The ancient Chicxulub meteorite crater was discovered by accident in 1978 during a geophysical expedition organized by Pemex (Petroleum Mexicana) to search for oil deposits at the bottom of the Gulf of Mexico. Geophysicists Antonio Camargo and Glen Penfield first discovered an incredibly symmetrical 70-kilometer underwater arc, then examined a gravity map of the area and found a continuation of the arc on land - near the village of Chicxulub (“tick demon” in the Mayan language) in the northwestern part of the peninsula. Having closed, these arcs formed a circle with a diameter of about 180 km. Penfield immediately hypothesized the impact origin of this unique geological structure: this idea was suggested by the gravitational anomaly inside the crater, the samples he discovered of “impact quartz” with a compressed molecular structure and glassy tektites, which form only under extreme temperatures and pressures. Alan Hildebrant, a professor at the Department of Earth Sciences at the University of Calgary, managed to scientifically prove that a meteorite with a diameter of at least 10 km fell in this place in 1980.
In parallel, the question of the supposed fall of a giant meteorite to Earth at the Cretaceous-Paleozoic boundary (about 65 million years ago) was studied by Nobel laureate in physics Luis Alvarez and his son geologist Walter Alvarez from the University of California, who, based on the presence of an abnormally high content of iridium in the soil layer of that period ( extraterrestrial origin) suggested that the fall of such a meteorite could have caused the extinction of the dinosaurs. This version is not generally accepted, but is considered quite probable. During that period, rich in natural disasters, the Earth was subjected to a series of meteorite impacts (including the meteorite that left the 24-kilometer Boltysh crater in Ukraine), but Chicxulub seemed to surpass all others in scale and consequences. The fall of the Chicxulub meteorite affected life on Earth more seriously than any of the strongest volcanic eruptions known today. The destructive force of its impact was millions of times greater than the force of the atomic bomb explosion over Hiroshima. A column of dust, rock fragments, and soot shot up into the sky (the forests were burning), hiding the sun for a long time; the shock wave circled the planet several times, causing a series of earthquakes, volcanic eruptions and tsunamis 50-100 m high. The nuclear winter with acid rain, destructive for almost half of the species diversity, lasted several years... Before this global catastrophe, dinosaurs, marine plesiosaurs, and mosasaurs reigned on our planet and flying pterosaurs, and then - not immediately, but in a short time, almost all of them became extinct (Cretaceous-Paleogene crisis), freeing up an ecological niche for mammals and birds.
Before the discovery in 1978, the area around the Mexican village of Chicxulub in the northwest of the Yucatan Peninsula was famous only for its abundance of ticks. The fact that it is here that a 180-kilometer meteorite crater lies half on land and half under the water of the bay is completely impossible to determine by eye. Nevertheless, the results of chemical analyzes of the soil under the sedimentary rocks, the gravitational anomaly of the place and detailed photography from space leave no doubt: a huge meteorite fell here.
Now the Chicxulub crater is being intensively studied by scientists from literally all sides, that is, from above - from space, and from below - using deep drilling.
On a gravity map, the impact zone of the Chicxulub meteorite appears broadly as two yellow-red rings on a blue-green background. On such maps, a gradation from cold to warm colors means an increase in the force of gravity: green and blue show areas with reduced gravity, yellow and red - areas with increased gravity. The smaller ring is the epicenter of the impact, which occurred in the vicinity of the current village of Chicxulub, and the larger ring, covering not only the north-west of the Yucatan Peninsula, but also the bottom within a radius of 90 km, is the edge of the meteorite crater. It is noteworthy that a strip of cenotes (sinkholes with underground freshwater lakes) in the north-west of Yucatan almost coincides with the explosion, with the largest accumulation in the eastern part of the circle and individual cenotes outside. Geologically, this can be explained by the filling of the crater with limestone deposits up to a kilometer thick. The processes of destruction and erosion of limestone rocks caused the formation of voids and drainage wells with fresh underground lakes at the bottom. The cenotes on the outside of the ring probably arose from the impact of meteorite fragments thrown outside the crater by the explosion during the fall. Cenotes (not counting the rains, this is the only source of drinking water on the peninsula, so Mayan-Toltec cities later grew up near them) are conventionally designated as white dots on the gravity map. But there are no more blank spots left on the map of Yucatan: in 2003, the results of space photography of the crater surface, taken by the Endeavor shuttle back in February 2000, were published (American astronauts were interested not only in Yucatan: in addition to the volumetric space survey of Chicxulub from the shuttle in During NASA's 11-day radar topography mission, 80% of the earth's surface was surveyed).
In photographs taken from space, the boundary of the Chicxulub crater is clearly visible. For this purpose, the images underwent special computer processing, which “cleaned off” the surface layers of sediment. The space image even shows a trace of the fall in the form of a “tail,” from which it was determined that the meteorite approached the Earth at a low angle from the southeast, moving at a speed of approximately 30 km/sec. At a distance of up to 150 km from the epicenter, secondary craters are visible. Probably, immediately after the meteorite fell, a ring-shaped ridge several kilometers high rose up around the main crater, but the ridge quickly collapsed, causing strong earthquakes, and this led to the formation of secondary craters.
In addition to space exploration, scientists have begun in-depth research of the Chicxulub crater: it is planned to drill three wells with a depth of 700 m to 1.5 km. This will make it possible to restore the original geometry of the crater, and chemical analysis of rock samples taken at the depth of the wells will make it possible to determine the scale of that distant environmental disaster.
general information
Ancient meteorite crater.Location: in the northwest of the Yucatan Peninsula and at the bottom of the Gulf of Mexico.
Date of meteorite fall: 65 million years ago.
Administrative affiliation of the crater: Yucatan state, Mexico.
The largest settlement on the crater territory: state capital city - 1,955,577 people. (2010).
Languages: Spanish (official), Mayan (language of the Mayan Indians).
Ethnic composition: Mayan Indians and mestizos.
Religion: Catholicism (majority).
Currency unit: Mexican Peso.
Water sources: natural wells cenotes (water from an underground karst lake).
Nearest airport: Manuel Cressencio Rejon International Airport, Merida.
Numbers
Crater diameter: 180 km.Meteorite diameter: 10-11 km.
Crater depth: not exactly clear, presumably up to 16 km.
Impact energy: 5×10 23 joules or 100 teratons of TNT equivalent.
Tsunami wave height(estimated): 50-100 m.
Climate and weather
Tropical.Dry, very hot, woodlands and xerophytic shrubs predominate.
Average January temperature: +23°С.
Average temperature in July: +28°С.
Average annual precipitation: 1500-1800 mm.
Economy
Industry: forestry (cedar), food, tobacco, textile.Agriculture: farms grow henequin agave, corn, citrus fruits and other fruits and vegetables; Breeding cattle; beekeeping.
Fishing.
Service sector: financial, trade, tourism.
Attractions
■ Natural: Cenote area.■ Cultural-historical: ruins of Mayan-Toltec cities in the cenote zone: Mayapan, Uxmal, Itzmal, etc. (Merida is a modern city on the ruins of an ancient one).
Curious facts
■ The ancient cities of the Mayans and the Toltecs who conquered them were built near the cenotes. It is known that some of these cenotes (the most important one in Chichen Itza) were sacred to the Maya-Toltec civilization. Through the “eye of god” the Indian priests communicated with the gods, and they threw human sacrifices into it.■ Even before the discovery of the Chicxulub meteorite crater, the scientific community in the late 1970s was developing a theory about the extraterrestrial (meteorite) origin of the Cretaceous-Paleogene crisis, which led to the death of the dinosaurs. Thus, father and son Alvarez (physicist and geologist), successively analyzing the composition of the soil in an archaeological section taken in Mexico, discovered in a clay layer aged 65 million years an abnormally increased (15 times) concentration of iridium - a rare element for the Earth, typical of a certain species asteroids. After the discovery of the Chicxulub crater, it would seem that their guesses were confirmed. However, similar studies of soil sections in Italy, Denmark and New Zealand showed that in a layer of the same age the iridium concentration also exceeds the nominal one - 30, 160 and 20 times, respectively! This proves that perhaps a meteor shower occurred over the Earth at that time.
■ In the first week after the meteorite fell, scientists believe that the fewest and most vulnerable species, already in danger of extinction, died out - the last of the giant sauropods and apex predators. Due to acid rain and lack of light, some plant species began to die out, the photosynthesis process of the remaining ones slowed down, as a result there was a lack of oxygen and a second wave of extinction began... It took thousands of years for the ecological balance to be restored.
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 blocked 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 vegetation 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"
Scientists have clarified the details of the disaster that occurred 66 million years ago. Then an asteroid crashed into our planet - in the place where the Gulf of Mexico is now located. It is believed that it was he who killed the dinosaurs, making the climate on Earth unacceptable for them.
“So it was,” assure Sean Gulick, professor of geophysics at the University of Texas at Austin and professor Joanna Morgan from Imperial College London, who organized the drilling of the Chicxulub crater, formed as a result of the impact of an asteroid.
“But the dinosaurs were not killed by a blast wave or shrapnel or a tsunami. They died as a result of catastrophic climate change.
Chicxulub Crater
Scientists drilled in the Gulf of Mexico in April-May last year
Scientists' drilling platform
Cores that drillers brought to the surface from a depth of 1,300 meters indicate that the asteroid hit directly into a deposit of gypsum stone, which partially evaporated. As a result, sulfate dust and sulfur dioxide gases rose into the atmosphere - essentially, substances that volcanoes emit into the sky.
Cores with samples of deep rocks: they demonstrated that the asteroid fell into a gypsum stone deposit
And the impact of the asteroid became tantamount to an eruption of unprecedented power - a cloud containing 100 billion tons of sulfur hung over the Earth. It became dark and cold. The temperature dropped by 26 degrees. Winter came, which lasted for several decades. The plants that the herbivorous dinosaurs fed on died. And they themselves died of hunger. And after the herbivores, predatory dinosaurs followed the herbivores.
Scientists believe a 15-kilometer asteroid fell into the Gulf of Mexico. It crashed into our planet at a speed of about 60 thousand kilometers per hour. The explosion created a crater with a diameter of 120 and a depth of 30 kilometers. Soon the crater collapsed and expanded to 200 kilometers in diameter. Now it is hidden under a 600-meter layer of bottom sediments, through which scientists penetrated.
Scheme of events 66 million years ago
And the most interesting thing: Gulick and Morgan claim that dinosaurs could have survived if the asteroid had arrived at least a few seconds earlier. Or later. Then it would not have fallen into shallow water, where it easily reached the bottom and exploded the gypsum there, but would have crashed into the deep ocean and raised only splashes.
In this case, the consequences of the collision would not be so catastrophic for the climate. And for dinosaurs. They would have continued to eat more or less normally and, perhaps, would have coexisted with mammals that appeared later. And even now they were hanging around somewhere, scaring us.
ANOTHER OPINION
The dinosaurs didn't stand a chance. They began to die out even before the asteroid hit them
Professor Paul Renne and his team from the University of California at Berkeley, U.S. clarified the age of particles of matter that scattered across the globe after an asteroid impact in the Gulf of Mexico, compared with the age of sediments in which there were Numerous dinosaur remains have been found. And he made conclusions that he published in the journal Science.
Firstly, the professor was the first to clarify: the same asteroid that left a crater with a diameter of about 200 kilometers fell to Earth 180 thousand years earlier than was generally believed. The exact time of the cataclysm is not “about 65 million years ago,” as they said before Renne’s calculations, but 66 million 30 thousand years. It is this date that everyone now refers to.
Researchers have found that even before the asteroid fell, the climate on Earth was greatly spoiled by numerous volcanic eruptions. It's already getting cold here. Both frozen and starved dinosaurs were already on the verge of extinction. The professor believes that the strike from space finished off the lizards, greatly aggravating their situation. But they did not disappear immediately, but over about 30 thousand years.
“The fall of the asteroid,” explains Renne, “was the “last straw” as a result of which the Earth moved from the Mesozoic era to the current Cenozoic era. This cataclysm, of course, became the main reason for the extinction of dinosaurs, but not the only one.
By the way, researchers found that after the fall of the asteroid, the carbon cycle in the Earth’s atmosphere returned to normal for more than 5 thousand years. The oceans took about 2 million years to recover.
Many researchers are of the opinion that dinosaurs died as a result of the fall of a large meteorite almost 66 million years ago. True, there are experts who claim that he simply finished off the ancient lizards, who began to die out before the fall of the space “aliens.”
Nevertheless, the very fact of the meteorite fall is naturally not disputed by scientists. Moreover, some experts are carefully studying the impact crater near the Yucatan Peninsula, which is somehow associated with the extinction of dinosaurs.
The impact crater is called Chicxulub (Mayan word for "demon of ticks"). Last spring, an international team of researchers drilled a well in one part of the Chicxulub crater - to a depth of 506 to 1335 meters under the seabed (the crater is partially submerged under the waters of the Gulf of Mexico). And thanks to this, not so long ago scientists were able to determine sea level measurements from prehistoric times.
Now experts have extracted rock samples from under the Gulf of Mexico that were hit by that same meteorite. This material helped scientists obtain vital details that allow them to better understand the ancient event. It turned out that a giant asteroid could not have found a worse place to land on our planet.
The shallow sea covers the “target”, which means that as a result of the fall of the space “alien”, colossal volumes of sulfur released from the mineral gypsum were released into the atmosphere. And following the immediate firestorm that occurred after the meteorite fell, a long period of “global winter” began.
Researchers say that if the intruder had fallen in a different location, the outcome could have been completely different.
"The irony of history is that it wasn't the size of the meteorite or the scale of the explosion that caused the disaster, but where it fell," says Ben Garrod, co-host of The Day the Dinosaurs Died. Day The Dinosaurs Died with Alice Roberts), in which the scientists’ findings were presented.
In particular, experts say, if the asteroid, which was supposedly 15 kilometers across, had reached the Earth a few seconds earlier or later, it would have landed not in shallow coastal waters, but in the deep ocean. A fall in the Atlantic or Pacific Oceans would have resulted in much less rock—including deadly calcium sulfate—evaporating.
The clouds would be less dense, so the sun's rays could make their way to the Earth's surface. Accordingly, the consequences that occurred could have been avoided.
“In that cold, dark world, food ran out in the ocean within one week, and then on land a short time later. Without a food source, the mighty dinosaurs had little chance of survival,” notes Garrod.
It is noted that the core (rock sample) was extracted from depths of up to 1300 meters during drilling in the crater area. The deepest parts of the rock were mined in the so-called "peak ring". By analyzing the properties of this material, the authors of the work hope to reconstruct in more detail the picture of the fall of the asteroid and the subsequent changes, the BBC News website reports.
Researchers, by the way, found that the energy released during the formation of the crater was equal to the energy of approximately ten billion atomic bombs, similar to the one dropped on Hiroshima. Researchers are also studying how the site began to come back to life several years after the meteorite struck.
Let us add that some experts are inclined to believe that, for example, dark matter is to blame for the extinction of dinosaurs, and microbes are also under the “gun.” It is possible that volcanoes also contributed.
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 ancient 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 a thick layer 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 was much more widespread than on land. Among the extinct sea creatures were ammonites that 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, bony fishes (12% died out), 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.
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