Why dinosaurs became extinct: a parade of hypotheses

During the existence of dinosaurs, dozens of their species disappeared, replacing new ones (the average life expectancy of the species was 2-3 million years). But the end of the Cretaceous period (65 million years ago) was marked by the final and irrevocable death of huge lizards the inhabitants of the Earth, the sky and the ocean.

So, a certain catastrophe burst out on the whole planet, leaving not a single or not a single “island of salvation” for outlandish reptiles. Why dinosaurs died out? Why did it happen? To explain this cataclysm, many hypotheses were put forward.

First: Asteroid killer

Astronomers say: an asteroid with a diameter of 10-20 km hit the surface of the Earth in Central America in the area of ​​the Yukatan peninsula. From this blow, a gigantic cloud of dust rose into the air, which closed the sun and blocked the flow of light and heat to the surface of the earth. As a result ecological disaster.

Evidence of such an event is the so-called iridium anomaly an unusually high content of the chemical element iridium in rocks formed about 65 million years ago. Since iridium is found in large quantities in meteorites, it can be assumed that a collision occurred the Earth collided precisely with a large celestial body ..

For proponents of the new impact theory, the boundary layer boundary contains two key clues. In 1979. scientists discovered that there was a high concentration of a rare element iridium. According to scientists, iridium can only be formed from the fall of an asteroid. Iridium was in the rocks, which looked like “balls” that arose under the influence of the enormous pressure of the shock wave during the fall of an asteroid.

Based on the presence of balls, as well as a number of other evidence, Dr. Alan Hildebrand of the University of Calgary concludes that the impact occurred in the Yucatan Peninsula region, forming the crater known today as Chicxulub. Chemical analysis later confirmed that the balls did in fact originate from the rocks of the crater.

The impact theory seemed to give a complete answer to the question of the death of dinosaurs. So, Hildebrand and other supporters of the impact theory argued that the event that occurred 65 million years ago (the fall of an asteroid), and the consequences of this event, caused the death of dinosaurs.

Chicxulub crater in the Yucatan

  

But a group of scientists led by Professor Geert Keller of Princeton University and Professor Wolfgang Stinisbeck of the University of Karlsruhe are in no hurry to agree with the conclusions of Hildebrand’s theory. They found a number of geological inconsistencies that suggest the truth could be much more complicated. In short, the crater in the Yucatan is too old to be the cause of the death of the dinosaurs.

They focused their research on a number of rocks in Mexico, where the layer of iridium was separated from the balls by many meters of sandstone. This study has been criticized by impact theorists. Thus, Professor Ian Smith from the University of Vrij (Amsterdam) argued that the sandstone layer was formed by massive tsunami waves caused by an asteroid impact, and does not undermine the idea of ​​a single impact.

But another group scientists led by Keller found evidence such as ancient worm burrows they suggested that the sandstone deposits were not continuous, but were separated by fossil worm burrows. They concluded that there was a gap of about 300,000. years between the deposition of the balls (from Chicxulub crater) and the deposition of iridium (as part of the asteroid). Therefore, two conclusions can be drawn:

one. Chicxulub crater, they say, was too old to cause the death of dinosaurs.

2. There must have been another strike elsewhere that was responsible for the apocalypse. The crater from the fall of this meteorite has not yet been found.

Keller’s study sparked a lively scientific controversy. In 2001., to try to resolve the dispute, an international team of scientists studied samples from deep within the Yucatan crater. As expected, each side presented evidence to support their theories.

Recently, Keller’s work has received some support. And the circle of scientists expanded, who began to question other hypotheses related to the fall of the asteroid. Claire Belcher of the University of London has found evidence that shows fires were not widespread in North America after the asteroid hit.

Professor Dave Archibald of the University of San Diego is convinced that the survival of creatures such as frogs disproves the idea that dinosaurs died due to acid rain (comparable to battery acid) or that the “exposure” of winter caused a massive and sustained drop in temperature.

Dr Norman McLeod of the Natural History Museum in London is one of a large group of scientists who are convinced that dinosaurs were already on the verge of extinction as a result of climate change, long before the catastrophe caused by the asteroid impact.

Second: biological causes

According to one version, dinosaurs could well fall victim to poisoning by plants, which, defending themselves from destruction, adapted and began to contain poisonous alkaloids. The cause of extinction could also be epidemics, imbalance between the sexes, or starvation due to the extinction of certain plant species. In addition, active mammals played a role, which ate dinosaur eggs with appetite.

Third: bad ecology

One theory claims that dinosaurs died of suffocation because the amount of oxygen in the atmosphere decreased. As studies of fossil amber have shown, there was indeed a significant decrease in oxygen levels in the atmosphere at that time. It is possible that the poor animal had nothing to breathe due to volcanic activity or exposure to toxic gases from a celestial body flying near the Earth (for example, a comet).

Studies by American researchers Hertha Keller and her colleagues confirm this version, since a similar volcanic eruption under the Indian Ocean several million years before the death of dinosaurs had the same devastating impact on the environment. However, in the case of dinosaurs, there is no evidence of an asteroid impact at the time in question.

Fourth: extraterrestrial invasion

The extinction of dinosaurs could be caused by a collision with extraterrestrial life forms, alien viruses, or “Martians” who attacked Earth. Also, the dominance of the giants could be interrupted by a supernova explosion, an increase in radiation from the death (collapse) of a star, the intersection of the solar system with the plane of the galaxy, and even a shift in the Earth’s axis of rotation.

Fifth: carbon dioxide is a killer

Moscow researcher Vitaly Frolov offers his vision of the problem. His reasoning goes like this. There was a time on Earth when the atmosphere contained almost the same amount of oxygen and carbon dioxide about 10% each. That was the realm of organic life. Giant plants grew on land and in shallow water, the remains of which are the current coal.

But remember what all plants are made of? Mainly from water and fiber. What is fiber? Carbohydrate, i.e. carbon plus water. Where do plants get carbon to build their bodies?? From the atmosphere. They absorb carbon dioxide and, with the help of sunlight and water, synthesize sugars, starches and fiber, as well as proteins and fats from it. What are animals made of?? Mainly from proteins and fats, which also represent a polymer chain of carbon, nitrogen, sulfur, phosphorus and oxygen atoms.

These substances appear in animals mainly from food (vegetable or animal). Thus, the riot of life in that period was determined only by the high content of carbon dioxide. You can fantasize a lot about how that life would have evolved if there hadn’t been a sharp (for several decades, thousands of times!) reduction of carbon dioxide content in the Earth’s atmosphere.

The world ocean in the epoch under consideration was acidic due to the high residual content of sulfur released from the bowels of the Earth in an earlier epoch and its oxidation products. Augulex gas, as you know, is poorly dissolved in an acidic environment. Continuous showers washed off the salts of sodium, potassium, magnesium and calcium into the ocean.

As a result, the acidity of the water began to decrease and carbon dioxide began to dissolve in it, but from this its content in the atmosphere did not decrease. And this happened until the evolution produced microorganisms that began to build protective shells from carbon dioxide and magnesium.

In the conditions of excess building material, a chain reaction of the propagation of these microorganisms began, their demographic explosion. Carbon dioxide from the solution was rapidly converted into material for shells, and gas from the atmosphere passed into the solution to replace it to the solution. Already decades later, the content of carbon dioxide in the atmosphere almost reached the modern level, the bulk of the microorganisms died out, forming the enormous deposits of limestone. On land, plants that did not adapt to such a low ration died. It got colder. Did dinosaur eggs stop hatching?.

Sixth: dinosaurs killed … people

According to official science, giant lizards died out more than 70 million years before the first ancient people appeared on Earth. But … why then among the ancient images on the stones from the town of Ica in Peru and the clay products of Acambaro in Mexico there are images of lizards next to people?

Figurines from Acambaro

 

Why are the legends and fairy tales of many peoples (including Russian) describe in detail the battles of heroes and knights with dragons (lizards) and snakes? Why did ancient China have a whole cult of dragons? Perhaps due to the influence of dragon legends, or perhaps after watching science fiction films, but now half of the 2000 randomly polled US citizens believe that prehistoric man could have seen living dinosaurs with his own eyes.

So, on average, half of the enlightened earthlings are sure that our distant ancestors had to fight giant lizards. And… defeat them! There are eyewitnesses who claim that in some places on the Earth dinosaurs exist to this day ..

An interesting discovery belongs to the group of Professor Kurban Amanniyazov, made in 1983. on the plateau of the Kugitantau ridge in Turkmenistan. The scientists found that the surface of the plateau was covered with numerous chains of deep footprints. The fact is that 150-200 million years ago, in the legendary Jurassic period, instead of the high Kugitantau ridge on the territory of present-day Turkmenistan there was a coast of a sea lagoon.

Ornithischian dinosaurs roamed it, whose traces have survived to this day. Thousands of footprints of giant reptiles have been found. But the most amazing lurked inside! Among the numerous three-toed footprints was a chain of well-preserved traces of a human foot of about 43rd size.

The tracks followed each other at a distance of about half a meter, it seems that their owner was running from someone or after someone. At the same time, according to studies, the weight of a person was more than 120 kg. The discovery has baffled all modern paleontology. After all, according to official science, man appeared much later than the dinosaurs. But the age of this escaping (or catching up) person is equal to the age of dinosaurs.

Seventh: the dinosaurs were killed … by the moon

According to some assumptions, our neighbor the Moon appeared from the core of the Earth (there are different hypotheses) on a geological time scale recently: if not in the memory of people, then in the memory of dinosaurs for sure. What it’s like to experience the raging cataclysms that accompany the arrival of such a massive celestial body? The consequences were so catastrophic that the civilization of dinosaurs simply did not survive this ..

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