(era average life) - from 230 to 67 Ma - a total length of 163 Ma. The uplift of the land, which began in the previous period, continues. There is a single continent. Its total area is very large - much larger than at present. The continent is covered with mountains, the Urals, Altai and other mountain ranges are formed. The climate is becoming more and more arid.

Triassic - 230 -195 million years. The trends laid down in the Permian period are being consolidated. Most primitive amphibians are dying out, horsetails, club mosses, and ferns are almost disappearing. Gymnosperms predominate woody plants, since their reproduction is not associated with aquatic environment. Among the animals on land, herbivorous and carnivorous reptiles - dinosaurs - begin their triumphal procession. Among them there are already modern species: turtles, crocodiles, tuatara. Amphibians and various cephalopods still live in the seas, bony fishes appear quite modern look. This abundance of food attracts predatory reptiles to the sea, their specialized branch - ichthyosaurs - is separated. At the end Triassic period from some early reptiles, a small group separated itself, giving rise to mammals. They still breed with eggs, like modern echidnas and platypuses, but they already have an important feature that will give them advantages in the further struggle for existence. Mammals, like birds, also originating from reptiles, are warm-blooded animals - for the first time they acquire the mechanism of temperature self-regulation. But their time is still ahead, but for now dinosaurs continue to master the earthly spaces.

Jura - 195 - 137 Ma. Gymnosperms predominate in the forests, among them there is already a sequoia, which has survived to this day. The first angiosperms (flowering) plants appeared. Giant reptiles dominate, having mastered all habitats. On land, these are herbivorous and predatory dinosaurs, in the sea - ichthyosaurs and plesiosaurs, in the air - flying lizards hunting numerous insects and their smaller counterparts. From some of them, the first birds - Archeopteryxes - separated themselves. They had the skeleton of lizards, although greatly lightened, but were already covered with feathers - modified skin scales. IN warm seas In the Jurassic period, in addition to marine reptiles, bony fish and a variety of cephalopod mollusks - ammonites and belemnites, similar to modern nautilus and squid, thrive.

In the Jurassic period, a split of a single continent occurs and the divergence of continental plates begins to their current state. This led to isolation and relatively independent development of fauna and flora on different continents and island systems. Especially quickly and radically Australia became isolated, where the animal and plant composition as a result was very different from the inhabitants of other continents.

Cretaceous - 137 - 67 million years. The leading form in paleontological samples is foraminifera, testaceous protozoan animals that underwent mass extinction during this period and left huge sedimentary layers of chalk. Among the vegetation, angiosperms quickly spread and dominate, many of them quite modern in appearance and already have a real flower. Giant reptiles are being replaced by new dinosaurs moving on their hind legs. The first birds are quite common, but there are also real warm-blooded birds with a characteristic beak, without long tail. meet and small mammals; in addition to marsupials, placental ones also appeared, which for a long time bear cubs in the mother's womb in contact with blood through the placenta. Insects take over the flower, which benefits both insects and flowering plants.

End Cretaceous was marked by a significant general cooling. The complex food chain of reptiles, built on a limited circle of producers, collapsed "overnight" (by the standards of our conventional calendar). Within a few million years, the major groups of dinosaurs died out. There are different versions of the reasons for what happened at the end of the Cretaceous, but, apparently, it is primarily a matter of climate change and destruction food chains. In the colder seas, large cephalopods, the main food of sea lizards, have disappeared. Naturally, this led to the extinction of the latter. On land, there was a reduction in the zone of growth and biomass of soft succulent vegetation, which led to the extinction of herbivores, and after them predatory dinosaurs. The food base for large insects has also decreased, and flying lizards, both insectivorous and their predatory counterparts, began to disappear behind them. It must be borne in mind that the reptiles were cold-blooded animals and were not adapted to exist in a new, much more severe climate. Survived in this worldwide biological catastrophe and received further development small reptiles - lizards, snakes; and large ones - such as crocodiles, turtles, tuatara - survived only in the tropics, where the necessary food supply and a relatively warm climate remained.

Thus, the Mesozoic era is rightfully called the era of reptiles. For 160 million years, they survived their heyday, the widest divergence in all habitats and died out in the fight against the inevitable elements. Against the backdrop of these events, warm-blooded organisms - mammals and birds, who have moved to the development of the liberated ecological spheres, received huge advantages. But it was already a new era. There were 7 days left until the New Year.

Cenozoic era(era of new life) - from 67 million years to the present. This is the era of flowering plants, insects, birds and mammals. Man also appeared in this era.

The Tertiary period is divided into the Paleogene (67 - 25 million years) and the Neogene (25 - 1.5 million years). There is a wide distribution of flowering plants, especially herbaceous ones. Vast steppes are formed - the result of retreat rainforest due to cold weather. The animals are dominated by mammals, birds, and insects. Separate groups of reptiles continue to disappear and cephalopods. About 35 million years ago, a detachment of primates (lemurs, tarsiers) appeared in the class of mammals, which subsequently gave rise to monkeys and humans. The first people appeared about 3 million years ago (7 hours before the "New Year") in the eastern Mediterranean.

The Quaternary period, or Anthropogen, includes the last 1.5 million years of the development of life. A modern plant and animal world. There is a rapid evolution and domination of man. There are four periodic glaciations of the northern hemisphere of the Earth. During this time, mammoths, many large animals, and ungulates died out. An important role in this was played by people who were actively engaged in hunting and farming. Periodic freezing and thawing of water changed the level of the seas, either building or destroying bridges between Asia and North America, Europe and Britain, Indochina and the Islands. These circumstances made it possible for animals and plants to migrate, supporting their evolutionary changes in small adaptive traits. Australia has complete isolation from other continents, which has created special directions and rates of evolution there. The absence of predators allowed the preservation of ancient marsupials and oviparous mammals, long extinct on other continents. There were changes in the family of people, but we will talk about them in a separate topic. Here we note that a modern type of man was formed only 50 thousand years ago (at 23 hours 53 minutes on December 31 of our conditional year for the development of life on Earth; this year we exist only for its last 7 minutes!).

The Mesozoic era began 230 million years ago and lasted 163 million years. It is divided into three periods: Triassic (35 million years), Jurassic, or Jurassic period(58 million years), and the Cretaceous, or Cretaceous period (70 million years).

In the seas, even in the Permian period, trilobites finally died out. But this was not the sunset of the marine invertebrates. On the contrary: each extinct form was replaced by several new ones. During mesozoic era The oceans of the Earth abounded with mollusks: squid-like belemnites (their fossil shells are called "devil's fingers"), and ammonites. The shells of some ammonites reached 3m. In diameter. No one else on our planet, either before or later, had such colossal shells!

In the forests of the Mesozoic, conifers and cypresses, as well as cycads, dominated. We are used to seeing insects hovering over flowers. But such a spectacle became possible only from the middle of the Mesozoic, when the first flower bloomed on Earth. By the Cretaceous flowering plants conifers and cycads have already begun to crowd.

The Mesozoic, especially the Jurassic, can be called the kingdom of reptiles. But even at the very beginning of the Mesozoic, when the reptiles were just moving towards their dominance, small, woolly, warm-blooded mammals appeared next to them. For a long 100 million years, they lived next to the dinosaurs, almost invisible against their background, patiently waiting in the wings.

In the Jurassic, dinosaurs also had other warm-blooded rivals - the first birds (Archaeopteryx). They had a lot more in common with reptiles: for example, jaws studded with sharp teeth. In the Cretaceous period, real birds also descended from them.

At the end of the Cretaceous period, the climate on Earth became colder. Nature could no longer feed animals weighing more than ten kilograms. Began mass extinction(stretched, however, for millions of years) dinosaur giants. Now the vacated place could be occupied by animals and birds.

Scientists studying the ancient world argue that our ancestors lived much less than modern man. No wonder, because before there was no such developed medicine, there was no such knowledge in the field of our health that allows a person today to take care of himself and portend dangerous diseases.

However, there is another opinion that our ancestors, on the contrary, lived much longer than you and I. They ate organic food, used natural medicines(herbs, decoctions, ointments). And the atmosphere of our planet was much better than now.

The truth, as always, is somewhere in the middle. This article will help to better understand what was the life expectancy of people in different eras.

The ancient world and the first people

Science has proven that the first people appeared in Africa. Human communities did not appear immediately, but in the process of a long and painstaking formation of a special system of relationships, which today are called "public" or "social". Gradually, ancient people moved from place to place and occupied new territories of our planet. And around the end of the 4th millennium BC, the first civilizations began to appear. This moment became a turning point in the history of mankind.

The times of the primitive communal system so far occupy most of the history of our species. It was the era of the formation of man as a social being and as a biological species. It was during this period that the ways of communication and interaction were formed. Languages ​​and cultures were created. Man learned to think and make reasonable decisions. The first rudiments of medicine and healing appeared.

This primary knowledge has become a catalyst for the development of mankind, thanks to which we live in the world that we have now.

Anatomy of an ancient person

There is such a science - paleopathology. She studies the structure of ancient people from the remains found during archaeological sites. And according to the data obtained during the study of these findings, scientists have found that ancient people got sick just like us, although before the advent of this science everything was completely different. Scientists believed that prehistoric man did not get sick at all and was completely healthy, and diseases appeared as a result of the emergence of civilization. Thanks to knowledge in this area, modern scientists have found that diseases appeared before man.

It turns out that our ancestors were also at risk from harmful bacteria and various diseases. According to the remains, it was determined that tuberculosis, caries, tumors and other diseases were not uncommon among ancient people.

Lifestyle of ancient people

But not only diseases created difficulties for our ancestors. Constant struggle for food, for territory with other tribes, non-observance of any hygiene rules. Only during the hunt for a mammoth from a group of 20 people could return about 5-6.

ancient man completely reliant on himself and his abilities. Every day he fought for survival. About mental development there was no talk. Ancestors hunted and defended the territory they inhabited.

Only later did people learn to pick berries, roots, grow some kind of crops. But from hunting and gathering to the agrarian society that marked the beginning new era, humanity has been going on for a very long time.

The lifespan of a primitive man

But how did our ancestors cope with these diseases in the absence of any medicines or knowledge in the field of medicine? The very first people had a hard time. The maximum to which they lived was the age of 26-30 years. However, over time, a person has learned to adapt to certain environmental conditions, and to understand the nature of certain changes occurring in the body. Gradually, the life expectancy of ancient people began to increase. But this happened very slowly with the development of healing skills.

There are three stages in the formation of primitive medicine:

• Stage 1 - the formation of primitive communities. People were just beginning to accumulate knowledge and experience in the field of healing. They used animal fats, applied various herbs to wounds, prepared decoctions from ingredients that came to hand;
• Stage 2 - the development of the primitive community and the gradual transition to their disintegration. Ancient man learned to observe the processes of the course of the disease. I began to compare the changes that occurred in the process of healing. The first "medicines" appeared;
• Stage 3 - the collapse of primitive communities. At this stage of development, finally began to form medical practice. People have learned to treat certain ailments effective ways. We realized that death can be cheated and avoided. The first doctors appeared;

In ancient times, people died from the most insignificant diseases, which today do not cause any concern and are treated in one day. A man died in the prime of his life, not having time to live to old age. The average duration of a person in prehistoric times was extremely low. IN better side everything began to change in the Middle Ages, which will be discussed further.

Middle Ages

The first scourge of the Middle Ages is hunger and disease, which still migrated from ancient world. In the Middle Ages, people not only starved, but also satisfied their hunger with terrible food. Animals were killed on dirty farms in complete unsanitary conditions. There was no talk of sterile methods of preparation. In medieval Europe, the swine flu epidemic claimed tens of thousands of lives. In the 14th century, a plague pandemic that broke out in Asia wiped out a quarter of Europe's population.

Medieval lifestyle

What did people do in the Middle Ages? The eternal problems remain the same. Diseases, the struggle for food, for new territories, but everything was added to this more problems that appeared in a person when he became more intelligent. Now people began to wage wars for ideology, for an idea, for religion. If earlier man fought with nature, now he fought with his fellows.

But along with this, many other problems also went away. Now people have learned how to make fire, build themselves reliable and durable dwellings, and began to observe primitive rules of hygiene. Man learned to skillfully hunt, invented new methods to simplify everyday life.

Lifespan in Antiquity and the Middle Ages

The miserable state in which medicine was in ancient times and the Middle Ages, many diseases that were incurable at that time, poor and terrible food - all these are signs that characterize the early Middle Ages. And this is not to mention the constant strife between people, about the conduct of wars and crusades that took hundreds of thousands human lives. The average life expectancy still did not exceed 30-33 years. Forty-year-old men were already called "mature husband", and a man of fifty was even called "elderly". Residents of Europe in the 20th century lived up to 55 years.

IN Ancient Greece people did live an average of 29 years. This does not mean that in Greece a person lived to be twenty-nine years old and died, but it was considered old age. And this despite the fact that in those days the first so-called "hospitals" had already been formed in Greece.

The same can be said about Ancient Rome. Everyone knows about the powerful Roman soldiers who were in the service of the empire. If you look at the ancient frescoes, then in each of them you can recognize some god from Olympus. One immediately gets the impression that such a person will live long and remain healthy throughout his life. But the statistics say otherwise. Life expectancy in Rome was hardly 23 years old. The average duration throughout the Roman Empire was 32 years. So the Roman wars weren't all that healthy after all? Or are incurable diseases to blame for everything, from which no one was insured? It is difficult to answer this question, but data taken from more than 25,000 epitaphs on the tombstones of cemeteries in Rome speaks of such figures.

In the Egyptian empire, which existed even before the beginning of our era, which is the cradle of civilization, the SOL was no better. She was only 23 years old. What can we say about the less civilized states of antiquity, if life expectancy even in ancient egypt was negligible? It was in Egypt that people first learned to treat people with snake venom. Egypt was famous for its medicine. At that stage in the development of mankind, it was advanced.

Late Middle Ages

What about the later Middle Ages? In England, from the 16th to the 17th century, plague raged. Average life expectancy in the 17th century. was only 30 years old. In Holland and Germany in the 18th century, the situation was no better: people lived to an average of 31 years.

But life expectancy in the 19th century. began to increase slowly but surely. Russia XIX century was able to increase the figure to 34 years. In those days, in the same England, people lived less: only 32 years.

As a result, we can conclude that life expectancy in the Middle Ages remained at a low level and did not change over the centuries.

Modernity and our days

And only with the onset of the 20th century did humanity begin to equalize the indicators of average life expectancy. New technologies began to appear, people mastered new methods of curing diseases, the first medicines appeared in the form in which we are used to seeing them now. Life expectancy began to increase sharply in the middle of the twentieth century. Many countries began to develop rapidly and improve their economies, which made it possible to increase the standard of living of people. Infrastructure, medical equipment, everyday life, sanitary conditions, the emergence of more complex sciences. All this has led to a sharp improvement in the demographic situation throughout the planet.

The twentieth century foreshadowed new era in the development of mankind. It was truly a revolution in the world of medicine and in improving the quality of life of our species. For some half a century, life expectancy in Russia has almost doubled. From 34 years to 65. These figures are amazing, because for several millennia a person could not increase his life expectancy even by a couple of years.

But the sharp rise was followed by the same stagnation. From the middle of the twentieth century until the beginning of the twenty-first century, no discoveries were made that radically changed the idea of ​​\u200b\u200bmedicine. Certain discoveries were made, but this was not enough. Life expectancy on the planet has not increased as rapidly as it did in the middle of the 20th century.

XXI Century

The question of our connection with nature has sharply arisen before mankind. Ecological situation on the planet began to deteriorate sharply against the backdrop of the twentieth century. And many are divided into two camps. Some believe that new diseases appear due to our disregard to nature and environment, others, on the contrary, believe that the more we move away from nature, the more we prolong our stay in the world. Let's consider this question in more detail.

Of course, it is foolish to deny that without special achievements in the field of medicine, humanity would have remained at the same level of self-knowledge, its body at the same level as in the middle, and even later centuries. Now mankind has learned to treat such diseases that destroyed millions of people. Entire cities were taken away. Achievements in the field of various sciences such as: biology, chemistry, physics allow us to open new horizons in improving our quality of life. Unfortunately, progress requires sacrifice. And as we accumulate knowledge and improve technology, we inexorably destroy our nature.

Medicine and healthcare in the XXI century

But this is the price we pay for progress. Modern man lives many times longer than its distant ancestors. Today, medicine works wonders. We have learned how to transplant organs, rejuvenate the skin, delay the aging of body cells, and detect pathologies at the formation stage. And this is only a small part of what modern medicine can offer every person.

Doctors have been valued throughout human history. Tribes and communities with more experienced shamans and healers survived longer than others and were stronger. States in which medicine was developed suffered less from epidemics. And now those countries in which the healthcare system is developed, people can not only be treated for diseases, but also significantly prolong their lives.

Today, the vast majority of the world's population is free from the problems that people faced before. No need to hunt, no need to make fire, no need to be afraid of dying from a cold. Today man lives and accumulates wealth. Every day he does not survive, but makes his life more comfortable. He goes to work, rests on weekends, has a choice. He has all the means for self-development. People today eat and drink as much as they want. They do not need to worry about getting food when everything is in stores.

Life expectancy today

Average life expectancy today is approximately 83 years for women and 78 years for men. These figures do not go to any comparison with those that were in the Middle Ages and even more so in antiquity. Scientists say that biologically a person has been given about 120 years. So why are older people who turn 90 still considered centenarians?

It's all about our attitude to health and lifestyle. After all, the increase in the average life expectancy of a modern person is associated not only with the improvement of medicine. Here, the knowledge that we have about ourselves and the structure of the body also plays an important role. People have learned to follow the rules of hygiene and body care. A modern person who cares about his longevity, leads a correct and healthy lifestyle, does not abuse bad habits. He knows that it is better to live in places with a clean environment.

Statistics show that in different countries where the culture healthy lifestyle life is instilled in citizens from childhood, the mortality rate is much lower than in states where this is not given due attention.

The Japanese are the longest living nation. People in this country are accustomed to the right way of life from childhood. And how many examples of such countries: Sweden, Austria, China, Iceland, etc.

It took a long time for a person to reach such a level and life expectancy. He overcame all the trials that nature threw him. How much we suffered from illnesses, from cataclysms, from the awareness of the fate that is in store for all of us, but still we moved on. And we are still moving towards new achievements. Think about the path we have traveled through the centuries of history of our ancestors and that their legacy should not be wasted, that we should only continue to improve the quality and duration of our lives.

About life expectancy in different eras (video)

Palaeozoic.

This era, which began 570 million years ago. years ago, lasted 340 million years. Scientists divide it into six periods. Scientists divide it into six parts.

• 1. The earliest is the Cambrian (lasted 70 million years).
• 2. It was followed by the Ordovician (lasted 60 million years). The first round-mouthed - relatives - appear. They do not yet have jaws, but the structure of the mouth allows them to grab live prey, which is much more profitable than straining silt.
• 3. Silurian (30 million years), the first plants (psilophyte) come to land, covering the shores with a green carpet 25 cm high.
• 4. next period- Devonian (60 million years) The land is inhabited by club mosses, ferns, horsetails, mosses. The first insects already live in their thickets.
• 5. The next period is the Carboniferous, or Stone Age (65 million years). In the first vast expanses of land, swampy forests of tree-like ferns, horsetails and club mosses were covered.
• 6. The last period of the era - Perm, or the Permian period (55 million). The climate became cold and drier. wet forests from ferns and club mosses have disappeared.

The era of middle life (Mesozoic).

The Mesozoic era began 230 million years ago and lasted 163 million years. It is divided into three periods: Triassic (35 million years), Jurassic, or Jurassic period (58 million years), and Cretaceous, or Cretaceous period (70 million years).

In the seas, even in the Permian period, trilobites finally died out. But this was not the sunset of the marine invertebrates. On the contrary: each extinct form was replaced by several new ones. During the Mesozoic era, the Earth's oceans abounded with mollusks: squid-like belemnites (their fossil shells are called "devil's fingers") and ammonites. The shells of some ammonites reached 3m. In diameter. No one else on our planet, either before or later, had such colossal shells!

The Mesozoic, especially the Jurassic, can be called the kingdom of reptiles. But even at the very beginning of the Mesozoic, when the reptiles were just moving towards their dominance, small, furry, warm-blooded mammals appeared next to them. For a long 100 million years they lived next to the dinosaurs, almost invisible against their background, patiently waiting in the wings.

In the Jurassic, dinosaurs also had other warm-blooded rivals - the first birds (Archaeopteryx). They had a lot more in common with reptiles: for example, jaws studded with sharp teeth. In the Cretaceous period, real birds also descended from them.

At the end of the Cretaceous period, the climate on Earth became colder. Nature could no longer feed animals weighing more than ten kilograms. A mass extinction began (stretching, however, for millions of years) of dinosaur giants. Now the vacated place could be occupied by animals and birds.

The accumulated materials on the geological structure of the earth's crust and the development of life made it possible to break it geological history by six eras and draw up a scale of geological time - a geochronological scale.

Each era is divided into periods, period into eras, eras into centuries.

Archean era - the era of the beginning of life

Proterozoic era - the era of primary life

Riphean - the era of early life

Paleozoic era of ancient life

Mesozoic - the era of middle life

Cenozoic - the era of modern life.

The eras are united into two eons by Kryptose and Phanerosa.

Croptozoic unites the Archean, Proterozoic and Riphean eras. This eon accounts for almost 4 billion years, or 5/6 of the entire geological chronology.

This is the time of the origin of life, the appearance of primitive unicellular organisms. The skeletal fauna is completely absent.

They are characterized by active tectonic activity, as a result of which the geological structure of the earth's crust was formed, the appearance of water and the first simplest forms of life, and the accumulation of the first thick layers of sedimentary rocks. First, the platforms of the northern hemisphere and the Australian were formed, later the Hindustan, South American, African and Antarctic. At the same time, the first geosynclines (folded mountains) took shape.

The geological formations of these eras are represented by igneous, ancient sedimentary and metamorphic rocks: crystalline schists, limestones, marbles, etc. In an unweathered state, these rocks are a good foundation and good building materials. They form the crystalline foundation of the Russian, West Siberian and other plains, come to the surface in our country south of Voronezh, in Karelia, the Murmansk region, in Eastern Siberia, in the Urals, in Central Asia and in Altai.

Other eras - Pleozoic, Mesozoic and Cenozoic - are combined into the Phanerozoic (approximately 570 million years). Phaenerozoic is the most important stage in the geological history of the Earth, which is characterized by the emergence and wide development of skeletal organisms, the flourishing of the organic world and the emergence of man.

Palaeozoic-Pz began about 525-570 million years ago and lasted about 340 million years. The Paleozoic era is divided into six periods: Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian. If necessary, changes were introduced into the standard stratigraphic scale, reflecting regional specifics. For example, in Europe there is a Carboniferous period, and in the USA two correspond to it - Mississippi and Pennsylvania.

The Paleozoic era is distinguished mainly by a very warm and humid subtropical climate, which led to the formation of many rocks of organogenic origin. During this period, two major phases of mountain building took place, accompanied by intense crushing of rocks. The first, Caledonian phase took place on the territory of Scotland, Western Scandinavia, Greenland, on the territory of Russia, this is the region of Transbaikalia. During the second, Hercynian phase, the Ural Mountains, Tien Shan, Altai, etc. were formed. In the era of rock formation, the tropical climate was replaced by a sharp cooling, and during the era of the Hercynian phase, glaciation even occurred.

In the Paleozoic era, limestones, marls, dolomites were formed in the seas, on the continents - clays, sands and sandstones. In the last periods of the Paleozoic - Carboniferous and Permian - powerful deposits of coal, limestones, sandstones, shales, as well as chemical sedimentary rocks - gypsum, anhydrite, rock salt were formed. The rocks formed during this era contain many remains of fauna and flora. The forms were primitive and very far from modern, these are spore plants and invertebrates, and subsequently extinct vertebrates.

Most of the rocks of the Paleozoic era can serve as a reliable foundation and be used as building materials.

Mesozoic era Mz (the era of middle life) began 190 million years ago and had a duration of about 125 million years, divided into three periods Triassic, Jurassic and Cretaceous. The era is distinguished by a relatively warm, uniform climate and tectonic calm. Only in the Jurassic period did the Cimmerian phase of mountain building take place, as a result of which the formation of the Caucasus and Crimean mountains began. At the same time, a continental climatic situation is observed, in which coals and clays were formed.

During the Mesozoic, marine and continental deposits were equally distributed. Within the Russian plain, powerful deposits of chalk, limestone, and clay were formed. The possibilities of using the rocks of the Mesozoic era for construction purposes are the same as in the Paleozoic period.

During this era, reptiles were very large. Fauna and flora were of a transitional nature - from ancient forms of the organic world to modern ones.

Cenozoic erakz(era of new life) began 65 million years ago. The flora and fauna are approaching modern forms, a man appears. The era is divided into three periods: Paleogene, Neogene and Quaternary. The first two periods are usually combined into one - the tertiary. The Quaternary period takes only 1 million years and has been studied in the most detail. It was at the beginning of the Quaternary period that man appeared.

The Cenozoic era is distinguished by different, sharply different climatic conditions. During the Paleogene period, the climate was warm, almost tropical, during the Neogene period, cooling is observed, which in the Quaternary period turned into an ice age with periodic glaciations. Glaciations captured a vast territory of the northern part of Europe and Asia.

In the Cenozoic era, the so-called Alpine folding, the formation of which began as early as the Jurassic, was very intensively manifested. In the Tertiary period, the formation of the Caucasus and Crimean mountains ended. At the same time, ridges appeared North Africa, Alps, Carpathians, Pamir Mountains, Tien Shan, Himalev, on the Kuril Islands, Sakhalin Kamchatka. The Alpine orogenic phase has not ended yet.

In the Tertiary period, rocks of marine and continental origin were formed. Tertiary marine deposits - clays, shell limestones, etc. are located on the Black Sea coast and in other places. Continental Tertiary deposits are ubiquitous.

The rocks of the Quaternary period are overwhelmingly continental deposits - loose rocks and rocks of organogenic origin. They are usually called Quaternary rocks or alluvial rocks, in contrast to the earlier rocks, which I call bedrock. Marine Quaternary deposits are rare in Russia - on the coasts of the seas, to the north and east of the Caspian Sea and on the northern coast of the Black Sea. The composition and properties of these deposits are similar to those of the Tertiary. Marine silts form a special group among them.

The thickness of Quaternary deposits varies from a few centimeters to tens and hundreds of meters. These rocks are less reliable as bases than roots. Their properties vary widely and largely depend on genetic characteristics.

The bedrocks are usually represented by rocky and compacted sandy and clayey rocks, and among the Quaternary deposits loose formations, weakly cemented and cohesive, predominate.