There are very few impact craters, or, as they are called, multi-ringed, ringed, on Earth. They are more characteristic of other planets in the solar system. The most famous crater of this kind is Valhalla, located on Callisto, a moon of Jupiter. And on Earth, all traces of the meetings of the Earth with heavenly wanderers, as a rule, are destroyed by erosion and tectonic processes.
Valhalla crater on Callisto
So, craters on the surface(this is the topic of the article) testify to the repeated collision of asteroids with our planet (about 175 confirmed meteorite craters are known on Earth). Millions, and in some cases even billions of years of erosion, do not allow us to accurately determine the size of the fallen celestial bodies, but the largest of them are well known.
Now, in the database compiled by the Siberian Center for the Study of Global Catastrophes, there are more than 800 geological formations that, with varying degrees of certainty, can be considered meteorite craters. The largest ones have a diameter of more than a thousand kilometers, and the smallest ones are measured in tens of meters. In fact, apparently, there are a lot more meteorite wounds on the body of the Earth, just not all of them are still open.
Wilkes Land Crater
Wilkes Land Crater is a geological formation located under the ice sheet of Antarctica, in the region of Wilkes Land, with a diameter of about 500 km. It is assumed that this is a giant meteorite crater.
Since the structure is located under the Antarctic ice sheet, direct observations of it are not yet possible. If this formation is indeed an impact crater, then the meteorite that created it was about 6 times larger than the meteorite that created the Chicxulub crater, which is believed to have caused the mass extinction at the Cretaceous-Cenozoic border (Cretaceous-Paleogene extinction).
According to scientists, the collision of the Earth with this meteorite caused the Permian-Triassic extinction about 250 million years ago. The one that gave the "green light" to the dinosaurs and marked the beginning of the era of their prosperity on the planet. Up to 90 percent of all living beings died out! If there had been a civilization at that time, it would no doubt have perished. Well, with shellfish and primitive fish, they somehow got along. Evolution went even faster, after that mammals appeared ...
The size and location of the crater also suggests that its formation caused the breakup of the Gondwana supercontinent, creating a tectonic fissure that pushed Australia north.
“The crater on the Yucatan Peninsula, the appearance of which 65 million years ago put an end to the history of giant reptiles, is about two to three times smaller than the Antarctic one,”
The researchers note.
Wilkes Land, located between 150 and 90 E, occupies approximately 1/5 of the entire area of Antarctica. Here, outlet and shelf glaciers impede the movement of research teams. In the sea near the shore opposite Wilkes Land is the South Magnetic Pole. Its approximate coordinates are 65 south latitude. and 140 east
Antarctica - view from space
Vredefort Crater
The Vredefort Crater is an impact crater on Earth, located 120 kilometers from Johannesburg, South Africa. This crater with a diameter of about 300 kilometers occupies 6% of the area of South Africa, which makes it the largest on the planet (not counting the unexplored probable Wilkes Land crater with a diameter of 500 kilometers in Antarctica), and therefore the crater can only be observed on satellite images (unlike small craters, which can be "covered" with a glance).
Named after the city of Vredefort located inside the crater (there are even three cities and a lake in the crater!). In 2005, it was included in the list of UNESCO World Heritage Sites.
Meteorite, from the fall of which one of the main attractions was formed Republic of South Africa, has changed the landscape of the Earth more than all other meteorites. The asteroid was one of the largest ever to come into contact with the planet after its formation; according to modern estimates, its diameter was about 10, possibly 15 kilometers.
It was born more than 2 billion years ago. And it is one of the oldest in the world. He lagged behind with the appearance of only 300 million from the Suoyarvi crater, which is located in Russia.
There is a hypothesis that the energy released as a result of the impact greatly changed the course of evolution of unicellular organisms.
"Kara Crater"
And in Russia, the largest impact crater is the Karsky crater, which is located on the Yugorsky Peninsula, on the shores of Baydaratskaya Bay ...
The territory of Russia is so large that it is here that scientists find most of the largest craters in the world. Calculations by Professor V.L. Masaitis and M.S. Mashchak (St. Petersburg) show that on the territory of Russia and neighboring countries there should have been 1280 astroblems more than 1 km in diameter, not erased by erosion and exposed on the surface. We know so far only 42 meteorite craters in this area (including small ones and those covered by younger sediments).
So you think Tunguska meteorite was great? What about a meteorite that left behind a crater a hundred in diameter? :)
Kara crater with a diameter of about 65 km - 7th largest impact crater in the world, which was formed as a result of a meteorite fall about 70 million years ago, which suggests its connection with the Great Mesozoic extinction - according to researchers, the Kara impact event led to a global natural crisis: the climate on our planet became colder, a mass extinction of organisms began, in including dinosaurs.
It is also possible to identify a chain of coeval impact structures (about 75-65 million years) of one meteorite swarm. This chain begins in Ukraine - the Gusevsky craters (3 km in diameter) and Boltyshsky (25 km) located to the north of it. In the northern Cis-Urals, this chain has its continuation in the form of the Karskaya (62 km) and Ust-Karskaya (>60 km) astroblems; further the flight path of the fireballs passed along the coast of the North. the Arctic Ocean (where traces of the fall have not yet been established), then over the Bering Sea (where a large asteroid supposedly fell) and, finally, ended with the formation of the largest Chicxulub astrobleme in the chain (180 km) on the Yucatan Peninsula and the Gulf of Mexico.
However, the figures for the Kara diameter are not yet accurate: there is a theory that the waters of the Kara Sea hide the true dimensions of the crater - presumably at least 120 kilometers in diameter.
The crater is located in the foothills of the Pai-Khoi ridge, 15 km west of the Kara River. In relief, it is an elongated depression open to the sea. The Kara crater is filled with fragments of rocks formed during the explosion, partially melted down and solidified in the form of a vitreous mass.
The impactites of the Kara structure also contain diamonds. During the impact, coal turned into a high-density X-ray amorphous polymer of carbon and into crystalline diamond - as a result of the impact at the site of the current settlement of Ust-Kara, sea water was thrown tens, hundreds of kilometers away. And at the bottom a funnel with a diameter of 65 km formed - the Kara crater. Part of the fragments of the meteorite, having received the second cosmic speed, went back into space. The rocks at the site where the meteorite fell partially melted. Under the cover of the sea and sea silt, the melt slowly solidified, turning into glass, cementing fragments. Under the influence of ultrahigh explosive pressures, the texture of minerals changed. Today, the surface of the crater is a marshy-lake plain, rising above sea level.
There are two points of view on the size of this structure. According to the first, it consists of two craters - Karsky 60 km in diameter and 25 km Ust-Karsky partially covered by the sea. The main part of the rocks in the form of fragments of various sizes - from dust-like to kilometers, was thrown out of the crater in the form of an explosive column. The rocks constituted allogeneic breccias, i.e., undisplaced impactites. under cover sea waters and silt, the impact melt slowly solidified, turning into glass, cementing the fragments. This is how zuvites were formed.
However, there are a number of facts that allow us to assume that the Kara crater had a diameter of 110 - 120 kilometers, and the Ust-Kara crater does not exist. Basically, they include the presence of suevites and breccias on the river. Syadma-Yakha and the absence of anomalous gravitational and magnetic fields in the region of the Ust-Kara crater, which is unusual, since even much smaller craters are well expressed in geophysical fields. It is assumed that after the formation of the crater, its erosion (erosion) occurred, as a result of which only the central 60-km basin was preserved, and the outcrops of impactites on the shore, attributed to the Ust-Kara crater, are the remains of the impact stratum that once filled the entire crater that survived the erosion. Suvites and authigenic breccia, emerging at a distance of 55 km from the center of the crater in the valley of the river. Syadma-Yakha are also the remains of a crater.
The meteorite nature of the Kara depression was proved by the Russian scientist M.A. Maslov through gravimetric, magnetometric and seismic work, as well as analyzes of rocks mined by drilling wells.
Travelers who want to see the amazing crater will have to go through a difficult path; you can only get directly to the crater by private helicopter. For researchers, the Kara crater continues to be the most important object; valuable diamond deposits have been discovered on its territory. The size of some of them reaches 4 mm, and the total content precious stones in the rock reaches 50 carats per ton.
The most famous (and hypothetical) meteorite craters
Bermudian. Diameter: 1250 km. Geophysical anomalies caused by the impact of a meteorite impact may explain the effect " bermuda triangle". However, the meteorite nature of the depression has not been fully proven.
Ontong Java. Diameter: 1200 km. Age: approximately 120 million years. The crater is under water and has been studied very poorly.
Lesse Antilles. Diameter 950 km. According to one hypothesis, the main part of the Caribbean Sea is a meteorite crater.
bangui. Diameter: 810 km. Age: 542 Ma. The largest geophysical anomaly in Africa. According to one version, it happened as a result of a blow cosmic body.
Balkhash-Ili. Diameter: 720 km. Identified by satellite images and analysis of geophysical fields.
Ural. Diameter: 500 km. There is a hypothesis that the deposits of gold, uranium and other minerals of the Urals are associated with the fall of a giant meteorite.
Chesterfield. Diameter: 440 km. A series of rings with single center. It looks like a meteorite.
South Caspian. Diameter: 400 km. The idea that the Caspian Sea was formed as a result of the impact of a giant celestial body, put forward by Galileo.
Vredefort. Diameter: 300 km. Age: approximately 2 billion years. The largest of the craters, whose meteorite nature is fully proven. The energy of the explosion was equivalent to 1.4 billion kilotons of TNT.
Chicxulub. Diameter: 180 km. Age: 65.2 million years. It is believed that this is a crater from the meteorite that killed the dinosaurs.
popigay. Diameter: 100 km. Age: 35 million years. The crater is literally strewn with diamonds that arose as a result of the impact.
Khabarovsk. Diameter: 100 km. In 1996, a meteorite weighing 300 g was found. It is believed that this is part of a large iron meteorite, most of which is buried under the deposits of the Amur and Ussuri.
Goler. Diameter: 90 km. Age: 590 Ma. The diameter of the meteorite is about 4 km.
Karsky. Diameter: 62 km. Age: 70 million years. The "Kara explosion" is also considered one of the possible culprits for the death of ancient animals.
Barringer. Diameter: 1186 m. Age: 50 thousand years. Preserved better than all the others. In the 1960s, astronauts trained here before flying to the moon.
Another contender is Gulf of Mexico. There is a speculative version that this is a giant crater with a diameter of 2500 km.
Popular Geochemistry
How to distinguish an impact crater from other features of the relief?
“The most important sign of meteorite origin is that the crater is superimposed on geological relief randomly,
Explains the head of the meteoritics laboratory of the Institute of Geochemistry and analytical chemistry them. IN AND. Vernadsky (GEOKHI) RAS Mikhail Nazarov.
The volcanic origin of the crater must correspond to certain geological structures, and if there are none, but there is a crater, this is already a serious reason to consider the option of impact origin.
Another confirmation of the meteorite origin may be the presence in the crater of the actual meteorite fragments (impactor). This feature works for small craters (hundreds of meters in diameter - kilometers), formed by impacts of iron-nickel meteorites (small stony meteorites usually crumble when passing through the atmosphere). Impactors that form large (tens of kilometers or more) craters, as a rule, completely evaporate upon impact, so finding their fragments is problematic. But traces nevertheless remain: say, chemical analysis can detect an increased content of platinum group metals in the rocks at the bottom of the crater. The rocks themselves also change under the influence of high temperatures and the passage shock wave explosion: minerals melt, enter into chemical reactions, rebuild crystal lattice- in general, there is a phenomenon called impact metamorphism. The presence of resulting rocks- impactites - also serves as evidence of the impact origin of the crater. Typical impactites are diaplectic glasses formed at high pressures from quartz and feldspar. There are also exotic things - for example, diamonds were recently discovered in the Popigai crater, which were formed from graphite contained in rocks at high pressure created by a shock wave.
Another external sign of a meteorite crater is layers of underlying rocks squeezed out by the explosion (basement swell) or ejected crushed rocks (filled swell). Moreover, in the latter case, the order of occurrence of rocks does not correspond to the “natural” one. When falling large meteorites in the center of the crater, due to hydrodynamic processes, a hill or even an annular rise is formed - about the same as on the water, if someone throws a stone there.
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Meteor Crater in Arizona, USA
It is located 65 km east of Flagstaff. The diameter of the crater is 1220m, the depth is 180m, the age is about 40,000 years. The crater is believed to have been formed by a meteorite about 50 feet in diameter and weighing about 150 tons, composed mostly of nickel and iron. Crater from 1903 is privately owned by the Barringer family. Tourists who visit it pay $15.
Wolf Creek Crater, Australia
Like Arizona Crater, Wolf Creek owes its good condition to the dry Australian climate, though it is about 300,000 years old. The crater has a cosmic origin: fragments of a meteorite and glass, which appeared as a result of the melting of sand, were found at its bottom. In addition, at the center of the crater is a white gypsum-based mineral that retains water and allows trees and other vegetation to thrive in these inhospitable conditions.
Manicouagan Crater, Quebec, Canada
It is one of the oldest craters. Located 300 km north of the city of Baye Como, in the valley of St. Lawrence. Researchers David Rowley, John Sperey and Simon Kelly put forward the theory that the craters Mantouagan, Rochechouart (France), Saint Martin (Manitoba, Canada), Obolon (Ukraine) and Red Wing (North Dokota, USA) form a chain that appeared as a result of the fall fragments of an asteroid that broke up into fragments in the upper layers of the Earth's atmosphere. 214 million years ago, the craters were located close to each other, but as a result of tectonic movements (the collapse of the Pangea mainland), they "scattered" around the world.
Wetampka Crater, Alabama, USA
Almost 82 million years ago, a meteorite 350 meters in diameter fell into the cold waters of the northern seas, which were located in the area of \u200b\u200bthe current city of Montgomery, Alabama. What remains today is one of the best preserved craters formed as a result of the fall of cosmic bodies into the water . Wetampka has a diameter of 8 km.
Crater Lake, Lonar, India
One of the most famous meteorite craters in India has a diameter of no more than 1.6 km, it is partially filled with salt water. The crater was formed by a comet or meteorite impact approximately 52,000 years ago. It has well preserved its original shape and appearance from part due to the hardness of the basaltic volcanic rocks that make up most of the area.
Pingualuit Crater, Quebec, Canada
It was opened in the mid-40s, but the natives have known it for a long time, they call it Crysatal Eye. Arose from a meteorite impact 1.4 million years ago. The water level in the lake is replenished due to precipitation. The water is exceptionally clear, the salt content is very low - only 3 parts per minute, while the average salinity of the Great Lakes is 500 parts per million.
Kaali Crater, Estonia
Formed around 660 BC. as a result of the fall of 9 fragments of a meteorite on the Baltic island of Saaremaa. The largest crater, Kaali, is about 100 meters wide and is filled with underground water, the level of which varies depending on the season. It was named "Holy Lake". In the ancient epic poems of the Vikings and Scandinavian mythology there is mention of the terrible human tragedies that occurred during the formation of the Kaali craters.
Crater Gosses Bluff, Australia
We can say about this crater that it looks good for its age: about 142 million years. It is located 180 km west of Alice Springs. A meteorite that fell in this place caused great destruction and left a crater with a diameter of 22 km. However, time and the local climate have shaped its current dimensions of 5 km in diameter.
Clearwater Lakes, Quebec, Canada
These are two water-filled craters near Hudson Bay. Like other ancient craters, this case, about 300 million years old - these two have been preserved thanks to the rigid base of the Canadian Shield. The diameters of the craters are 26 and 36 km. Double craters are rare on Earth. Often they are found on other planets and moons of our solar system. As for these two, they arose as a result of the fall of two parts of a cosmic body that disintegrated in the atmosphere of our planet.
Wilkes Land Crater, Antarctica
Usage modern technologies allows you to penetrate beyond the limits of human vision and find new ones where they cannot be seen. So a crater was discovered on south pole covered in ice for millions of years. It is assumed that the diameter of this crater is 483 km. and it arose about 250 million years ago. The climate of Antarctica at that time was more moderate. A 50-kilometer asteroid fell in these places, causing an explosion of epic proportions. Wilkes Land crater, possibly related to BEDO crater, near Australia, 200km wide.
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A study published in Nature Climate Change presented new theory about how a mysterious "crater" formed in East Antarctica. It turns out that the weather in this region may be the cause, and not the impact of a meteorite, as previously thought.
The Crater is located on the King Baudouin Ice Shelf. Its width is 2 kilometers, depth is about 3 meters. For the first time, the public learned about it in 2015, when there were suggestions that it could result from the impact of a meteorite. Leading scientists initially suggested that a meteorite fell on the region back in 2004.
How did the crater form?
But now a team of researchers from the Netherlands, Belgium and Germany think wind may be the cause. Using a combination of fieldwork, satellite imagery, and climate models in the experiment, they suggest that strong and persistent winds can bring warm, dry air into the region, blowing snow away. 
As a result, the surface darkened, which allowed it to more easily absorb the sun's rays. This led to the formation of localized "hot spots" where the ice began to melt, forming a lake on top of the glacier, which eventually collapsed, leaving behind a circular crater. The water flowed into the ocean through three holes in the ice called moulins. 
“The buildup of pressure on the lake, which was large enough and full of water, led to the collapse of the glacier and the formation of what we initially mistook for a crater,” said study author Jan Lenarts from the University of Utrecht in the Netherlands. 
What does the appearance of such "craters" indicate?
The researchers said they found similar lakes below the surface. This confirms that this has happened before. The very existence of the "crater" suggests that East Antarctica is far more vulnerable to climate change than predicted, with ice shelves melting faster than previous estimates suggested. If the ice sheet breaks, most of the ice will fall into the ocean and sea levels will rise. 
Scientists' opinion
“The amount of melt water is very different from year to year, but it clearly increases in the warm season,” says Stef Lhermit from University of Technology Delft. - Previous research has shown that West Antarctica is extremely sensitive to climate change. But this study suggests that the ice sheet in East Antarctica is also very vulnerable at this time.”
Wilkes Land Crater
Wilkes Land Crater
Wilkes Land Crater- geological formation located under the ice sheet Antarctica, near Wilkes Lands, with a diameter of about 500 km. It is supposed to be a giant meteorite crater.
Assumptions that a giant impact crater is located in this place were expressed as early as 1962, but before research GRACE sufficient evidence was not found.
In 2006, a team led by Ralph von Frese and Laramie Potts measured gravitational field Earth satellites GRACE, was discovered bulk concentrate about 300 km in diameter, around which, according to radar data, there is a large ring structure. This combination is typical for impact craters. Recent studies in 2009 also show that an impact crater is located in this place.
Since the structure is located under the Antarctic ice sheet, direct observations of it are not yet possible. There are alternative explanations for the appearance of the mass concentrate, such as mantle plumes and other types of large-scale volcanic activity. If this formation is indeed an impact crater, then the meteorite that created it was about 6 times larger than the meteorite that created the crater Chicxulub, which is believed to have caused a massive extinction on the border chalk and Cenozoic.
There is a hypothesis that this impact event could cause Permian-Triassic extinction about 250 million years ago.
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- , research news, Pam Frost Gorder, June 1, 2006.
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Excerpt characterizing Wilkes Land Crater
The door opened into the back entrance. In the corner sat an old servant of the princesses and knitted a stocking. Pierre had never been in this half, did not even imagine the existence of such chambers. Anna Mikhailovna asked the girl who was ahead of them, with a decanter on a tray, (calling her sweetheart and dove) about the health of the princesses and dragged Pierre further along the stone corridor. From the corridor, the first door to the left led to the living rooms of the princesses. The maid, with a decanter, in a hurry (as everything was done in a hurry at that moment in this house) did not close the door, and Pierre and Anna Mikhailovna, passing by, involuntarily looked into the room where, talking, the elder princess and Prince Vasily. Seeing the passersby, Prince Vasily made an impatient movement and leaned back; the princess jumped up and with a desperate gesture slammed the door with all her might, shutting it.This gesture was so unlike the princess’s usual calmness, the fear expressed on the face of Prince Vasily was so unusual for his importance that Pierre, stopping, inquiringly, through his glasses, looked at his leader.
Anna Mikhailovna did not express surprise, she only smiled slightly and sighed, as if to show that she had expected all this.
- Soyez homme, mon ami, c "est moi qui veillerai a vos interets, [Be a man, my friend, I will look after your interests.] - she said in response to his look and went even faster down the corridor.
Pierre did not understand what was the matter, and even less what it meant veiller a vos interets, [observe your interests,] but he understood that all this should be so. They went down a corridor into a dimly lit hall that adjoined the count's waiting room. It was one of those cold and luxurious rooms that Pierre knew from the front porch. But even in this room, in the middle, there was an empty bathtub and water had been spilled over the carpet. To meet them on tiptoe, paying no attention to them, a servant and a clerk with a censer. They entered the reception room, familiar to Pierre, with two Italian windows, access to the winter garden, with a large bust and a full-length portrait of Catherine. All the same people, in almost the same positions, sat whispering in the waiting room. Everyone, falling silent, looked back at Anna Mikhailovna, who entered, with her tear-stained, pale face, and at the fat, big Pierre, who, with lowered head, dutifully followed her.
Anna Mikhaylovna's face expressed the consciousness that the decisive moment had arrived; she, with the receptions of a businesslike Petersburg lady, entered the room, not letting go of Pierre, even bolder than in the morning. She felt that since she was leading the one whom she wanted to see dying, her reception was assured. With a quick glance at everyone in the room, and noticing the count's confessor, she, not only bending over, but suddenly becoming smaller, swam up to the confessor with a shallow amble and respectfully accepted the blessing of one, then another clergyman.
