Cretaceous period, Cretaceous era, Cretaceous period of the Mesozoic era, Cretaceous dinosaurs, Cretaceous dinosaurs. Cretaceous period Why is the Cretaceous period called so?
The Cretaceous period is considered the longest period of the Mesozoic, as it lasted about 79 million years.
Geography
The separated parts of the supercontinent Pangea drifted away from each other. The Tethys Ocean continued to separate the northern continent of Laurasia from southern Gondwana. The North and South Atlantic were still inaccessible. By the middle of the period, ocean levels were much higher; most of The land known to us was still under water. By the end of the period, the continents acquired outlines close to modern ones. Africa and South America accepted their distinctive shapes; but India had not yet encountered Asia, and Australia remained part of Antarctica.
Climate
During Cretaceous period climatic conditions the Earth has become warmer. It was colder at the poles. Fossils tropical plants and ferns confirm this assumption.
Animals lived everywhere, even in colder areas. For example, fossil hadrosaurs dating back to the Late Cretaceous were discovered in Alaska.
When the asteroid struck, the world likely experienced what is known as a "nuclear winter," when dust particles blocked many sun rays to the surface of the land.
Vegetable world
One of distinctive features The Cretaceous period was the development of flowering plants. The oldest angiosperm fossil is Archaefructus liaoningensis- was found in China. This plant is believed to be most similar to modern black pepper and is believed to be at least 122 million years old.
It was previously thought that pollinating insects such as bees and wasps evolved around the same time as angiosperms, a process called coevolution. However, new research indicates that insect pollination was likely common even before the first flowers. While the oldest bee fossil is about 80 million years old, evidence has been found that bees or wasps built their nests in Arizona's "Petrified Forest" ( National Park Petrified Forest).
These nests, found by Stefan Chasiotis and his team at the University of Colorado, are at least 207 million years old. It is now thought that competition for insect attention likely contributed to the relatively rapid success and diversification of flowering plants. Because a variety of flower forms attracted insects for pollination, insects adapted to in various ways collecting nectar and moving pollen, thereby creating the complex co-evolutionary systems we are familiar with today.
There is limited evidence that dinosaurs ate angiosperms. According to a study published at the 2015 annual meeting of the Society of Paleontology. Two dinosaur coprolites (fossilized poop) were discovered in Utah that contained angiosperm particles. This finding, as well as others (including the presence of angiosperm fruits in the guts of Early Cretaceous ankylosaurs), suggests that some animals fed on flowering plants.
Animal world
During the Cretaceous period, more began to fly, joining pterosaurs in the air. The origin of flight is debated by many experts. The tree-down theory suggests that small reptiles may have evolved from jumping behavior. The ground-up hypothesis suggests that small theropods may have jumped high to catch prey and were able to develop the ability to fly. Feathers probably evolved from early skin coverings, the main function of which was most likely thermoregulation.
In any case, it is clear that birds were quite successful and became widely diversified during the Cretaceous. Confuciusornis (125-120 million years ago) is a bird with a modern beak and huge claws on the tips of its fingers. Iberomesornis was the size of a sparrow, could run, and probably fed on insects.
By the end of the Jurassic, some large sauropods, such as Apatosaurus and Diplodocus, became extinct. But other giant sauropods, including titanosaurs, flourished, especially during the late Cretaceous period.
Large herds of herbivorous ornithischian dinosaurs also flourished during the Cretaceous, including iguanodonts, ankylosaurs, and horned dinosaurs. Theropods, including Tyrannosaurus rex , continued to remain at the top until the end of the Cretaceous period.
Mass Cretaceous-Paleogene (C-T) extinction
About 66 million years ago, almost all large and many tropical ones became extinct. Geologists call this the Cretaceous-Paleogene extinction event because it marks the boundary between the Cretaceous and Paleogene periods.
In 1979, a geologist studying rock layers between the Cretaceous and Paleogene discovered a thin layer of gray clay separating the two eras. Other scientists have found this gray layer around the world, and tests have shown that it contains high concentrations of iridium, which is rare on Earth but common in most meteorites.
Also present in this layer are signs of "shocked quartz" and tiny glass particles called tektites, which form when rock is rapidly heated and cooled, as happens when an extraterrestrial object hits Earth with great force.
The Chicxulub crater on the Yucatan Peninsula dates back to this time. The size of the crater is more than 180 kilometers in diameter, and chemical analysis shows that sedimentary rocks areas were melted and mixed together due to the impact of an asteroid about 10 km in diameter.
When the asteroid hit Earth, it caused shock waves, massive tsunamis and sent a large cloud of hot rocks and dust into the atmosphere. As the hot debris fell to Earth, it caused numerous Forest fires, increasing the ambient temperature.
A rain of dust and rocks raised the planet's global temperature within hours of the impact and wiped out animals that were too large to seek shelter. Small fauna that took refuge underground or in water, in caves or large tree trunks, were probably able to survive this catastrophe.
The tiny fragments likely remained in the atmosphere, blocking some of the sun's rays for months or years. When the amount of sunlight decreased, plants could not participate and died, as did the animals that fed on them.
Smaller, land-based animals such as mammals, lizards, turtles and birds may have been able to survive as scavengers by feeding on the carcasses of dead dinosaurs, fungi, roots and rotting plant matter.
There is also evidence that a series of huge volcanic eruptions occurred along the tectonic boundary between India and Asia, starting just before the Cretaceous-Paleogene extinction event. It is likely that these regional disasters affected many living organisms on the planet.
Cretaceous period -- geological period, the last period of the Mesozoic era.
Began 145 million years ago and ended 65 million years ago. The Cretaceous period lasted about 80 million years.
In the Cretaceous period, the first angiosperms - flowering plants - appeared. This resulted in an increase in the diversity of insects that became flower pollinators. The evolution of the plant world gave impetus to the rapid development of the animal world, including dinosaurs. The diversity of dinosaur species reached its peak during the Cretaceous period.
Cretaceous tectonics
During the Cretaceous period, continental movement continued. Laurasia and Gondwana were falling apart. Africa, India and Australia also began to diverge in different directions, and giant islands eventually formed south of the equator. South America and Africa were moving away from each other, and Atlantic Ocean became wider and wider. There were no obvious catastrophes during the Cretaceous period, so the process of evolution continued naturally. The earth took on shapes very close to those known to us.
Cretaceous climate
The climate has changed compared to the Jurassic period. Due to the changing position of the continents, the change of seasons became more and more noticeable. Snow began to fall at the poles, although there were no such ice caps on Earth as there are now. The climate varied on different continents. This caused differences in the development of flora and fauna in different parts of the world.
Flora of the Cretaceous period
The flora of the Cretaceous period was rich and varied. In addition to the plant species carried over from the Jurassic period, a new, revolutionary branch of flowering plants appears
Gradually populating the land, new groups of plants began to form vast forests. There, a wide variety of leaves and other edible vegetation were available to land animals. Thanks to the appearance of flowering plants during the Cretaceous period, the amount of plant biomass increased.
The reverse process took place at sea. This was again facilitated by the development of flowering plants. Dense roots prevented soil erosion and therefore less minerals entered the sea. The amount of phytoplankton has decreased.
Cretaceous – The Cretaceous period is the last period of the Mesozoic era, began 145.5 million years ago and ended 65.5 million years ago. It lasted about 80 million years.
In the Cretaceous period, angiosperms - flowering plants - appeared. This resulted in an increase in the diversity of insects that became flower pollinators. So the plant cover of the Earth in the Cretaceous period would no longer surprise modern man. The same cannot be said about the animal world of that time.
Among the land animals, a variety of dinosaurs reigned. Dinosaurs are divided into two groups - lizard-hatched, which included both predators and herbivorous forms, and ornithischian, exclusively herbivorous. The most famous lizard-hipped dinosaurs are tyrannosaurs, tarbosaurs, and brontosaurs. Among ornithischian lizards, ceratopsians, iguanodons, and stegosaurs are known. This was the heyday of giant lizards - many dinosaurs reached 5-8 meters in height and 20 meters in length.
Winged reptiles - pterodactyls - occupied almost all the niches of aerial predators, although real birds had already appeared. Thus, in parallel there were flying lizards - pterosaurs, gliding, and perhaps flying lizards such as Archeopteryx, enantiornis birds and true fan-tailed birds.
The Cretaceous period, which is considered the era of dinosaurs, was also the time when most modern groups mammals. In the Cretaceous period, the first placental mammals appeared, and groups of ungulates, insectivores, predators and primates had already emerged.
Modern lizards and snakes evolved, so snakes are a relatively young group. One of the groups of lizards went into the water - this is how mosasaurs arose, formidable predators the end of the Cretaceous period, sometimes reaching 20 meters in length. There were no mammals in the seas yet, but a niche large predators occupied by aquatic reptiles - ichthyosaurs, plesiosaurs, pliosaurs. The sharks were large and numerous, some of them lived in fresh water bodies.
The diversity of marine invertebrates was very large. As in the Jurassic period, ammonites and belemnites, brachiopods, bivalves and sea urchins. Among bivalves big role in marine ecosystems played by rudists that appeared at the end of the Jurassic - mollusks, similar to single corals, in which one valve looked like a cup, and the second covered it like a kind of lid.
By the end of the Cretaceous period, many heteromorphic forms appeared among ammonites. Heteromorphs arose earlier, in the Triassic, but the end of the Cretaceous became the time of their mass appearance. The shells of heteromorphs were not similar to the classic spiral-twisted shells of monomorphic ammonites. These could be spirals with a hook at the end, various balls, knots, unfolded spirals. Paleontologists have not yet come to a common explanation of the reasons for the emergence of such forms and their way of life.
Almost modern octopuses and squids already lived in the seas; paleontologists believe that they arose at the end of the Jurassic, although they were rarely preserved in the fossil record due to the lack of shells. Whether they contributed to the extinction of their relatives - ammonites and belemnites, or simply occupied vacated niches after the global crisis - we do not yet know.
During the Cretaceous period, the continental breakup continued. Laurasia and Gondwana were falling apart. South America and Africa moved away from each other, and the Atlantic Ocean became wider and wider. Africa, India and Australia also began to diverge in different directions, and giant islands eventually formed south of the equator.
At the end of the Cretaceous period, the most famous and very large extinction of many groups of plants and animals occurred. Many gymnosperms, all dinosaurs, pterosaurs, and aquatic reptiles became extinct. Ammonites, many brachiopods, and almost all belemnites disappeared. In the surviving groups, 30-50% of species became extinct.
The causes of the Cretaceous disaster are not fully understood. Now the most popular theory has become the asteroid theory, which explains the extinction of dinosaurs and other organisms by the fall of a giant asteroid and the subsequent “asteroid winter.” Apparently, this is not entirely true. This version cannot explain why certain organisms survived when others died. In addition, many groups of animals clearly began to die out long before the end of the Cretaceous. The transition of the same ammonites to heteromorphic forms also clearly indicates some kind of instability. It is very possible that many species had already been undermined by some long-term processes and were on the path to extinction, and a catastrophe - an asteroid, increased volcanism or climate change due to the movement of continents - simply accelerated the process.
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Starting 145 million years ago, it lasted about 79 million years and ended 66 million years ago. Its name comes from the abundance of writing chalk, formed from dying invertebrate organisms, in its sediments. The Cretaceous period is significant for the second largest (after the Permian) worldwide extinction of species.
In 2016, the International Union of Geological Sciences adopted the following division of the Cretaceous:
Periods, geography and climate of the Cretaceous
During the Cretaceous period, the division of Laurasia into the North American continent and the Euro-Asian continent continued. Gondwanaland finally split into the South American continent, the African, Indian segments, Antarctica and Australia. Throughout the Cretaceous, these gigantic land areas diverged more and more from each other, the southern and northern parts of the Atlantic Ocean were no longer connected by narrow straits, but acquired an integral oceanic structure. But despite this, a significant part of Europe, the Middle East, the Caucasus and Northern part Africa was still under water until the very end of the Cretaceous period.
The climate of the Cretaceous period became noticeably colder compared to the previous Jurassic period. At first it average temperature throughout the planet fell by 5 degrees, which led to the formation of polar ice caps, but after some time the climate warmed again, and in general the entire planet was relatively warm, winter temperatures even in the coldest zones globe on average fluctuated within +4°C. By the end of the period caused by side factors Greenhouse effect led to an even greater and sharp increase in temperature.
Sedimentation
The Cretaceous period is characterized by the maximum flysch accumulation in geosyncal areas in the entire history of the Earth. As a result of violent magmatism caused by the splitting of continental regions, siliceous and split-dibasic formations were formed, and granitoid emissions were extensive and colossal. In general, the accumulation of trigenic and volcanogenic strata was widespread during the Cretaceous period. Such rift zones appeared in Africa and Brazil. IN sea depths Huge layers of writing chalk accumulate.
Animals of the Cretaceous period
The most significant marine invertebrates during the Cretaceous period were cephalopods. In the Upper Cretaceous, the role of external-shells (ammonoids) slightly decreased, but internal-shells (belemnites) were fundamental until the very end of the period. Closer to the middle, some ammonoids, for example, such as ammotoceras, reached 2 meters in size.
Molluscs such as pelecypods (bivalves) and gastropods (gastropods) also developed widely. Most bivalves would become completely extinct by the end of the Cretaceous. Irregular sea urchins also developed along with large foraminifera.
The insects of the Cretaceous period also felt great, having adapted to existing flowering plants. Due to biological changes in vegetation, they also progressed in their development. All kinds of worms also felt great. The first lobsters and other predatory crustaceans such as crabs and shrimp appeared in coastal seas and oceanic areas.
Dinosaurs
The vertebrates of the Cretaceous period - dinosaurs - stood out because among them, as in the Jurassic period, reptiles reigned supreme (Fig. 1). Among them were crawling creatures, walking on four limbs, moving only on two hind limbs, waterfowl and, of course, flying Hymenoptera. The richness of their diversity and forms was truly amazing. This entire numerous army of reptiles constantly devoured both huge masses of green space and themselves, meanwhile increasing in numbers until, in an incomprehensible way, in the upper Maastrichtian stage of the Cretaceous period it became almost completely and universally extinct.
Rice. 1 – Dinosaurs of the Cretaceous period
The first snakes appeared (Fig. 2). Some grew to truly gigantic sizes and hunted mainly in aquatic environment, in coastal or river basins. It was not difficult for some of them to wrap around and crush or strangle a gaping one and a half meter raptor.
Rice. 2 – Cretaceous snake
The variety of flying dinosaurs was also great. The real giant was the pteradon, whose wingspan averaged 8 meters. These giant reptiles hunted mainly over the sea, easily diving in air currents and every now and then snatching fish and other representatives of marine fauna from the water.
Birds also developed widely, the first varieties of which appeared in the Jurassic period. In the Cretaceous period, highly organized and specialized formations appeared among them.
And in the depths of the sea we got further development fish with hard bones. The ray-finned offspring of the Triassic and Jurassic multiplied unusually, a huge number of new varieties appeared both among the inhabitants of freshwater and inland basins, and among salty marine and oceanic species (Fig. 3).
Rice. 3 – Marine animals of the Cretaceous period
Despite the undivided dominance of reptiles, in the Cretaceous period they still advanced in their evolutionary development mammals. Having appeared on the threshold of the Mesozoic, these beast-like animals (synapsids) slowly but surely waited in the wings throughout the entire era, increasingly adapting to the difficult life in the background. Synapsids often settled in cold areas of continents, where predatory but heat-loving reptiles were rare guests. Those who were forced to live among reptiles in hot areas went out to hunt mainly at night. All this greatly contributed to their adaptation to difficult conditions, which determined the mammals’ survival in difficult conditions the asteroid winter that struck the Earth at the end of the Cretaceous.
All synapsids were divided into three main varieties - dicynodonts, cynodonts and allotherians. Dicyodonts and cynodonts almost completely went extinct during the Cretaceous period, and allodonts developed into mammals. During the Late Jurassic and subsequent Cretaceous period, they clearly divided into three branches - oviparous, marsupial and placental. Oviparous animals, unable to withstand competition with marsupials and placentals, soon also disappeared; today marsupials survive only in Australia, and it is from placentals that all subsequent species of modern mammals developed. Placentals at that time were divided into Laurasiatherians and Gondwanatherians. It was Gondwanotherium that were the ancestors of modern rodents and primates.
From the marsupial branch, possum-like animals evolved, and from the oviparous branch, only platypuses remain today. The ancestor of primates is considered ancient mammal purgatorius.
Basically, mammals of the Cretaceous period (Fig. 4) weighed no more than half a kilogram and rarely exceeded the size of a modern rat. Of course, there were also such rare specimens as meter-long and fourteen-kilogram repenomamas, but they were too few in number.
Rice. 4 – Mammals of the Cretaceous period
For the most part, reptiles owe their extinction to these small creatures, which, having multiplied unusually towards the end of the Cretaceous period, fed mainly on insects, but did not disdain the eggs of reptiles.
Despite the fact that the first flowering plants began to appear long before the Cretaceous period, it was at this time that the formation of flowering vegetation entered a real boom stage. It is no coincidence that half of all currently existing famous plants refers specifically to flowering plants. And this is connected with this.
By spreading spores in the wind, primitive plants took a great risk. And not in vain, since the bulk of the disputes never achieved their intended goal. And many plants of that era had not yet acquired at least some varieties of spore spraying mechanisms. Their spores were forced to fall to the ground, right in the same place where the plants themselves grew. It is clear that with such reproduction it was not possible to achieve a more or less reliable result. This is where it came from a vital necessity in the development of new, more effective methods of pollen distribution. And insects came to the aid of plants.
A kind of union began to develop and become stronger between the flower groups. While insects carried pollen from plants, plants produced nectar for them so that they would work more intensively on pollination. In the process of evolution, it turned out that many insects simply could no longer do without flowering plants, since their entire lives and body biology were inextricably linked and aimed at a life associated with such plants. And the plants, with the help of their insect helpers, began to multiply many times faster, and soon dense vegetation spread even to those areas of land where it had never existed before. This type The partnership between plants and insects continues to this day.
Rice. 5 – Plants of the Cretaceous period
Underwater plants of the Cretaceous period were in many ways similar to plants of previous periods of the Mesozoic. The only difference was that microscopic algae such as nanoplankton (for example, golden coccolithophores) and diatoms multiplied unusually. It is nanoplankton and small foramnifera that are responsible for the formation of such thick layers of writing chalk.
Towards completion Mesozoic era The flora of the land has undergone a number of significant changes. From the middle of the Cretaceous period, the first angiosperms began to appear, which towards the end of the Cretaceous already constituted the overwhelming majority among terrestrial plants. The first varieties of plants with foliage of increased succulence began to appear. This most applies to places where the climate has become more arid and hot.
Cretaceous extinction
Occurring at the boundary of the Mesozoic and Cenozoic, or more precisely, in the Maastrichtian final stage of the Upper Division, the Cretaceous extinction of species was the second largest after the Permian. Overnight, coccolithophores ceased to exist, and there were no Cretaceous planktonic foramonifers, ammonites, belemnites, or coral-like bivalves—rudists. Dinosaurs and many other species of reptiles disappeared from the face of the earth. Many species of birds and insects, both above-water and underwater world. In particular, the total number of all kinds of rliolarians decreased by 50%, 75% of all brachiopods, from 30 to 75% of bivalves and gastropods, sea lilies and hedgehogs. Only 25% of the total shark population remains. More than 100 different families of marine invertebrates have become extinct. In general, the damage suffered by flora and fauna was truly enormous.
What caused such a mass extinction of species during the Cretaceous period is still not known. Scientists' opinions on this matter are divided. Opinions have also been expressed that powerful cosmic radiation generated as a result of a supernova explosion reached the Earth. Some people talk about a strong greenhouse effect associated with an extremely aggravated volcanic activity. But the majority support the version that is based on the fall of a giant asteroid to the earth (Fig. 6). This version is confirmed by the presence of iridium inclusions in the strata of this era, which is constantly found in places where meteorites fall.
Rice. 6 – Asteroid impact
It is alleged that an asteroid with a magnitude of 10 to 15 km entered the earth's atmosphere, split into several segments, which collided earth's surface. The explosive energy, amounting to approximately 10 30 erg, raised from earth's crust a lot of pollutant, which for a long time blocked plants and animals from accessing sunlight. Thus, as a result of the unique “asteroid winter” that was created, most terrestrial animals became extinct. Apparently, this did not have such an impact on flora because the atmosphere cleared in a relatively short period of time. And if the plant seeds were able to safely survive this catastrophe in the soil and soon simply sprouted as if nothing had happened, then animal world Cretaceous period with such ease to transfer this global catastrophe could not. And as a result, only the most adapted and more tenacious species survived, such as, for example, mammals.
Minerals of the Cretaceous period
The Cretaceous period is unusually prolific in different kinds minerals, most of which arose as a result of intrusive magmatism and volcanism, which accompanied the worldwide division of Pangea into smaller components. About 20% of coal deposits were accumulated during this time. The largest coal basins this time - Lensky and Zyryansky, as well as a number of North American coal basins.
Also associated with the Cretaceous period are most Russian, French and Spanish bauxite deposits, Western Siberian oil and gas fields, and oil and gas fields of Kuwait and Canada. In the territory Western Siberia extensive deposits of oolitic minerals were discovered iron ores. There are also numerous phosphate deposits in the territories of Russia, Morocco, and Syria. Extensive salt deposits have been found on the territory of Turkmenistan and in some North American regions. In the northeast of Russia, in the territory North America deposits of tin, lead and gold were discovered. The famous Indian and South African diamond deposits also belong to the Cretaceous period.
Writer's chalk has been found almost everywhere in Cretaceous sediments.
million years ago
as of April 2016.
Geology
During the Cretaceous period, the continental breakup continued. Laurasia and Gondwana were falling apart. South America and Africa moved away from each other, and the Atlantic Ocean became wider and wider. Africa, India and Australia also began to diverge in different directions, and giant islands eventually formed south of the equator.
Climate
70 million years ago the Earth was cooling. Ice caps formed at the poles. The winters became harsher. The temperature dropped below +4 degrees in some places. For the dinosaurs of the Cretaceous period, this difference was sharp and very noticeable. Such temperature fluctuations were caused by the breakup of Pangea, and then Gondwana and Laurasia. Sea levels have risen and fallen. The jet streams in the atmosphere have changed, causing ocean currents to change.
At the end of the Cretaceous period, temperatures began to rise sharply. There is a hypothesis that the oceans were the cause of these changes: instead of absorbing heat, they may have reflected it back into the atmosphere. Thus, they caused the greenhouse effect.
Vegetation
In the Cretaceous period, angiosperms - flowering plants - appeared. This led to an increase in the diversity of insects, which became flower pollinators. As temperatures rose during the late Cretaceous period, plants with richer foliage evolved.
Animal world
Among the land animals, a variety of large reptiles reigned. This was the heyday of giant lizards - many dinosaurs reached 5-8 meters in height and 20 meters in length. Winged reptiles - pterodactyls - occupied almost all the niches of aerial predators, although real birds had already appeared. Thus, flying lizards, lizard-tailed birds such as Archeopteryx, and true fan-tailed birds existed in parallel.
There were no mammals in the seas, and the niche of large predators was occupied by reptiles - ichthyosaurs, plesiosaurs, mosasaurs, sometimes reaching 20 meters in length.
The diversity of marine invertebrates was very large. As in the Jurassic, ammonites and belemnites, brachiopods, bivalves and sea urchins were very common. Among bivalves, a major role in marine ecosystems was played by rudists that appeared at the end of the Jurassic - mollusks similar to solitary corals, in which one valve looked like a cup, and the second covered it like a kind of lid.
By the end of the Cretaceous period, many heteromorphic ones appeared among ammonites. Heteromorphs arose earlier, in the Triassic, but the end of the Cretaceous became the time of their mass appearance. The shells of heteromorphs were not similar to the classic spiral-twisted shells of monomorphic ammonites. These could be spirals with a hook at the end, various balls, knots, unfolded spirals. Paleontologists have not yet come to a common explanation of the reasons for the emergence of such forms and their way of life.
Orthoceras were still found in the seas - relics of the long-past Paleozoic era. Small shells of these straight-shelled cephalopods are found in the Caucasus.
Cretaceous disaster
At the end of the Cretaceous period, the most famous and very large extinction of many groups of plants and animals occurred. Many gymnosperms, aquatic reptiles, pterosaurs, and all dinosaurs became extinct (but birds survived). Ammonites, many brachiopods, and almost all belemnites disappeared. In the surviving groups, 30-50% of species became extinct. The causes of the Cretaceous disaster are not fully understood.
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Notes
Literature
- Iordansky N. N. Development of life on earth. - M.: Education, 1981.
- Koronovsky N.V., Khain V.E., Yasamanov N.A. Historical geology: Textbook. - M.: Academy, 2006.
- Ushakov S.A., Yasamanov N.A. Continental drift and climates of the Earth. - M.: Mysl, 1984.
- Yasamanov N.A. Ancient climates of the Earth. - L.: Gidrometeoizdat, 1985.
- Yasamanov N.A. Popular paleogeography. - M.: Mysl, 1985.
Links
- - A site with information about the state of research in the field of Cretaceous stratigraphy and paleogeography in Russia. Library scientific publications related to the study of Cretaceous deposits.
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| ← | Triassic (252,2-201,3) |
Jurassic period (201,3-145,0) |
Cretaceous period (145,0-66,0) |
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Excerpt characterizing the Cretaceous period
“And I dare to report: a good deed, your Excellency.”“How easy he thinks it is,” thought Pierre. “He doesn’t know how scary it is, how dangerous it is.” Too early or too late... Scary!
- How would you like to order? Would you like to go tomorrow? – Savelich asked.
- No; I'll put it off a little. I'll tell you then. “Excuse me for the trouble,” said Pierre and, looking at Savelich’s smile, he thought: “How strange, however, that he does not know that now there is no Petersburg and that first of all it is necessary for this to be decided. However, he probably knows, but he’s only pretending. Talk to him? What does he think? - thought Pierre. “No, someday later.”
At breakfast, Pierre told the princess that he had been to Princess Marya yesterday and found there - can you imagine who? - Natalie Rostov.
The princess pretended that she did not see anything more extraordinary in this news than in the fact that Pierre had seen Anna Semyonovna.
- Do you know her? asked Pierre.
“I saw the princess,” she answered. “I heard that they were marrying her to young Rostov.” This would be very good for the Rostovs; They say they are completely ruined.
- No, do you know Rostov?
“I only heard about this story then.” Very sorry.
“No, she doesn’t understand or is pretending,” thought Pierre. “It’s better not to tell her either.”
The princess also prepared provisions for Pierre's journey.
“How kind they all are,” thought Pierre, “that now, when they probably couldn’t be more interested in this, they are doing all this. And everything for me; That’s what’s amazing.”
On the same day, the police chief came to Pierre with a proposal to send a trustee to the Faceted Chamber to receive the things that were now being distributed to the owners.
“This one too,” thought Pierre, looking into the police chief’s face, “what a nice, handsome officer and how kind!” Now he deals with such trifles. They also say that he is not honest and takes advantage of him. What nonsense! But why shouldn’t he use it? That's how he was raised. And everyone does it. And such a pleasant, kind face, and smiles, looking at me.”
Pierre went to dinner with Princess Marya.
Driving through the streets between the burned-out houses, he was amazed at the beauty of these ruins. Chimneys houses, fallen-off walls, picturesquely reminiscent of the Rhine and the Colosseum, stretched, hiding each other, along the burnt blocks. The cab drivers and riders we met, the carpenters who cut the log houses, the traders and shopkeepers, all with cheerful, beaming faces, looked at Pierre and said as if: “Ah, here he is! Let's see what comes out of this."
Upon entering the house of Princess Marya, Pierre was filled with doubt as to the justice of the fact that he was here yesterday, saw Natasha and spoke with her. “Maybe I made it up. Maybe I’ll walk in and not see anyone.” But before he had time to enter the room, in his entire being, after the instant deprivation of his freedom, he felt her presence. She was wearing the same black dress with soft folds and the same hairstyle as yesterday, but she was completely different. If she had been like this yesterday when he entered the room, he could not have failed to recognize her for a moment.
She was the same as he had known her almost as a child and then as the bride of Prince Andrei. A cheerful, questioning gleam shone in her eyes; there was a gentle and strangely playful expression on her face.
Pierre had dinner and would have sat there all evening; but Princess Marya was going to the all-night vigil, and Pierre left with them.
The next day Pierre arrived early, had dinner and sat there all evening. Despite the fact that Princess Marya and Natasha were obviously pleased with the guest; despite the fact that the whole interest of Pierre’s life was now concentrated in this house, by the evening they had talked everything over, and the conversation constantly moved from one insignificant subject to another and was often interrupted. Pierre stayed up so late that evening that Princess Marya and Natasha looked at each other, obviously waiting to see if he would leave soon. Pierre saw this and could not leave. He felt heavy and awkward, but he kept sitting because he couldn’t get up and leave.
Princess Marya, not foreseeing an end to this, was the first to get up and, complaining of a migraine, began to say goodbye.
– So you’re going to St. Petersburg tomorrow? – said oka.
“No, I’m not going,” Pierre said hastily, with surprise and as if offended. - No, to St. Petersburg? Tomorrow; I just don't say goodbye. “I’ll come for the commissions,” he said, standing in front of Princess Marya, blushing and not leaving.
Natasha gave him her hand and left. Princess Marya, on the contrary, instead of leaving, sank into a chair and looked sternly and carefully at Pierre with her radiant, deep gaze. The fatigue she had obviously shown before was now completely gone. She took a deep, long breath, as if preparing for a long conversation.
All of Pierre's embarrassment and awkwardness, when Natasha was removed, instantly disappeared and was replaced by excited animation. He quickly moved the chair very close to Princess Marya.
“Yes, that’s what I wanted to tell you,” he said, answering her glance as if in words. - Princess, help me. What should I do? Can I hope? Princess, my friend, listen to me. I know everything. I know I'm not worthy of her; I know it's impossible to talk about it now. But I want to be her brother. No, I don't want to... I can't...
He stopped and rubbed his face and eyes with his hands.
“Well, here,” he continued, apparently making an effort on himself to speak coherently. “I don’t know since when I love her.” But I have loved only her, only one, all my life and love her so much that I cannot imagine life without her. Now I don’t dare ask her hand; but the thought that maybe she could be mine and that I would miss this opportunity... opportunity... is terrible. Tell me, can I have hope? Tell me what should I do? “Dear princess,” he said, after being silent for a while and touching her hand, since she did not answer.
“I’m thinking about what you told me,” answered Princess Marya. - I'll tell you what. You’re right, what should I tell her about love now... - The princess stopped. She wanted to say: it is now impossible to talk to her about love; but she stopped because for the third day she saw from Natasha’s sudden change that not only would Natasha not be offended if Pierre expressed his love to her, but that this was all she wanted.