The largest craters on earth. Arizona Crater is a unique meteorite crater in Arizona.

Background

One of the first scientists to link the crater to a meteorite impact was Daniel Barringer (1860-1929). He studied the impact crater in Arizona that now bears his name. However, these ideas were not widely accepted at the time (nor was the fact that the Earth was regularly bombarded by meteorites).

In the 1920s, American geologist Walter Bacher, who studied a number of craters in the United States, suggested that they were caused by some kind of explosive events within the framework of his theory of “Earth pulsation.”

Space research has shown that impact craters are the most common geological structure in the Solar System. This confirmed the fact that the Earth is subject to regular meteorite bombardment.

File:Astrobleme.Morphology.1.jpg

Rice. 1. Structure of the astrobleme.

Geological structure

The structural features of craters are determined by a number of factors, among which the main ones are impact energy (depending, in turn, on the mass and speed of the cosmic body, the density of the atmosphere), the angle of contact with the surface and the hardness of the substances forming the meteorite and the surface.

With a tangential impact, groove-shaped craters of small depth appear with weak destruction of the underlying rocks; such craters are destroyed quite quickly due to erosion. An example is the Rio Quarta crater field in Argentina, which is about 10,000 years old: the largest crater field is 4.5 km long and 1.1 km wide with a depth of 7-8 m.

Rice. 2. Astrobleme Mjolnir (Norway, diameter 40 km), seismic data

When the collision direction is close to vertical, rounded craters appear, the morphology of which depends on their diameter (see Fig. 1). Small craters (3-4 km in diameter have a simple bowl-shaped shape, their crater is surrounded by a shaft formed by uplifted layers of underlying rocks (Fig. 1, 6) (basement shaft), covered with debris ejected from the crater (fill shaft, allogeneic breccia (Fig. 1) : 1)). Under the bottom of the crater lie authigenic breccias (Fig. 1: 3) - rocks crushed and partially metamorphosed (Fig. 1: 4) during a collision; under the breccia there are fractured rocks (Fig. 1: 5,6) The depth to diameter ratio of such craters is close to 1/3, which distinguishes them from crater-shaped structures of volcanic origin, in which the depth to diameter ratio is ~0.4.

Rice. 3. Yalali Astrobleme (Australia, diameter 12 km), magnetic survey data

With large diameters, a central hill appears above the impact point (at the point of maximum compression of the rocks); with even larger crater diameters (more than 14-15 km), ring uplifts are formed. These structures are associated with wave effects (like a drop falling on the surface of water). As the diameter increases, the craters quickly flatten: the depth/diameter ratio drops to 0.05-0.02.

The size of the crater may depend on the softness of the surface rocks (the softer the rock, the smaller the crater usually is).

On bodies that do not have a dense atmosphere, long “rays” (formed as a result of the ejection of matter at the moment of impact) can remain around the craters.

According to the international classification of impactites (International Union of Geological Sciences, 1994), impactites localized in the crater and its surroundings are divided into three groups (according to composition, structure and degree of impact metamorphism):

• impacted rocks - target rocks that are weakly transformed by the shock wave and thereby retain their characteristic features;
• melt rocks are products of solidification of the impact melt;
• impact breccias are clastic rocks formed without the participation of impact melt or with a very small amount of it.

Impact events in Earth's history

It is estimated that once every million years a meteorite hits the Earth, creating a crater at least 20 km wide. This suggests that fewer craters (including “young” ones) were discovered than there should be.

List of the most famous terrestrial craters:

• Chesapeake Bay impact crater (East USA)
• Haughton impact crater (Canada)
• Lonar crater (India)
• Mahuika crater (New Zealand)
• Manson crater (USA)
• Mistastin crater (Canada)
• Nordlinger Ries (Germany)
• Panther Mountain New York, (USA)
• Rochechouart crater (France)
• Sudbury Basin (Canada)
• Silverpit crater (UK, in the North Sea)
• Rio Cuarto craters (Argentina)
• The Siljan Ring (Sweden)
• Vredefort crater (Vredefort, South Africa)
• Weaubleau-Osceola impact structure (USA Center)

Crater erosion

Craters are gradually destroyed by erosion and geological processes that change the surface. Erosion occurs most intensely on planets with dense atmospheres. The well-preserved Arizona crater Barringer is no more than 50 thousand years old.

At the same time, there are bodies with very low cratering and at the same time almost devoid of atmosphere. For example, on Io the surface is constantly changing due to volcanic eruptions, and on Europa - as a result of the reshaping of the ice shell under the influence of the internal ocean. In addition, on ice bodies the relief of craters is smoothed out as a result of ice melting (over geologically significant periods of time), since ice is more plastic than rocks. An example of an ancient crater with erased relief is Valhalla on Callisto. Another unusual type of erosion was discovered on Callisto - destruction presumably as a result of sublimation of ice under the influence of solar radiation.

The ages of known impact craters on Earth range from 1000 years to almost 2 billion years. Very few craters older than 200 million years have survived on Earth. Craters located on the seabed are even less tenacious.

Notes

Literature

• V. I. Feldman. Astroblems - star wounds of the Earth, Soros educational magazine, No. 9, 1999
• Ring structures of the face of the planet. - M.: Knowledge, K 62 1989. - 48 p. - (New in life, science, technology. Series “Earth Sciences”; No. 5)

Links

• Classification and nomenclature of impactites. International Union of Geological Sciences (IUGS), Subcommission of the Systematics of Metamorphic Rocks (SCMR), Study group K (Chairman: D. Stöffler)
• Detailed aeromagnetic survey over the Yallalie astrobleme, Western Australia by Phil Hawke & M. C. Dentith, Center for Global Metallogeny, The Univercity of Western Australia

Earth Craters Google Maps KMZ(KMZ tag file for Google Earth)

Moon
Physical peculiarities	Internal structure Gravity Topography Magnetic field Atmosphere
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Lunar surface	Selenography Visible side Far side of the Sea Impact crater

Meteorites and asteroids are the heavy artillery of space. They plowed, opened its crust to the very depths of the mantle, and covered the surface with scatterings of craters. Our Earth, unlike its airless satellite, is protected from space rocks. In it, most of the “aliens” burn out before they even touch the surface. But there are meteorites that break through the barrier and are capable of destroying entire cities and countries. The Arizona Crater, also known as Barringer Crater and Devil's Canyon, reminds us of this - the trace from the closest meteorite fall to us.

How the crater appeared

50 thousand years ago, the Arizona Desert in the USA was not such a hot and arid place. Then it was a flowering field, crossed by forests and oak groves - the landscape was somewhat reminiscent of the forest-steppes of Ukraine and Russia. Mammoths and giant sloths, not much smaller than mammoths, roamed around them. The valley was cut through by numerous rivers, and it rained heavily; nothing prevented the lush growth of vegetation. But one day the primitive idyll was interrupted.

The peaceful slumber was broken by a bright flash, and then by growing thunder - a fireball appeared in the sky, which fell to the Earth with lightning speed. A meteorite with a girth of 50 meters and a mass of 300 thousand tons cannot be called large - there are ones that are hundreds of times larger. Nevertheless, the explosion from the fall of the Arizona meteorite was colossal. The power was 150 megatons of TNT equivalent, which is three times more powerful than the most powerful exploded nuclear charge in history, the Tsar Bomba. This is not strange, because the fallen space rock belonged to the “heavy class” of meteorites containing a lot of nickel and iron.

The force of the meteorite devastated the surrounding area. An earthquake with a magnitude of seven reached 300 kilometers away, and the sound of the explosion was as strong as the noise of active construction. A fireball with a radius of 700 meters rose above the horizon - its radiation set fire to grass and trees nearby. Rain of rubble and debris covered an area with a radius of 100 kilometers. And the meteorite itself half evaporated from the force of its own impact - and its fragments scattered throughout the crater and the surrounding area.

The Arizona crater is visited by thousands of tourists, but they are not allowed to go down. On our website, using Google StreetView, you can walk along the bottom of the crater like a real scientist!

Arizona Meteor Crater today

However, time passed, and the Earth healed the wound on itself. Water and air smoothed out the outlines of the crater and transformed its appearance - it even managed to become a lake into which nearby rivers flowed. The bottom was covered with sediment and seasonal vegetation, growing after rare desert rains, and the edges were smoothed. But the peculiarities of the desert climate of Arizona have allowed the crater to be preserved better than many of its counterparts. Today we highlight:

• The funnel is 1.2 kilometers in diameter and 170 meters deep. It will fit a small skyscraper with the top on! In addition, the rim of the crater rises to a height of 46 meters.
• Unusual crater shape. Typically, impact marks are round or elliptical - and the Arizona crater, a photo of which was taken from the air at the beginning of the 20th century, resembles a rounded square, like a chocolate bar. Scientists explain such anomalous outlines by shifts in the earth's crust caused by the force of the impact.

• The largest well-preserved crater on the planet. Yes, there are bigger meteorite craters on Earth. The record holder, the Vredefort crater, stretches 125 kilometers in all directions - its area would fit several dwarf European countries. However, it is only possible to understand that Vredefort is a crater from a satellite. Water, wind and movement blurred the clarity of its form. And the Arizona crater is not only intact, but also looks almost fresh, as if a meteorite fell quite recently.

Although Indians have been collecting metal meteorite fragments for spears and arrows since ancient times, scientists have long thought that the Arizona crater was left from a volcano, and not from a cosmic body. However, engineer Daniel Berringer, after whom the crater was named, thought differently. He believed that only a meteorite could have dug such a huge bowl-shaped hole, and hoped to find it under the crater and get rich. He bought the entire territory of the crater and spent decades searching for the remains of cosmic iron. According to legend, he died of a heart attack when physicists calculated that there was nothing to look for underground.

However, now the crater brings his family considerable income. Scientists are looking for minerals on the untouchable bottom of the crater that can give them doctorates, tourists admire the majestic remains of a cosmic explosion from observation platforms. In the USA, the Arizona crater is called the “Tomb of Hat” - a strong wind rages over the edges of the crater, which blows the caps and hats of dozens of tourists into the inviolable bottom of the crater. It was also in the crater that the Apollo astronauts practiced their mission to the Moon. After all, this is the only place on Earth whose landscape repeats the topography of our satellite.

Barringer Crater December 19th, 2012

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Approximately 30,000-50,000 years ago, a giant block of rock fell to Earth near Devil's Canyon in Arizona, creating a bowl-shaped sinkhole 1,250 m in diameter and 174 m deep on the surface of the planet. Barringer Crater, which is also known as Arizona Crater, Un Goro Crater, Devil's Canyon, is a meteorite crater (astrobleme) located approximately 43 miles (69 kilometers) east of the city of Flagstaff, 30 kilometers west of the city of Winslow in desert of Northern Arizona in the USA. Because the U.S. Board of Geographic Names typically names natural features according to the name of the nearest post office, the crater is also known as "Meteor Crater" due to the nearby post office being called Meteor.

This site was previously known as Devil's Canyon Crater, and the meteorite fragments that are located at the bottom of the crater were officially named the Devil's Canyon meteorite. Scientists call the crater Barringer Crater - in honor of the discoverer of this place, Philadelphia mining engineer Daniel Moreau Barringer. It was he who first put forward the hypothesis that the giant crater appeared as a result of a meteorite hitting the earth.

Meteorite from crater Barringer, Arizona.

To create such a huge crater, the meteorite flew through the atmosphere at a speed of 69,000 km/h or so. The force of its impact on the Earth was equal to the force of an explosion of 500,000 tons of explosive material (almost 40 times more powerful than the explosion of the atomic bomb that destroyed Hiroshima). 100 million tons of crushed rocks were thrown into the atmosphere. Sediments formed that now make up the slopes of the crater. Drops of molten metal from the meteorite scattered over an area of ​​260 km2. The fragments were no larger than pebbles, although some reached 630 kg. The rocks ejected from the crater were a mixture of sandstone and limestone - remnants of the fossil-rich rocks of a prehistoric lake bed that once existed in the region. A thick lens-shaped layer of the same rocks, called breccia, now covers the crater floor. In the 1930s, funds were allocated to drill through the breccia to the crater floor. At a depth of up to 260 m, traces of nickel and iron appeared; below this level, the rocks remained untouched. It can be assumed that the remains of the meteorite lie under the southern edge of the crater, but make up no more than 10% of the main rocks. The main mass of the meteorite was dispersed during the collision, turning into iron-nickel fragments. In 1960, traces of two rare forms of silica were discovered in the crater bowl - coesite and stishovite, which are also obtained artificially under conditions of high pressure and temperature. (Although stishovite can form under high pressure deep within the Earth's crust, it reverts to quartz when it comes to the surface.) The presence of these minerals in natural form in the crater area provides compelling evidence of a violent impact. All doubts about the nature of the origin of the crater were dispelled, and Barringer’s assumptions about the meteorite nature of the crater that now bears his name were completely confirmed. Although the crater is a geological landmark, it is not protected as a national monument. This status requires that the object be in federal ownership. Barringer Crater became a National Natural Landmark in November 1967.

Daniel Barringer Barringer Meteor Crater is located at an altitude of about 1,740 meters (5,709 ft) above sea level. It is a giant earthen bowl about 1,200 meters (4,000 ft) in diameter, about 170 meters (570 ft) deep, surrounded by a rim that rises 45 meters (150 ft) above the surrounding plains. The center of the crater is filled with a layer of rubble and nickel iron fragments totaling 210-240 meters (700-800 ft) thick, which lies at the bottom of a giant earthen bowl. One of the interesting features of the crater is its square outline.

The crater was formed about 50 thousand years ago during the Pleistocene era, when the local climate on the Colorado Plateau was much cooler and wetter. At that time, this area was meadows and pastures where mammoths roamed. There were most likely no human settlements in this area; the first official evidence of the appearance of humans in the territory of both Americas dates back to a much later period. The first people appeared near the crater approximately 25 thousand years ago. The Indians, whose tribes inhabited this area, told a legend that many years ago a fiery god descended to earth on his chariot, after which a crater was formed. Therefore, the Indians used meteorite fragments as an amulet and placed them in the graves of their dead relatives.

The object that caused the crater when it hit the ground was a nickel meteorite that was about 50 meters (54 yards) across. The meteorite crashed into the plain at a speed of several kilometers per second. The impact energy is estimated at 10 megatons. The speed of the collision itself has been the subject of some debate. As a result of their modeling, scientists initially suggested that the meteorite hit the ground at speeds of up to 20 kilometers per second (45,000 mph), but recent research suggests that the speed was significantly lower, at approximately 12.8 kilometers per second (28,600 mph). h). It is believed that about half the meteorite's 300,000 metric tons weight was vaporized in the atmosphere and upon impact with Earth. That is why the search for the meteorite undertaken by the discoverer of the crater, Daniel Barringer, was unsuccessful.

Today, Barringer Meteor Crater is a popular tourist attraction, privately owned by the third generation of the Barringer family. Anyone wishing to view the crater must pay a small fee. Literally on the edge of the crater there is a museum with interactive exhibits and displays about meteorites and asteroids, space, the solar system and comets. In addition, photographs of all American astronauts in full space gear are stored here - a kind of “wall of fame.” Here you can also see a 1,406-pound meteorite found nearby, as well as meteorite fragments from Barringer Crater itself, which you can even touch. In addition, there is a cinema, a souvenir shop, and an observation deck from which you can admire the crater. Tours of Barringer Crater are offered daily.

Arizona Crater (Barringer Crater, Devil's Canyon) is one of the largest and best preserved meteorite craters located near Diablo Canyon in northern Arizona (USA). The current dimensions of the crater: diameter - 1220 m, depth - 184 m, height of the shaft 50 m. It is assumed that the crater was created as a result of the fall to Earth about 50 thousand years ago of a two-million-ton nickel meteorite measuring 61-79 m. The explosion from the fall was similar in power explosion of 1000 atomic bombs similar to the one dropped on Hiroshima.

His fame is determined by many reasons. First of all, this is the first such formation for which it has been proven that it arose when a huge meteorite hit the Earth. More than 30 tons of meteorite iron fragments were collected in and around the crater, and the largest of them weighed 639.1 kg. In addition, around the crater in the soil and on the surface there is a mass of small and tiny balls and dust particles of meteorite iron. Moreover, this is the first meteorite in which diamonds were found.
The first people settled near the crater 25 thousand years ago. And the Indians who inhabited this area told a legend that the once fiery god descended on a chariot, after which a crater remained. Therefore, the Indians wore fragments of the meteorite as amulets and placed them in the graves of their dead relatives.

Scientists became aware of the existence of the crater only in 1891. In 1902, mining engineer Barringer bought a piece of land with a crater. Barringer gave 26 years of his life searching for the meteorite and convincing others that his crater was of extraterrestrial meteorite origin. From that time to the present day, the Arizona Crater is the only natural object of its type that is privately owned. It belongs to the third generation of the Barringer family.

The crater has been used more than once as a backdrop for filming science fiction films about earthlings’ travels to other planets and the arrival of huge UFOs in their secret harbor, closed from prying eyes.

This is not the largest meteorite to fall to Earth. In Antarctica, on Wilkes Island, a meteorite crater with a diameter of 241 kilometers and a depth of 800 m was discovered in 1962. In Canada, on the coast of Hudson Bay, there is a crater with a diameter of 443 km.

Origin of the crater

The crater appeared about 50 thousand years ago after the fall of a 60-80 meter meteorite, weighing 300 thousand tons and flying at a speed of 45-60 thousand km/h. The explosion from the fall was three times more powerful than the explosion and was similar in power to the explosion of 20 million tons or 1000 atomic bombs similar to those dropped on. Fragments of meteorite nickel iron have been found in and around the Arizona Crater.

History of discovery and research

The location of the crater was known for a long time to local Indians, who used metal fragments of the meteorite for their own purposes. Local tribes have a huge number of legends and traditions associated with this sacred place. Scientists became aware of the existence of the crater only a year ago.

Astronauts training in the crater

The Arizona crater was recognized as the only place on Earth that most closely resembles a lunar landscape, and it was there that, under the leadership of Shoemaker, all the astronauts who were to go on a flight to the Moon underwent part of their training. And it was in this crater that the shortcomings of the spacesuits in which the first earthlings were to leave their mark on the Moon were identified and eliminated.

Tourism

It is impossible not to mention the museum, which stands literally on the edge of the crater and stores photographs of all the “lunar” astronauts in full space gear. If you don’t know that these pictures were taken literally two steps from where you are standing, you might believe that they are of lunar origin. Arizona Crater is one of the attractions. Many tourists visit it every day. To attract tourists, local residents regularly report numerous observations of airglow and hovering over this place, as well as mysterious geomagnetic anomalies inside the crater.

The sale of meteorites found in this crater (or passed off as them) is a thriving and quite profitable business. The cost of such meteorites in online stores averages $1 for each gram of weight.

Comparison with other meteorite craters on Earth

Meteor Crater in Arizona, often called Barringer Crater after its discoverer, is by no means the largest on Earth. A meteorite crater with a diameter of 241 kilometers and a depth of 800 meters was discovered on Wilkes Island. In Canada, on the coast of Hudson Bay, there is a crater with a diameter of 443 kilometers. However, unlike the largest ones, whose diameter is measured in hundreds of kilometers, the Arizona crater is the only one that has retained its almost pristine appearance. As the museum’s official brochure proudly states, “although there are larger impacts on Earth, this crater was the first to be proven to be of meteorite origin and is the best preserved of its original appearance.”