Periods Jurassic Cretaceous and others. Jurassic period

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Jurassic period, Jurassic period movie
Jurassic period (Yura) - middle (second) period Mesozoic era. Began 201.3 ± 0.2 million years ago, ended 145.0 million years ago. Thus it continued for about 56 million years. A complex of sediments (rocks) corresponding to a given age is called Jurassic system. In different regions of the planet, these deposits differ in composition, genesis, and appearance.

For the first time, deposits of this period were described in the Jura (mountains in Switzerland and France); This is where the name of the period came from. The deposits of that time are quite diverse: limestones, clastic rocks, shales, igneous rocks, clays, sands, conglomerates, formed in a variety of conditions.

• 1 Jurassic Division
  • 1.1 Geological events
  • 1.2 Climate
  • 1.3 Vegetation
  • 1.4 Marine organisms
  • 1.5 Land animals
• 2 Notes
• 3 Literature
• 4 Links

Jurassic System Division

Jurassic system is divided into 3 departments and 11 tiers:

system	Department	tier	Age, million years ago
Chalk	Lower	Berriasian	less
	Upper (malm)	Titonian	145,0-152,1
		Kimmeridge	152,1-157,3
		Oxford	157,3-163,5
	Average (dogger)	Callovian	163,5-166,1
		Bathian	166,1-168,3
		Bayocian	168,3-170,3
		Aalensky	170,3-174,1
	Lower (lias)	Toarsky	174,1-182,7
		Pliensbachian	182,7-190,8
		Sinemyursky	190,8-199,3
		Hettangian	199,3-201,3
Triassic	Upper	Rhetic	more
Subsections are given according to IUGS as of January 2015

Geological events

213-145 million years ago, the single supercontinent Pangea began to break up into separate continental blocks. Shallow seas formed between them.

Climate

The climate in the Jurassic period was humid and warm (and by the end of the period - arid in the equator region).

Vegetation

Drooping cycad (Cycas revoluta) is one of the cycads growing today
Ginkgo biloba (Ginkgo biloba). Botanical illustration from Siebold and Zuccarini's book Flora Japonica, Sectio Prima, 1870

In the Jurassic, vast areas were covered with lush vegetation, primarily diverse forests. They mainly consisted of ferns and gymnosperms.

Cycads are a class of gymnosperms that predominated in the green cover of the Earth. Nowadays they are found in the tropics and subtropics. Dinosaurs roamed under the shade of these trees. Externally, cycads are so similar to low (up to 10-18 m) palm trees that even Carl Linnaeus placed them among palm trees in his plant system.

During the Jurassic period, groves of gingkovic trees grew throughout the then temperate zone. Ginkgos are deciduous (unusual for gymnosperms) trees with an oak-like crown and small fan-shaped leaves. Only one species has survived to this day - ginkgo biloba.

The conifers were very diverse, similar to modern pines and cypresses, which flourished at that time not only in the tropics, but had already mastered temperate zone. The ferns gradually disappeared.

Marine organisms

Leedsichthys and Liopleurodon

Compared to the Triassic, the population of the seabed has changed greatly. Bivalves displace brachiopods from shallow waters. Brachiopod shells are replaced by oysters. Bivalve mollusks fill all life niches of the seabed. Many stop collecting food from the ground and switch to pumping water using their gills. A new type of reef community is emerging, approximately the same as what exists now. It is based on six-rayed corals that appeared in the Triassic.

Land animals

Reconstruction of Archeopteryx,
Oxford University Museum

One of the fossil creatures that combines the characteristics of birds and reptiles is Archeopteryx, or the first bird. His skeleton was first discovered in the so-called lithographic shales in Germany. The discovery was made two years after the publication of Charles Darwin's On the Origin of Species and became a strong argument in favor of the theory of evolution. Archeopteryx still flew quite poorly (gliding from tree to tree), and was approximately the size of a crow. Instead of a beak, it had a pair of toothy ones, although weak jaws. It had free fingers on its wings (of modern birds, only hoatzin chicks have them).

During the Jurassic period, small, furry, warm-blooded animals called mammals lived on Earth. They live next to dinosaurs and are almost invisible against their background. In the Jurassic, mammals were divided into monotremes, marsupials and placentals.

Dinosaurs (English Dinosauria, from ancient Greek δεινός - terrible, terrible, dangerous and σαύρα - lizard, lizard), dominant on land, lived in forests, lakes, and swamps. The range of differences between them is so great that family ties between their types are established with great difficulty. There were dinosaurs ranging in size from a cat to a whale. Different types of dinosaurs could walk on two or four limbs. Among them were both predators and herbivores. Of the latter, the Jurassic period saw the heyday of sauropods - diplodocus, brachiosaurs, apatosaurs, and camarasaurs. Sauropods were hunted by other lizard-hipped dinosaurs, namely large theropods.

Brachiosaurus

Ceratosaurus

Pseudotribos

Notes

1. International Stratigraphic Chart (January 2013 version) on the website of the International Commission on Stratigraphy

Literature

• Iordansky N. N. Development of life on earth. - M.: Education, 1981.
• Karakash N.I. Jurassic system and period // encyclopedic Dictionary Brockhaus and Efron: in 86 volumes (82 volumes and 4 additional). - St. Petersburg, 1890-1907.
• 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

• Jurassic.ru - Site about the Jurassic period, a large library of paleontological books and articles.

←	P A l e O h O th	Mesozoic (251-65 million years ago)			TO A th n O h O th	→
←		Triassic (251-199)	(199-145)	Cretaceous period (145-65)		→

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Jurassic Period Information About

From 213 to 144 million years ago.
By the beginning of the Jurassic period, the giant supercontinent Pangea was in the process of active disintegration. There was still a single vast continent south of the equator, which was again called Gondwana. Later it also split into parts that formed today's Australia, India, Africa and South America. Terrestrial animals of the northern hemisphere could no longer move freely from one continent to another, but they still spread unhindered throughout the southern supercontinent.
At the beginning of the Jurassic period, the climate throughout the Earth was warm and dry. Then, as heavy rains began to soak the ancient Triassic deserts, the world became greener again, with more lush vegetation. The Jurassic landscape was thick with horsetails and club mosses, which had survived from the Triassic period. Palm-shaped bennettites are also preserved. In addition, there were many grios around. Vast forests of seed, common and tree ferns, as well as fern-like cycads, spread from bodies of water inland. Were still common coniferous forests. In addition to ginkgo and araucaria, the ancestors of modern cypresses, pines and mammoth trees grew in them.

Life in the seas.

As Pangea began to break apart, new seas and straits emerged, in which new types of animals and algae found refuge. Gradually, fresh sediment accumulated on the seabed. They are home to many invertebrates, such as sponges and bryozoans (sea mats). In warm and shallow seas Other important events also took place. Giant ones formed there Coral reefs, sheltering numerous ammonites and new varieties of belemnites (old relatives of today's octopuses and squids).
On land, in lakes and rivers, there lived many different types crocodiles, widely spread across the globe. There were also saltwater crocodiles with long snouts and sharp teeth for catching fish. Some of their varieties even grew flippers instead of legs to make swimming more convenient. The tail fins allowed them to develop greater speed in the water than on land. New species of sea turtles have also appeared. Evolution also produced many species of plesiosaurs and ichthyosaurs, competing with new, fast-moving sharks and extremely agile bony fish.

This cycad is a living fossil. It is almost no different from its relatives that grew on Earth during the Jurassic period. Nowadays, cycads are found only in the tropics. However, 200 million years ago they were much more widespread.
Belemnites, living projectiles.

Belemnites were close relatives of modern cuttlefish and squid. They had internal skeleton cigar-shaped. Its main part, consisting of calcareous substance, is called the rostrum. At the front end of the rostrum there was a cavity with a fragile multi-chambered shell that helped the animal stay afloat. This entire skeleton was placed inside the soft body of the animal and served as a solid frame to which its muscles were attached.
The solid rostrum is preserved in fossil form better than all other parts of the belemnite body, and it is usually the one that falls into the hands of scientists. But sometimes fossils without rostra are also found. The first such finds were at the beginning of the 19th century. have baffled many experts. They guessed that they were dealing with the remains of belemnites, but without the accompanying rostra these remains looked rather strange. The solution to this mystery turned out to be extremely simple, as soon as more data was collected about the feeding method of ichthyosaurs - the main enemies of belemnites. Apparently, the growthless fossils were formed when an ichthyosaur, having swallowed a whole school of belemnites, regurgitated the soft parts of one of the animals, while its hard internal skeleton remained in the stomach of the predator
Belemnites, like modern octopuses and squids, produced an inky liquid and used it to create a “smoke screen” when trying to escape from predators. Scientists have also discovered fossilized ink sacs of belemnites (organs in which a supply of ink liquid was stored). One Victorian scientist, William Buckland, even managed to extract some ink from fossilized ink sacs, which he used to illustrate his book, The Bridgewater Treatise.

Plesiosaurs, barrel-shaped marine reptiles with four broad flippers that they used to row through the water like oars.
Glued fake.

No one has yet managed to find a complete fossil belemnite (soft part plus rostrum), although in the 70s. XX century in Germany a rather ingenious attempt was made to fool the whole scientific world with the help of skillful forgery. Whole fossils, allegedly obtained from one of the quarries in southern Germany, were purchased by several museums at very high prices before it was discovered that in all cases the limestone rostrum had been carefully glued to the fossilized soft parts of the belemnites!
This famous photograph, taken in 1934 in Scotland, was recently declared a fake. Nevertheless, for fifty years it fueled the enthusiasm of those who believed that the Loch Ness monster was a living plesiosaur.

Mary Anning (1799 - 1847) was only two years old when she discovered the first fossil skeleton of an ichthyosaur at Lyme Regis in Doroeth, England. Subsequently, she was lucky enough to also find the first fossil skeletons of a plesiosaur and pterosaur.
This child could find
Glasses, pins, nails.
But then we got in the way
Ichthyosaur bones.

Born for Speed

The first ichthyosaurs appeared in the Triassic. These reptiles were ideally adapted to life in the shallow seas of the Jurassic period. They had a streamlined body, fins of different sizes and long narrow jaws. The largest of them reached a length of about 8 m, but many species were no larger than a person. They were excellent swimmers, feeding mainly on fish, squid and nautiloids. Although ichthyosaurs were reptiles, their fossil remains suggest that they were viviparous, that is, they gave birth to ready-made offspring, like mammals. Perhaps ichthyosaur babies were born on the open sea, like whales.
Another group predatory reptiles, also widespread in the Jurassic seas, are plesiosaurs. Their long-necked varieties lived near the surface of the sea. Here they hunted for schools of very large fish with the help of their flexible necks. Short-necked species, the so-called pliosaurs, preferred life at great depths. They ate ammonites and other mollusks. Some large pliosaurs apparently also hunted smaller plesiosaurs and ichthyosaurs.

Ichthyosaurs looked like exact copies dolphins, except for the shape of the tail and an extra pair of fins. For a long time, scientists believed that all fossil ichthyosaurs they came across had a damaged tail. In the end, they realized that the spine of these animals had a curved shape and at its end there was a vertical tail fin (unlike the horizontal fins of dolphins and whales).
Life in the Jurassic air.

During the Jurassic period, insect evolution accelerated dramatically, and as a result, the Jurassic landscape eventually became filled with the endless buzzing and crackling sounds of many new species of insects crawling and flying everywhere. Among them were predecessors
modern ants, bees, earwigs, flies and wasps. Later, in the Cretaceous period, a new evolutionary explosion occurred when insects began to “establish contacts” with newly emerging flowering plants.
Until this time, real flying animals were found only among insects, although attempts to master air environment were also observed in other creatures that learned to plan. Now whole hordes of pterosaurs have taken to the air. These were the first and largest flying vertebrates. Although the first pterosaurs appeared at the end of the Triassic, their true “takeoff” occurred precisely in the Jurassic period. The lung skeletons of pterosaurs consisted of hollow bones. The first pterosaurs had tails and teeth, but in more highly developed individuals these organs disappeared, which made it possible to significantly reduce their own weight. Some fossil pterosaurs have visible hair. Based on this, it can be assumed that they were warm-blooded.
Scientists still disagree about the lifestyle of pterosaurs. For example, it was originally believed that pterosaurs were a kind of “living gliders” that hovered, like vultures, above the ground in currents of rising hot air. Perhaps they even glided above the surface of the ocean, driven by sea winds, like modern albatrosses. However, some experts now believe that pterosaurs could flap their wings, that is, actively fly, like birds. Perhaps some of them even walked like birds, while others dragged their bodies along the ground or slept in the nesting areas of their relatives, hanging upside down, like bats.

Data obtained from the analysis of fossilized stomachs and droppings (coprolites) of ichthyosaurs indicate that their diet consisted mainly of fish and cephalopods(ammonites, nautiloids and squids). The contents of the stomachs of ichthyosaurs allowed us to make an even more interesting discovery. Small hard spines on the tentacles of squids and other cephalopods, apparently, caused ichthyosaurs a lot of inconvenience, since they were not digested and, accordingly, could not pass freely through them. digestive system. As a result, the thorns accumulated in the stomach, and from them scientists are able to find out what a given animal has eaten throughout its life. Thus, when studying the stomach of one of the fossil ichthyosaurs, it turned out that it swallowed at least 1,500 squids!
How birds learned to fly.

There are two main theories that try to explain how birds learned to fly. One of them claims that the first flights took place from the bottom up. According to this theory, it all started with bipedal animals, the predecessors of birds, running and jumping high into the air. Perhaps this is how they tried to escape from predators, or maybe they caught insects. Gradually, the feathered area of ​​the “wings” became larger, and the jumps, in turn, lengthened. The bird did not touch the ground longer and remained in the air. Add to this the flapping movements of their wings - and it will become clear to you how, after a long time, these “pioneers of aeronautics” learned to remain in flight for a long time, and their wings little by little acquired properties that allowed them to support their bodies in the air.
However, there is another theory, the opposite, according to which the first flights took place from top to bottom, from trees to the ground. Potential “flyers” had to first climb to a considerable height, and only then throw themselves into the air. In this case, the first step on the path to flight should have been planning, since with this type of movement the energy consumption is extremely insignificant - in any case, much less than with the “running-jumping” theory. The animal does not need to make additional efforts, because when gliding it is pulled down by the force of gravity.

The first fossil of Archeopteryx was discovered two years after the publication of Charles Darwin's book On the Origin of Species. This important discovery was further confirmation of Darwin's theory, which stated that evolution occurs very slowly and that one group of animals gives rise to another, undergoing a series of successive transformations. Famous scientist and close friend Darwin, Thomas Huxley, predicted the existence of an animal similar to Archeopteryx in the past, even before its remains fell into the hands of scientists. In fact, Huxley described this animal in detail when it had not yet been discovered!
Step flight.

One scientist proposed an extremely interesting theory. It describes a series of stages through which the "pioneers of aeronautics" must have passed during the evolutionary process that eventually turned them into flying animals. According to this theory, once upon a time one of the groups of small reptiles, called pro-topbirds, switched to an arboreal lifestyle. Perhaps the reptiles climbed into the trees because it was safer there, or it was easier to get food, or it was more convenient to hide, sleep, or build nests. It was cooler in the treetops than on the ground, and these reptiles developed warm-bloodedness and feathers for better thermal insulation. Any extra long feathers on the limbs were useful - after all, they provided additional thermal insulation and increased the surface area of ​​the wing-shaped “arms”.
In turn, the soft, feathered forelimbs softened the impact on the ground when the animal lost its balance and fell from the ground. tall tree. They slowed down the fall (acting as a parachute), and also provided a more or less soft landing, serving as a natural shock absorber. Over time, these animals began to use feathered limbs as proto-wings. Further transition from para-
The transition from the gliding stage to the gliding stage should have been a completely natural evolutionary step, after which it was the turn of the last, flight, stage, which Archeopteryx almost certainly reached.

"Early" bird
The first birds appeared on Earth towards the end of the Jurassic period. The oldest of them, Archeopteryx, looked more like a small feathered dinosaur than a bird. She had teeth and a long, bony tail adorned with two rows of feathers. Three clawed fingers protruded from each of its wings. Some scientists believe that Archeopteryx used its clawed wings to climb trees, from where it periodically flew back to the ground. Others believe that he lifted himself off the ground using gusts of wind. In the process of evolution, bird skeletons became lighter, and toothed jaws were replaced by toothless beaks. They developed a wide sternum, to which powerful muscles necessary for flight were attached. All these changes made it possible to improve the structure of the bird’s body, giving it a structure optimal for flight.
The first fossil find of Archeopteryx was a single feather, discovered in 1861. Soon, a complete skeleton of this animal (with feathers!) was found in the same area. Since then, six fossilized skeletons of Archeopteryx have been discovered: some complete, others only fragmentary. The last such find dates back to 1988.

Age of dinosaurs.

The very first dinosaurs appeared more than 200 million years ago. Over the 140 million years of their existence, they have evolved into many different species. Dinosaurs spread across all continents and adapted to life in a wide variety of habitats, although none of them lived in burrows, climbed trees, flew or swam. Some dinosaurs were no larger than squirrels. Others weighed more than fifteen adult elephants combined. Some were swaying heavily on all fours. Others ran on two legs faster than Olympic champions in a sprint.
65 million years ago, all dinosaurs suddenly went extinct. However, before they disappeared from the face of our planet, they left us in the rocks a detailed “report” about their life and their time.
The most common group of dinosaurs in the Jurassic period were prosauropods. Some of them developed into the largest land animals of all time - sauropods ("lizard-footed"). These were the "giraffes" of the dinosaur world. They probably spent all their time eating leaves from the treetops. To provide vital energy Such a huge body required an incredible amount of food. Their stomachs were capacious digestive containers that continuously processed mountains of plant food.
Later, many varieties of small, fleet-footed dinos appeared.
saurs - the so-called hadrosaurs. These were the gazelles of the dinosaur world. They nibbled low-growing vegetation with their horny beaks and then chewed it with their strong molars.
The largest family of large carnivorous dinosaurs were the megalosaurids, or "huge lizards." The megalosaurid was a monster weighing a ton, with huge, sharp saw-like teeth with which it tore the flesh of its victims. Judging by some of the fossilized footprints, his toes were turned inward. It may have waddled around like a giant duck, swinging its tail from side to side. Megalosaurids populated all areas globe. Their fossil remains have been found in places as far apart as North America, Spain and Madagascar.
The early species of this family were, apparently, relatively small animals of fragile build. And later megalosaurids became truly bipedal monsters. Their hind legs ended in three toes armed with powerful claws. Muscular forelimbs helped in hunting large plant-eating dinosaurs. The sharp claws undoubtedly left terrible lacerations in the side of the surprised victim. The powerful muscular neck of the predator allowed it to plunge its dagger-shaped fangs deep into the body of its prey with terrible force and tear out huge pieces of still warm meat.

In the Jurassic period, packs of Allosaurus roamed most of the earth's land. They, apparently, were a nightmarish sight: after all, each member of such a flock weighed more than a ton. Together, allosaurs could easily defeat even a large sauropod.

, conglomerates formed in a variety of conditions.

Jurassic System Division

The Jurassic system is divided into 3 divisions and 11 tiers:

system	Department	tier	Age, million years ago
Chalk	Lower	Berriasian	less
Yura	Upper (malm)	Titonian	152,1-145,0
		Kimmeridge	157,3-152,1
		Oxford	163,5-157,3
	Average (dogger)	Callovian	166,1-163,5
		Bathian	168,3-166,1
		Bayocian	170,3-168,3
		Aalensky	174,1-170,3
	Lower (lias)	Toarsky	182,7-174,1
		Pliensbachian	190,8-182,7
		Sinemyursky	199,3-190,8
		Hettangian	201,3-199,3
Triassic	Upper	Rhetic	more
Divisions are given according to IUGS as of April 2016

Geological events

213-145 million years ago, the single supercontinent Pangea began to break up into separate continental blocks. Shallow seas formed between them.

Climate

The climate in the Jurassic period was humid and warm (and by the end of the period - arid in the equator region).

Vegetation

During the Jurassic, vast areas were covered with lush vegetation, primarily diverse forests. They mainly consisted of ferns and gymnosperms.

Land animals

One of the fossil creatures that combines the characteristics of birds and reptiles is Archeopteryx, or the first bird. His skeleton was first discovered in the so-called lithographic shales in Germany. The discovery was made two years after the publication of Charles Darwin's work "On the Origin of Species" and became a strong argument in favor of the theory of evolution - it was initially considered a transitional form from reptiles to birds (in fact, it was a dead-end branch of evolution, not directly related to real birds) . Archeopteryx flew rather poorly (gliding from tree to tree), and was approximately the size of a crow. Instead of a beak, it had a pair of toothy, albeit weak, jaws. It had free fingers on its wings (of modern birds, only hoatzin chicks have them).

During the Jurassic period, small, furry, warm-blooded animals called mammals lived on Earth. They live next to dinosaurs and are almost invisible against their background. During the Jurassic period, the division of mammals into monotremes, marsupials and placentals occurred.

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Notes

Literature

• Iordansky N. N. Development of life on earth. - M.: Education, 1981.
• Karakash N. I. ,. Jurassic system and period // Encyclopedic Dictionary of Brockhaus and Efron: in 86 volumes (82 volumes and 4 additional). - St. Petersburg. , 1890-1907.
• 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

• - Site about the Jurassic period, a large library of paleontological books and articles.

←	P A l e O h O th	Mesozoic (252.2-66.0 million years ago)			TO A th n O h O th	→
←		Triassic (252,2-201,3)	Jurassic period (201,3-145,0)	Cretaceous period (145,0-66,0)		→

An excerpt characterizing the Jurassic period

The trees stood bare and featureless, lazily moving their drooping, thorny branches. Further behind them stretched the joyless, burnt-out steppe, getting lost in the distance behind a wall of dirty, gray fog... Many gloomy, drooping human beings restlessly wandered back and forth, senselessly looking for something, not paying any attention to the world around them, which, and however, it did not evoke the slightest pleasure so that one would want to look at it... The whole landscape evoked horror and melancholy, seasoned with hopelessness...
“Oh, how scary it is here...” Stella whispered, shuddering. – No matter how many times I come here, I just can’t get used to it... How do these poor things live here?!
– Well, probably these “poor things” were too guilty once if they ended up here. No one sent them here - they just got what they deserved, right? – still not giving up, I said.
“But now you’ll look...” Stella whispered mysteriously.
A cave overgrown with grayish greenery suddenly appeared in front of us. And out of it, squinting, came a tall, stately man who in no way fit into this wretched, chilling scenery...
- Hello, Sad! – Stella greeted the stranger affectionately. - I brought my friend! She doesn't believe what can be found here good people. And I wanted to show you to her... You don’t mind, do you?
“Hello, dear...” the man answered sadly, “But I’m not that good to show off to anyone.” You're wrong...
Oddly enough, I actually immediately liked this sad man for some reason. He exuded strength and warmth, and it was very pleasant to be around him. In any case, he was in no way like those weak-willed, grief-stricken people who surrendered to the mercy of fate, with whom this “floor” was chock-full.
“Tell us your story, sad man...” Stella asked with a bright smile.
“There’s nothing to tell, and there’s nothing particularly to be proud of...” the stranger shook his head. - And what do you need this for?
For some reason, I felt very sorry for him... Without knowing anything about him, I was already almost sure that this man could not have done anything truly bad. Well, I just couldn’t!.. Stela, smiling, followed my thoughts, which she apparently really liked...
“Well, okay, I agree - you’re right!..” Seeing her happy face, I finally honestly admitted.
“But you don’t know anything about him yet, but with him everything is not so simple,” Stella said, smiling slyly and contentedly. - Well, please tell her, Sad...
The man smiled sadly at us and said quietly:
– I’m here because I killed... I killed many. But it was not out of desire, but out of need...
I was immediately terribly upset - he killed!.. And I, stupid, believed it!.. But for some reason I stubbornly did not have the slightest feeling of rejection or hostility. I clearly liked the person, and no matter how hard I tried, I couldn’t do anything about it...
- Is it really the same guilt - to kill at will or out of necessity? – I asked. – Sometimes people have no choice, do they? For example: when they have to defend themselves or protect others. I have always admired heroes - warriors, knights. I generally always adored the latter... Is it possible to compare simple murderers with them?
He looked at me for a long time and sadly, and then also quietly answered:
- I don’t know, dear... The fact that I am here says that the guilt is the same... But the way I feel this guilt in my heart, then no... I never wanted to kill, I just defended my land, I was a hero there... But here it turned out that I was just killing... Is this right? I think no...
- So you were a warrior? – I asked hopefully. - But then, this is a big difference - you defended your home, your family, your children! And you don’t look like a murderer!..
- Well, we are all not like the way others see us... Because they see only what they want to see... or only what we want to show them... And about the war - I also first just as you thought, you were even proud... But here it turned out that there was nothing to be proud of. Murder is murder, and it doesn’t matter how it was committed.
“But this is not right!..” I was indignant. - What happens then - a maniac-killer turns out to be the same as a hero?!.. This simply cannot be, this should not happen!
Everything inside me was raging with indignation! And the man sadly looked at me with his sad, gray eyes, in which understanding was read...
“A hero and a murderer take lives in the same way.” Only, probably, there are “extenuating circumstances,” since a person protecting someone, even if he takes a life, does so for a bright and righteous reason. But, one way or another, they both have to pay for it... And it’s very bitter to pay, believe me...
– Can I ask you how long ago you lived? – I asked, a little embarrassed.
- Oh, quite a long time ago... This is the second time I’m here... For some reason, my two lives were similar - in both of them I fought for someone... Well, and then I paid... And it’s always just as bitter ... – the stranger fell silent for a long time, as if not wanting to talk about it anymore, but then he quietly continued. – There are people who love to fight. I always hated it. But for some reason, life is returning me to the same circle for the second time, as if I was locked in this, not allowing me to free myself... When I lived, all our peoples fought among themselves... Some seized foreign lands - others they defended the lands. Sons overthrew fathers, brothers killed brothers... Anything happened. Someone accomplished unimaginable feats, someone betrayed someone, and someone turned out to be simply a coward. But none of them even suspected how bitter the payment would be for everything they had done in that life...
– Did you have family there? – to change the subject, I asked. - Were there children?
- Certainly! But that was already so long ago!.. They once became great-grandfathers, then they died... And some are already living again. That was a long time ago...
“And you’re still here?!..” I whispered, looking around in horror.
I couldn’t even imagine that he had been existing here like this for many, many years, suffering and “paying” his guilt, without any hope of leaving this terrifying “floor” even before the time came for him to return to the physical Earth!.. And there he will again have to start all over again, so that later, when his next “physical” life ends, he will return (perhaps here!) with a whole new “baggage”, bad or good, depending on how he will live his “next” earthly life... And he could not have any hope of freeing himself from this vicious circle (be it good or bad), since, having begun his earthly life, each person “dooms” himself to this endless, eternal circular “journey”... And, depending on his actions, returning to the “floors” can be very pleasant, or very scary...

Geological events

213-145 million years ago, the single supercontinent Pangea began to break up into separate continental blocks. Shallow seas formed between them.

Climate

The climate in the Jurassic was highly variable.

From the Aalenian to the Bathonian ages, the climate was warm and humid. Then there was glaciation, which took most Callovian, Oxfordian and the beginning of the Kimmeridgian, and then the climate warmed again.

Vegetation

During the Jurassic, vast areas were covered with lush vegetation, primarily diverse forests. They mainly consisted of ferns and gymnosperms.

Land animals

One of the fossil creatures that combines characteristics of birds and reptiles is Archeopteryx. His skeleton was first discovered in the so-called lithographic shales in Germany. The discovery was made two years after the publication of Charles Darwin's On the Origin of Species and became a strong argument in favor of the theory of evolution - it was initially considered a transitional form from reptiles to birds. But later it was also proposed that this was a dead-end branch of evolution, not directly related to real birds. Archeopteryx flew rather poorly (gliding from tree to tree), and was approximately the size of a crow. Instead of

According to modern ideas of scientists, the geological history of our planet is 4.5-5 billion years. In the process of its development, it is customary to distinguish geological periods Earth.

general information

The geological periods of the Earth (the table below) represent the sequence of events that occurred during the development of the planet from the moment of its formation earth's crust. Over time, various processes occur on the surface, such as the emergence and destruction of land areas submerged under water and their uplift, glaciation, as well as the appearance and disappearance of different species of plants and animals, etc. Our planet bears obvious traces of its formation. Scientists claim that they are able to record them with mathematical accuracy in different layers of rocks.

Main groups of sediments

Geologists, trying to reconstruct the history of the planet, study rock layers. It is customary to divide these deposits into five main groups, highlighting the following geological eras Earth: ancient (Archaean), early (Proterozoic), ancient (Paleozoic), middle (Mesozoic) and new (Cenozoic). It is believed that the border between them runs along the largest evolutionary phenomena that occurred on our planet. The last three eras, in turn, are divided into periods, since the remains of plants and animals are most clearly preserved in these deposits. Each stage is characterized by events that had a decisive influence on the current topography of the Earth.

The oldest stage

The Earth was characterized by rather violent volcanic processes, as a result of which igneous granite rocks appeared on the surface of the planet - the basis for the formation of continental plates. At that time, only microorganisms existed here that could do without oxygen. It is assumed that the deposits Archean era cover individual areas of the continents with an almost complete shield; they contain a lot of iron, silver, platinum, gold and ores of other metals.

Early stage

It is also characterized by high volcanic activity. During this period, the mountain ranges of the so-called Baikal fold were formed. They have practically not survived to this day; today they represent only isolated insignificant rises on the plains. During this period, the Earth was inhabited by simple microorganisms and blue-green algae, and the first multicellular organisms appeared. The Proterozoic rock layer is rich in minerals: mica, non-ferrous metal ores and iron ores.

Ancient stage

The first period of the Paleozoic era was marked by the formation of mountain ranges. This led to a significant reduction in sea basins, as well as the emergence of huge areas of land. Individual ridges of that period have survived to this day: in the Urals, Arabia, Southeast China and Central Europe. All these mountains are “worn out” and low. The second half of the Paleozoic is also characterized by mountain-building processes. Ranges were formed here. This era was more powerful; vast mountain ranges arose in the territories of the Urals and Western Siberia, Manchuria and Mongolia, Central Europe, as well as Australia and North America. Today they are represented by very low blocky massifs. Animals of the Paleozoic era are reptiles and amphibians, the seas and oceans are inhabited by fish. Among flora algae predominated. Palaeozoic It is characterized by large deposits of coal and oil that arose during this era.

Middle stage

The beginning of the Mesozoic era is characterized by a period of relative calm and gradual destruction of mountain systems created earlier, and the immersion of lowland areas (part of Western Siberia) under water. The second half of this period was marked by the formation of the Mesozoic folding ridges. Very vast mountainous countries appeared, which still have the same appearance today. An example is the mountains Eastern Siberia, Cordillera, parts of Indochina and Tibet. The earth was densely covered with lush vegetation, which gradually died and rotted. Thanks to the hot and humid climate active formation of peat bogs and swamps took place. This was the era of giant lizards - dinosaurs. The inhabitants of the Mesozoic era (herbivores and predators) spread throughout the entire planet. At the same time, the first mammals appeared.

New stage

The Cenozoic era, which replaced the middle stage, continues to this day. The beginning of this period was marked by an increase in the activity of the internal forces of the planet, which led to a general uplift of huge areas of land. This era is characterized by the emergence of mountain ranges within the Alpine-Himalayan belt. During this period, the Eurasian continent acquired its modern shape. In addition, there was a significant rejuvenation of the ancient massifs of the Urals, Tien Shan, Appalachians and Altai. The climate on Earth changed sharply, and periods of powerful ice sheets began. The movements of glacial masses changed the topography of the continents. As a result, hilly plains with a huge number of lakes were formed. Animals Cenozoic era- these are mammals, reptiles and amphibians, many representatives of the initial periods have survived to this day, others have become extinct (mammoths, woolly rhinoceroses, saber tooth tigers, cave bears and others) for one reason or another.

What is a geological period?

The geological stage as a unit of our planet is usually divided into periods. Let's see what the encyclopedia says about this term. Period (geological) is a large interval of geological time during which formations were formed. rocks. In turn, it is subdivided into smaller units, which are commonly called epochs.

The first stages (Archean and Proterozoic), due to the complete absence or insignificant amount of animal and plant deposits in them, are not usually divided into additional areas. The Paleozoic era includes the Cambrian, Ordovician, Silurian, Devonian, Carboniferous and Permian periods. This stage is characterized the largest number subintervals, the rest were limited to only three. The Mesozoic era includes the Triassic, Jurassic and Cretaceous stages. The Cenozoic era, the periods of which are the most studied, is represented by the Paleogene, Neogene and Quaternary subinterval. Let's take a closer look at some of them.

Triassic

The Triassic period is the first subinterval of the Mesozoic era. Its duration was about 50 million years (beginning 251-199 million years ago). It is characterized by renewal of marine and terrestrial fauna. At the same time, a few representatives of the Paleozoic continue to exist, such as spiriferids, tabulates, some elasmobranchs, etc. Among invertebrates, ammonites are very numerous, giving rise to many new forms important for stratigraphy. Six-rayed forms predominate among corals, among brachiopods - terebratulides and rhynchonelids, in the group of echinoderms - sea ​​urchins. Vertebrates are mainly represented by reptiles - large lizard-hipped dinosaurs. Thecodonts are widely distributed - fast-moving land reptiles. Besides, in Triassic appear first large inhabitants aquatic environment - ichthyosaurs and plesiosaurs, but they reached their peak only in the Jurassic period. Also at this time, the first mammals arose, which were represented by small forms.

Flora during the Triassic (geological) period loses Paleozoic elements and acquires an exclusively Mesozoic composition. Fern plant species, sago, conifers and ginkgos predominate here. Climatic conditions characterized by significant warming. This leads to the drying out of many inland seas, and in the remaining ones the salinity level increases significantly. In addition, the areas of inland water bodies are greatly reduced, resulting in the development of desert landscapes. For example, the Tauride formation of the Crimean Peninsula belongs to this period.

Yura

The Jurassic period gets its name from the Jurassic Mountains in Western Europe. It constitutes the middle part of the Mesozoic and most closely reflects the main features of the development of organic matter of this era. In turn, it is usually divided into three sections: lower, middle and upper.

The fauna of this period is represented by widespread invertebrates - cephalopods (ammonites, represented by numerous species and genera). In terms of sculpture and the nature of their shells, they differ sharply from the representatives of the Triassic. In addition, during the Jurassic period, another group of mollusks flourished - belemnites. At this time, six-rayed reef-building corals, lilies and urchins, as well as numerous elasmobranchs, reach significant development. But the Paleozoic brachiopod species completely disappear. Marine fauna vertebrate species differs significantly from the Triassic, it reaches enormous diversity. During the Jurassic period, fish, as well as aquatic reptiles - ichthyosaurs and plesiosaurs, were widely developed. At this time, the transition from land and adaptation to marine environment crocodiles and turtles. Various types of terrestrial vertebrates - reptiles - achieve enormous diversity. Among them, dinosaurs come to their heyday, which are represented by herbivores, predators and other forms. Most of them reach 23 meters in length, for example, Diplodocus. In sediments of this period it is found the new kind reptiles - flying lizards, which are called "pterodactyls". At the same time, the first birds appear. The Jurassic flora reaches a lush flourishing: gymnosperms, ginkgos, cycads, conifers (araucarias), bennettites, cycads and, of course, ferns, horsetails and mosses.

Neogene

The Neogene period is the second period of the Cenozoic era. It began 25 million years ago and ended 1.8 million years ago. At this time, significant changes occurred in the composition of the fauna. A wide variety of gastropods and bivalves, corals, foraminifera and coccolithophores emerge. Amphibians have developed widely, sea ​​turtles and bony fish. IN Neogene period Terrestrial vertebrate forms also reach great diversity. For example, rapidly progressing hipparion species appeared: hipparions, horses, rhinoceroses, antelopes, camels, proboscideans, deer, hippopotamuses, giraffes, rodents, saber-toothed tigers, hyenas, apes and others.

Under the influence of various factors, the organic world is rapidly evolving at this time: forest-steppes, taiga, mountain and lowland steppes appear. In tropical areas - savannas and rain forests. Climatic conditions are approaching modern ones.

Geology as a science

The geological periods of the Earth are studied by the science of geology. It appeared relatively recently - at the beginning of the 20th century. However, despite her youth, she was able to shed light on many controversial issues about the formation of our planet, as well as the origin of the creatures inhabiting it. There are few hypotheses in this science; mostly only observational results and facts are used. There is no doubt that the traces of the planet’s development stored in the earth’s layers will in any case provide a more accurate picture of the past than any written book. However, not everyone can read these facts and understand them correctly, so even in this exact science, erroneous interpretations of certain events may arise from time to time. Where traces of fire are present, it can be confidently stated that there was fire; and where there are traces of water, we can say with equal confidence that there was water, and so on. And yet, mistakes also happen. In order not to be unfounded, let's consider one such example.

"Frosty patterns on glass"

In 1973, the magazine “Knowledge is Power” published an article by the famous biologist A. A. Lyubimtsev “ Frost patterns on the glass." In it, the author draws readers' attention to the striking similarity of ice patterns with plant structures. As an experiment, he photographed the pattern on the glass and showed the photograph to a botanist he knew. And without hesitation he recognized the fossilized footprint of a thistle in the photograph. From a chemical perspective, these patterns arise due to gas-phase crystallization of water vapor. However, something similar happens when producing pyrolytic graphite by pyrolysis of methane diluted with hydrogen. Thus, it was found that dendritic forms are formed away from this flow, which are very similar to plant remains. This is explained by the fact that there are general laws that govern the formation of forms in inorganic matter and living nature.

For a long time, geologists dated each geological period based on traces of plant and animal forms found in coal deposits. And only a few years ago, statements by some scientists appeared that this method was incorrect and that all the fossils found were nothing more than a by-product of the formation earth layers. There is no doubt that everything cannot be measured equally, but it is necessary to approach dating issues more carefully.

Was there a worldwide glaciation?

Let's consider another categorical statement by scientists, and not only geologists. All of us, starting from school, were taught about the worldwide glaciation that covered our planet, as a result of which many species of animals became extinct: mammoths, woolly rhinoceroses and many others. And the modern younger generation is being brought up on the Ice Age quadrology. Scientists unanimously assert that geology is an exact science that does not allow theories, but uses only verified facts. However, this is not the case. Here, as in many areas of science (history, archeology and others), one can observe the ossification of theories and the unshakability of authorities. For example, since the end of the nineteenth century, there have been heated debates on the sidelines of science about whether glaciation occurred or not. In the mid-twentieth century, the famous geologist I. G. Pidoplichko published a four-volume work “On ice age" In this work, the author gradually proves the inconsistency of the version of global glaciation. He does not rely on the works of other scientists, but on the geological excavations he personally carried out (and some of them he carried out as a soldier of the Red Army, participating in battles against the German invaders) throughout the territory Soviet Union And Western Europe. He proves that the glacier could not cover the entire continent, but was only local in nature, and that it was not it that caused the extinction of many species of animals, but completely different factors - these are catastrophic events that led to the displacement of the poles (“Sensational History of the Earth”, A . Sklyarov); And economic activity the person himself.

Mysticism, or Why Scientists Don't Notice the Obvious

Despite the irrefutable evidence provided by Pidoplichko, scientists are in no hurry to abandon the accepted version of glaciation. And then it gets even more interesting. The author's works were published in the early 50s, but with the death of Stalin, all copies of the four-volume work were confiscated from the country's libraries and universities, preserved only in the library storerooms, and obtaining them from there is very difficult. IN Soviet time everyone who wanted to borrow this book from the library was registered by the secret services. And even today there are certain problems in obtaining this printed publication. However, thanks to the Internet, anyone can familiarize themselves with the works of the author, who analyzes the periods in detail geological history planets, explains the origin of certain traces.

Is geology an exact science?

It is believed that geology is an exclusively experimental science that draws conclusions only from what it sees. If the case is doubtful, then she does not assert anything, expresses an opinion that allows for discussion, and postpones the final decision until unambiguous observations are received. However, as practice shows, exact sciences also make mistakes (for example, physics or mathematics). Nevertheless, mistakes are not a disaster if they are accepted and corrected in a timely manner. Often they are not global in nature, but have local significance; you just need to have the courage to accept the obvious, draw the right conclusions and move on, towards new discoveries. Modern scientists show radically opposite behavior, because most of the luminaries of science at one time received titles, awards and recognition for their activities, and today they do not want to part with them. And this behavior has been noticed not only in geology, but also in other fields of activity. Only strong people are not afraid to admit their mistakes; they rejoice at the opportunity to develop further, because discovering a mistake is not a disaster, but, on the contrary, a new opportunity.