light that it receives from it is affected by three factors: its tilt (which is in the range from 24.5 to 22.1 degrees on a cycle of 41,000 years), its eccentricity (change of the form of the orbit around Sun, which ranges from the near circumference to an oval shape) and her swinging (one full swing occurs every 19-23 thousand years).
In 1976, a sign document in the journal Science presented evidence that these three orbital parameters explain the glacial cycles of the planet.
The theory of Milankovich is that orbital cycles are predictable and very consistent in the history of the planet. If the earth is experiencing a glacial period, it will be covered with a large or smaller amount of ice, depending on these orbital cycles. But if it is too warm on Earth, no changes will occur, at least with respect to the growing amount of ice.
What can affect the heating of the planet?
The first to mind comes gas, such as carbon dioxide. Over the past 800 thousand years, carbon dioxide levels ranged from 170 to 280 parts per million (meaning that from 1 million air molecules 280 are carbon dioxide molecules). It would seem a minor difference in 100 parts per million leads to the appearance of glacial and intergaren periods. But the level of carbon dioxide today is significantly higher, compared with the past periods of oscillations. In May 2016, carbon dioxide over Antarctic reached 400 parts per million.
The land heated so much before. For example, during dinosaurs, the air temperature was even higher than now. But the problem is that modern world It grows by a record pace, as we threw too much carbon dioxide into the atmosphere in a short time. In addition, considering that the rate of emissions today are not reduced, it can be concluded that the situation is unlikely to change in the near future.
Consequences of warming
Warming caused by the presence of this carbon dioxide will have great consequences because even a small increase average temperature Earth can lead to sharp changes. For example, the land was on average just 5 degrees Celsius colder during the last glacial period than today, however, it led to a significant change in regional temperature, the disappearance of a huge part of the flora and fauna and to the emergence of new species.
If global warming will lead to the melting of all the glacial covers of Greenland and Antarctica, the level of oceans will grow by 60 meters, compared with today's indicators.
What leads to big glacial periods?
The factors that cause long periods of glaciation, such as quaternary, are not so well studied by scientists. But one of the ideas is that the mass drop in the level of carbon dioxide can lead to lower temperatures.
For example, in accordance with the hypothesis of raising and weathering, when the tactonics of the slabs leads to an increase in mountain ranges, a new unprotected breed appears on the surface. It is easy to weathelate and fall apart, falling into the oceans. Marine Organisms Use these breeds to create their shells. Over time, stones and shells take carbon dioxide from the atmosphere and its level is significantly reduced, which leads to the period of glaciation.
Just during the powerful development of all forms of life on our planet, the mysterious glacial period begins with its new temperature fluctuations. We have already spoken about the reasons for the appearance of this ice age earlier.
In the same way, when the occasion of the time of the year, he had led to the selection of more advanced, more capable of adapted by animals and created a variety of mammalian breeds, and now, in this ice age, a person is distinguished from mammals, in an even more painful fight against impending glaciers than The fight against the millennium shift of the seasons. It was not enough only to one adaptation through a significant change in body. It was necessary to mind, which would manage to pay for the benefit of the very nature and conquer it.
We have finally achieved the highest level of life development :. He mastered the land, and his mind, developing farther and further, learned to cover the whole universe. With the advent of a person, truly began at all new era Creation. We are still on one of its lower stages, we are the simplest among the creatures, gifted by the mind that dominate the forces of nature. It began to start the path to unknown majestic goals!
There were at least four large glacial periods, which, for their part, again disintegrate into smaller waves of temperature fluctuations. Between the glacial periods lay the periods warmer; Then, thanks to the melting glether, raw valleys were covered with lush meadow vegetation. Therefore, precisely in these interledstial periods could especially well develop herbivores.
In the sediments of the Quaternary era, which closes the glacial periods, and in the sediments of the Delivevian era, which followed the last universal glaciation of the globe, and the immediate continuation of which is our time, we are pushing on huge thick-skinned, namely on Mammoth Mastodont, the fossil remnants of which we are still Now we find often in Tundra Siberia. Even with this giant, a primitive man loosened to get involved in the struggle, and, in the end, he came out of her winner.
Mastodont (restored) of the Delivevian era.
We involuntarily return the thought again to the emergence of the world, if we look at the flourishing of the fine present of the present of the chaotic dark primitive conditions. The fact that in the second half of our research remained all the time only on our little land is explained by the fact that we know all these different stages of development only on it. But, taking into account the same procedure for the world of matter and the Universality of the Matter of Nature's Matters, we will come to complete consistency of all the main features of the world's education that we can observe in the sky.
We do not have any doubt that in the distant universe there must be more millions of worlds like our Earth, although we do not have any accurate information about them. On the contrary, it is from the relatives of the earth, the rest of our planets solar systemwhich we can better explore, thanks to their more intimacy to us, there are characteristic differences from our Earth, such as the sisters of very different ages. Therefore, we should not be surprised if we are not met by traces of life, similar to the life of our Earth. Also, Mars with its channels remains the mystery to us.
If we look up, on the sky on top of the solns, then we can be sure that we will meet with the views of living beings who look at our daylight luminaries like us on their sun. Perhaps we are not entirely so far from the time when, mastered by all the forces of nature, a person will be able to penetrate these gave the universe and send a signal outside our globe living beings on another celestial body - and get an answer from them .
Just like life, at least, sometimes we cannot imagine it came to us from the Universe and spread on the ground, starting with the simplest, and the person, in the end, will spread the narrow horizon, covering him of the earth, and Will be demolished with other worlds of the universe, from where these primary elements of life appeared on our planet. The universe belongs to man, his mind, his knowledge, his strength.
But no matter how high the fantasy raised us, we will once again overthrow down. The world development circuit is lifted and falling.
Ice period on Earth
After terrible shower, such a flood, made damp and cold. From the high mountains, the glaciers are slightly lit into the valley, because the sun could no longer melt continuously falling from above the mass of snow. As a result, the places where the temperature was kept above the zero before the summer, were also covered with ice on ice. for a long time. We now see something similar in the Alps, where the individual "languages" of Gletters are descended significantly below the borders of eternal snow. In the end, most of the plains at the foot of the mountains were also covered above the ragged ice cover. The universal ice age came, whose traces of which we really can observe everywhere on the whole globe.
It is necessary to recognize the huge merit of the world traveler Hans Meier from Leipzig found them proofs, both on Kilimanjaro and Cordillera South AmericaEven in tropical areas, the glaciers are held everywhere at the time significantly lower than now. The connection set out here between the extraordinary volcanic activities and the onset of the ice age for the first time was assumed by the Salessen brothers in Basel. How did it happen?
On the assigned question after thorough research, the following can be answered. The whole chain of the Andes during the geological periods, which, of course, are calculated by hundreds of thousands and millions of years, it was formed at the same time, and its volcanoes were a consequence of this grandiose-based process on Earth. At this time, almost all the land dominated, approximately, tropical temperature, which, however, very soon after that was to change the strong universal cooling.
Penk found that there was at least four large glacial periods, in between which were concluded warmer periods of time. But it seems that these large glacial periods are dismembered by an even greater number of smaller time intervals in which there were more insignificant universal temperature fluctuations. From here it can be seen what turpened times experienced the earth and, in what constant excitement was then the air ocean.
How long it continued this time, it can only be indicated very approximately. It is calculated that the beginning of this glacial period can be attributed, about half a million years ago. Since the last "small glaciation" passed, in all likelihood, only 10 to 20 millennia, and we live now, probably, only in one of those "interledstial periods", which were before the last universal glaciation.
Through all these glacial periods, traces of a primitive person developing from the animal pass. Talk of Flood, which moved to us from primitive times, can stand in connection with the incidents described above. Persian legend almost undoubtedly indicates volcanic phenomena preceding the beginning of the Great Flood.
This Persian legend describes the Great Flood as follows: "A large fiery dragon rose from the south. Everything was devastated by him. The day turned into the night. Stars disappeared. Zodiac was closed with a huge tail; Only the sun and the moon could notice in the sky. Boiling water fell on the ground and looked down to the roots of the trees. Among the frequent lightning fell drops of rain with a magnitude with a human head. Water covered the ground is higher than in human height. Finally, after the dragon struggle lasted 90 days and 90 nights, the enemy of the land was destroyed. A terrible storm rose, the water went down, the dragon plunged into the depths of the earth. "
This dragon, on the view of the famous Vienna Geology Zyus, was nothing but strong active volcano, whose fiery eruption spread across the sky like a long tail. All other phenomena described in the language are fully consistent with the phenomena observed after a strong volcanic eruption.
Thus, on the one hand, we have shown that after splitting and collapsed a huge block, a number of volcanoes should have been formed, the eruptions of which followed the fosters and glaciation. On the other hand, we have a number of volcanoes in the Andes located in the huge breakdown of the Pacific shore, and also proved that a glacier era came shortly after the occurrence of these volcanoes. Flood legends even more replenish the picture of this thorough period of development of our planet. When the Krakatau is erupted, we watched a small scale, but in all details, the consequences of the dive of the volcano into the marine bunch.
Taking into account all of the above, we are unlikely to doubt that the relationship between these phenomena was, indeed, as we suggested. Thus, the entire Pacific Ocean, indeed, arose as a result of the separation and failure of his present bottom, which before that was a huge mainland. Was it "death of the world" in the sense, how do they usually understand? If the fall happened suddenly, it was probably the most terrible and most grand catastrophe, which the Earth had ever seen since the organic life appeared on it.
This question is now difficult to answer. But still we can say the following. If the collapse on the coast Pacific Ocean Performed gradually, they would remain completely inexplicable those terrible volcanic eruptions, which at the end of the "tertiary era" took place along the entire chain of the Andes and the very weak consequences of which are also observed there.
If the coastal area fell there so slowly that for the detection of this lowering, whole centuries were required, as we observe even now in some seashore shores, then all the movements of the masses would be performed very slowly, and only occasionally took place Volcanic eruptions.
In any case, we see that there are opposition to these forces producing shifts in the earth's crust, otherwise they could not have the place of sudden shudders of earthquakes. But we had to also recognize the fact that the stresses resulting from these opposition could not become too big because earth's crust It turns out plastic, supple for large, but slow existing forces. All these considerations lead us to the conclusion, maybe against our desire that it was precisely sudden forces in these catastrophes.
The Pleistocene era began about 2.6 million years ago and ended 1100 years ago. At the end of this era, the last to date the Ice Age was passed when the glaciers covered the huge sections of the continents of the Earth. Since the beginning of Earth's formation, 4.6 billion years ago, at least five documented basic glacier periods passed on it. Pleistocene is the first era, in which Homo Sapiens evolved: by the end of the era, people settled almost throughout the planet. What was the last ice age?
Ice rink magnitude with the world
It is during the period of Pleistocene that the continents are located on Earth as we are accustomed. At some point of the ice age, the layers of ice covered all Antarctica, most of Europe, North and South America, as well as small areas of Asia. In North America, they extended Greenland and Canada and parts of the Nordic United States. The remains of the glaciers of this period can still be seen in some parts of the world, including Greenland and Antarctic. But the glaciers not just "stood in place." Scientists celebrate about 20 cycles, when the glaciers moved and retreated when they melted and grow again.
In general, the climate was then much colder and land than today. Since most of the water on the surface of the Earth is flooded, the precipitation was a little - about two times less than today. In peak periods, when most of the water was frozen, global average temperatures were 5 -10 ° C below today temperature norms. However, winter and summer still replaced each other. True, in those summer money would not have succeeded.
Life during the glacial period
While Homo Sapiens in the severe situation of eternal cold temperatures began to develop the brain to survive, many vertebrates, especially large mammals, also courageously transferred the harsh climatic conditions of this period. In addition to all famous woolly mammoths, during this period, saber-toothed cats, giant ground sloths and mastodonts wandered on Earth. Although many vertebrates have died out during this period, in those years, mammals lived on Earth, which can be found today: including monkeys, large cattle, deer, rabbits, kangaroo, bears and members of the pet family and feline.
Dinosaurs, except for several early birds, was not in the ice age: they died out at the end of the Cretaceous period, more than 60 million years before the start of the Pleistocene era. But the birds themselves felt good at that time, including the relatives of the ducks, geese, hawks and eagles. Pernava had to compete with mammals and other creatures for limited food and water reserves, since a significant part of it was frozen. Also during the Pleistocene period, crocodiles, lizards, turtles, pythons and other reptiles lived.
It was worse with vegetation: in many areas it was difficult to find dense forests. More often met individual coniferous trees, such as pines, cypress and tees, as well as some broad-sized trees, like beeches and oaks.
Mass extinction
Unfortunately, about 13,000 years ago, more than three quarters of large animals of the glacial period, including woolly mammoths, mastodones, saber-toothed tigers and giant bears, extinct. Scientists are arguing many years about the causes of their disappearance. There are two main hypotheses: human resourcefulness and climate change, but both cannot explain extinction on the planet.
Some researchers believe that here, as with dinosaurs, it did not cost without extraterrestrial intervention: recent studies show that an extraterrestrial object, possibly a comet of about 3-4 kilometers, could explode over Southern Canada, almost destroying the ancient culture of the Stone Age, and Also Megafauna like mammoths and mastodonts.
Based on LiveScience.com.