We all know that our Earth was influenced from space. On its surface, scientists have identified more than 170 craters that were formed as a result of meteorites falling onto the earth's surface.
We offer you photos of several of the largest meteorite craters. “Messengers from Space” have had a positive impact on our planet to some extent. Magnificent lakes have formed at the impact sites of some large asteroids.
Barringer Crater, Arizona, USA
This crater is also called “Devil's Canyon”. About 49 thousand years ago, a huge iron-nickel meteorite, 150 feet across, weighing several hundred thousand tons, moving at a speed of 40,000 km per hour, fell on our planet. As a result, a huge crater with a diameter of 1.2 km was formed. This crater is considered one of the best preserved.
Bosumtwi, Ghana
Due to a collision with a huge meteorite with a diameter of half a kilometer about 1.3 million years ago, Lake Bosumtwi was formed with almost ideal outlines. The diameter of this lake is about 10 km. The study of this lake is also complicated by the fact that a dense forest has grown around it. The local Ashanti people consider the lake a shrine. This crater is also considered to be well preserved.
Deep Bay, Canada
This crater is located in Saskatchewan. Its diameter is 13 km and its depth is 220 meters. A shallow lake formed at the site of the crater. The age of the crater is about 99 million years.
This crater with a diameter of 17 kilometers is located in Chad (Sahara Desert, Africa). The crater is approximately 345 million years old. It was formed due to the fall of a meteorite 1.7 km in diameter.
This crater is 142 million years old. Its diameter is 22 kilometers. It is located in the center of Australia. This crater looks simply amazing. Gosses Bluff was formed due to the fall of a huge meteorite, which crashed into the earth's surface at a speed of 65,000 km per hour. The depth of the crater he created was 5 km.
As a result of the collision of this meteorite 38 million years ago, Lake Mistatin was created, which is located in the Canadian province of Labrador. The dimensions of the crater are 11 by 17 km. However, it is believed that it was originally larger but became smaller due to erosion. The uniqueness of the crater is that it is elliptical in shape. This indicates that the asteroid did not fall straight, but at an acute angle.
Clearwater, Canada
This is a unique case. 290 million years ago, a huge asteroid, upon entering the atmosphere of the globe, split into two parts before falling. As a result, two craters were formed at once. One of the lakes is 36 km in diameter, and the other is 26 km. Moreover, initially they were even larger.
Kara-Kul, Tajikistan
This crater is located in the northern part of the Pamirs at an altitude of almost 4,000 meters. A magnificent lake measuring 24 by 33 kilometers was formed here. The age of the crater is about 5,000,000 years.
Manicouagan, Canada
At the site of a huge 5-kilometer meteorite that fell 212 million years ago, there is a reservoir known as the Eye of Quebec. The area of the crater is 100 kilometers. The extraordinary thing about the crater is that it was not filled with water naturally, although a ring of water formed around it.
Chicxulub Crater, Mexico
Some scientists believe that it was as a result of the fall of this asteroid 65 million years ago that dinosaurs could become extinct. This is considered the most powerful collision in the entire history of our planet. The energy of a huge asteroid the size of a city was about 1 billion kilotons. Due to the fall of the meteorite, a crater measuring 168 kilometers was formed. In addition, it caused powerful earthquakes, tsunamis and volcanic eruptions.
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In the case of the death of dinosaurs, the main suspect has emerged, who left evidence at the crime scene - a crater with a diameter of about 180 kilometers. Oddly enough, scientists noticed the trace of a giant asteroid quite recently.
Such a large-scale disaster occurred on the Yucatan Peninsula - the southern tip of Mexico.
The unfortunate incident took place approximately 65 million years before the fall of the Tunguska meteorite, and therefore went unnoticed by wide sections of the world community.
For many years, people did not see the gigantic funnel with a maximum depth of 900 meters, which was also partially hidden by the waters of the Gulf of Mexico of the Atlantic Ocean.
Only in the 1990s its cosmic origin was proven by Canadian scientist Alan Hildebrand. This required detailed ground-based and satellite studies.
If you were in his place, you would probably fuss (photo from bbc.co.uk).
Although, back in 1980, something similar was suggested by the American Nobel laureate physicist Luis Alvarez.
The crater was named Chicxulub, after the name of a poor village located nearby.
Not surprisingly, local residents had no idea that they were walking on the memorial. The height difference across the five kilometers of the outer boundary of the crater is only a few meters.
According to scientists' calculations, the diameter of the asteroid that caused such significant destruction should have been about 10 kilometers. Unless the damage was caused by a passing comet.
The consequences of the collision turned out to be disastrous for all earthly living creatures at the end of the Mesozoic era.
Presumably, gigantic masses of dust rose into the air, obscuring the Sun and preventing plant growth.
The arrows indicate the boundary of the crater “trough” (NASA photo).
The instantaneous evaporation of billions of tons of rock led to climate change on the planet.
Sulfur fumes from the disaster site caused acid rain.
To top it all off, volcanic activity that had died down intensified.
In total, according to various estimates, from 70 to 90 percent of living creatures of that era were ordered to live long. Maybe this is for the best: otherwise we would not see the dominance of mammals and you would not read our article.
By the way, on the territory of Ukraine there is the Boltysh crater with a diameter of 24 km. According to the latest estimates, it was formed at about the same time as Chicxulub, plus or minus a “pathetic” 250 thousand years.
The largest meteorite funnel is located in this circle (photo from bbc.co.uk).
That is, most likely, an asteroid “doublet” took place. Although the Ukrainian heavenly guest was smaller - ten times.
The Chicxulub crater is currently undergoing intensive scientific research. It is planned to drill three wells, with a depth of 700 meters and one and a half kilometers. The cost of the work is estimated at $1.5 billion.
The fact is that the source of the explosion has since long been filled with limestone deposits, the thickness of which in some places reaches one kilometer. The processes of destruction and erosion of limestone rocks caused the formation of voids and drainage wells.
These natural containers were practically used by the disappeared civilization of the Mayan Indians to perform sacrifices.
In-depth research will help restore the original geometry of the funnel.
A chemical analysis of the composition of the rock at the bottom of the drilled wells will make it possible to understand the scale of the environmental disaster that almost buried earthly life, and to examine other evidence that still remains at the “crime scene.”
Free artistic fantasy based on ancient events (photo from home.lanet.lv).
You may ask why we suddenly remembered about the Yucatan collapse, although nothing has really been proven yet. Maybe they wouldn’t have remembered if it weren’t for NASA.
At the very beginning of March 2003, the American agency finally published the results of space photography of the crater surface taken by the Endeavor shuttle back in 2000.
During the 11-day February event, called the Shuttle Radar Topography Mission (SRTM), the shuttle carried out volumetric space imaging of Chicxulub, and at the same time another 80% of the earth's surface.
The study of the results resulted in the processing of eight terabytes of information from 200 billion qualitative measurements of the planetary topography. The whole process took three years, so the Americans only got around to publishing it now.
Very timely, in our opinion, since the investigation
Mercury, Pluto, the Moon, Titan, other satellites and asteroids of the Solar System - they are all full of craters, traces of large and not so large collisions with meteorites and comets. Our Earth is well protected, in which most space invaders burn out even before the surface - but large and fast ones break through, leaving indelible marks. Today we will look at the largest craters on Earth and restore the meteorites that managed to dig them.
Five minutes of theory
Before we find out where the largest crater on Earth is located, we need to understand the mechanism of their formation. After all, hundreds of years have passed since the fall of the big ones, and many craters are only now being discovered using the circular contours of the landscape from satellites or by analyzing the composition of minerals at the fall site. Folk tales also help to find craters - for example, the history of the Wolf Creek crater in Australia remained in the memory of the aborigines, although thousands of years have passed since the fall.
The main point is that the craters are hundreds of times larger than the meteorites that left them. The thing is that the fall of a cosmic body at enormous speed releases colossal energy - the most massive, dense and fast meteorites that fell to Earth are hundreds of times more powerful than the most powerful nuclear bomb. The shock wave creates a pressure of millions of atmospheres, and the temperature at the epicenter of contact is higher than 15,000 ° C! From such heat, the rocks instantly evaporate and turn into plasma, which explodes and spreads the remains of the meteorite and destroyed rocks over hundreds of kilometers.
In the hot forge of a crater, molten rocks behave like liquids - a small hill forms at the center of the impact (like the one that rises on water when a drop falls), and even if the meteorite struck at an acute angle, the outline of the crater will be invariably round. And pressure gives rise to special rocks - impactites (from the English “impact” - imprint, blow). They are very dense, contain meteoric iron, iridium and gold, and often take crystalline and glassy forms. African impact diamonds, which can cut through regular diamonds, are also the product of a giant meteorite impact.
Scientists use these tracks to look for craters. And while some are visible to a non-specialist, others become sensations - people have been living in crater bowls for centuries and have no idea about it!
Akraman Crater
The world's sixth largest crater is hidden in the south of Australia - formed 590 million years ago, it stretches 45 kilometers to the sides. At the time of the fall, the mess was a shallow, warm sea inhabited by primitive mollusks and arthropods - the meteorite impact scattered their remains with sedimentary rocks for hundreds of kilometers around. Over the years, the outlines of the crater have been smoothed, but it is clearly visible on satellite images.
Now Arkaman does not look as menacing as his smaller brothers, and a significant part of it is occupied by the seasonal lake of the same name, which dries up in the heat. But 590 million years ago, a meteorite hit shook the entire planet. The diameter of the space traveler was 4 km, and it consisted of a chondrite - a meteorite relative of terrestrial granite. Hitting the ground at a speed of 25 km/sec, the Arkaman meteorite exploded with a force of 5200 gigatons, which is comparable perhaps to the entire nuclear arsenal of the world. Thunder with a volume of 110 dB, causing pain in the ears and damaging hearing, was heard even 300 kilometers from the crash site, and a wind squall with a force of 357 m/s could even blow away skyscrapers!
The Manicouagan crater in Quebec, Canada, is one of the most distinct and beautiful giant craters on the planet. The distance from its centers to the outer edges is 50 kilometers, and inside the crater bowl there is a ring-shaped Lake Manicouagan surrounding the central island. The asteroid that created the crater was 5 kilometers in circumference, and flew into prehistoric Canada 215 million years ago, during the Triassic period. Since the impact of the Manicouagan meteorite was 7 teratons, it has long been considered as the cause of the mass extinction of animals of that period.
And the Manicouagan crater has brothers all over the Earth - astronomers believe that a whole meteor shower took place that year. Possible “coeval” craters are the Obolon crater in Ukraine, the Red Wing crater in North Dakota, and the St. Martin crater in Matoba, Canada. They follow each other in a chain across the planet - perhaps they were generated by the same huge one, split into pieces, or by a whole flock of them. However, it is not yet possible to find out for sure.
The Popigai crater is the largest trace of a meteorite impact on the territory of modern Russia, located in northern Siberia. Its diameter is about 100 kilometers, and people even live in it - the village of Popigai, with a population of about 340 people, is located 30 kilometers from the center of the crater. Such a large imprint was left by an 8-kilometer-long chondritic meteorite that fell into Eurasia 37 million years ago.
The asteroid impact gave the crater special value - graphite deposits under the surface turned into impact diamonds within a radius of 13.6 kilometers from the impact site. They are very small - up to 1 cm in diameter - and therefore are not suitable for jewelry. But their unusual strength is very useful in industry and science, since “meteorite” diamonds are stronger than even the strongest synthetic ones. And in Popigaya, as in the Manicouagan crater, there are also relatives, traces of meteorite bombardment. These meteorites are believed to have led to a global cooling that allowed large, complex mammals—the ancestors of modern dogs, lions, elephants, and horses—to dominate.
Chicxulub Crater
The impact mark is impressive - the diameter of the crater is 180 kilometers, it extends to land and sea, and the maximum depth reaches 20 kilometers! The force of the meteorite explosion was 100 thousand megatons; The Tsar Bomba, the most powerful thermonuclear charge in the world, is capable of delivering only a tenth of one percent of the total energy of the Chicxulub meteorite. From such an impact, fountains of lava rose on the far side of the Earth, 200 thousand cubic kilometers of rock were thrown into the air, and forests caught fire from the hot wind.
Earthquakes, tsunamis, volcanic eruptions - the consequences of the impact that created the Chicxulub crater changed the Earth's climate for a long time. By the way, the meteorite that did all this belongs to the Baptistina family of asteroids. This group often crosses the orbit of our planet - among other traces of the family, the Tycho crater is noted. These are all, of course, just theories: asteroids can definitely be blamed for the death of dinosaurs only when spacecraft bring back samples of their soil.
An interesting fact is that the crater-like nature of the Chicxulub circular basin was not discovered through scientific research. Symmetrical rings on the continent and ocean floor, as well as impact seals, were noticed by oil prospectors.
Sudbury Crater
Canada is definitely lucky when it comes to craters - Sudbury, the second largest crater in the world with a girth of 250 kilometers, is located in the Canadian province of Ontario. The fall occurred during the Paleoproteozoic era, 1.849 billion years ago - since then the outlines of the crater have been smoothed out, and it began to resemble a huge valley 62 kilometers long, 30 kilometers wide and 15 kilometers deep. A worthy asteroid dug such a crater - according to modern estimates, its radius was 7.5 kilometers.
The Sudbury meteorite impact penetrated all the way to the mantle, and large pieces of rock were found within a radius of 800 kilometers - in total, debris was scattered over an area of 1,600,000 km2. But this big bang enriched Canada. Hundreds of millions of years ago, the crater crater was filled with magma rich in heavy elements such as gold, nickel, copper, palladium and platinum - and now the Sudbury Basin belongs to the largest mining areas in the world. And the rich mineral composition of the soil stimulates plant growth; Only the cold climate prevents it from reaching agricultural heights.
The largest crater on Earth is the Vredefort Crater in South Africa. Its diameter reaches 300 kilometers, and the size of the meteorite that created the crater is estimated at 20 km. This is not only the largest, but also the second oldest crater - a meteorite explosion occurred 2.023 billion years ago. Only the Suavjärvi crater in Russia is older, 2.3 billion years old.
The Vredefort Crater is so large that it could fit several dwarf European countries. It contains several concentric rings that only remain from exceptionally violent impacts, and are rarely preserved on Earth due to tectonic plate movement and erosion. The favorable location helped Vredefort survive - the central depression from the impact is especially clearly visible. Like other meteorite craters, valuable minerals can be found there, particularly gold. However, so far the crater is dominated by farmers - the center of the community is the town of Vredefort, nestled in the center of the crater.
Theoretically, there are even larger craters - a 540-kilometer crater from an asteroid impact is hidden under the ice of Antarctica; The Caribbean Sea and many other bodies of water may also have been created by meteorites. However, this will become known for sure only in the future, with the development of new technologies for scanning soil depths and diving under water - for the most part, it was miners and oil workers who discovered the craters of antiquity. So we will keep an eye on both the miners and the scientists.
Chicxulub Crater is the largest meteorite crater on Earth, located in the northwestern part of the Yucatan Peninsula and at the bottom of the Gulf of Mexico.
Chicxulub Crater Location (Dementia) Chicxulub Coast (Karyn Christner)
Chicxulub Crater is a large meteorite crater in the northwestern part of the Yucatan Peninsula and at the bottom of the Gulf of Mexico. With a diameter of approximately 180 km, it is one of the largest known impact craters on Earth. Chicxulub is located approximately half on land and half under the waters of the gulf.
Due to the gigantic size of the Chicxulub crater, its existence cannot be determined by eye. Scientists discovered it only in 1978, and quite by accident, while conducting geophysical research at the bottom of the Gulf of Mexico.
Location of the Chicxulub crater (Dementia)
During these studies, a huge underwater arc with a length of 70 km, shaped like a semi-circle, was discovered.
According to gravitational field data, scientists have found a continuation of this arc on land, in the north-west of the Yucatan Peninsula. When they come together, the arcs form a circle whose diameter is approximately 180 km.
The impact origin of the Chicxulub crater was proven by the gravitational anomaly inside the ring-shaped structure, as well as by the presence of rocks characteristic only of impact-explosive rock formation. This conclusion is also confirmed by chemical studies of soils and detailed satellite imaging of the area. So there is no longer any doubt about the origin of the huge geological structure.
Consequences of a meteorite fall
It is believed that the Chicxulub crater was formed by the fall of a meteorite at least 10 kilometers in diameter. According to available calculations, the meteorite moved from the southeast at a slight angle. Its speed was about 30 kilometers per second.
Chicxulub Coast (Karyn Christner)
The fall of this giant cosmic body occurred approximately 65 million years ago, at the turn of the Cretaceous and Paleogene periods. Its consequences were truly catastrophic and had a profound impact on the development of life on our planet.
The power of the meteorite impact exceeded the power of the atomic bomb dropped on Hiroshima by several million times.
Immediately after the fall, a huge ridge formed surrounding the crater, the height of which could reach several thousand meters.
However, it was soon destroyed by earthquakes and other geological processes. The impact caused a powerful tsunami; It is assumed that the wave height was between 50 and 100 meters. The waves traveled far into the continents, destroying everything in their path.
A shock wave with a high temperature and causing forest fires passed around the Earth several times. Tectonic processes and volcanism have intensified in different parts of our planet.
As a result of numerous volcanic eruptions and forest burning, huge amounts of dust, ash, soot and gases were released into the Earth's atmosphere. The raised particles caused the effect of a volcanic winter, when most of the solar radiation is screened by the atmosphere and global cooling sets in.
Such drastic climate changes, along with other negative consequences of the impact, were disastrous for all life on Earth. There was not enough light for plants to carry out photosynthesis, causing the oxygen content in the atmosphere to be greatly reduced.
Due to the disappearance of a significant part of the plant cover of our planet, animals that lacked food began to die out. It was as a result of these events that dinosaurs became completely extinct.
Cretaceous-Paleogene extinction
The fall of this meteorite is the most convincing cause of the Cretaceous-Paleogene mass extinction. The version of the extraterrestrial origin of these events took place even before the discovery of the Chicxulub crater.
It was based on the abnormally high content of such a rare element as iridium in sediments that are about 65 million years old. Since high concentrations of this element were found not only in the sediments of the Yucatan Peninsula, but also in many other places on Earth, it is possible that a meteor shower occurred at that time. There are other versions, however, they are less widespread.
At the boundary of the Cretaceous and Paleogene, all the dinosaurs, marine reptiles and flying dinosaurs that reigned on our planet in the Cretaceous period became extinct.
Existing ecosystems were completely destroyed. In the absence of large lizards, the evolution of mammals and birds, the biological diversity of which greatly increased in the Paleogene, accelerated significantly.
It can be assumed that other mass extinctions of species throughout the Phanerozoic were also caused by falls of large meteorites.
Existing calculations show that impacts of celestial bodies of this size on Earth occur approximately once every hundred million years, which roughly corresponds to the time intervals between mass extinctions.
Documentary film "Asteroid Fall"
On the pages of the site there are many discussions about what happened on Earth 1000 years ago, 10 thousand years ago. There is complete confusion about who is doing what. And everyone is right as usual. On the one hand, if we don’t know such a “recent” past, how can we know what was there 65 million years ago? Sometimes it seems that we know more about those distant times. At least quite extensive archaeological research has been done using precise equipment. Or are the dinosaurs fake too?!
So what do scientists report? At the end of the Cretaceous period, i.e. 65 million years ago a huge meteorite fell on planet Earth. It was a planetary catastrophe. Not the first and not the last time. A meteorite that fell near what is now located on the coast of the Mexican Yucatan Peninsula Chicxulub village, left its mark not only in its appearance, but also in the history of the development of life on Earth.
Before this cataclysm, dinosaurs and related reptiles reigned on land, in the air and in the sea. After the catastrophe they became extinct, and mammals and birds took the path of evolutionary development.
The Chicxulub Crater is not a place of legend. It was found in the 1970s, but they did not immediately study it, since the depression was covered with thick layers of sedimentary rocks. In the 1990s, the crater was examined again, and scientists determined that the date of its formation exactly corresponds to the boundary of the Cretaceous and Paleogene periods.
Dead and survivors
At the site where the Chicxulub meteorite fell, the sky was covered with clouds of dust. Forest fires raged everywhere, adding smoke and soot to the dust. The situation was getting even worse. For several weeks, the sky over the entire globe darkened, the light of the Sun did not penetrate to the surface of the planet, which did not allow plants on land and in the oceans to normally carry out their main function - photosynthesis.
Plants began to die. But they serve as food for herbivores, and these, in turn, feed on predators. Any serious disturbance in the chemical and physical situation on Earth, such as a sharp decrease in illumination or a drop in temperature, instantly affects the flora of the planet. The reverberations of these disturbances reverberated throughout the entire ecosystem.
Probably, after the fall of the meteorite, the microscopic plants of the ocean were the first to die out. Thus, the marine ecosystem collapsed. However, there is evidence that the meteorite only accelerated their death. The seagrass began to die off long before the impact, likely due to major changes in the patterns of ocean currents. On land, it is believed that the meteorite impact not only obscured the Sun, but also caused large-scale fires and acid rain, which caused serious damage to land plants.
A study of rocks at Hell Creek, Montana, showed that more than 75% of plant species in inland North America became extinct after a meteorite impact. It is believed that the most recently emerged flowering plants, as well as some of the plants typical of the Mesozoic era, such as ginkgos and cycads, were hit the hardest. In a short time period after the impact, ferns stood relatively calmly, and in a longer period, conifers quickly recovered. Oddly enough, land plants in the Southern Hemisphere hardly died out, which means that the impact was actually not as catastrophic as some assume.
Gradually, vegetation around the globe began to slowly return to its lost positions. Flowering plants were the best able to take advantage of the situation. Eventually they diversified into a great variety of species, from small grasses to huge trees, and conquered almost every landscape on the globe.
EXTINCTION
This herbivorous dinosaur, Triceratops, was widespread during the Cretaceous period. By the end of the period they were still thriving and abundant. But then they disappeared, like all dinosaurs.
Among marine fauna, the extinction at the end of the Cretaceous period was much more widespread than on land. Among the extinct sea creatures were ammonites, which lived in the oceans for 300 million years.
The end of the dinosaur era
Many animals did not survive the disaster. The most famous example is dinosaurs and flying pterosaurs. Along with them, giant marine reptiles such as mosasaurs and plesiosaurs disappeared. There is still debate about why dinosaurs became extinct, while many other groups survived despite the disaster. Thus, teleost fishes (12%), frogs (0%), salamanders (0%), lizards (6%) and placental mammals (14%) almost did not suffer from extinction.
Dinosaurs were not the only reptiles in that era. Before the Chicxulub meteorite struck, 45 families of turtles, crocodiles, lizards and snakes lived on Earth. Turtles and crocodiles suffered significantly, however, like plants, those who survived soon adapted to the new conditions.
The initial decline in the number and influence of reptiles contributed to the rapid spread of mammals, although they too suffered mass extinctions. About 20% of the ancient mammal families of the Cretaceous period disappeared.
In total, about 75% of animal species disappeared at the turn of the Cretaceous and Paleogene periods. Many of them were already rare and on the verge of extinction, but scientists have not been able to give a reliable explanation of why some species became extinct while others survived. Some biologists believe that extinction or survival was simply a matter of luck.
http://www.3planet.ru/history/terra/1590.htm
