In the beginning there was nothing. In the endless space there was only a giant cloud of dust and gases. It can be assumed that from time to time they rushed through this substance at great speed. spaceships with representatives of the universal mind. The humanoids looked boredly out the windows and did not even remotely realize that in a few billion years intelligence and life would arise in these places.

The gas and dust cloud transformed over time into the Solar System. And after the star appeared, the planets appeared. One of them was our native Earth. This happened 4.5 billion years ago. It is from those distant times that the age of the blue planet is counted, thanks to which we exist in this world.

Stages of Earth's development

The entire history of the Earth is divided into two huge stages.. The first stage is characterized by the absence of complex living organisms. There were only single-celled bacteria that settled on our planet about 3.5 billion years ago. The second stage began approximately 540 million years ago. This is the time when living multicellular organisms spread across the Earth. This refers to both plants and animals. Moreover, both seas and land became their habitat. The second period continues to this day, and its crown is man.

Such huge time stages are called eons. Each eon has its own eonothema. The latter represents certain stage geological development of the planet, which is radically different from other stages in the lithosphere, hydrosphere, atmosphere, biosphere. That is, each eonoteme is strictly specific and not similar to others.

There are 4 eons in total. Each of them, in turn, is divided into eras of the Earth, and those are divided into periods. From this it is clear that there is a strict gradation of large time intervals, and the geological development of the planet is taken as the basis.

Katarhey

The oldest eon is called Katarchean. It began 4.6 billion years ago and ended 4 billion years ago. Thus, its duration was 600 million years. Time is very ancient, so it was not divided into eras or periods. During the times of the Catarchaeus there was neither earth's crust, no core. The planet was a cold cosmic body. The temperature in its depths corresponded to the melting point of the substance. From above, the surface was covered with regolith, like the lunar surface in our time. The relief was almost flat due to constant powerful earthquakes. Naturally, there was no atmosphere or oxygen.

Archaea

The second eon is called Archean. It began 4 billion years ago and ended 2.5 billion years ago. Thus, it lasted 1.5 billion years. It is divided into 4 eras: Eoarchean, Paleoarchean, Mesoarchean and Neoarchean.

Eoarchaean(4-3.6 billion years) lasted 400 million years. This is the period of formation of the earth's crust. A huge number of meteorites fell on the planet. This is the so-called Late Heavy Bombardment. It was at that time that the formation of the hydrosphere began. Water appeared on Earth. Comets could have brought it in large quantities. But the oceans were still far away. There were separate reservoirs, and the temperature in them reached 90° Celsius. The atmosphere was characterized by a high content carbon dioxide and low nitrogen content. There was no oxygen. At the end of the era, the first supercontinent of Vaalbara began to form.

Paleoarchaean(3.6-3.2 billion years) lasted 400 million years. During this era, the formation of the solid core of the Earth was completed. A strong magnetic field appeared. His tension was half the current one. Consequently, the surface of the planet received protection from solar wind. This period also saw primitive forms of life in the form of bacteria. Their remains, which are 3.46 billion years old, were discovered in Australia. Accordingly, the oxygen content in the atmosphere began to increase, due to the activity of living organisms. The formation of Vaalbar continued.

Mesoarchean(3.2-2.8 billion years) lasted 400 million years. The most remarkable thing about it was the existence of cyanobacteria. They are capable of photosynthesis and produce oxygen. The formation of the supercontinent has completed. By the end of the era it had split. There was also a huge asteroid impact. Its crater still exists in Greenland.

Neoarchaean(2.8-2.5 billion years) lasted 300 million years. This is the time of formation of the present earth's crust - tectogenesis. Bacteria continued to develop. Traces of their life were found in stromatolites, whose age is estimated at 2.7 billion years. These lime deposits were formed by huge colonies of bacteria. They were found in Australia and South Africa. Photosynthesis continued to improve.

With the end of the Archean era, the Earth's era continued in the Proterozoic eon. This is a period of 2.5 billion years - 540 million years ago. It is the longest of all the eons on the planet.

Proterozoic

The Proterozoic is divided into 3 eras. The first one is called Paleoproterozoic(2.5-1.6 billion years). It lasted 900 million years. This huge time interval is divided into 4 periods: siderian (2.5-2.3 billion years), rhyasium (2.3-2.05 billion years), orosirium (2.05-1.8 billion years) , stateria (1.8-1.6 billion years).

Siderius notable in the first place oxygen catastrophe. It happened 2.4 billion years ago. Characterized by a dramatic change in the Earth's atmosphere. Free oxygen appeared in it in huge quantities. Before this, the atmosphere was dominated by carbon dioxide, hydrogen sulfide, methane and ammonia. But as a result of photosynthesis and extinction volcanic activity at the bottom of the oceans, oxygen filled the entire atmosphere.

Oxygen photosynthesis is characteristic of cyanobacteria, which proliferated on Earth 2.7 billion years ago. Before this, archaebacteria dominated. They did not produce oxygen during photosynthesis. In addition, oxygen was initially consumed in the oxidation of rocks. IN large quantities it accumulated only in biocenoses or bacterial mats.

Eventually, a moment came when the surface of the planet became oxidized. And the cyanobacteria continued to release oxygen. And it began to accumulate in the atmosphere. The process accelerated due to the fact that the oceans also stopped absorbing this gas.

As a result, anaerobic organisms died, and they were replaced by aerobic ones, that is, those in which energy synthesis was carried out through free molecular oxygen. The planet was enveloped ozone layer and the greenhouse effect decreased. Accordingly, the boundaries of the biosphere expanded, and sedimentary and metamorphic rocks turned out to be completely oxidized.

All these metamorphoses led to Huronian glaciation, which lasted 300 million years. It began in Sideria, and ended at the end of Rhiasia 2 billion years ago. The next period of orosiria is notable for its intense mountain building processes. At this time, 2 huge asteroids fell on the planet. The crater from one is called Vredefort and is located in South Africa. Its diameter reaches 300 km. Second crater Sudbury located in Canada. Its diameter is 250 km.

Last staterian period notable for the formation of the supercontinent Columbia. It includes almost all the continental blocks of the planet. There was a supercontinent 1.8-1.5 billion years ago. At the same time, cells were formed that contained nuclei. That is, eukaryotic cells. This was a very important stage of evolution.

The second era of the Proterozoic is called Mesoproterozoic(1.6-1 billion years). Its duration was 600 million years. It is divided into 3 periods: potassium (1.6-1.4 billion years), exatium (1.4-1.2 billion years), sthenia (1.2-1 billion years).

During the time of Kalimium, the supercontinent Colombia broke up. And during the Exatian times the red ones appeared multicellular algae. This is indicated by a fossil find on the Canadian island of Somerset. Its age is 1.2 billion years. A new supercontinent, Rodinia, formed in Stenium. It arose 1.1 billion years ago and disintegrated 750 million years ago. Thus, by the end of the Mesoproterozoic there was 1 supercontinent and 1 ocean on Earth, called Mirovia.

The last era of the Proterozoic is called Neoproterozoic(1 billion-540 million years). It includes 3 periods: Thonian (1 billion-850 million years), Cryogenian (850-635 million years), Ediacaran (635-540 million years).

During the Thonian era, the supercontinent Rodinia began to disintegrate. This process ended in cryogeny, and the supercontinent Pannotia began to form from 8 separate pieces of land formed. Cryogeny is also characterized by complete glaciation of the planet (Snowball Earth). The ice reached the equator, and after it retreated, the process of evolution of multicellular organisms sharply accelerated. The last period of the Neoproterozoic Ediacaran is notable for the appearance of soft-bodied creatures. These multicellular animals are called Vendobionts. They were branching tubular structures. This ecosystem is considered the oldest.

Life on Earth originated in the ocean

Phanerozoic

Approximately 540 million years ago, the time of the 4th and last eon began - the Phanerozoic. There are 3 very important eras of the Earth. The first one is called Paleozoic(540-252 million years). It lasted 288 million years. Divided into 6 periods: Cambrian (540-480 million years), Ordovician (485-443 million years), Silurian (443-419 million years), Devonian (419-350 million years), Carboniferous (359-299 million years) and Permian (299-252 million years).

Cambrian considered to be the lifespan of trilobites. These are marine animals similar to crustaceans. Along with them, jellyfish, sponges and worms lived in the seas. Such an abundance of living beings is called Cambrian explosion. That is, there was nothing like this before and suddenly it suddenly appeared. Most likely, it was in the Cambrian that mineral skeletons began to emerge. Previously, the living world had soft bodies. Naturally, they were not preserved. Therefore, complex multicellular organisms of more ancient eras cannot be detected.

The Paleozoic is notable for the rapid expansion of organisms with hard skeletons. From vertebrates, fish, reptiles and amphibians appeared. The plant world was initially dominated by algae. During Silurian plants began to colonize the land. At first Devonian The swampy shores are overgrown with primitive flora. These were psilophytes and pteridophytes. Plants reproduced by spores carried by the wind. Plant shoots developed on tuberous or creeping rhizomes.

Plants began to colonize land during the Silurian period

Scorpions and spiders appeared. The dragonfly Meganeura was a real giant. Its wingspan reached 75 cm. Acanthodes are considered the oldest bony fish. They lived during the Silurian period. Their bodies were covered with dense diamond-shaped scales. IN carbon, which is also called the Carboniferous period, a wide variety of vegetation rapidly developed on the shores of lagoons and in countless swamps. It was its remains that served as the basis for the formation of coal.

This time is also characterized by the beginning of the formation of the supercontinent Pangea. It was fully formed during the Permian period. And it broke up 200 million years ago into 2 continents. These are the northern continent of Laurasia and the southern continent of Gondwana. Subsequently, Laurasia split, and Eurasia and North America were formed. And from Gondwana arose South America, Africa, Australia and Antarctica.

On Permian there were frequent climate changes. Dry times alternated with wet ones. At this time, lush vegetation appeared on the banks. Typical plants were cordaites, calamites, tree and seed ferns. Mesosaur lizards appeared in the water. Their length reached 70 cm. But by the end of the Permian period, early reptiles died out and gave way to more developed vertebrates. Thus, in the Paleozoic, life firmly and densely settled on the blue planet.

The following eras of the Earth are of particular interest to scientists. 252 million years ago came Mesozoic. It lasted 186 million years and ended 66 million years ago. Consisted of 3 periods: Triassic (252-201 million years), Jurassic (201-145 million years), Cretaceous (145-66 million years).

The boundary between the Permian and Triassic periods is characterized by mass extinction of animals. 96% of marine species and 70% of terrestrial vertebrates died. The biosphere was dealt a very strong blow, and it took a very long time to recover. And it all ended with the appearance of dinosaurs, pterosaurs and ichthyosaurs. These sea and land animals were of enormous size.

But the main tectonic event of those years was the collapse of Pangea. A single supercontinent, as already mentioned, was divided into 2 continents, and then broke up into the continents that we know now. The Indian subcontinent also broke away. It subsequently connected with the Asian plate, but the collision was so violent that the Himalayas emerged.

This is what nature was like in the early Cretaceous period

The Mesozoic is notable for being considered the warmest period of the Phanerozoic eon.. This time global warming. It began in the Triassic and ended at the end of the Cretaceous. For 180 million years, even in the Arctic there were no stable pack glaciers. Heat spread evenly across the planet. At the equator, the average annual temperature was 25-30° Celsius. The circumpolar regions were characterized by a moderately cool climate. In the first half of the Mesozoic, the climate was dry, while the second half was characterized by humid climate. It was at this time that the equatorial climate zone was formed.

In the animal world, mammals arose from the subclass of reptiles. This was related to improvement nervous system and brain. The limbs moved from the sides under the body, and the reproductive organs became more advanced. They ensured the development of the embryo in the mother's body, followed by feeding it with milk. Hair appeared, blood circulation and metabolism improved. The first mammals appeared in the Triassic, but they could not compete with dinosaurs. Therefore, for more than 100 million years they occupied a dominant position in the ecosystem.

The last era is considered Cenozoic(beginning 66 million years ago). This is the current geological period. That is, we all live in the Cenozoic. It is divided into 3 periods: Paleogene (66-23 million years), Neogene (23-2.6 million years) and the modern Anthropocene or Quaternary period, which began 2.6 million years ago.

There are 2 main events observed in the Cenozoic. The mass extinction of dinosaurs 65 million years ago and the general cooling of the planet. The death of the animals is associated with the fall of a huge asteroid with a high content of iridium. The diameter of the cosmic body reached 10 km. As a result, a crater was formed Chicxulub with a diameter of 180 km. It is located on the Yucatan Peninsula in Central America.

Surface of the Earth 65 million years ago

After the fall, there was an explosion of enormous force. Dust rose into the atmosphere and covered the planet from sun rays. The average temperature dropped by 15°. The dust hung in the air for a whole year, which led to a sharp cooling. And since the Earth was inhabited by large heat-loving animals, they became extinct. Only small representatives of the fauna remained. It was they who became the ancestors of the modern animal world. This theory is based on iridium. The age of its layer in geological deposits corresponds exactly to 65 million years.

During the Cenozoic, the continents diverged. Each of them formed its own unique flora and fauna. The diversity of marine, flying and terrestrial animals has increased significantly compared to the Paleozoic. They became much more advanced, and mammals took a dominant position on the planet. Higher angiosperms appeared in the plant world. This is the presence of a flower and an ovule. Cereal crops also appeared.

The most important thing in the last era is anthropogen or quaternary period, which began 2.6 million years ago. It consists of 2 eras: the Pleistocene (2.6 million years - 11.7 thousand years) and the Holocene (11.7 thousand years - our time). During the Pleistocene era Mammoths, cave lions and bears, marsupial lions, saber-toothed cats and many other species of animals that became extinct at the end of the era lived on Earth. 300 thousand years ago, man appeared on the blue planet. It is believed that the first Cro-Magnons chose the eastern regions of Africa. At the same time, Neanderthals lived on the Iberian Peninsula.

Notable for the Pleistocene and Ice Ages. For as long as 2 million years, very cold and warm periods of time alternated on Earth. Over the past 800 thousand years, there have been 8 ice ages with an average duration of 40 thousand years. During cold times, glaciers advanced on the continents, and retreated during interglacial periods. At the same time, the level of the World Ocean rose. About 12 thousand years ago, already in the Holocene, the next ice age ended. The climate became warm and humid. Thanks to this, humanity spread throughout the planet.

The Holocene is an interglacial. It has been going on for 12 thousand years. Over the past 7 thousand years, human civilization has developed. The world has changed in many ways. Flora and fauna have undergone significant transformations thanks to human activity. Nowadays, many animal species are on the verge of extinction. Man has long considered himself the ruler of the world, but the era of the Earth has not gone away. Time continues its steady course, and the blue planet conscientiously revolves around the Sun. In a word, life goes on, but the future will show what will happen next.

The article was written by Vitaly Shipunov

We present to your attention an article about the classical understanding of the development of our planet Earth, written in a non-boring way, understandable and not too long..... If any of the older people have forgotten, it will be interesting to read, well, for those who are younger, and even for an abstract, it’s generally excellent material .

In the beginning there was nothing. In the endless space there was only a giant cloud of dust and gases. It can be assumed that from time to time spaceships carrying representatives of the universal mind rushed through this substance at great speed. The humanoids looked boredly out the windows and did not even remotely realize that in a few billion years intelligence and life would arise in these places.

The gas and dust cloud transformed over time into the Solar System. And after the star appeared, the planets appeared. One of them was ours motherland. This happened 4.5 billion years ago. It is from those distant times that the age of the blue planet is counted, thanks to which we exist in this world.

The entire history of the Earth is divided into two huge stages.

• The first stage is characterized by the absence of complex living organisms. There were only single-celled bacteria that settled on our planet about 3.5 billion years ago.
• The second stage began approximately 540 million years ago. This is the time when living multicellular organisms spread across the Earth. This refers to both plants and animals. Moreover, both seas and land became their habitat. The second period continues to this day, and its crown is man.

Such huge time stages are called eons. Each eon has its own eonothema. The latter represents a certain stage of the geological development of the planet, which is radically different from other stages in the lithosphere, hydrosphere, atmosphere, and biosphere. That is, each eonoteme is strictly specific and not similar to others.

There are 4 eons in total. Each of them, in turn, is divided into eras of the Earth’s development, and those are divided into periods. From this it is clear that there is a strict gradation of large time intervals, and the geological development of the planet is taken as the basis.

Katarhey

The oldest eon is called Katarchean. It began 4.6 billion years ago and ended 4 billion years ago. Thus, its duration was 600 million years. Time is very ancient, so it was not divided into eras or periods. At the time of the Katarchaean there was neither the earth's crust nor the core. The planet was a cold cosmic body. The temperature in its depths corresponded to the melting point of the substance. On top, the surface was covered with regolith, like the lunar surface in our time. The relief was almost flat due to constant powerful earthquakes. Naturally, there was no atmosphere or oxygen.

Archaea

The second eon is called Archean. It began 4 billion years ago and ended 2.5 billion years ago. Thus, it lasted 1.5 billion years. It is divided into 4 eras:

• Eoarchaean
• paleoarchean
• mesoarchaean
• neoarchaean

Eoarchaean(4–3.6 billion years) lasted 400 million years. This is the period of formation of the earth's crust. A huge number of meteorites fell on the planet. This is the so-called Late Heavy Bombardment. It was at that time that the formation of the hydrosphere began. Water appeared on Earth. Comets could have brought it in large quantities. But the oceans were still far away. There were separate reservoirs, and the temperature in them reached 90° Celsius. The atmosphere was characterized by a high content of carbon dioxide and a low content of nitrogen. There was no oxygen. At the end of this era of Earth's development, the first supercontinent of Vaalbara began to form.

Paleoarchaean(3.6–3.2 billion years) lasted 400 million years. During this era, the formation of the solid core of the Earth was completed. A strong magnetic field appeared. His tension was half the current one. Consequently, the surface of the planet received protection from the solar wind. This period also saw primitive forms of life in the form of bacteria. Their remains, which are 3.46 billion years old, were discovered in Australia. Accordingly, the oxygen content in the atmosphere began to increase, due to the activity of living organisms. The formation of Vaalbar continued.

Mesoarchean(3.2–2.8 billion years) lasted 400 million years. The most remarkable thing about it was the existence of cyanobacteria. They are capable of photosynthesis and produce oxygen. The formation of the supercontinent has completed. By the end of the era it had split. There was also a huge asteroid impact. The crater from it still exists in Greenland.

Geological history The earth is reconstructed based on the study of the rocks that make up the earth's crust. The absolute age of the oldest currently known rocks is about 3.5 billion years, and the age of the Earth as a planet is estimated at 4.5 billion years. Earth Education and First stage its developments date back to pre-geological history. The geological history of the Earth is divided into two unequal stages: the Precambrian, which occupies about 5/6 of the entire geological history (about 3 billion years), and the Phanerozoic, covering the last 570 million years. The Precambrian is divided into Archaean and Proterozoic. The Phanerozoic includes the Paleozoic, Mesozoic and Cenozoic eras. The most studied is the history of the continental part of the earth's crust, within which, about 1500-1600 million years ago, the formation of the ancient (Precambrian) platforms that made up the main massifs ended. modern continents. These are: Eastern European (Russian) in Europe; Siberian, Chinese-Korean, South Chinese and Indian in Asia; African, Australian, South and North American (Canadian), as well as Antarctic platforms. The history of the continental crust is largely determined by the development of its geosynclinal belts, consisting of individual geosynclinal systems. The evolution of all geosynclinal systems begins with a long geosynclinal stage of the formation and development of deep subparallel troughs, or geosynclines, separated by uplifts (geoanticlines) and usually filled with the sea, in whose waters thick layers of sedimentary and volcanic rocks were deposited. Then the geosynclinal system underwent intense folding, which transformed it into a folded system (folded structure), entered the stage of mountain building (orogenesis) and rose high as a whole in the form of a mountainous country. At this final orogenic stage, only here and there in the newly formed internal (intermountain) depressions and the foredeeps formed along the margins of neighboring platforms, mainly coarse sediments accumulated and so-called orogenic volcanism, associated with faults in the earth’s crust, developed over vast areas. With the end of the orogenic stage, the folded system lost its former tectonic mobility, its relief was gradually leveled by denudation, and it turned into the foundation of a young platform, within which sections were subsequently isolated, overlain by a newly deposited platform cover (plates). The development of most Phanerozoic geosynclinal systems fits within the framework of a few generalized tectonic cycles of planetary significance. Although the beginning and end of each of them differ in different cases by tens of millions of years, in general they are natural stages of the general evolution of the structure of the continental crust. Two of them - Caledonian and Hercynian - occur in the Paleozoic era (570-230 million years ago). The Caledonian and Hercynian folds that completed them formed the foundations of the most extensive and most typically constructed Epipaleozoic young platforms. All subsequent tectonic history is often considered as a single Alpine cycle. However, it clearly breaks down into private cycles of not universal significance, largely overlapping each other chronologically, but having a completely independent significance in the development of certain regions globe. The first of them is most typical for the geosynclinal belt surrounding the Pacific Ocean. Its beginning refers to the last segment Paleozoic era- the Permian period and coincides in time with the final stages of the Hercynian cycle in other areas. But the main part falls already on Mesozoic era(230-70 million years ago), which is why the cycle itself and the folding that completes it are usually called Mesozoic. Mesozoic folded systems are still characterized by mountainous terrain, and true epi-Mesozoic plates with a well-developed platform cover are rare. Another, actually Alpine, development cycle is most typical for the Mediterranean geosynclinic belt, stretching from Southern Europe through the Himalayas to Indonesia, and less typically manifested itself in some geosynclinal systems of the Pacific coast. Its beginning occurs in the early Mesozoic, and its end occurs in different periods of the last, Cenozoic era of the geological past. Only a few alpine geosynclinal systems contain currently developing geosynclines (e.g. deep-sea basins inland seas Mediterranean type). The vast majority of them are experiencing an orogenic stage and in their place are located high and intensively growing mountain systems - areas of young Cenozoic, or Alpine, folding. Modern geosynclinal systems (or areas) are concentrated mainly along the western periphery Pacific Ocean, to a lesser extent - in other oceanic regions. Sometimes they are also classified as areas of Cenozoic folding, although they are in the most active stage of geosynclinal development. After the end of the cycle, geosynclinal development can be repeated, but always some part of the geosynclinal areas at the end of the next cycle turns into a young platform. In this regard, over the course of geological history, the area occupied by geosynclines decreased, and the area of ​​platforms increased. It was the geosynclinal systems that were the place of formation and further growth of the continental crust with its granite layer. The periodic nature of vertical movements during the tectonic cycle (mainly subsidence at the beginning and predominantly uplift at the end of the cycle) each time led to corresponding changes in the surface topography, to a change in transgressions and regressions of the sea. The same periodic movements influenced the nature of the sedimentary rocks deposited, as well as the climate, which experienced periodic changes. Already in the Precambrian, warm epochs were interrupted by glacial ones. During the Paleozoic glaciation, Brazil was at times covered, South Africa , India and Australia. The last glaciation (in the Northern Hemisphere) was during the Anthropocene. The first half of each tectonic cycle took place on the continents, in general, under the sign of the advance of the sea, which flooded an increasingly larger area both on platforms and in geosynclines. In the Caledonian cycle, the advance of the sea developed during the Cambrian and Ordovician periods, in the Hercynian cycle - during the second half of the Devonian period and the beginning of the Carboniferous, in the Mesozoic - during the Triassic period and the beginning of the Jurassic, in the Alpine - during the Jurassic and Cretaceous periods , in the Cenozoic - during the Paleogene period. The seas were initially dominated by the deposition of sandy-clayey sediments, which, as the area of ​​the seas increased, gave way to limestone. When, in the middle of the cycle, uplifts of the earth's crust became dominant, the sea began to retreat, the land area increased, and mountains arose in geosynclines. By the end of the tectonic cycle, almost everywhere the continents were freed from sea basins. The nature of the sedimentary rocks formed in the depressions changed accordingly. At first it was still marine sediments, but not limestones, but sands and clays. The rocks became increasingly coarse-grained. At the end of the tectonic cycle, marine sediments were almost everywhere replaced by continental sediments. This process of changing sediments towards increasingly coarse and, finally, continental in the Caledonian cycle occurred in the Silurian period and the beginning of the Devonian, in the Hercynian cycle - at the end of the Carboniferous, Permian and the beginning of the Triassic period, in the Alpine cycle - during the Cenozoic, in the Mesozoic cycle - in the Cretaceous period, and in the Cenozoic - in the Neogene period. At the end of the cycle, chemogenic lagoon sediments (salt, gypsum) were also formed, which were the product of the evaporation of salts from the water of closed and shallow sea basins. Periodic changes in the conditions of sedimentation led to similarities between sedimentary formations belonging to the same stages of different tectonic cycles. And this in some cases led to the re-emergence of mineral deposits of sedimentary origin. For example, the largest coal deposits are confined to that stage of the Hercynian and Alpine cycles when the predominance of subsidence of the earth's crust has just passed to uplift (the middle and end of the Carboniferous period in the Hercynian cycle and the Paleogene period in the Alpine). The formation of large deposits of table and potassium salts was confined to the end of the tectonic cycle (the end of the Silurian period and the beginning of the Devonian in the Caledonian cycle, the Permian period and the beginning of the Triassic in the Hercynian, the Neogene and Anthropogenic periods in the Alpine). However, the similarity of sedimentary formations belonging to the same stage of different cycles is not complete. Thanks to the progressive evolution of the animal and flora Rock-forming organisms changed from cycle to cycle, and the nature of the influence of organisms on rocks also changed. For example, the lack of appropriate vegetation cover on the continents in the early Paleozoic was the reason for the absence in the Caledonian cycle of coal deposits that were characteristic of the Hercynian and later cycles. The transformation of tectonic mobile zones of the continental crust into platforms is not limited to the patterns of its development. Many geosynclinal systems, for example in the Verkhoyansk-Kolyma region and in a significant part of the Mediterranean geosynclinal belt, were formed in the body of more ancient folded structures, including ancient platforms, of which some internal massifs are relics. Along with such assimilation of sections of neighboring platforms by geosynclinal systems, vast zones within these latter experienced at times tectonic activation, expressed in significant relative vertical movements of large blocks along fault systems and general uplifts, leading to the appearance of previously leveled spaces of mountainous relief in place. Such epiplatform orogenesis differs greatly from the above-described epigeosynclinal orogenesis in the absence of real folding and the accompanying phenomena of deep magmatism, as well as the weak manifestation of volcanism.

Processes of tectonic activation have repeatedly affected the platforms throughout geological history. They manifested themselves especially clearly at the end of the Neogene, when the platforms rose again. high mountains, formed at the end of the Caledonian or Hercynian cycles and since then leveled (for example, Tien Shan, Altai, Sayan Mountains and many others); at the same time on the platforms formed large systems grabens - rifts, indicating the process of deep splitting of the earth's crust (Baikal rift system, East African fault zone). The process of reducing the area occupied by geosynclines and, accordingly, increasing the area of ​​platforms was subject to a certain spatial pattern: the first stable platforms formed in the Middle Proterozoic on the site of Archean geosynclines subsequently played the role of “foci of stabilization,” which were overgrown with increasingly younger platforms from the periphery. As a result, by the beginning of the Mesozoic, geosynclinal conditions were preserved in two narrow but extended belts - the Pacific and Mediterranean. Under the influence of the interaction of internal and external forces, nature earth's surface has changed throughout geological history. The relief, the outlines of continents and oceans, climate, vegetation and animal world. The development of the organic world was closely connected with the main stages of earth's development, among which there are long periods of relatively quiet development and periods of relatively short-term rearrangements of the earth's crust, accompanied by changes in physical and geographical conditions on its surface.

Studying the contents of the paragraph provides the opportunity to: study the history of the formation of the Earth and methods for determining the age of rocks; become familiar with the geochronological scale and its use in practical activities.

What is the Universe, the Solar theme? What are “gravitational forces”? There are many different hypotheses for the origin of the Earth. They are discussed in detail in the astronomy course. Currently, the most common hypothesis is O. Yu. gas-dust cloud.

These clouds, revolving around the Sun, collided, “stuck together,” forming clumps that grew like a snowball. It is believed that age solar system(including the Earth) is about 5 billion years. As a result of the evolution of the Earth, the rocks that make up the earth's crust were formed.
The time and sequence of formation of rocks is called geological chronology. There are absolute and relative ages of rocks. The absolute age is calculated from the beginning of rock formation to the present. It dates back thousands, millions and even billions of years and is mainly determined by studying the decay of radioactive chemical elements. The age of the most ancient rocks studied on the globe reaches 3.8 billion years.
Relative age reflects the sequence of deposition of rock layers in a geological section. The main methods for determining the relative age of rocks are stratigraphic (from Latin stratum - layer and Greek grapho - describe) - the ratio of layers, sedimentary strata
"petrographic (from the Greek petros - stone, grapho - description) - the study of the composition of rocks; paleontological (from the Greek palaios - ancient, logas - study) - the study of the remains of ancient extinct organisms; spore-pollen analysis - based on the results of analysis of spores and pollen of ancient plants" isotopic - based on radioactive isotopes.
The branch of historical geology that studies the sequence of formation of the forge is called stratigraphy. When rocks are undisturbed, the upper layers are younger than the lower ones. The arrangement of geological layers as they form from older to younger is called a stratigraphic column or stratigraphic scale. If this scale is expressed in time units divided into eras, periods and epochs, then it is called the geological time scale or geochronological scale (see Appendices). (Think about what you think the names of geological eras reflect. Which era is the most recent?)
The geochronological scale can reflect the time of formation mountain systems, minerals, the emergence of life or the disappearance of its individual forms.
The entire history of the Earth is usually divided into 2 stages: the Precambrian, or cryptozoic (planetary period), and the Phanerozoic (geological period).
If we take the age of the Earth to be 4.6 billion years, then the Cryptozoic lasted about 4 billion years, and the Phanerozoic lasted 570 million years.
The Precambrian (cryptozoic) is a period of time in the history of the evolution of the Earth, which is conventionally called its planetary stage.
The Precambrian is divided into two eras: Archean (ancient) and Proterozoic (early). The Archean is characterized by several epochs of folding, the formation of a shallow ocean with many volcanic islands, and the formation of an atmosphere with the presence of free oxygen. With the advent of the atmosphere and hydrosphere, the process of physical weathering and images began: ia of sedimentary deposits.
In the Archean, life arose in the aquatic environment, which was not interrupted on Earth throughout further history its development.
The next era - the Proterozoic - is characterized by several eras of folding, the formation of crystalline rocks of the foundation of ancient platforms. During this period, the volume of water in the ocean increased, the composition of the atmosphere changed (oxygen content reached 0.01% of the modern level), and invertebrates developed. Precambrian rocks form the foundation and lower part of the ancient platform cover: platforms.
The Phanerozoic spans the Paleozoic, Mesozoic and Cenozoic eras of geological history.
The Paleozoic is divided into 6 periods. (What are these periods called?) In the Ordovician, water acquired a composition close to that of today. In the Ordovician and Silurian, the Caledonian folding appeared. The land rose, and extensive retreats of warm seas occurred. The oxygen content in the atmosphere reached 10% of the modern level, and the formation of the ozone layer occurred.
The Devonian, Carboniferous (Carboniferous) and Permian are characterized by another combination of procontinents. In the Paleozoic, plants and animals began to move onto land. Active transformation has begun environment living organisms through biological and biochemical processes. This contributed to the differentiation (diversity) of natural complexes, the complication of physical-geographical conditions and the diversity of landscapes.
In the Carboniferous, thick layers of coal were formed, which determined the name of the period. The oxygen content in the atmosphere has approached current state. During the Permian period, a planetary cooling of the climate occurred, and glaciations formed in the Northern and Southern Hemispheres.
During the Mesozoic era, young mountains formed in areas of Mesozoic folding, the formation of modern oceans began, in which sediments accumulated, giant reptiles (dinosaurs) flourished, and then their extinction occurred.
The next era of the geological history of the Earth is the Cenozoic (Cenozoic). (Using a geochronological scale, determine the beginning and division of the era into periods.)
The last period of the Cenozoic era is called the Quaternary (or Anthropocene), which is divided into the Eopleistocene, Pleistocene and Holocene. (Remember from history how many years ago man appeared.)
The first segment of the Anthropocene, due to powerful glaciations, is also called the Ice Age. The total area of ​​the continental glacier at that time reached 48 ml! km2, which is three times the area of ​​Antarctica. In Europe, the glacier spread south to 49.5° N. sh., in North America- tgt; o7.5° N. w.
Glaciations consist of several stages, which alternated with interglacial eras.
The Czech scientist J. Augusta spoke very eloquently about the relationship and duration of different eras, periods and epochs in the general geological history of the Earth in his book “On the Paths of the Development of Life”: “... if the duration of the entire geological history of the Earth is conventionally taken to be the duration of one year. Then, on this scale, the Archean and Proterozoic will correspond almost entirely to the first three quarters of the year, that is, the time from the beginning of January to the last days of September; the formation of the earth's crust would have occurred in early spring, but without oceans and before the emergence of life. The emergence of life would have occurred around the beginning of May, and the first stage of invertebrate development during the Proterozoic period would have taken all summer until the beginning of autumn, until approximately half of September, when the Paleozoic would begin with the flowering of invertebrates, fish and amphibians. This period would have continued until approximately the last days of November, when the Mesozoic would have begun - the era of giant reptiles - which would have ended in last week December... On this scale, the Quaternary period would have taken only less than a day, and on this day a person would have appeared at approximately 8 o'clock in the evening. The entire history of science and culture of mankind would fit into this scale in just a few last minutes of the year!.."
? 1. How is geological chronology used to determine the age of the Earth?
2. Make a free-form table reflecting major events that occurred on Earth in the Paleozoic, Mesozoic, and Cenozoic eras.
3*. Why did the emergence of plants and animals on land contribute to the differentiation of the geographical envelope?

Paleozoic era (era ancient life) is distinguished by several stages of powerful mountain building, . During this era, the Scandinavian mountains, the Urals, Altai, etc. arose. At this time, animal organisms with a hard skeleton appeared. Vertebrates appeared for the first time: fish, amphibians, and reptiles. In the Middle Paleozoic, land vegetation appeared. Tree ferns, moss ferns, etc. served as material for the formation of coal deposits.

The Mesozoic era (the era of middle life) is also characterized by intense folding. Mountains formed in areas adjacent to. Reptiles (dinosaurs, proterosaurs, etc.) dominated among animals; birds and mammals appeared for the first time. The vegetation consisted of ferns, conifers, and angiosperms appeared at the end of the era.

During the Cenozoic era (the era of new life), the modern distribution took shape and intense mountain-building movements occurred. Mountain ranges are formed on the shores of the Pacific Ocean, in southern Europe and Asia (Coast Ranges, etc.). At the beginning of the Cenozoic era, the climate was much warmer than today. However, the increase in land area due to the rise of continents led to cooling. Extensive covers appeared in the north and. This led to significant changes in the flora and fauna. Many animals became extinct. Plants and animals close to modern ones appeared. At the end of this era, man appeared and began to intensively populate the land.

The first three billion years of Earth's development led to the formation of land. According to scientists, at first there was one continent on Earth, which subsequently split into two, and then another division occurred and as a result, five continents were formed today.

The last billion years of Earth's history are associated with the formation of folded regions. At the same time, in the geological history of the last billion years, several tectonic cycles (epochs) are distinguished: Baikal (end of the Proterozoic), Caledonian (early Paleozoic), Hercynian (late Paleozoic), Mesozoic (Mesozoic), Cenozoic or Alpine cycle (from 100 million years to present tense).
As a result of all the above processes, the Earth acquired its modern structure.