Meteor Crater, also known as Barringer Crater
|Diameter||0.737 miles (1.186 km)|
|Depth||560 feet (170 m)|
|Rise||148 feet (45 m)|
|Impactor diameter||160 feet (50 m)|
|Bolide type||Iron meteorite|
|Location||Coconino County, Arizona|
Meteor Crater is a meteorite impact crater approximately 37 miles (60 km) east of Flagstaff and 18 miles (29 km) west of Winslow in the northern Arizona desert of the United States. Because the United States Board on Geographic Names commonly recognizes names of natural features derived from the nearest post office, the feature acquired the name of "Meteor Crater" from the nearby post office named Meteor. The site was formerly known as the Canyon Diablo Crater and fragments of the meteorite are officially called the Canyon Diablo Meteorite. Scientists refer to the crater as Barringer Crater in honor of Daniel Barringer, who was first to suggest that it was produced by meteorite impact. The crater is privately owned by the Barringer family through their Barringer Crater Company, which proclaims it to be the "best preserved meteorite crater on Earth". Despite its importance as a geological site, the crater is not protected as a national monument, a status that would require federal ownership. It was designated a National Natural Landmark in November 1967.
A meteorite is a solid piece of debris from an object, such as a comet, asteroid, or meteoroid, that originates in outer space and survives its passage through the atmosphere to reach the surface of a planet or moon. When the object enters the atmosphere, various factors such as friction, pressure, and chemical interactions with the atmospheric gases cause it to heat up and radiate that energy. It then becomes a meteor and forms a fireball, also known as a shooting star or falling star; astronomers call the brightest examples "bolides". Meteorites vary greatly in size. For geologists, a bolide is a meteorite large enough to create an impact crater.
An impact crater is an approximately circular depression in the surface of a planet, moon, or other solid body in the Solar System or elsewhere, formed by the hypervelocity impact of a smaller body. In contrast to volcanic craters, which result from explosion or internal collapse, impact craters typically have raised rims and floors that are lower in elevation than the surrounding terrain. Impact craters range from small, simple, bowl-shaped depressions to large, complex, multi-ringed impact basins. Meteor Crater is a well-known example of a small impact crater on Earth.
Flagstaff is a city in and the county seat of Coconino County in northern Arizona, in the southwestern United States. In 2015, the city's estimated population was 70,320. Flagstaff's combined metropolitan area has an estimated population of 139,097. The city is named after a ponderosa pine flagpole made by a scouting party from Boston to celebrate the United States Centennial on July 4, 1876.
Meteor Crater lies at an elevation of about 5,710 ft (1,740 m) above sea level. It is about 3,900 ft (1,200 m) in diameter, some 560 ft (170 m) deep, and is surrounded by a rim that rises 148 ft (45 m) above the surrounding plains. The center of the crater is filled with 690–790 ft (210–240 m) of rubble lying above crater bedrock. One of the interesting features of the crater is its squared-off outline, believed to be caused by existing regional jointing (cracks) in the strata at the impact site.
A joint is a break (fracture) of natural origin in the continuity of either a layer or body of rock that lacks any visible or measurable movement parallel to the surface (plane) of the fracture. Although they can occur singly, they most frequently occur as joint sets and systems. A joint set is a family of parallel, evenly spaced joints that can be identified through mapping and analysis of the orientations, spacing, and physical properties. A joint system consists of two or more intersecting joint sets.
The crater was created about 50,000 years ago during the Pleistocene epoch, when the local climate on the Colorado Plateau was much cooler and damper.The area was an open grassland dotted with woodlands inhabited by mammoths and giant ground sloths.
The Pleistocene is the geological epoch which lasted from about 2,588,000 to 11,700 years ago, spanning the world's most recent period of repeated glaciations. The end of the Pleistocene corresponds with the end of the last glacial period and also with the end of the Paleolithic age used in archaeology.
In geochronology, an epoch is a subdivision of the geologic timescale that is longer than an age but shorter than a period. The current epoch is the Holocene Epoch of the Quaternary Period. Rock layers deposited during an epoch are called a series. Series are subdivisions of the stratigraphic column that, like epochs, are subdivisions of the geologic timescale. Like other geochronological divisions, epochs are normally separated by significant changes in the rock layers to which they correspond.
The Colorado Plateau, also known as the Colorado Plateau Province, is a physiographic and desert region of the Intermontane Plateaus, roughly centered on the Four Corners region of the southwestern United States. This province covers an area of 336, 700 km2 (130,000 mi2) within western Colorado, northwestern New Mexico, southern and eastern Utah, and northern Arizona. About 90% of the area is drained by the Colorado River and its main tributaries: the Green, San Juan, and Little Colorado. Most of the remainder of the plateau is drained by the Rio Grande and its tributaries.
The object that excavated the crater was a nickel-iron meteorite about 160 feet (50 meters) across. The speed of the impact has been a subject of some debate. Modeling initially suggested that the meteorite struck at up to 45,000 mph (20 km/s) but more recent research suggests the impact was substantially slower, at 29,000 mph (12.8 km/s). It is believed that about half of the impactor's bulk was vaporized during its descent through the atmosphere. Impact energy has been estimated at about 10 megatons. The meteorite was mostly vaporized upon impact, leaving few remains in the crater.
Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel belongs to the transition metals and is hard and ductile. Pure nickel, powdered to maximize the reactive surface area, shows a significant chemical activity, but larger pieces are slow to react with air under standard conditions because an oxide layer forms on the surface and prevents further corrosion (passivation). Even so, pure native nickel is found in Earth's crust only in tiny amounts, usually in ultramafic rocks, and in the interiors of larger nickel–iron meteorites that were not exposed to oxygen when outside Earth's atmosphere.
Iron is a chemical element with symbol Fe and atomic number 26. It is a metal, that belongs to the first transition series and group 8 of the periodic table. It is by mass the most common element on Earth, forming much of Earth's outer and inner core. It is the fourth most common element in the Earth's crust.
TNT equivalent is a convention for expressing energy, typically used to describe the energy released in an explosion. The "ton of TNT" is a unit of energy defined by that convention to be 4.184 gigajoules, which is the approximate energy released in the detonation of a metric ton of TNT. In other words, for each gram of TNT exploded, 4,184 joules of energy are released.
Since the crater's formation, the rim is thought to have lost 50–65 ft (15–20 m) of height at the rim crest as a result of natural erosion. Similarly, the basin of the crater is thought to have approximately 100 ft (30 m) of additional post-impact sedimentation from lake sediments and of alluvium. These erosion processes are the reason that very few remaining craters are visible on Earth, since many have been erased by these geological processes. The relatively young age of Meteor Crater, paired with the dry Arizona climate, have allowed this crater to remain almost unchanged since its formation. The lack of erosion that preserved the crater's shape helped lead to this crater being the first crater recognized as an impact crater from a natural celestial body.
In earth science, erosion is the action of surface processes that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location. This natural process is caused by the dynamic activity of erosive agents, that is, water, ice (glaciers), snow, air (wind), plants, animals, and humans. In accordance with these agents, erosion is sometimes divided into water erosion, glacial erosion, snow erosion, wind (aeolic) erosion, zoogenic erosion, and anthropogenic erosion. The particulate breakdown of rock or soil into clastic sediment is referred to as physical or mechanical erosion; this contrasts with chemical erosion, where soil or rock material is removed from an area by its dissolving into a solvent, followed by the flow away of that solution. Eroded sediment or solutes may be transported just a few millimetres, or for thousands of kilometres.
Alluvium is loose, unconsolidated soil or sediment that has been eroded, reshaped by water in some form, and redeposited in a non-marine setting. Alluvium is typically made up of a variety of materials, including fine particles of silt and clay and larger particles of sand and gravel. When this loose alluvial material is deposited or cemented into a lithological unit, or lithified, it is called an alluvial deposit.
The crater came to the attention of scientists after American settlers discovered it in the 19th century. They named it the Canyon Diablo crater after Canyon Diablo, Arizona, which was the closest community to the crater in the late 19th century. The crater had initially been ascribed to the actions of a volcano. That was not an unreasonable assumption, as the San Francisco volcanic field lies only about 40 miles (64 km) to the west.
Canyon Diablo is a ghost town in Coconino County, Arizona, United States on the edge of the arroyo Canyon Diablo. The community was settled in 1880 and died out in the early 20th century.
A volcano is a rupture in the crust of a planetary-mass object, such as Earth, that allows hot lava, volcanic ash, and gases to escape from a magma chamber below the surface.
The San Francisco volcanic field is an area of volcanoes in northern Arizona, north of Flagstaff, USA. The field covers 1,800 square miles (4,700 km²) of the southern boundary of the Colorado Plateau. The field contains 600 volcanoes ranging in age from nearly 6 million years old to less than 1,000 years, of which Sunset Crater is the youngest. The highest peak in the field is Humphreys Peak, at Flagstaff's northern perimeter: the peak is Arizona's highest at 12,633 feet and is a part of the San Francisco Peaks, an extinct stratovolcano complex.
In 1891, the mineralogist Albert E. Foote presented the first scientific paper about the meteorites of Northern Arizona. 600 lb (270 kg). Foote identified several minerals in the meteorites, including diamond, albeit of little commercial value. His paper to the Association for the Advancement of Science provided the first geological description of the crater to a scientific community.Several years earlier, Foote had received an iron rock for analysis from a railroad executive. Foote immediately recognized the rock as a meteorite and led an expedition to search and retrieve additional meteorite samples. The team collected samples ranging from small fragments to over
In November 1891, Grove Karl Gilbert, chief geologist for the U.S. Geological Survey, investigated the crater and concluded that it was the result of a volcanic steam explosion.Gilbert had assumed that if it were an impact crater then the volume of the crater, as well as meteoritic material, should be present on the rim. Gilbert also assumed a large portion of the meteorite should be buried in the crater and that this would generate a large magnetic anomaly. Gilbert's calculations showed that the volume of the crater and the debris on the rim were roughly equivalent, so that the mass of the hypothetical impactor was missing, nor were there any magnetic anomalies. Gilbert argued that the meteorite fragments found on the rim were coincidental. Gilbert publicized his conclusions in a series of lectures. In 1892, however, Gilbert would be among the first to propose that the Moon's craters were caused by impact rather than volcanism.
In 1903, mining engineer and businessman Daniel M. Barringer suggested that the crater had been produced by the impact of a large iron-metallic meteorite. Barringer's company, the Standard Iron Company, staked a mining claim to the land and received a land patent signed by Theodore Roosevelt for 640 acres (2.6 km2) around the center of the crater in 1903. The claim was divided into four quadrants coming from the center clockwise from north-west named Venus, Mars, Jupiter and Saturn. In 1906, Roosevelt authorized the establishment of a newly named Meteor, Arizona, post office (the closest post office before was 30 miles (48 km) away in Winslow, Arizona).
Standard Iron Company conducted research on the crater's origins between 1903 and 1905. It concluded that the crater had indeed been caused by an impact. Barringer and his partner, the mathematician and physicist Benjamin Chew Tilghman, documented evidence for the impact theory in papers presented to the U.S. Geological Survey in 1906 and published in the Proceedings of the Academy of Natural Sciences in Philadelphia.
Barringer's arguments were met with skepticism, as there was a reluctance at the time to consider the role of meteorites in terrestrial geology. He persisted and sought to bolster his theory by locating the remains of the meteorite. At the time of discovery, the surrounding plains were covered with about 30 tons of large oxidized iron meteorite fragments. This led Barringer to believe that the bulk of the impactor could still be found under the crater floor. Impact physics was poorly understood at the time and Barringer was unaware that most of the meteorite vaporized on impact. He spent 27 years trying to locate a large deposit of meteoric iron, and drilled to a depth of 1,375 ft (419 m) but no significant deposit was ever found.
Barringer, who in 1894 was one of the investors who made US$15 million in the Commonwealth silver mine in Pearce, Cochise County, Arizona, had ambitious plans for the iron ore.He estimated from the size of the crater that the meteorite had a mass of 100 million tons. The current estimate of 300,000 tons for the impactor is less than 1/300th (0.3 percent) of Barringer's estimate. Iron ore of the type found at the crater was valued at the time at US$125/ton, so Barringer was searching for a lode he believed to be worth more than a billion 1903 dollars.
Despite Barringer's findings and other excavations in the early 20th century, geologists' skepticism continued until the 1950s when planetary science gained in maturity and understanding of cratering processes increased.Professor Herman Leroy Fairchild, an early promoter of impact cratering, argued Barringer's case in an article in Science in 1930.
It was not until 1960 that later research by Eugene Merle Shoemaker confirmed Barringer's hypothesis. The key discovery was the presence in the crater of the minerals coesite and stishovite, rare forms of silica found only where quartz-bearing rocks have been severely shocked by an instantaneous overpressure. It cannot be created by volcanic action; the only known mechanisms of creating it is naturally through an impact event, or artificially through a nuclear explosion.In 1960, Edward C. T. Chao and Shoemaker identified coesite at Meteor Crater, proving the crater was formed from an impact generating extremely high temperatures and pressures. The impact would have disintegrated the main body of iron mass, while the pieces of Canyon Diablo meteorite found scattered around the site, had broken away from the main body before impact.
Geologists used the nuclear detonation that created the Sedan crater, and other such craters from the era of atmospheric nuclear testing, to establish upper and lower limits on the potential energy of the meteor impactor.
The impact created an inverted stratigraphy, so that the layers immediately exterior to the rim are stacked in the reverse order to which they normally occur; the impact overturned and inverted the layers to a distance of one to two kilometers outward from the crater's edge.Specifically, climbing the rim of the crater from outside, one finds:
Soils around the crater are brown, slightly to moderately alkaline gravelly or stony loam of the Winona series; on the crater rim and in the crater itself the Winona is mapped in a complex association with Rock Outcrop.
During the 1960s and 1970s, NASA astronauts trained in the crater to prepare for the Apollo missions to the Moon.
On August 8, 1964, a pair of commercial pilots in a Cessna 150 flew low over the crater. After crossing the rim, they could not maintain level flight. The pilot attempted to circle in the crater to climb over the rim. During the attempted climb out, the aircraft stalled, crashed and caught fire. It is commonly reported that the plane ran out of fuel, but this is incorrect. Both occupants were severely injured but survived their ordeal.A small portion of the wreckage not removed from the crash site remains visible.
In 2006, a project called METCRAX (for METeor CRAter eXperiment) investigated "the diurnal buildup and breakdown of basin temperature inversions or cold air pools and the associated physical and dynamical processes accounting for their evolving structure and morphology."
Meteor Crater is a popular tourist attraction privately owned by the Barringer family through the Barringer Crater Company, with an admission fee charged to see the crater. The Meteor Crater Visitor Center on the north rim features interactive exhibits and displays about meteorites and asteroids, space, the Solar System, and comets. It features the American Astronaut Wall of Fame and such artifacts on display as an Apollo boilerplate command module (BP-29), a 1,406-pound (638 kg) meteorite found in the area, and meteorite specimens from Meteor Crater that can be touched. Formerly known as the Museum of Astrogeology, the Visitor Center includes a movie theater, a gift shop, and observation areas with views inside the rim of the crater. Guided tours of the rim are offered daily, weather permitting.
|Wikimedia Commons has media related to Barringer Crater .|
|Wikivoyage has a travel guide for Meteor Crater .|
|Wikisource has the text of the 1920 Encyclopedia Americana article Crater Mound, Arizona .|
The Wabar craters are impact craters located in Saudi Arabia first brought to the attention of Western scholars by British Arabist, explorer, writer and Colonial Office intelligence officer St John Philby, who discovered them while searching for the legendary city of Ubar in Arabia's Rub' al Khali in 1932.
Eugene Merle Shoemaker, also known as Gene Shoemaker, was an American geologist and one of the founders of the field of planetary science. He is best known for co-discovering the Comet Shoemaker–Levy 9 with his wife Carolyn S. Shoemaker and David H. Levy. This comet hit Jupiter in July 1994: the impact was televised around the world.
Coesite is a form (polymorph) of silicon dioxide SiO2 that is formed when very high pressure (2–3 gigapascals), and moderately high temperature (700 °C, 1,300 °F), are applied to quartz. Coesite was first synthesized by Loring Coes Jr., a chemist at the Norton Company, in 1953.
Daniel Barringer was a geologist best known as the first person to prove the existence of an impact crater on the Earth, the Meteor Crater in Arizona. The site, owned privately by Barringer and now by his family, has been renamed the Barringer Crater in his honor, although this name is mainly used in the scientific community.
Sierra Madera crater is a meteorite crater (astrobleme) in southwestern Pecos County, Texas, United States. The central peak of the rebound structure of the impact crater rises 793 ft (242 m) above the surrounding land. The peak is visible from U.S. Highway 385 between Fort Stockton, Texas and Marathon, Texas. The Sierra Madera crater is located on private property on the La Escalera Ranch.
Upheaval Dome is an impact structure, the deeply eroded bottom-most remnants of an impact crater, in Canyonlands National Park southwest of the city of Moab, Utah, in the United States. The crater is located in the Island in the Sky section of the park, and is approximately 42 miles (67 km) by vehicle from Moab.
Veevers crater is an impact crater located on a flat desert plain between the Great Sandy and Gibson Deserts in the center of the state of Western Australia. The site is very remote and difficult to visit. The crater was discovered from the air in July 1975 during a government geological survey and named in honor of Australian geologist John Veevers who had worked in the area in the late 1950s. At the time of discovery a meteorite impact origin was suspected, but could not be proven. The subsequent discovery of iron meteorite fragments around the crater by E.M. and C.S. Shoemaker in 1984 removed any doubt about its origin.
Grove Karl Gilbert, known by the abbreviated name G. K. Gilbert in academic literature, was an American geologist.
Planetary geology, alternatively known as astrogeology or exogeology, is a planetary science discipline concerned with the geology of the celestial bodies such as the planets and their moons, asteroids, comets, and meteorites. Although the geo- prefix typically indicates topics of or relating to Earth, planetary geology is named as such for historical and convenience reasons; due to the types of investigations involved, it is closely linked with Earth-based geology.
The Canyon Diablo meteorites include the many fragments of the asteroid that created Barringer Crater, Arizona, United States. Meteorites have been found around the crater rim, and are named for nearby Canyon Diablo, which lies about three to four miles west of the crater.
H. Jay Melosh is an American geophysicist specialising in impact cratering. He earned a degree in physics from Princeton University and a doctoral degree in physics and geology from Caltech in 1972. Melosh's research interests include impact craters, planetary tectonics, and the physics of earthquakes and landslides. His recent research includes studies of the giant impact origin of the moon, the Chicxulub impact that is thought to have extinguished most dinosaurs, and studies of ejection of rocks from their parent bodies. He is active in astrobiological studies that relate chiefly to the exchange of microorganisms between the terrestrial planets.
Coconino Sandstone is a geologic formation named after its exposure in Coconino County, Arizona. This formation spreads across the Colorado Plateau province of the United States, including northern Arizona, northwest Colorado, Nevada, and Utah.
Edward Ching-Te Chao was one of the founders of the field of impact metamorphism, the study of the effects of meteorite impacts on the Earth's crust.
Meteoritics & Planetary Science is a monthly peer-reviewed scientific journal that was established in 1953. It is published by Wiley-Blackwell on behalf of the Meteoritical Society. Since January 1, 2003, the editor-in-chief is A.J. Timothy Jull. The journal's broad focus is planetary science.
Peter H. Schultz is Professor of Geological Sciences at Brown University specializing in the study of planetary geology, impact cratering on the Earth and other objects in the Solar System, and volcanic modifications of planetary surfaces. He was co-investigator to the NASA Science Mission Directorate spacecraft Deep Impact and the Lunar Crater Observation and Sensing Satellite (LCROSS). He was awarded the Barringer Medal of the Meteoritical Society in 2004 for his theoretical and experimental studies of impact craters.
The Odessa Meteor Crater is a meteorite crater in the southwestern part of Ector County, southwest of the city of Odessa of West Texas, United States. It is accessible approximately 3 mi (5 km) south of Interstate 20 at Exit 108. This is one of three impact crater sites found in Texas, the others being the older and much larger Sierra Madera crater and the Marquez crater.