Cenozoic group and era. Quaternary (anthropogenic) system (period). Development of life in the Cenozoic. Geology, climate, flora and fauna Fossils of the Quaternary period of the Cenozoic era

Cenozoic era

The Cenozoic era - the era of new life - began about 67 million years ago and continues in our time. In this era, the modern relief, climate, atmosphere, animal and vegetable world, Human.

The Cenozoic era is divided into three periods: Paleogene, Neogene and Quaternary.

Paleogene period

The Paleogene period (in translation - born long ago) is divided into three epochs: Paleocene, Eocene and Oligocene.

In the Paleogene period, the northern continent of Atlantia still exists, separated by a wide strait from Asia. Australia and South America V common features oh already bought modern forms. South Africa was formed with the island of Madagascar, in the place of its northern part there were large and small islands. India in the form of an island approached Asia almost closely. At the beginning of the Paleogene period, the land sank, as a result of which the sea flooded large areas.

In the Eocene and Oligocene, mountain-building processes (Alpine orogeny) took place, which formed the Alps, the Pyrenees, and the Carpathians. The formation of the Cordillera, the Andes, the Himalayas, the mountains of Central and South Asia continues. Coal-bearing strata are formed on the continents. Sands, clays, marls and volcanic rocks predominate among marine sediments during this period.

The climate changed several times, becoming either warm and humid, or arid and cool. Snow fell in the northern hemisphere. Climatic zones were clearly traced. There were seasons.

The shallow seas of the Paleogene period were inhabited by a huge number of nummulites, whose coin-like shells often overwhelm Paleogene deposits. There were relatively few cephalopods. Of the once numerous genera, only a few remained, mostly living in our time. There were many gastropods, radiolarians, sponges. In general, most invertebrates of the Paleogene period differ from invertebrates living in modern seas.

The number of bony fish increases, and the number of ganoid fish becomes smaller.

At the beginning of the Paleogene period, marsupial mammals spread significantly. They had many features in common with reptiles: they multiplied by laying eggs; often their body was covered with scales; the structure of the skull resembled the structure of the skull of reptiles. But unlike reptiles, marsupials had constant temperature bodies and fed their young with milk.

Among the marsupial mammals were herbivores. They resembled modern kangaroos and marsupial bears. There were also predators: a marsupial wolf and a marsupial tiger. Many insectivores settled near water bodies. Some marsupials have adapted to life in trees. Marsupials gave birth to underdeveloped cubs, which were then nurtured for a long time in skin pouches on their stomachs.

Many marsupials ate only one type of food, for example, a koala - only eucalyptus leaves. All this, along with other primitive features of organization, led to the extinction of marsupials. More advanced mammals gave birth to developed young and fed on a variety of vegetation. In addition, unlike clumsy marsupials, they easily escaped from predators. The ancestors of modern mammals began to inhabit the earth. Only in Australia, which separated early from other continents, evolutionary process as if frozen. Here the kingdom of marsupials has survived to this day.

In the Eocene, the first horses (Eohippus) appeared - small animals that lived in forests near swamps. On the front legs they had five toes, on four of them there were hooves, on the back - three hooves. They had a small head on a short neck and had 44 teeth. The molars were low. This suggests that the animals ate mainly soft vegetation.

Eohippus.

Subsequently, the climate changed, and arid steppes with hard grass formed in place of marshy forests.

The descendants of the Eohippus, the Orohippus, were almost the same in size, but had high tetrahedral molars, with which they could grind rather tough vegetation. The skull of the Orohippus is more similar to that of the modern horse than that of the Eohippus. It is the same size as the skull of a fox.

The descendants of the orogippus - the mesohippus - adapted to the new living conditions. Three fingers remained on their front and hind legs, the middle of which were larger and longer than the side ones. This allowed the animals to run quickly on hard ground. The small soft hooves of the Eohippus, adapted to soft marshy soils, turn into a real hoof. Mesogippus were the size of a modern wolf. They inhabited the Oligocene steppes in large herds.

The descendants of the mesogippus - the merikhippus - were the size of a donkey. They had cement on their teeth.

Merikhippus.

In the Eocene, the ancestors of rhinos appear - large hornless animals. At the end of the Eocene, untatherians originated from them. They had three pairs of horns, dagger-like long fangs, and a very small brain.

Titanotherium, the size of modern elephants, also representatives of Eocene animals, had large branched horns. The teeth of titanotheres were small, probably, the animals fed on soft vegetation. They lived in meadows near numerous rivers and lakes.

Arsenotherium had a pair of large and small horns. Their body length reached 3 m. The distant descendants of these animals are domans, small ungulates living in our time.

Arsenotherium.

On the territory of modern Kazakhstan in the Oligocene period, the climate was warm and humid. Many lived in the forests and steppes hornless deer. Long-necked indricotheriums were also found here. Their body length reached 8 m, and the height was about 6 m. Indrikotheria fed on soft plant foods. When the climate became arid, they died out from lack of food.

Indricotherium.

In the Eocene period, the ancestors of the living proboscis appear - animals the size of a modern tapir. Their tusks were small, and the trunk was an elongated upper lip. From them descended dinoteria, the lower jaw of which descended at a right angle. There were tusks at the end of the jaws. Dinotheriums already had real trunks. They lived in moist forests with lush vegetation.

At the end of the Eocene, the first representatives of elephants appear - paleomastodons and the first representatives of toothed and toothless whales, sirenians.

Some ancestors of monkeys and lemurs lived in trees, fed on fruits and insects. They had long tails, which helped them climb trees, and limbs with well-developed fingers.

In the Eocene, the first pigs, beavers, hamsters, porcupines, pygmy humpless camels, the first bats, broad-nosed monkeys, in Africa - the first great apes.

Predatory creodonts, small, wolf-like animals, did not yet have true "predatory" teeth. Their teeth were almost the same in size, the structure of the skeleton was primitive. In the Eocene, they gave rise to real predators with differentiated teeth. In the course of evolution, all representatives of canines and felines developed from these predators.

The Paleogene period is characterized by an uneven distribution of fauna across the continents. Tapirs, titanotheres developed mainly in America, proboscis and predatory - in Africa. Marsupials continue to live in Australia. Thus, gradually the fauna of each continent acquires an individual character.

Paleogene amphibians and reptiles are no different from modern ones.

Many toothless birds appeared, which are also characteristic of our time. But along with them lived huge flightless birds, completely extinct in the Paleogene - diatryma and fororakos.

Diatryma was 2 m in height with a long, up to 50 cm beak. On strong paws she had four fingers with long claws. Diatryma lived in arid steppes, fed small mammals and reptiles.

Diatryma.

Fororakos reached 1.5 m in height. Its sharp hooked half-meter beak was a very formidable weapon. Because it had small, undeveloped wings, it could not fly. The long, strong legs of Phororacos indicate that they were excellent runners. According to some researchers, the birthplace of these huge birds was Antarctica, covered at that time with forests and steppes.

Fororacos.

In the Paleogene period, the vegetation cover of the Earth also changes. Many new genera of angiosperms appear. Two plant areas emerged. The first, covering Mexico, Western Europe and Northern Asia, was a tropical region. Evergreen laurels, palms, myrtles, giant sequoias, tropical oaks and tree ferns. In the territory modern Europe chestnuts, oaks, laurels, camphor trees, magnolias, breadfruit trees, palm trees, arborvitae, araucaria, grapes, and bamboo grew.

In the Eocene, the climate became even warmer. There are many sandalwood and soap trees, eucalyptus, cinnamon trees. At the end of the Eocene, the climate became somewhat colder. Poplars, oaks, maples appear.

The second plant area covered North Asia, America and the modern Arctic. This area was a temperate zone. Oaks, chestnuts, magnolias, beeches, birches, poplars, viburnum grew there. Somewhat less were sequoia, ginkgo. Sometimes there were palm trees and firs. The forests, the remains of the trees of which turned into brown coal over time, were very marshy. They were dominated by conifers, towering above the swamps on numerous aerial roots. Oaks, poplars, and magnolias grew in drier places. The banks of the swamps were covered with reeds.

In the Paleogene period, many deposits of brown coal, oil, gas, manganese ores, ilmenite, phosphorites, glass sands, and oolitic iron ores were formed.

The Paleogene period lasted 40 million years.

Neogene period

The Neogene period (translated as a newborn) is divided into two sections: the Miocene and the Pliocene. During this period, Europe is connected to Asia. Two deep gulfs that arose on the territory of Atlantia subsequently separated Europe from North America. Africa was fully formed, the formation of Asia continued.

On the site of the modern Bering Strait, the isthmus continues to exist, connecting Northeast Asia with North America. From time to time this isthmus was flooded by a shallow sea. The oceans have taken on a modern shape. Thanks to mountain building movements, the Alps, the Himalayas, the Cordillera, and the East Asian ranges are formed. At their foot, depressions are formed, in which thick strata of sedimentary and volcanic rocks are deposited. Twice the sea flooded vast areas of the continents, laying clay, sand, limestone, gypsum, and salt. At the end of the Neogene, most of the continents are freed from the sea. The climate of the Neogene period was quite warm and humid, but somewhat cooler compared to the climate of the Paleogene period. At the end of the Neogene, it gradually acquires modern features.

The organic world is also becoming similar to the modern one. Primitive creodonts are driven out by bears, hyenas, martens, dogs, badgers. Being more mobile and having a more complex organization, they adapted to a variety of living conditions, intercepted prey from creodonts and marsupial predators, and sometimes fed on them.

Along with species that, having changed somewhat, survived to our time, there were also species of predators that died out in the Neogene. These include primarily the saber-toothed tiger. It is so named because its upper fangs were up to 15 cm long and were slightly arched. They protruded from the closed mouth of the animal. In order to use them, the saber-toothed tiger had to open its mouth wide. Tigers hunted horses, gazelles, antelopes.

Saber-toothed tiger.

The descendants of the Paleogeon Merikhippus, the Hipparions, already had teeth like those of a modern horse. Their small side hooves did not touch the ground. The hooves on the middle fingers became larger and wider. They kept the animals well on solid ground, gave them the opportunity to tear up the snow in order to extract food from under it, and protect themselves from predators.

Along with the North American center for the development of horses, there was also a European one. However, in Europe, ancient horses died out at the beginning of the Oligocene, leaving no descendants. Most likely they were exterminated by numerous predators. In America, ancient horses continued to develop. Subsequently, they gave real horses, which through the Bering Isthmus penetrated into Europe and Asia. In America, horses died out at the beginning of the Pleistocene, and large herds of modern mustangs, freely grazing on the American prairies, are distant descendants of horses brought by the Spanish colonialists. Thus, there was a kind of exchange of horses between the New World and the Old World.

Giant sloths lived in South America - megateria (up to 8 m in length). Standing on their hind legs, they ate the leaves of trees. Megatheria had a thick tail, a low skull with a small brain. Their front legs were much shorter than their hind legs. Being clumsy, they became easy prey for predators and therefore completely died out, leaving no descendants.

Changing climatic conditions led to the formation of vast steppes, which favored the development of ungulates. Numerous artiodactyls - antelopes, goats, bison, rams, gazelles, whose strong hooves were well adapted to fast running in the steppes, originated from small hornless deer that lived on swampy soil. When there were so many artiodactyls that a shortage of food began to be felt, some of them settled in new habitats: rocks, forest-steppes, deserts. From giraffe-like humpless camels living in Africa, real camels originated, inhabiting the deserts and semi-deserts of Europe and Asia. Hump ​​with nutrients allowed camels to do without water and food for a long time.

The forests were inhabited by real deer, of which some species are still found today, while others, such as megaloceras, which were one and a half times larger than ordinary deer, have completely died out.

Giraffes lived in the forest-steppe zones, hippos, pigs, and tapirs lived near lakes and swamps. Rhinos and anteaters lived in dense bushes.

Among proboscideans appear mastodons with straight long fangs and real elephants.

Lemurs, monkeys, great apes live on trees. Some lemurs have switched to a terrestrial lifestyle. They moved on their hind legs. Reached 1.5 m in height. They ate mainly fruits and insects.

The giant bird dinornis that lived in New Zealand reached 3.5 m in height. The head and wings of the dinornis were small, the beak was underdeveloped. He moved on the ground on long strong legs. Dinornis survived until the Quaternary period and, obviously, was exterminated by man.

In the Neogene period, dolphins, seals, walruses appear - species that live in modern conditions.

At the beginning of the Neogene period in Europe and Asia there were many predatory animals: dogs, saber-toothed tigers, hyena. Herbivores were dominated by mastodons, deer, and one-horned rhinos.

In North America, carnivores were represented by dogs and saber-toothed tigers, and herbivores by titanotheres, horses, and deer.

South America was somewhat isolated from North. Representatives of its fauna were marsupials, megateria, sloths, armadillos, broad-nosed monkeys.

In the Upper Miocene period, an exchange of fauna takes place between North America and Eurasia. Many animals moved from mainland to mainland. North America is inhabited by mastodons, rhinos, predators, and horses move to Europe and Asia.

With the beginning of the Ligocene, hornless rhinos, mastodons, antelopes, gazelles, pigs, tapirs, giraffes, saber-toothed tigers, and bears settle in Asia, Africa and Europe. However, in the second half of the Pliocene, the climate on Earth became cool, and animals such as mastodons, tapirs, giraffes move south, and bulls, bison, deer, and bears appear in their place. In the Pliocene, the connection between America and Asia was interrupted. At the same time, communication between North and South America was resumed. The North American fauna migrated to South America and gradually replaced its fauna. Of the local fauna, only armadillos, sloths and anteaters remained, bears, llamas, pigs, deer, dogs, and cats spread.

Australia was isolated from other continents. Consequently, significant changes in the fauna did not occur there.

Among marine invertebrates at this time, bivalves and gastropods, sea urchins predominate. Bryozoans and corals form reefs in southern Europe. The Arctic zoogeographic provinces are traced: the northern one, which included England, the Netherlands and Belgium, the southern one - Chile, Patagonia and New Zealand.

The brackish-water fauna has spread strongly. Its representatives inhabited large shallow seas formed on the continents as a result of the advance of the Neogene Sea. Corals, sea urchins and stars are completely absent in this fauna. In terms of the number of genera and species, mollusks are significantly inferior to mollusks that inhabited the ocean with normal salinity. However, in terms of the number of individuals, they are many times greater than the ocean ones. The shells of small brackish-water mollusks literally overwhelm the sediments of these seas. Fish are no longer different from modern ones.

A cooler climate caused the gradual disappearance of tropical forms. Climatic zonation is already well traced.

If at the beginning of the Miocene the flora almost does not differ from the Paleogene, then in the middle of the Miocene palms and laurels already grow in the southern regions, conifers, hornbeams, poplars, alders, chestnuts, oaks, birches and reeds predominate in the middle latitudes; in the north - spruces, pines, sedges, birches, hornbeams, willows, beeches, ash trees, oaks, maples, plums.

In the Pliocene period in the south of Europe there were still laurels, palm trees, southern oaks. However, along with them there are ash and poplar. In northern Europe, heat-loving plants have disappeared. Their place was taken by pines, spruces, birches, hornbeams. Siberia was covered coniferous forests and only in the river valleys were walnuts found.

In North America, during the Miocene, heat-loving forms are gradually replaced by broad-leaved and coniferous ones. At the end of the Pliocene, tundra existed in the north of North America and Eurasia.

Deposits of oil, combustible gases, sulfur, gypsum, coal, iron ores, and rock salt are associated with deposits of the Neogene period.

The Neogene period lasted 20 million years.

Quaternary period

The Quaternary period is divided into two sections: the Pleistocene (the time of almost new life) and the Holocene (the time of a completely new life). Four great glaciations are associated with the Quaternary period. They were given the following names: Gunz, Mindel, Ris and Würm.

During the Quaternary period, the continents and oceans took on their modern shape. The climate has changed repeatedly. At the beginning of the Pliocene period there was a general uplift of the continents. The huge Gunz glacier moved from the north, carrying with it a large number of debris material. Its thickness reached 800 m. In large spots, it covered most of North America and the alpine region of Europe. Under the glacier was Greenland. Then the glacier melted, and the detrital material (moraine, boulders, sands) remained on the soil surface. The climate became relatively warm and humid. At that time, the islands of England were separated from France by a river valley, and the Thames was a tributary of the Rhine. The Black and Azov seas were much wider than the modern ones, and the Caspian was deeper.

In Western Europe lived hippos, rhinos, horses. Elephants, up to 4 m high, inhabited the territory modern France. Lions, tigers, wolves, hyenas were found on the territory of Europe and Asia. The biggest predator of that time was the cave bear. It is almost a third larger than modern bears. The bear lived in caves, fed mainly on vegetation.

Cave bear.

The tundra and steppes of Eurasia and North America were inhabited by mammoths reaching 3.5 m in height. On their back they had a large hump with fat reserves, which helped them endure hunger. Thick wool and a thick layer of subcutaneous fat protected the mammoths from the cold. With the help of strongly developed curved tusks, they raked snow in search of food.

Mammoth.

Early Pleistocene plants are represented mainly by maples, birches, spruces, and oaks. Tropical vegetation is no longer completely different from modern.

The Mindelsky glacier reached the territory of the modern Moscow region, covered the Northern Urals, the upper reaches of the Elbe and part of the Carpathians.

In North America, the glacier has spread to most of Canada and the northern part of the United States. The thickness of the glacier reached 1000 m. Subsequently, the glacier melted, and the detrital material brought by it covered the soil. The wind moved this material, the waters washed it, gradually forming powerful strata of loess. Sea levels have risen significantly. The valleys of the northern rivers were flooded. A strait formed between England and France.

In Western Europe, dense forests of oaks, elms, yews, beeches, and mountain ash grew. There were rhododendrons, figs, boxwood. Consequently, the climate at that time was much warmer than today.

Typical polar fauna (arctic fox, polar wolf, reindeer) moves to the northern tundra. Along with them live mammoths, woolly rhinoceros, big-horned deer. The woolly rhinoceros was covered with thick long hair. It reached a height of 1.6 m, a length of about 4 m. On its head, a woolly rhinoceros had two horns: a sharp large one, up to one meter long, and a smaller one located behind the large one.

Woolly rhinoceros.

The big-horned deer had huge antlers, reminiscent in shape of the horns of a modern elk. The distance between the ends of the horns reached 3 m. They weighed about 40 kg. Great-horned deer were widely settled in Europe and Asia and survived until the Holocene.

Bighorn deer.

South of the tundra lived long-horned bison, horses, deer, saigas, brown and cave bears, wolves, foxes, rhinos, cave and ordinary lions. Cave lions were almost a third larger than ordinary ones. They had thick fur and long shaggy manes. There were cave hyenas, almost twice as large as modern hyenas. Hippos lived in the south of Europe. Sheep and goats lived in the mountains.

The Ris glaciation covered the northern part of Western Europe with a thick - up to 3000 m - ice layer, reached the territory of present-day Dnepropetrovsk, the Timan Ridge and the upper reaches of the Kama with two long glaciers.

Ice covered almost the entire northern part of North America.

Near the glaciers lived mammoths, reindeer, arctic foxes, white partridges, bison, woolly rhinos, wolves, foxes, brown bears, hares, musk oxen.

Mammoths and woolly rhinos spread to the borders of modern Italy, settled in the territory of present-day England and Siberia.

The glacier melted and the sea level rose again, causing it to flood the northern coast of Western Europe and North America.

The climate remained humid and cold. Forests are spreading in which spruces, hornbeams, alders, birches, pines, maples grew. Tours, deer, lynxes, wolves, foxes, hares, roe deer, wild boars, bears lived in the forests. Rhinos were encountered in the forest-steppe zone. Herds of bison, bison, horses, saigas, and ostriches roamed in the vast southern steppes that had formed. They were hunted by wild dogs, lions, hyenas.

The Wurm glaciation covered with ice the northern part of Western Europe, the modern territory of the European part of the Soviet Union up to the latitudes of Minsk, Kalinin, and the upper reaches of the Volga. Glacier patches covered the northern part of Canada. The thickness of the glacier reached 300–500 m. Its terminal and bottom moraines formed the modern moraine landscape. Cold and dry steppes arose near the glaciers. There grew dwarf birches and willows. In the south, the taiga began, where spruces, pines, and larches grew. Mammoths, woolly rhinos, musk oxen, arctic foxes, reindeer, white hares and partridges lived in the tundra; in the steppe zone - horses, rhinos, saigas, bulls, cave lions, hyenas, wild dogs; ferrets, ground squirrels; in the forest - deer, lynx, wolves, foxes, beavers, bears, tours.

The Wurm glacier retreated gradually. Having reached the Baltic Sea, he stopped. Nearby, many lakes were formed, where the so-called band clays were deposited - a rock with alternating layers of sand and clay. Sand interlayers were deposited in the summer, when rapid streams formed as a result of intensive ice melting. In winter, there was less water, the force of the streams weakened, and the water could carry and deposit only small particles from which layers of clay were formed.

Finland at that time looked like an archipelago. The Baltic Sea was connected by a wide strait to the Arctic Ocean.

Later, the glacier retreated to the center of Scandinavia, tundra formed in the north, and then taiga. Rhinos and mammoths are dying out. Polar forms of animals migrate to the north. The fauna gradually acquires modern look. However, unlike the modern one, it is characterized by a significant number of individuals. Huge herds of bison, saigas, horses inhabited the southern steppes.

Lions, hyenas lived in the savannahs of Europe, sometimes tigers came here. In its forests there were tours, snow leopards. There were much more modern representatives of the forest fauna. And the forests themselves occupied a large area.

IN deep rivers Europe had a lot of fish. And giant herds of reindeer and musk ox walked along the tundra.

Giant dinornis, flightless birds - moas, dodos - still live in New Zealand. In Madagascar, ostrich-like epiornis are found, reaching a height of 3-4 m. Their eggs are now in the swamps of the island. Passenger pigeons in the 19th century settled in America in huge flocks. Great auks lived near Iceland. All these birds were exterminated by man.

Deposits of gold, platinum, diamonds, emeralds, sapphires, as well as the formation of deposits of peat, iron, sand, clay and loess are associated with the Quaternary period.

The Quaternary Period continues to this day.

Human Origins

The Quaternary period is also called Anthropogenic (giving birth to a person). Since ancient times, people have thought about how they appeared on Earth. The hunting tribes believed that humans were descended from animals. Each tribe had its own ancestor: a lion, a bear or a wolf. These animals were considered holy. It was strictly forbidden to hunt them.

According to the ancient Babylonians, the god Bel created man from clay. The Greeks considered the creator of people to be the king of the gods Zeus.

Ancient Greek philosophers tried to explain the appearance of man on Earth by more earthly causes. Anaximander (610-546 BC) explained the origin of animals and humans by the action of the sun on mud and water. Anaxagoras (500-428 BC) believed that humans were descended from fish.

In the Middle Ages, it was believed that God created man from clay "in his own image and likeness."

The Swedish scientist Carl Linnaeus (1770–1778), although he believed in the divine origin of man, nevertheless, in his systematics, combined man with great apes.

Professor of Moscow University Karl Frantsevich Rulye (1814–1858) argued that at first marine organisms appeared on Earth, which then moved to the shores of water bodies. Later they began to live on land. Man, in his opinion, descended from animals.

The French explorer Georges Buffon (1707–1788) emphasized the anatomical similarities between humans and animals. The French scientist Jean-Baptiste Lamarck (1744-1829), in his book Philosophy of Zoology, published in 1809, defended the idea that man is a descendant of great apes.

Charles Darwin (1809-1882) in his book "The Descent of Man and Sexual Selection" analyzed in the light of the theory of natural selection the problem of the origin of man from animal ancestors. In order for a person to form, writes Darwin, he had to free his hands. The greatest strength of man lies in mental activity, which eventually led him to the manufacture of stone tools.

Friedrich Engels explained the reasons for the release of hands in the ape-like ancestors of people and showed the role of labor in the formation of man.

The theory of the origin of man from ape-like ancestors was met with indignation by most researchers. We needed proof. And there was evidence. The Dutch explorer Eugene Dubois unearthed the remains of Pithecanthropes in Java - creatures that had both human and monkey characteristics, therefore, they represented a transitional stage from ape to man. Professor of Beijing Medical Institute Davidson Black in 1927 finds the remains of Sinanthropus, very similar to Pithecanthropus. In 1907, the remains of a European relative of Pithecanthropus, the Heidelberg man, were found in Germany. In 1929, the anthropologist Raymond Dart finds in South Africa Australopithecus remains. And finally, L. Leakey and his son R. Leakey in 1931 and 1961 found the remains of the most ancient australopithecines - Zinjantrops, who inhabited South Africa 2.5 million years ago.

Together with the remains of the Zinjanthropes, stone tools made of split pebbles and fragments of bones were found. Consequently, the Zinjantrops used tools and hunted game. There was still a lot of ape in their structure, but they already walked on their feet, had a relatively large brain and human-like teeth. All this gave grounds to the researchers to attribute the Zinjantrops to the most ancient people.

How did man develop?

At the beginning of the Paleogene period, some of the insectivorous mammals adapted to life in trees. They gave rise to semi-monkeys, and from the latter in the Eocene, narrow-nosed and broad-nosed monkeys, in turn, originated. In the Oligocene forests of Africa, there lived small monkeys - propliopithecus - the ancestors of the Miocene driopithecus, widely settled in the tropical forests of Africa, Europe and Asia. On the surface of the lower molars of driopithecus there were five tubercles, as in modern great apes. It is from dryopithecus, and possibly from forms similar to them, that all modern anthropoid apes originated.

At the end of the Miocene, a noticeable cooling set in. In place of tropical forests, steppes and forest-steppes were formed. Some monkeys moved south, where dense rainforests continued to grow. Others remained in place and gradually adapted to the new conditions of life. Moving on the ground, they have lost the habit of climbing trees. Unable to carry prey in relatively weak jaws, they carried it in their front paws. Consequently, they moved on their hind legs, which eventually led to the division of limbs into legs and arms. As a result of walking on two legs, the figure of the anthropoid ape gradually straightened, the arms became shorter, the legs, on the contrary, were longer and more muscular. Thumb the legs gradually became thicker and approached the other fingers, which made it easier to walk on hard ground.

When walking straight, the neck straightened. The large mouth was reduced, since it was no longer necessary to tear the prey. Freed from walking and climbing, the hand became more and more dexterous. She could already take a stone or a stick - a tool. With a decrease in the area of ​​\u200b\u200bforests, the fruits that the great apes ate also became smaller. So they had to look for some other food.

Apes began to hunt animals, using sticks, bone fragments, and stones as weapons. Since the great apes were relatively weak, they united for hunting in groups, communication increased between them, which, in turn, contributed to the development of the brain. The shape of the head changes: the face decreases, the cranium increases.

In the descendants of the Dryopithecus - Ramapithecus and Kenyapithecus - the teeth are already similar to human teeth, the posture is adapted to walking on two legs, and the arms are short compared to the hands of the Dryopithecus. Height reached 130 cm, weight - 40 kg. Kenyapithecus lived in sparse forests. Eat plant foods and meat. The first people descended from the Kenyapithecus.

The first man on Earth - Australopithecus (southern monkey) - appeared in South Africa 2.5 million years ago. The skull of Australopithecus resembles that of a chimpanzee: its face is short. The pelvic bones are similar to the human pelvic bones. Australopithecus walked straight. His teeth in structure almost did not differ from human teeth. This suggests that Australopithecus could eat quite solid food. The volume of his brain reached 650 cm3. This is almost half the size of a human brain, but almost equal to the brain of a gorilla, although Australopithecus was much smaller than a gorilla.

Australopithecus lived in the steppes, near numerous limestone cliffs. Antelopes and baboons were hunted with sticks, sharp stones and bones. They killed animals from an ambush by throwing stones at them from rocks. In addition to the meat and brain of animals, which were mined by splitting bones with a sharp stone, Australopithecus ate roots, fruits, and edible herbs.

Australopithecus.

Along with Australopithecus, whose growth corresponded to the growth of modern African pygmies, lived the so-called massive Australopithecus, which were almost a third larger than Australopithecus. Somewhat later, developed australopithecines appear, in which, unlike ordinary australopithecines, the figure is more straightened, and the brain is larger. Developed Australopithecus, in order to make weapons for hunting, split pebbles and bones. From the developed australopithecines a million years ago, straight people originated. They already had an almost completely straight posture, relatively short arms and long legs. Their brains were larger than those of an Australopithecus, and their faces were shorter. The upright man made hand axes and knew how to use fire. He settled in Africa, Asia and Europe.

From straightened people came early people. Their skulls are very different in shape from the skulls of monkeys, the shoulders are turned, the skeleton is somewhat thinner than that of straightened people. Early people, upholstering flint, made rather monotonous tools - hand axes.

Simultaneously with early people 20 thousand years ago on about. Java was inhabited by Pithecanthropes (monkey people), very similar to early humans. Pithecanthropes roamed the steppes and forests in small herds in search of food. They ate fruits, roots, hunted small animals. From fragments of stones they made their own tools: scrapers, drills.

Pithecanthropes.

By sharpening sticks, Pithecanthropes made primitive spears. Their brain volume was 800–1000 cm3. The frontal parts of the brain were highly developed, which is important for the development of higher nervous activity. The visual and auditory areas of the brain also developed. Pithecanthropes began to talk.

Sinanthropes (Chinese people) lived on the territory of modern China. Getting fire from fires, they kept it in their camps. They cooked food, warmed themselves by the fire, defended themselves from predators.

Synanthropes.

Protanthropes (primitive people) lived on the territory of modern Europe. The climate at that time was relatively warm and humid. Ancient elephants, rhinos, horses, pigs, and elks lived in rare forests. Saber-toothed tigers, lions, hyenas fed on them. Protanthropes roamed in small herds along the rivers. Using sharp sticks and stone tools made from quartzite sandstones, they hunted game. Gathered roots and fruits.

Heidelberg Protanthropes.

Neanderthals descended from early people, and possibly from very similar synanthropes and protanthropes. They got their name from the Neandertal valley in West Germany, where their remains were first discovered. Subsequently, the remains of Neanderthals were found in France, Belgium, England, Czechoslovakia, Spain, the USSR, China, as well as in Africa and on the island of Java.

Neanderthals lived 150,000–350,000 years ago. They had sloping foreheads, low craniums, large teeth that did not differ in structure from the teeth of a modern person. The average height of Neanderthals was 160 cm. The brain was almost the same as that of a modern person. Parietal, frontal, occipital and temporal parts of the brain developed.

The jaws of Neanderthals protruded somewhat forward. Neanderthals had a wide and long face, a wide nose, prominent brow ridges, small eyes, a thick and short neck, a massive spine, a narrow pelvis, and short tibiae. The body was covered with thick hair.

Neanderthals lived in small groups, hunted small animals, collected roots, fruits, berries. Tools and weapons were made of stone. Neanderthals made hand axes in the shape of a triangle or oval. They made knives, drills, scrapers with very sharp blades from fragments of stones. As a rule, flint was used for tools. Sometimes they were made from the bones or tusks of predators. Neanderthals made clubs from wood. Burning the ends of the branches, they received primitive spears. Fleeing from the cold, Neanderthals wrapped themselves in skins. To keep warm and protect themselves from predators, Neanderthals built fires in caves. Often the caves were occupied by cave bears. Neanderthals drove them out with torches, beat them with clubs, and threw stones at them from above.

Neanderthals.

Neanderthals began to hunt large animals. They drove Siberian goats into the abysses, and dug deep traps for rhinos. For hunting, Neanderthals united in hunting groups, therefore, they were forced to communicate with each other using speech and gestures. Their speech was very primitive and consisted only of simple words. Having exterminated game near their dwellings, the Neanderthals moved to new places, taking with them skins, tools, and weapons.

The life expectancy of Neanderthals was short - 30-40 years, they often got sick. They were especially annoyed by rheumatism, which developed under the conditions of life in cold, damp caves. Many died from the attack of pigs, rhinos. Neanderthal tribes appeared, hunting people.

Neanderthals buried their dead relatives in shallow pits, in which stone tools, bones, teeth, and horns were placed.

It is likely that they believed in an afterlife. Before hunting, Neanderthals performed rituals: they worshiped the skulls of animals they were going to hunt, etc.

Along with the classical type of Neanderthal, about a hundred thousand years ago, atypical Neanderthals appeared, who had a higher forehead, a less massive skeleton and a more flexible spine.

A sharp change in physical and geographical conditions, the change of glaciations by interglacial periods, as well as vegetation and fauna, accelerated the evolutionary process of mankind. From atypical Neanderthals came intelligent people, morphologically no different from modern ones. They settled widely in Asia, Africa, Europe, reached Australia and America. They were called Cro-Magnons. For the first time, Cro-Magnon skeletons were found in the Cro-Magnon Grotto (France). This is where their name comes from. It turned out that modern man in its anatomical structure, it is almost no different from the Cro-Magnon.

The Cro-Magnons lived for a long time next to the Neanderthals, but subsequently forced them out, intercepting prey, caves. Between Neanderthals and Cro-Magnons, apparently, there were clashes.

Cro-Magnons.

The first Cro-Magnons were hunters. They made quite perfect weapons and tools: bone spears with stone tips, bows, arrows, slings with stone balls, clubs with sharp teeth, sharp flint daggers, scrapers, axes, awls, needles. Small tools were inserted into bone handles. The Cro-Magnons dug pit traps and covered them with branches and grass from above, built fences. In order to quietly get close to the prey, they put on the skins of animals. Animals were driven into pit traps or into abysses. Bison, for example, were driven into the water, where the animals became less mobile, and therefore safer for hunters. Mammoths were driven into pit traps or separated from the herd, and then killed with long spears.

Children and women collected edible roots and fruits. Cro-Magnons learned to dry and smoke meat, therefore, unlike Neanderthals, they prepared meat in reserve. They lived in caves, and where there were no caves, they dug dugouts, built huts, dwellings from the bones of mammoths, rhinos, bison.

Cro-Magnons learned how to make fire by rubbing sticks or striking sparks from flint. Near the hearth there were workshops in which the Cro-Magnons made weapons and equipment. Nearby, women sewed clothes. In winter, the Cro-Magnons wrapped themselves in fur capes, put on fur clothes, fastened with bone needles and clasps. Clothes were decorated with shells and teeth. Cro-Magnons made bracelets, necklaces, amulets. The body was painted with colored clay. The dead Cro-Magnons were buried in deep pits, surrounded by stones or mammoth shovels.

Rock paintings, sometimes occupying tens and hundreds of square meters of rocks and cave walls, were primarily of ritual significance.

There were Cro-Magnons and musical instruments. They made drums from tree trunks or from the shoulder blades of the skeleton of large animals. The first flutes made from drilled bones appeared. Hunting dances were performed.

Wild dogs tamed by the Cro-Magnons helped them hunt and protected them from predators.

The glaciers were receding. The vegetation has changed. The rough, poorly processed tool of the Cro-Magnon era, called the Paleolithic (ancient stones), was replaced by a polished tool that had the correct geometric shape. Neolithic (new stones) begins.

Many lakes have formed on the site of the melted glacier. Fisheries are developing. Man invented the fishing rod and the boat. Some tribes built their dwellings on the water, on high piles. Surrounded by water, they could not be afraid of enemies and predatory animals. And you don't have to go far to fish. Hunting is still very important.

Gradually the climate became drier, the lakes became shallower. The number of game decreased. In dry seasons and in winter, food was scarce. People made stocks by drying fish and meat, collecting edible roots and fruits. Having caught young animals, they no longer ate them, as before, but fattened them in order to get more meat, wool, and skin. Thus, at first, animals were used as a kind of stock. Gradually, the Cro-Magnons began to tame and breed animals. They slaughtered only those that did not breed or gave little wool, meat, milk. In the forest areas, people tamed pigs, in the steppe - goats, sheep, horses. In India, cows, buffaloes, chickens were tamed.

Gathering wild cereals, people scattered grains. New plants grew from the scattered grain. Noticing this, people began to grow them - agriculture. In the interfluve of the Tigris and Euphrates, already 30 thousand years ago, people switched to a settled way of life, growing many different types of cereals. In the boundless steppes of Europe and Asia, cattle breeding developed at that time. And in the north, people continued to live by hunting sea animals.

The historical era has begun. The development of mankind occurs due to the improvement of tools, dwellings, clothing, the use of nature for its needs. Thus, to replace biological evolution came social. The steady improvement of the tools of labor has become decisive in the development of human society.

IN Paleogene the climate was warm and humid, as a result of which tropical and subtropical plants became widespread. Representatives of the marsupial subclass were widespread here.

The class of insects developed intensively. Among them, highly organized species arose that contributed to cross pollination flowering plants and fed on plant nectar. The number of reptiles has decreased. Birds and mammals lived on land and in the air, fish lived in the water, as well as mammals that re-adapted to life in the water. During the Neogene period, many genera of currently known birds appeared.

IN quaternary period there was a repeated displacement of the ice of the Arctic Ocean to the south and back, which was accompanied by cooling and the movement of many heat-loving plants to the south. With the retreat of the ice, they moved to their former places. This re-migration (from lat. migratio - relocation) of plants led to the mixing of populations, the extinction of species not adapted to changing conditions, and contributed to the emergence of other, adapted species.

human evolution

By the beginning of the Quaternary period, human evolution is accelerating. The methods of manufacturing tools and their use are being significantly improved. People start to change environment learn to create favorable conditions for themselves. The increase in the number and wide distribution of people began to influence the plant and animal world. Hunting by primitive people leads to a gradual reduction in the number of wild herbivores. The extermination of large herbivores has led to a sharp decrease in the number of cave lions, bears and other large predatory animals that feed on them. Trees were cut down and many forests turned into pastures.

This era is subdivided into the Paleogene, Neogene and Anthropogenic periods. There was a division of the Cenozoic era into two periods - Tertiary and Quaternary, of which the Tertiary united the Paleogene and Neogene, and the Quaternary corresponded to the Anthropogenic period.

In the Paleogene, and especially in the Neogene, a new powerful folding and mountain building took place, which was called the Alpine era. Several phases of folding are noted, of which the most stressful occur in the Neogene. During this era, the largest mountainous countries were formed (Atlas, the Andalusian mountains, the Pyrenees, the Apennines, the Alps, the Carpathians, the mountains of the Balkan Peninsula, the mountains of Asia Minor, the Caucasus, the mountains of Iran, the Pamirs, the Himalayas, the mountains South-East Asia and the Malay Archipelago, the mountains of Kamchatka and Sakhalin, the Kor-

dealers and the Andes of North and South America). In addition, in a number of more ancient mountainous countries, already severely destroyed by this time by denudation, new powerful faults arose, uplifts and subsidence occurred (central Europe, Tien Shan, Altai, etc.). Simultaneously with mountain building, which took place mainly in the northern hemisphere, in the southern hemisphere there was a separation of Australia from Asia, a depression of the Red Sea was formed, deep faults dissected East Africa, large faults also spread to the northern hemisphere, where the formation of the northern part Atlantic Ocean, the depression of which acquired outlines close to modern ones. The areas of manifestation of volcanism were close to those existing at the present time.

Mountain building, which took place along the outskirts of previously formed platforms, involved these platforms in its movement, in connection with which the outlines of the seas changed greatly. On the territory of the USSR, powerful transgressions swept the south of the Russian Plain, Central Asia, and Western Siberia.

The climate in the Paleogene (before the manifestation of intense mountain building) is warm, humid without sharp temperature fluctuations over vast areas. In the Neogene, the climate becomes more continental, with sharply defined climatic provinces, but generally remains warmer than today.

The flora of the Paleogene and Neogene, which was dominated by angiosperms, is very similar to the vegetation of modern tropical and subtropical latitudes, and these plant species spread in the Paleogene up to the northern islands of Europe and North America. In the Neogene, the area of ​​moisture-loving forests was greatly reduced, and drought-resistant flora and steppe spaces appeared in temperate latitudes.

The fauna of the Paleogene and Neogene is rich and diverse. On land, various mammals and birds dominate. Marine fauna becomes very close to modern; marine mammals appear. In the Neogene, with the appearance of steppe spaces, ungulates (antelopes, horses, etc.) quickly begin to evolve. At the same time, the development of humanoids takes place. In the Neogene deposits of the island of Java, the remains of an ape-man (pithecanthropus) were found, and in China - a man (sinatrop), who used stone tools and fire.

The deposits of the Paleogene and Neogene are rich in various minerals, among which deposits of oil, gas and coal are of great importance.

Climate change, which began in the Neogene, led at the beginning of the Anthropogenic (Quaternary) period to a significant cooling, as a result of which, first in the mountains, and then on the plains, powerful glaciation develops. In the Anthropogenic period, these glaciers either grew strongly or sharply reduced to approximately modern sizes. In this regard, it is customary to single out epochs of glaciation and epochs of interglacials. For Eastern European

plains, most researchers indicate four glaciations: Oka, Dnieper, Moscow and Valdai. The boundaries of the two glaciations are shown in Fig. 28.

Significant climate change has greatly affected the composition of flora and fauna. During the Anthropogenic period, polar and temperate

latitudes are inhabited by animals and plants adapted to harsh climatic conditions. Instead of the heat-loving flora of the Neogene, forests of the taiga type develop here, and later tundra flora also appears.

During this period, the duration of which is relatively short (1 000 000 years), there were no major changes in the outlines of the seas and continents. Small transgressions and regressions of the sea occurred in the coastal strip of the World Ocean in the interglacial and postglacial periods. The sizes of closed basins (Caspian Sea) changed more significantly. In this regard, deposits of marine origin in the area of ​​modern continents are very limited in distribution. Continental deposits (glacial, river, lacustrine, marsh, etc.) are more widespread.

After the intense manifestation of mountain building that occurred in the Neogene, the movements of the earth's crust in the Anthropogenic period did not stop and continue to the present, as evidenced by strong earthquakes, volcanism, uplift and subsidence of large blocks earth's crust occurring in the zones of Alpine folding. All these processes, together with the activity of external geological agents, affect the ancient relief of the lithosphere and are reflected in its modern relief.

On the whole, the Cenozoic era has now been marked by very important events. 1. A new thing happened - Alpine mountain building (see Fig. 27), mountain structures rose, which are currently the highest mountains of the Earth. 2. Mountainous countries that arose in the Paleozoic and Mesozoic eras. By the beginning of the Cenozoic, they were badly destroyed. In the era of Alpine folding, they experienced repeated movements, were broken by faults, raised to great height and again turned into mountainous countries with sharp landforms. 3. There was a further reduction of geosynclines and platforms grew due to them. 4. The uplift of young mountain ranges was accompanied by the uplift of adjacent platform sections, which affected the distribution of land and sea. This was also influenced by the faults of the earth's crust, which separated the continents. 5. As a result of volcanism, vast lava plateaus and plains were formed, high volcanic mountains and highlands arose, new mineral deposits were formed in the bowels of the Earth (at present still hidden under a thick sedimentary cover). 6. The climate has changed a lot. From warm and monotonous, characteristic of the beginning of the Cenozoic era, it became sharp, with a large number of climatic zones and provinces. 7. Large glaciers arose, repeatedly spreading over vast expanses of land. 8. The animal and plant world have taken on their modern look. 9. A man appeared and began his activity.

Finishing a brief description of the geological history of the Earth, its complexity should be noted. Without touching on the development of the organic world, let us turn to the development of the lithosphere and its relief, taking the territory of the USSR as an example.

Back to top Paleozoic era within this territory there were two rigid masses of the earth's crust: the Russian and Siberian platforms with their most rigid parts, shields. As a result of repeated epochs of folding and mountain building, the pliable zones (geosynclinal belts) located between these platforms, filled with thick strata of sediments, were crushed into folds and turned into mountain structures, attached to the outskirts of the platforms or connecting the platforms to each other. This process is clearly traced in the history of the Ural-Tyan-Shan geosyncline. At the beginning of the Paleozoic era, thick layers of sediments accumulated near the southern margin of the Siberian platform.

and mountain building took place (the Caledonian era of folding), as a result of which mountains arose in the area of ​​\u200b\u200bthe modern Baikal region, in the Sayans, in Altai. For the rest of the geosynclinal belt, this epoch was expressed as a preliminary one, since the mountains that arose here quickly collapsed and were again largely flooded by the sea (Kazakhstan, Western Altai, etc.). On the outskirts of the mountainous countries that had arisen, in actively sagging areas of the geosyncline that had not yet closed, the accumulation of new sediment layers continued, culminating in a new folding and mountain building that developed at the end of the Paleozoic era (the Hercynian epoch). Vast mountainous countries were formed: the Urals, Tien Shan, the Kazakh mountainous country and mountains in the place of a significant part of the West Siberian lowland. The subsequent history of these mountainous countries is different. Most of them were destroyed by denudation agents, experienced subsidence and are currently under a thick layer of Meso-Cenozoic deposits that make up the sedimentary cover of the West Siberian Lowland. The outlying western part, which has experienced minor uplifts as a result of recent movements, stretches along the edge of the Russian Platform in the form of the low Ural Mountains. Significant expanses of the ancient mountainous country, heavily destroyed by denudation agents, which did not experience significant uplifts and subsidence, are observed in Central Kazakhstan. The southernmost parts of the ancient mountainous country, once already destroyed to the state of small hills and later under the influence of powerful mountain-building movements of the Alpine folding era, were broken into blocks and raised to a great height, which led to the formation of the mountainous terrain of the Tien Shan.

The above example indicates that the earth's crust, developing according to the general plan from a pliable geosyncline, through a mountain structure to a rigid platform with a flat relief. achieves this in different parts in different ways. These paths are often clearly reflected in the relief and can explain its diversity.

GEOLOGICAL MAP AND PROFILES General information about geological maps

Among the maps reflecting natural phenomena, one of the first places is occupied by geological maps created as a result of geological surveys. The geological map gives an idea of ​​the geological structure of the site earth's surface and is essentially a vertical projection of bedrock outcrops plotted on a topographic base of a certain scale. Such a map is called a geological map proper, since its construction is based on the principle of separating rock strata of different ages.

The geological map is the basis for all other maps compiled in the course of complex geological mapping. The latter provides for the compilation of a series of maps that highlight certain aspects of the geological structure of the region. The noted complex of maps includes: lithological-petrographic, structural-tectonic, hydrogeological, facies-paleogeographic, geomorphological, engineering-geological, various geophysical, minerals.

Depending on the scale, all geological maps are divided into overview, regional medium-scale and large-scale.

Overview maps highlight the structure of individual continents and states. The largest scale is 1:1,000,000. The topographic base has been simplified.

Regional maps (small-scale) - display a section of the earth's surface, characterized by the unity of the geological structure (the Caucasus, the Urals, the Donbass, etc.). Map scale from 1:1,000,000 to 1:200,000. The topographic base has been simplified.

Medium-scale - display in detail the geology of a relatively small area. Their scale is from 1:200,000 to 1:25,000. The topographic base is simplified.

Large-scale geological maps - compiled for mineral deposits. The scales are from 1:1000 to 1:500. The topographic base is often compiled on purpose.

Geological work in the field usually begins with reconnaissance routes, which make it possible to get a general idea of ​​the area and identify the features of its individual parts. After the reconnaissance, the plan of field work and research is specified, time is allocated, and the order of routes is outlined. In this case, the degree of exposure of the area is of great importance, which can be judged with a sufficient degree of reliability from aerial photographs.

The most complete are subjected to priority research - supporting outcrops (sections) or wells with continuous core sampling (rock samples obtained from wells during drilling). Intermediate outcrops, in which only parts of the main section are exposed, are studied later.

Simultaneously with the description of natural and artificial sections, the vertical and planned binding of the marking (reference) layers and horizons identified in them, which are important for mutual coordination, is carried out. Depending on the scale of the shooting, the binding can be instrumental or visual. When describing the stratigraphic sequence of layers in sections, their thickness and occurrence elements must be measured. As a result, a summary section (column) is compiled.

Comparison of sections and tracking of identified stratigraphic units over the entire area of ​​the region makes it possible to

get an idea of ​​their structure (forms of occurrence) and facies changes. Binding the outcrops of these layers to the earth's surface makes it possible to draw the contours of the age boundaries of bedrock (pre-Quaternary) rocks on a topographic map - to create a geological map.

Proper geological maps

The methodology for compiling a geological map depends on the scale of the survey, exposure, and mainly on the geological structure of the area. With horizontal, inclined and folded occurrence of layers, it is different.

Horizontal occurrence is characterized by a close value of the absolute height marks of the roof or bottom of the layer. Depending on the depth of the dissection of the mapped area, with a horizontal occurrence on the surface, either only the upper layer (with a shallow dissection) or deeper layers (with a deep dissection) will be exposed. The horizontal occurrence of the layers is easily determined by the coincidence or almost parallel arrangement of the outlets of the mapped layer and the contours of the topographic base (Fig. 29).

If the layers are removed from their original horizontal position and have acquired a slope in one direction, then their occurrence is called monoclinal (one-slope). To determine the position of monoclinal layers in space, the method of finding the lines of strike and dip of layers is used. A straight line, which is obtained by crossing a monoclinal layer with a horizontal plane, is called the strike line (Fig. 30). Perpendicular to the strike line there is a dip line directed towards the greatest slope of the layer. The determination of the occurrence elements, the orientation of the lines of strike and fall according to the cardinal points is carried out using a mountain compass.

As mentioned above, in case of horizontal occurrence, the lines of layer outputs will coincide with the contour lines of the topographic map or be located parallel to them. With a vertical occurrence, the terrain will not affect the configuration of the lines of intersection of the layer by the plane, since in this case all stretch lines are projected onto the plane in one line, which will be straight with a straight vertical layer and curved with a curved vertical surface.

In addition to the above two extreme cases of the image on the plane of projections of horizontally and vertically lying layers, there can be countless variants of projections of obliquely lying layers, and their configuration will be directly dependent on the angle of incidence and the terrain. With a highly dissected relief and a gentle dip of the layers, the outcrop of the reservoir will have a more complex contour than with a steep bedding and weak

bohm dismemberment of the relief. The dip direction of inclined layers on geological maps is determined by their age sequence. The slope will always be towards the location of younger deposits (Fig. 31).

The folded forms of the occurrence of the layers significantly conditional / bend the pattern of the geological map. The exits of the selected age subdivisions are located in stripes, closed rounded or elliptical contours. Layers of the same age within the fold are always arranged symmetrically with respect to the central (axial) part of the fold, which does not have a paired exit. When reading geological maps depicting a folded structure, it is first necessary to determine the age relationships of the layers in order to establish the position of symmetrically located bands of ancient and young layers with respect to the central unpaired band. The position of the latter determines the presence of the axial part of the anticline or syncline. In the core of the anticline, older layers always outcrop, bordered by outcrops of layers of younger deposits. In the core of the syncline, on the contrary, younger layers lie surrounded by older ones (Fig. 32).

Tectonic disturbances on a geological map are represented by lines that break geological boundaries. The image of displacements of age boundaries in the plan and the configuration of the lines of discontinuities depend on the type of structure, the angles of incidence of the layers, the angle of inclination of the ejector, and other factors.

In the geological mapping of igneous rocks, the relationship of the latter with the enclosing strata is taken into account. Mutually

intrusion ratios are presented differently when studying intrusive rocks that have intruded into the sedimentary strata of the earth's crust and are exposed as a result of denudation processes and igneous rocks formed on the earth's surface as a result of volcanic processes. On geological maps, the contour of the outcrop of igneous bodies is depicted and their age and geological composition are indicated with the help of indices.

When compiling geological maps, established conventions three types: colored; indices (alphabetic and digital); dashed.

Color symbols determine the age of rocks, and when depicting outcrops of intrusions, their composition. Indices - determine the age of the distinguished units and sometimes their origin (intrusion and effusion indices). Stroke symbols can replace color symbols or, when applied to a color background, indicate the composition of rocks. Standards for color symbols for subdivision of the geochronological scale were proposed by the Russian geologist A.P. Karpinsky and approved in 1881 by the II International Geological Congress.

In the geochronological scale, two types of subdivisions are used. Some correspond to the period of time of the selected subdivision, others are thicker than the rocks formed at that time. Accordingly, an era is parallelized with a group, a period with a system, an epoch with a department, a century with a tier, and time with a zone.

Color designation standards are adopted for period systems.

Anthropogenic period, system - light gray color

Neogene » » -yellow

Paleogene » » -orange

Cretaceous » » - green

Jurassic » » -blue

Triassic » » -violet

Perm » » -brown-red

Coal » » - gray

Devon » » -brown

Silurian "" - light olive

Ordovician » » - olive dark

Cambrian » » - pink

Outcrops of Archean (AR) and Proterozoic (PR) rocks are indicated by various shades of red (large-scale maps of areas of the indicated age are colored with colors and strokes adopted for igneous rocks and formations). More subdivisions of the geochronological scale (departments, stages, etc.) are painted over with tones of the main color of the period (system), and the density of the tone weakens from ancient subdivisions to young ones.

When compiling a geological map on a scale larger than 1: 100,000, the standard color scale may not be enough. In this case, symbols are added in the form of specks, stripes and others, but in colors adopted for a given period (system).

Igneous rocks are indicated by bright colors with indices corresponding to the name of the rocks. Acid and intermediate rocks are indicated in red, alkaline in orange, basic rocks in green, and ultrabasic rocks in purple.

Effusive rocks on the maps of the old edition were indicated by different colors with indices put down in accordance with the composition of the rocks. Acid effusives were colored orange, basic ones - green. On the maps of the latest editions, effusives are painted over with a color showing their age, with the addition of indices and strokes that determine the composition of the rocks.

The system (period) index is used as the basis for the alphabetic and numerical designation of sedimentary, igneous and metamorphic rocks in the geochronological scale and on the geological map. When designating a department, a number is added to it, corresponding to the lower, middle, upper departments (epochs), or when divided into two parts - lower and upper. When subdividing a department (epoch) into tiers (centuries), letter designations are added to the index of the department (epoch), consisting of the first letter of the tier name and the first consonant letter in this name. The above can be illustrated by the example of the index of the Cretaceous system (period): the index of the system (period) - (K), the indices of departments (epochs) - (K 1) and (K 2), the index of one of the tiers (ages) - Valanginian - TO 1 v. Parts

tiers are indicated in Arabic numerals, put down at the bottom right of the index - TO 1 v 1 .

On detailed geological maps at the top right, above the index of the period (system), sometimes indices are affixed indicating the facies composition of the rocks: T- marine sediments, J- lake, h- coal-bearing, f- flash *.

In addition to age groups, it often becomes necessary to single out local subdivisions that correspond to certain stages of the geological development of a given area. In this case, the rocks are divided into series, suites, subsuites, and horizons. Where possible, local divisions are linked to a generally accepted age scale. Indices of local divisions are formed from two lowercase Latin letters (the first letter of the name and the nearest consonant). Letters are written to the right of the group, system or department index. For example: J 1 bg- Lower Jurassic section, Bezhitinskaya suite.

For a division covering two adjacent departments or systems, the index is formed by connecting them with a + (plus) sign or a dash - (hyphen). The + sign is put if two neighboring subdivisions are combined, represented in their full development J + K; dash (hyphen) is used in all other cases. The J-K index indicates the presence of the contact between the Cretaceous and the Jurassic in the selected subdivision without determining their more accurate age boundaries.

On geological maps, in the case of replacing color designations with dashed ones, the latter are chosen arbitrarily. When depicting the composition of rocks, dashed conventional signs have a certain standard.

A geological section is an image of the sequence of stratification and the structure of the layers of the surface parts of the earth's crust in a vertical section. When constructing a section with any occurrence of layers, its horizontal scale must correspond to the scale of the map. The choice of vertical scale depends on the thickness of the layers. The thinnest layer in the chosen scale should not be less than 1 mm. Ideally, the value of the vertical scale should be equal to the horizontal scale. In this case, there will be no distortion in the angles of incidence and powers on the profile.

In case of inclined and folded occurrence of layers, it is necessary to take into account the direction of the profile section in relation to the strike line of inclined and folded layers; in order to eliminate the distortion of angles, a correction calculated according to special tables must be introduced.

With a horizontal occurrence of layers, the most complete section will be the line of which passes through the highest and lowest points of the relief. To build a section with a horizontal occurrence

* Flysch - powerful monotonous and rhythmic sedimentary strata of shallow marine sediments.

layers on the geological map, the places of intersection of geological boundaries with the profile line on the map should be transferred to the terrain profile and connect the obtained points with horizontal lines.

When constructing a geological section with an inclined occurrence of layers, it must be remembered that a section built in the direction of dip, with equivalent vertical and horizontal scales, will always have the true angle of inclination of the layers and thickness. In the case when the cut passes in the direction of strike, the layers have a horizontal position.

When constructing a profile section on a geological map that reflects the folded occurrence of layers, as well as with horizontal and inclined occurrence, first of all, a topographic profile is built on the scale adopted for vertical constructions. Outcrops of geological boundaries and dip angles on the wings of folds are applied to the topographic profile. Then the geological section is drawn taking into account the position of the axial surfaces of the folds in the plan.

Compilation of profile sections crossing the territory with outcrops of secant intrusions requires solving problems that are not considered in the program of this book. In the general case, when a section passes through an intrusion, it should be shown as a body that interrupts the bedding of layers in the same way as in case of discontinuities.

Engineering geological maps

Engineering-geological maps reflect the engineering-geological conditions of the territory being mapped and provide a comprehensive natural assessment necessary for construction. The task of engineering geology is to determine the geological features of the study area in order to establish its suitability for the construction and operation of engineering structures.

The geological structure has an impact on the choice of location, layout, construction of the structure and on the methods of construction work.

The engineering-geological map, together with profile sections, stratigraphic columns and comprehensive characteristics of soils, is the main document obtained as a result of engineering-geological surveys. Among engineering-geological maps for various purposes, general survey, special survey, schematic and detailed maps are usually distinguished. General overview maps serve to design various types of construction and are compiled on a small scale (1: 200,000 and smaller). The remaining categories of carts are used to design a specific type of engineering structures and are drawn up on a scale that meets the requirements of construction.

When engineering and geological surveys and mapping, the nature of the relief, the geological structure must be taken into account.

tur, composition of rocks, hydrogeological conditions and dynamics of modern processes. Terrain information is needed to select a construction site, estimate the amount of earthworks, lay access roads and other design data. The geological structure gives an idea of ​​the occurrence of bedrocks and the position of their roof in relation to the modern hydrographic network. The composition of the rocks (ground conditions) is subject to particularly careful study and is depicted on the map in accordance with the established geological and petrographic classification.

The study of water content is essential. On the maps, conventional signs indicate the depth of groundwater, water abundance, pressure, and chemical characteristics. In some cases (on large-scale maps), the groundwater surface is depicted as isolines. The dynamics of modern geological processes is reflected on large-scale maps by conventional signs and boundaries that outline areas where certain processes develop (landslides, karst, permafrost, subsidence of rocks, various forms of erosion, etc.). The qualitative and quantitative assessment of dynamic processes is noted on the maps, the intensity of the development of the process is indicated.

When drawing up an engineering-geological map, it is essential to select colors and symbols that determine its visibility and ease of reading.

Tectonic maps

On tectonic maps structural elements of various scales, categories and ages are depicted.

The compilation of tectonic maps is one of the most important and active methods of studying and analyzing the development of the structures of the earth's crust. Depending on the size of the territory for which the map is being compiled, the scale and symbols, it is customary to distinguish between general (summary) and regional tectonic maps. In addition, so-called structural maps are compiled to display the morphology of tectonic structures. On general tectonic maps, structural elements of a large scale are depicted, which are the main structures of the earth's crust. The symbols (legend) used in the preparation of such maps are common to the entire surface of the Earth and can be used in any of its regions. Regional maps reflect the structure of a particular section of the earth's crust; the symbols adopted for it may be of little use for their use when drawing up a map of another area.

The relief of the surface of a particular structure depicted on a tectonic map is transmitted using isolines (horizontals) connecting points with an equal value of occurrence marks, calculated from the level of the World Ocean.

The starting point for general tectonic mapping is to establish the age of folding of the main structures,

the time of formation of the geosyncline, i.e. in time

graduation geosynclinal and the beginning of the platform stages of development of the study area. The moment of transformation of the geosynclinal folded system into a platform is a natural boundary in the development of the earth's crust.

Within Europe and neighboring parts of other continents, territories are distinguished that have survived the following main epochs of folding, the age of which is determined by the time of completion of the geosynclinal stage of development: Precambrian (Archaean and Proterozoic), Baikal, Caledonian, Hercynian and Alpine. Larger subdivisions (cycles) in the development of the earth's crust, uniting many eras and periods (stages) of folding, are called megachrons. In the history of the formation of the earth's crust, several megachrons can be distinguished, but the most studied is the last one, called neogey. In this new, last, megachron, a radical restructuring of the earth's crust and the formation of its modern structure took place. The age of these structures is reflected on tectonic maps by special indices and colors.

On the tectonic maps of the territory of the USSR for the Baikal folding (Proterozoic) is accepted Blue colour, for the Caledonian - lilac, for the Hercynian (Varisian) - brown, for the Alpine - yellow. Older megachrons are depicted in shades of red.

When depicting various zones of geosynclinal regions - eugeosynclines and miogeosynclines, shades of colors are used that determine the age of a particular folded structure and an alphabetic index is put. For example, the eugeosyn-clinal zone of the Caledonian folding is designated by the index - еС. Structural floors in folded structures are also distinguished by the density of tone of the accepted age coloration, and the lower structural floors are painted over with a more intense shade. Letter indices are supplemented with numbers. K 1, for example, denotes the lower floor of the Karelian folding (Proterozoic), C 2 - the middle floor of the Caledonian folding, A 3 - the upper structural floor of the Alpine folding, etc. There are alphabetic and numeric designations for more fractional divisions - subfloors. For example, A 2 1 is the upper sublevel of the lower structural level of Alpine folding.

The marginal troughs are indicated by a striped horizontal color of the color of the upper structural level of a given folding. In the case of overlapping the marginal deflection with a platform cover, translucent shading is used under the paint of the platform cover. Internal intermountain depressions, developing simultaneously with the marginal foredeeps, are indicated by the color of the upper structural stage with molasse specks *. Fill in the middle arrays

*Molasses are clastic rocks that fill deep troughs of geosyn-clinal zones V major eras of mountain building.

are colored by folding, which turned them into rigid blocks (for example, Hercynian massifs among the structures of Alpine folding in the Caucasus, etc.).

With the introduction of general tectonic maps of the designations of eu- and miogeosynclines, structural levels and internal depressions into the legend, with appropriate detail of the contours, these maps raise their accuracy to the level of regional maps.

Within platform structures, on general tectonic maps, areas of outcrops of a folded basement (shields) and slabs, on the area of ​​which the basement is covered by a sedimentary cover, are distinguished. On shields and exposed anteclise vaults, the folded foundation is subdivided according to the epochs of folding with the allocation of structural floors. On the territory of the slabs, the surface of the folded foundation is depicted using isohypses and stepped coloring, shading the areas of subsidence and uplifts. (The submerged areas are lighter than the uplifted ones.) The age of the platforms is emphasized on tectonic maps in a certain color, which differs from the folded areas in a paler tone. To designate the sedimentary cover of the platforms, the following color tones are adopted: the sedimentary cover of the ancient platforms is indicated by a brownish-pink color, the Epicaledonian - violet-green, the Hercynian - brownish-gray.

Outcrops of intrusive massifs are depicted in the same way as on geological maps, within their modern erosional cut. The division of intrusions is made according to their belonging to certain stages of tectogenesis (early orogenic, late orogenic and anorogenic). The age of the intrusions is indicated by indexes, the composition - by color and icons adopted for geological maps.

Large discontinuities are depicted on general tectonic maps by solid and dashed red lines. In addition, tectonic maps show zones of intensive development of metamorphism and centers of modern and ancient volcanism.

Conventional signs have been worked out in great detail to designate folded and discontinuous faults displayed on tectonic maps, as well as to designate boundaries and lines separating structures of various orders and ages.

Cenozoic era divided into two periods: Tertiary and Quaternary, which continues to this day. It is believed that the Quaternary period began 500-600 thousand years ago.

At the end of the Tertiary period, an event of the greatest importance took place: the first ape-men appeared on Earth.

Small warm-blooded animals of the Cretaceous period came out victorious in the struggle for life, and their descendants already at the beginning of the Tertiary period occupied a dominant position on Earth. Some of the warm-blooded animals reached enormous sizes. Such, for example, are arsinotherium, titanotherium, massive, clumsy six-horned dinoceras and huge hornless ancestors of rhinos - indricotherium - the largest land mammals that have ever existed.

At the same time, the ancestors of our elephants and small, slightly larger than cats, graceful eogippuses appeared - the ancestors of our horses, which had four fingers on the front and three on the hind legs, equipped with hooves.

The climate of the first half of the Tertiary period in Europe and Asia was still warm; in forests inhabited by many different animals, palm trees, myrtle trees, yews and giant conifers - sequoias grew.

Among the climbing, "arboreal" animals, we already find the first great apes - amphipithecus and propliopithecus. These were small animals 30-35 centimeters long (not counting the tail). In development, they have gone far from their insectivorous ancestors of the Cretaceous period. However, it took another 35 million years for the first humans to appear, the distant descendants of the Amphipithecus and Propliopithecine.

Particularly significant events in the history of the Earth occurred over the past 18-20 million years, in the second half of the Tertiary period - in the eras that were called the Miocene and Pliocene.

By this time, the number of tropical plants had noticeably decreased in the forests of Western Europe, and trees with leaves falling in winter began to be encountered quite often, but the winters were still very warm. Even in the present northern regions of the USSR it was so warm that, for example, near Tobolsk and even to the north of it, walnuts, maples, ash trees and hornbeams grew.

Among the animals, bears, hyenas, wolves, martens, badgers, and wild boars have already appeared, very similar to modern ones. Of the large mammals, the ancestors of the present elephants lived - mastodons, dinoteria, which had two tusks, like two blades bent down, protruding from mandible, giraffes, rhinos. Many monkeys lived on the trees, and among them were anthropoids - driopithecus, which often descended from the trees and went out to the edges of the forests in search of food. Real birds appeared, and among insects - butterflies and stinging insects. The seas and rivers abounded with animals already largely similar to modern ones.

In the last 6-7 million years, which cover the Pliocene epoch, all the direct ancestors of modern animals appeared.

Gradually, the climate in the northern parts of the Earth became colder. Among the animals, numerous three-toed ancestors of our horse appeared - hipparions, and then real horses. Gradually, mastodons disappeared almost everywhere, and huge flat-fronted elephants took their place. Wild camels, a variety of antelopes and deer, saber-toothed tigers and other predators, and of the birds - ostriches, which inhabited at that time the present Azov region, Kuban, and the Crimean coast, became common.

Among the many different species of great apes, australopithecines (which means southern monkeys) appeared, which already spent most of their lives on the ground, and not in trees. Their descendants gradually finally descended to earth and turned into ape-men - Pithecanthropes. Their remains were found on the island of Java. They were already very human-like creatures. There is reason to believe that they used stones and wood as a means of hunting animals; but whether they were familiar with the use of fire is unknown. A little more than a million years separate us from them. During this million years, and according to the calculations of some scientists, even within 600 thousand years, the Earth finally took on its modern form and the first people appeared on it. This is the period in the history of the earth in which we live; it is called Quaternary, or Anthropogenic (from Greek words“anthropos” - a person and “genos” - a kind, birth, i.e., the period of a person’s birth).

At the beginning of the Quaternary it was still relatively warm. The animal world was quite different from the modern one. The so-called ancient and southern elephants, Merck's rhinoceros, wild camels and large horses, various antelopes and deer, trogontheria living in burrows, like our marmots, but similar in appearance and size to beavers, huge broad-browed elks were widespread at that time. , and of the birds common in Europe and Asia were ostriches, now surviving only in Africa and South America. But the most outlandish animal in Europe and Asia at that time was the elasmotherium. This animal, the size of a large horse, resembled a rhinoceros, only it had a huge horn on its forehead, and not on its nose. The neck of an elasmotherium was about a meter thick. Some tertiary animals lived out their lives in warm countries (Africa, South America, New Zealand, Australia and Western Europe): saber-toothed tigers, mastodons, hipparions, various marsupials (in Australia) and others.

But millennia passed, the climate approached the modern one, and with it the animal and plant world became more and more similar to the modern one. However, even at the end of the Quaternary period, probably already at the very beginning of the Great Glaciation, the differences in climate and fauna compared to the current situation were still significant.

Imagine that we are in the vicinity of Moscow 100 thousand years ago. After a hot day, the evening coolness blew. In the water meadows of the prehistoric river, herds of long-horned bison and shoals of horses quietly graze; beautifully stand out on the horizon slender silhouettes of giant deer who came to drink. Their proudly raised heads are slightly thrown back under the weight of huge, elk-like horns. There are also hornless, shy females with carelessly frolicking cubs. But suddenly, with the speed of lightning, the deer disappeared, herds of horses rushed and disappeared like an avalanche, rhinoceros and bison became agitated, huge bulls with bloodshot eyes bowed low their shaggy heads with meter-long horns and ferociously dig the ground with their hooves. Animals noticed the approach of the terrible predator that time - cave lion. Only elephants - trogontheria - slowly shaking their huge heads, remained as if calm, but they also came close to their cubs, ready to protect them at any moment.

So it was on the site of modern Moscow 80-100 thousand years ago, when the first signs of the Great Glaciation already appeared in the North.

Hundreds of bones of these animals were found during the construction of the Moscow Canal.

At that time they still lived in the territory where it is now Soviet Union, and other now extinct animals - wild camels, markhorn antelope(spirocerus), cave hyenas and bears.

Along with these animals, wolves, foxes, hares, martens and others, which differed little from modern ones, were common.

Such was the animal world in the middle of the Quaternary period, just before the beginning of the Great Ice Age of the Earth. But about 100 thousand years ago, the first glaciers shone in the mountains; they slowly began to crawl onto the plains. In place of modern Norway, an ice cap appeared, which began to spread to the sides. The advancing ice buried more and more new territories, displacing the animals and plants that lived there to other places. The icy desert arose in the vast expanses of Europe, Asia and North America. In places, the ice cover reached a thickness of two kilometers. The era of the Great glaciation of the Earth has come. The huge glacier was either shrinking somewhat, or moving south again. For quite a long time he lingered at the latitude of Yaroslavl, Kostroma, Kalinin. Even 14,300 years ago, as we know, its remains were near Leningrad.

Not all animals survived ice age. Many of them could not adapt to the new living conditions and died out (Elasmotherium, wild camels). Others adapted, and as a result of gradual changes gave new species. So trogontherian elephants, for example, turned into mammoths, which became extinct at the end of the Ice Age. Many animals - bison, deer, wolverines and others - were crushed. Some of these animals (bison, giant deer, and others) died out in the post-glacial era, while the rest still live.

During the Ice Age, the most common animals were mammoths, woolly rhinoceros, and now living in the far north, arctic foxes, lemmings (pied), reindeer and others. In those days, as we already know, they lived much further south, even in the Crimea.

By the time the glacier melted, the animal and plant world had become approximately the same as it is now.

Some scientists believe that the Quaternary period had not one, but several glaciations, which were interspersed with warmer interglacial epochs.

Traces of glaciation are also known in the most ancient geological periods, but they have not yet been adequately studied everywhere.

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The time limits of the Cenozoic era are not difficult to determine: this is a period of geological time, originating from the Cretaceous-Paleogene extinction event that destroyed the dinosaurs 66 million years ago and continuing up to the present day. Unofficially, the Cenozoic era is often referred to as the "age of mammals" because it was only after the dinosaurs became extinct that mammals were able to fill the vacant ecological niches and become the dominant terrestrial life on the planet.

However, this characterization is somewhat unfair, since not only mammals flourished during the Cenozoic, but also reptiles, birds, fish, and even invertebrates!

Somewhat confusingly, the Cenozoic era is divided into various "periods" and "eras", and scientists do not always use the same terminology when describing their research or discoveries. (This situation contrasts sharply with the previous mesozoic era, which is more or less neatly divided into , and periods.)

In the case of the Cenozoic era, the following main periods and eras are distinguished:

Paleogene period

(66-23 million years ago) was the time when mammals began their dominance. The Paleogene consists of three distinct epochs:

Paleocene epoch

The Paleocene epoch, or Paleocene (66-56 million years ago) was quite calm from an evolutionary point of view.

During this time, the tiny mammalian survivors tasted their newfound freedom for the first time and began cautiously exploring new ecological niches. In the Paleocene epoch, they were abundant big snakes, crocodiles and turtles.

Eocene epoch

The Eocene epoch, or Eocene (56-34 million years ago) was the longest epoch of the Cenozoic era.

In the Eocene there was an enormous abundance of mammalian species; at this time, the first four-legged ungulates appeared on the planet, as well as the first recognizable primates.

Oligocene epoch

The Oligocene epoch, or Oligocene (34-23 million years ago), differs in climate change from the previous Eocene, which opened up even more ecological niches for mammals. This was the era when some mammals (and even some birds) began to develop to gigantic sizes.

Neogene period

(23-2.6 million years ago) was marked by the ongoing evolution of mammals and other life forms, many of which were huge. The Neogene consists of two epochs:

Miocene epoch

The Miocene epoch, or Miocene (23-5 million years ago) occupies the lion's share of the Neogene. Most mammals, birds and other animals began to acquire appearance, close to modern, although they were much larger.

Pliocene Epoch

The Pliocene epoch, or Pliocene (5-2.6 million years ago), is often confused with the subsequent Pleistocene. This was the time when many mammals migrated (often via land bridges) to the territories they continue to inhabit today. Horses, primates, and other animal species continued to evolve.

Quaternary period

(2.6 million years ago - to the present) is still the shortest of all the geological periods of the Earth. The Anthropogene consists of two even shorter epochs:

Pleistocene Epoch

The Pleistocene epoch, or Pleistocene (2.6 million - 12 thousand years ago) is characterized by large mammals megafauna, such as woolly and , which became extinct at the end of the last ice age (due in part to climate change and predation by the earliest humans).

Holocene epoch

The Holocene epoch, or Holocene (12,000 years ago - up to the present) represents almost the entire modern history humanity. Unfortunately, this is also an era when many mammals and other life forms became extinct due to environmental changes caused by negative anthropogenic impacts from human activities.