Meteor Crater

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.[2] The site was formerly known as the Canyon Diablo Crater and fragments of the meteorite are officially called the Canyon Diablo Meteorite.[3] 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.[4] 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".[5][6] 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.[7]

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.[1] 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.[8]

Meteor Crater
Barringer Crater
Meteor Crater - Arizona
Meteor Crater, also known as Barringer Crater
Impact crater/structure
ConfidenceConfirmed[1]
Diameter0.737 miles (1.186 km)
Depth560 feet (170 m)
Rise148 feet (45 m)
Impactor diameter160 feet (50 m)
Age50,000 years
ExposedYes
DrilledYes
Bolide typeIron meteorite
Location
LocationCoconino County, Arizona
Coordinates35°1′38″N 111°1′21″W / 35.02722°N 111.02250°WCoordinates: 35°1′38″N 111°1′21″W / 35.02722°N 111.02250°W
CountryUnited States
StateArizona
Meteor Crater is located in Arizona
Meteor Crater
Meteor Crater
Location of Meteor Crater in Arizona
AccessInterstate 40
DesignatedNovember 1967
Meteor Crater 08 2010 151
The Holsinger meteorite is the largest discovered fragment of the meteorite that created Meteor Crater and it is exhibited in the crater visitor center.
Landsat Meteor Crater
The Barringer Meteor Crater from space. The Diablo Canyon arroyo is to the west (left). The ghost town of Diablo Canyon, for which the meteorite is named, is on the canyon just to the north and out of the picture.
The Meteor Crater from 36,000 feet
The Meteor Crater from 36,000 ft (11,000 m)

Formation

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.[9][10] The area was an open grassland dotted with woodlands inhabited by mammoths and giant ground sloths.[11][12]

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.[13] Impact energy has been estimated at about 10 megatons. The meteorite was mostly vaporized upon impact, leaving few remains in the crater.[14]

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.[15] 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.[16]

Discovery and investigation

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.[17]

Meteorcrater
Aerial view of Arizona Meteor Crater, September 2010
Barringer-1001
Looking into the crater from the north rim. The rust colored area on the far (south) rim is where the last mining for the meteorite occurred in 1929 and was believed to be the site of the bulk of the meteorite. Rock around the south rim is uplifted.

Albert E. Foote

In 1891, the mineralogist Albert E. Foote presented the first scientific paper about the meteorites of Northern Arizona.[18] 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 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.[19]

Grove Karl Gilbert

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.[19] 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.[20] In 1892, however, Gilbert would be among the first to propose that the Moon's craters were caused by impact rather than volcanism.[21]

Daniel Barringer

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.[22][23][24] 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).[25]

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.[26]

Meteorite fragment from the Cañon Diablo Meteorite
Fragment of the Cañon Diablo Meteorite

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.[27]

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.[28] He estimated from the size of the crater that the meteorite had a mass of 100 million tons.[20] The current estimate of 300,000 tons for the impactor is more than 300 times less (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.[28]

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.[29] Professor Herman Leroy Fairchild, an early promoter of impact cratering, argued Barringer's case in an article in Science in 1930.[13][30]

Eugene M. Shoemaker

Barringer Crater aerial photo by USGS
Meteor Crater

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.[22][31] 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.[32]

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.[33]

Geology

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.[34][35] 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.[36]

Panoramic view from upper deck
Panoramic view from upper deck
Panoramic from the lower viewing deck
Panoramic from the lower viewing deck

Recent history

Barringer Crater bottom crop inset
Closeup of old mine shaft at the bottom of the crater. Note astronaut cutout and flag attached to fence (inset)          full size image
Meteor Crater Under a Big Sky 2010
Meteor Crater, 2010

During the 1960s and 1970s, NASA astronauts trained in the crater to prepare for the Apollo missions to the Moon.[37][38]

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.[39] A small portion of the wreckage not removed from the crash site remains visible.[40]

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."[41][42]

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.[43]

See also

Notes

  1. ^ a b "Barringer". Earth Impact Database. University of New Brunswick. Retrieved 2008-12-30.
  2. ^ "J. P. Barringer's acceptance speech." Meteoritics, vol. 28, p. 9 (1993). Retrieved on the SAO/NASA Astrophysics Data System.
  3. ^ La Pas, L. (1943). "Remarks on four notes recently published by C. C. Wylie", Popular Astronomy, vol. 51, p. 341
  4. ^ Grieve, R.A.F. (1990) "Impact Cratering on the Earth", Scientific American, 262 (4), 66–73.
  5. ^ "Barringer Meteorite Crater * Meteorites Craters and Impacts". Barringercrater.com. Retrieved 2010-03-16.
  6. ^ "Meteor Crater". Meteor Crater. Retrieved 2012-11-24.
  7. ^ "Barringer Meteor Crater". US Dept of Interior, National Park Service. Retrieved 19 February 2013.
  8. ^ Shoemaker, Eugene M.; Susan W. Kieffer (1979). Guidebook to the Geology of Meteor Crater, Arizona. Tempe, Arizona: Center for Meteorite Studies, Arizona State University. p. 45.
  9. ^ Roddy, D. J.; E. M. Shoemaker (1995). "Meteor Crater (Barringer Meteorite Crater), Arizona: summary of impact conditions". Meteoritics. 30 (5): 567.
  10. ^ Nishiizumi, K.; Kohl, C.P.; Shoemaker, E.M.; Arnold, J.R.; Klein, J.; Fink, D.; Middleton, R. (1991). "In situ 10Be-26Al exposure ages at Meteor Crater, Arizona" (PDF). Geochimica et Cosmochimica Acta. 55 (9): 2699–2703. Bibcode:1991GeCoA..55.2699N. doi:10.1016/0016-7037(91)90388-L.
  11. ^ Kring, David (1997). "Air blast produced by the Meteor Crater impact event and a reconstruction of the affected environment". Meteoritics and Planetary Science. 32 (4): 517–30. Bibcode:1997M&PS...32..517K. doi:10.1111/j.1945-5100.1997.tb01297.x.
  12. ^ Kring, David. "Barringer Meteor Crater and Its Environment". Lunar and Planetary Institute. Retrieved 2014-02-12.
  13. ^ a b Melosh HJ; Collins GS (2005). "Planetary science: Meteor Crater formed by low-velocity impact". Nature. 434 (7030): 157. Bibcode:2005Natur.434..157M. doi:10.1038/434157a. PMID 15758988.
  14. ^ Schaber, Gerald G. "A Chronology of Activities from Conception through the End of Project Apollo (1960–1973)", 2005, U.S. Geological Survey Open-File Report 2005-1190. (PDF)
  15. ^ Poelchau, Michael; Kenkmann, Thomas; Kring, David (2009). "Rim uplift and crater shape in Meteor Crater: Effects of target heterogeneities and trajectory obliquity". Journal of Geophysical Research. AGU. 114 (E1). Bibcode:2009JGRE..114.1006P. doi:10.1029/2008JE003235. Retrieved 11 October 2015.
  16. ^ "Meteorite Crater – The shape of the land, Forces and changes, Spotlight on famous forms, For More Information". scienceclarified.com.
  17. ^ McCall, Gerald Joseph Home; Bowden, A. J.; Howarth, Richard John (17 August 2017). "The History of Meteoritics and Key Meteorite Collections: Fireballs, Falls and Finds". Geological Society of London – via Google Books.
  18. ^ Foote, A. E (1891). "A new locality for meteoric iron with a preliminary notice of the discovery of diamonds in the iron". American Journal of Science (251): 413. doi:10.2475/ajs.s3-42.251.413.
  19. ^ a b Kring, David (2007). Guidebook to the Geology of Barringer Meteorite Crater. Houston, Texas: Lunar and Planetary Institute.
  20. ^ a b "Crater History: Investigating a Mystery". The Barringer Crater Company. Retrieved 19 February 2013.
  21. ^ Burke, John G. (1986). Cosmic Debris: Meteorites in History. Berkeley: University of California Press. p. 276. ISBN 0520056515.
  22. ^ a b Oldroyd, David Roger, ed. (2002). The Earth Inside and Out: Some Major Contributions to Geology in the Twentieth Century. Geological Society. pp. 28–32. ISBN 1-86239-096-7.
  23. ^ McCall, G.J.H.; Bowden, A.J.; Howarth, R.J., eds. (2006). The History of Meteoritics and Key Meteorite Collections. Geological Society. p. 61. ISBN 978-1-86239-194-9.
  24. ^ Barringer, B. (December 1964). "Daniel Moreau Barringer (1860–1929) and His Crater (the beginning of the Crater Branch of Meteoritics)". Meteoritics. Meteoritical Society. 2 (3): 186. Bibcode:1964Metic...2..183B. doi:10.1111/j.1945-5100.1964.tb01428.x.
  25. ^ "1983Metic..18..159H Page 162". articles.adsabs.harvard.edu. Bibcode:1983Metic..18..159H.
  26. ^ Barringer, D.M. (1906). "Coon Mountain and its Crater." Proceedings of the Academy of Natural Science of Philadelphia, 57:861–86. PDF
  27. ^ Smith, Dean. The Meteor Crater Story. Meteor Crater Enterprises, Inc. pp. 17–25.
  28. ^ a b Southgate, Nancy; Barringer, Felicity (2002). A Grand Obsession: Daniel Moreau and His Crater. Barringer Crater Co.
  29. ^ "Progress in Wide Search for Meteor". June 25, 1928. Retrieved 2010-07-13.
  30. ^ Fairchild HL (1930). "Nature and fate of the Meteor Crater bolide". Science. 72 (1871): 463–66. Bibcode:1930Sci....72..463F. doi:10.1126/science.72.1871.463. PMID 17800007.
  31. ^ Shoemaker, Eugene M. (1987). "Meteor Crater, Arizona", Geological Society of America Centennial Field Guide – Rocky Mountain Section.
  32. ^ Levy, David (2002). Shoemaker by Levy: The man who made an impact. Princeton: Princeton University Press. pp. 69, 74–75, 78–79, 81–85, 99–100. ISBN 9780691113258.
  33. ^ "Keyah Math – Numerical Solutions for Culturally Diverse Geology". keyah.asu.edu.
  34. ^ Kring, David (2007). Guidebook to the Geology of Barringer Meteorite Crater, Arizona. Houston, Texas: Lunar and Planetary Institute.
  35. ^ "Basic Stratigraphy of Barringer Meteor Crater". Department of Planetary Science, University of Arizona. Retrieved 19 February 2013.
  36. ^ https://websoilsurvey.sc.egov.usda.gov/App/WebSoilSurvey.aspx
  37. ^ "Apollo Lunar Training". nau.edu.
  38. ^ Phinney, William (2015). Science Training History of the Apollo Astronauts. NASA SP -2015-626. p. 180,187,193,220,222,224,233-234,238,245.
  39. ^ Harro Ranter. "ASN Aircraft accident 08-AUG-1964 Cessna 150 N6050T". aviation-safety.net.
  40. ^ Plane Crash At Meteor Crater Revisited, September 1, 2008 Meteorite-times.com
  41. ^ "University of Utah METCRAX page". Archived from the original on 2012-04-23.
  42. ^ "METCRAX". utah.edu.
  43. ^ "admissions - Meteor Crater". Meteor Crater. Retrieved 2018-01-16.

External links

Bopfingen

Bopfingen is a small city in Baden-Württemberg, Germany. It is situated in the Ostalbkreis, between Aalen and Nördlingen. It consists of the city Bopfingen itself and its suburbs Aufhausen, Baldern, Flochberg, Kerkingen, Oberdorf, Schloßberg, Trochtelfingen, and Unterriffingen.

Bopfingen is famous for its landmark Ipf, a table mountain which is part of the neighboring Schwäbische Alb to the east. To the west it borders to Bavaria and the meteor crater Nördlinger Ries.

The first known settlers came to the area 8000 years ago in the Holocene. Also Celtic and Roman relics were found. It was first mentioned between 775-850 AD in a deed of foundation of "Traditiones Fuldenses" where it was called "Pophingen".

Canyon Diablo

Canyon Diablo may refer to:

Canyon Diablo (canyon), Arizona, U.S.

Canyon Diablo (meteorite), fragments found in Meteor Crater near the canyon

Canyon Diablo Crater, former name of Meteor Crater

Canyon Diablo, Arizona, a ghost town near the canyon

Canyon Diablo Bridge, which crosses the canyon near the ghost town of Two Guns

Canyon Diablo shootout, a 1905 gunfight at the canyon

Canyon Diablo, Arizona

Canyon Diablo (Navajo: Kin Łigaaí) 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.

The town, which is about 12 mi (19 km) northwest of Meteor Crater, was the closest community to the crater when portions of the meteorite were removed. Consequently, the meteorite that struck the crater is officially called the "Canyon Diablo Meteorite."

Canyon Diablo (meteorite)

The Canyon Diablo meteorites include the many fragments of the asteroid that created Barringer Crater (Meteor 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.

Chubb

Chubb may refer to:

Chubb (surname), a surname

(Timothy) "Chubb" O'Connor (1906–1986), Irish Fianna Fáil politician

Chubb Rock, rapper

(James Talbot) "Chubb" Vigne (1868–1955), South African international rugby union player

Chubb illusion, an optical illusion dealing with visual perception

Chubb Limited, the U.S. insurance company

Chubb Locks, the British lock and security company

Chubb Security, a British firm specialised in fire protection

Chubb Crater, a meteor crater in Quebec

Chubb, a fictional family of Hobbits

Chubb, alternative spelling for Chub, a European river fish

HMS Chub, or HMS Chubb, the name of three ships of the Royal Navy

Daniel Barringer (geologist)

For other people named Daniel Barringer, see Daniel Barringer (disambiguation).Daniel Barringer (May 25, 1860 – November 30, 1929) 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.

Daniel Barringer, was the son of Daniel Moreau Barringer, a nephew of Confederate General Rufus Barringer and a cousin of Paul Brandon Barringer. He graduated from Princeton University in 1879 at the age of 19, and in 1882 graduated from the University of Pennsylvania's School of Law. He later studied geology and mineralogy at Harvard University and at the University of Virginia, respectively.

In 1892, Barringer, along with his friend Richard A. F. Penrose, Jr., and others, purchased a gold and silver mine near Cochise, Arizona. Later, Barringer also discovered the Commonwealth Silver Mine in Pearce, Arizona. These mining ventures made him a wealthy man.

Eugene Merle Shoemaker

Eugene Merle Shoemaker (April 28, 1928 – July 18, 1997), 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.

Shoemaker was also well known for his studies of terrestrial craters, such as Barringer Meteor Crater in Arizona. Shoemaker was also the first director of the United States Geological Survey's Astrogeology Research Program.

Geography of Alabama

The geography of Alabama describes a state in the Southeastern United States in North America. Alabama is 30th in size and borders four U.S. states: Mississippi, Tennessee, Georgia, and Florida. It also borders the Gulf of Mexico.

Geology of Alabama

The geology of Alabama is marked by abundant geologic resources and a variety of geologic structures from folded mountains in the north to sandy beaches along the Gulf of Mexico coast. Alabama spans three continental geologic provinces as defined by the United States Geological Survey, the Atlantic Plain, Appalachian Highlands, and Interior Plains. The Geological Survey of Alabama breaks these provinces down into more specific physiographic provinces.

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.

Impact craters are the dominant geographic features on many solid Solar System objects including the Moon, Mercury, Callisto, Ganymede and most small moons and asteroids. On other planets and moons that experience more active surface geological processes, such as Earth, Venus, Mars, Europa, Io and Titan, visible impact craters are less common because they become eroded, buried or transformed by tectonics over time. Where such processes have destroyed most of the original crater topography, the terms impact structure or astrobleme are more commonly used. In early literature, before the significance of impact cratering was widely recognised, the terms cryptoexplosion or cryptovolcanic structure were often used to describe what are now recognised as impact-related features on Earth.The cratering records of very old surfaces, such as Mercury, the Moon, and the southern highlands of Mars, record a period of intense early bombardment in the inner Solar System around 3.9 billion years ago. The rate of crater production on Earth has since been considerably lower, but it is appreciable nonetheless; Earth experiences from one to three impacts large enough to produce a 20-kilometre-diameter (12 mi) crater about once every million years on average. This indicates that there should be far more relatively young craters on the planet than have been discovered so far. The cratering rate in the inner solar system fluctuates as a consequence of collisions in the asteroid belt that create a family of fragments that are often sent cascading into the inner solar system. Formed in a collision 160 million years ago, the Baptistina family of asteroids is thought to have caused a large spike in the impact rate, perhaps causing the Chicxulub impact that may have triggered the extinction of the non-avian dinosaurs 66 million years ago. Note that the rate of impact cratering in the outer Solar System could be different from the inner Solar System.Although Earth's active surface processes quickly destroy the impact record, about 190 terrestrial impact craters have been identified. These range in diameter from a few tens of meters up to about 300 km (190 mi), and they range in age from recent times (e.g. the Sikhote-Alin craters in Russia whose creation was witnessed in 1947) to more than two billion years, though most are less than 500 million years old because geological processes tend to obliterate older craters. They are also selectively found in the stable interior regions of continents. Few undersea craters have been discovered because of the difficulty of surveying the sea floor, the rapid rate of change of the ocean bottom, and the subduction of the ocean floor into Earth's interior by processes of plate tectonics.

Impact craters are not to be confused with landforms that may appear similar, including calderas, sinkholes, glacial cirques, ring dikes, salt domes, and others.

Kara crater

Kara is a meteor crater in the Yugorsky Peninsula, Nenetsia, Russia.Heavily eroded, it is presently 65 kilometres (40 mi) in diameter, though it is thought to be originally 120 kilometres (75 mi) before erosion. Its age is estimated to be 70.3 ± 2.2 million years old (Late Cretaceous). Impactite outcrops located on the Baydarata Gulf (Baydaratskaya) shore north-east of the crater imply that the original size of the crater could have been the 4th largest on Earth. The crater is not exposed at the surface.

The Kara crater lies in the southeastern end of the Yugorsky Peninsula, while the Ust-Kara site lies offshore, 15 kilometres (9.3 mi) east of the small Kara or Karskaya Guba inlet. It was formerly believed that these two sites were two separate craters and that they formed a twin impact structure from the Late Cretaceous. However, it seems that the Ust-Kara site does not exist as a separate site. Apparently, the suevite outcrops of the Ust-Kara impact structure are only a part of the Kara impact structure.

Lappajärvi

Lappajärvi is a municipality in Finland in Southern Ostrobothnia region. The municipality has a population of 3,062 (31 January 2019) and covers an area of 522.98 square kilometres (201.92 sq mi) of which 102.89 km2 (39.73 sq mi) is water. The population density is

7.28 inhabitants per square kilometre (18.9/sq mi).

The municipality is unilingually Finnish.

Lake Lappajärvi, which gives the name to the municipality, is a meteor crater, one of the few meteor crater lakes found in Finland.

Singer and performer, Timo Kotipelto from the worldwide known Finnish power metal band Stratovarius was born and raised in Lappajärvi.

List of National Natural Landmarks in Arizona

From the list of National Natural Landmarks, these are the National Natural Landmarks in Arizona. There are 10 in total.

List of historic properties in Winslow, Arizona

This is a list, which includes a photographic gallery, of some of the remaining historic structures and monuments in Winslow, Arizona, some of which are listed in the National Register of Historic Places. Also included is a photographic gallery of Meteor Crater, which is designated a National Natural Landmark.

Meteor City, Arizona

Meteor City (Navajo: Tséłchííʼ Ńdeeshgiizh) is a populated place situated in Coconino County, Arizona. It has an estimated elevation of 5,033 feet (1,534 m) above sea level. Located next to Leupp Corner, it is so-named because of its proximity to Meteor Crater. Created as a tourist stop, it is the turn-off of Route 66 to visit the crater. At one time the sign upon entering the town once read, "Population: 1".

Odessa Meteor Crater

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 (Moss Road). 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.

The Handbook of Texas Online describes the Odessa meteor crater as the largest of several smaller craters in the immediate area that were formed by the impact of thousands of octahedrites (an iron metallic type) that fell in prehistoric times.The web site of the University of Texas of the Permian Basin (UTPB, Center for Energy and Economic Diversification), identifies five craters at the Odessa site and shows a distribution map of the meteorite fragments recovered from the area. The recoveries have generally come from an area to the north and northwest of the main crater site, with only a few found to the south. They indicate that the structure of the main crater, because it was one of the earliest to be recognized and studied, is now used to name similar impact sites on a worldwide basis. Over 1500 meteorites have been recovered from the surrounding area over the years, the largest of which weighed approximately 300 lb (136 kg), but excavations in the main crater confirm that there is no meteorite mass underground and probably never has been. The site has been designated as a National Natural Landmark by the National Park Service, and a small information area and nature trail has been set up on-site for a self-guided tour.

It is 550 ft (168 m) in diameter and the age is estimated to be around 63,500 years (Pleistocene or younger). The crater is exposed to the surface, and was originally about 100 ft (30 m) deep. Because of subsequent infilling by soil and debris, the crater is currently 15 ft (5 m) deep at its lowest point, which provides enough relief to be visible over the surrounding plains, but does not offer the dramatic relief found at the more famous Meteor Crater in Arizona.

Still, the site offers an excellent opportunity to view a relatively uncommon impact feature close to a major transportation artery near a major city.

The crater itself and the museum curator, Tom Rodman, were featured in the June 1, 2013 broadcast of Bob Phillips's syndicated television series, Texas Country Reporter.

Puchezh-Katunki crater

Puchezh-Katunki is a meteor crater located in the Nizhny Novgorod Oblast of the Volga Federal District, Russia. It is 80 km (50 mi) in diameter and is estimated to be 167 ± 3 million years old, placing it in the Middle Jurassic. The crater is not exposed to the surface, but appears as variation in the vegetation. The Earth Impact Database lists a rim-to-rim diameter of 40 kilometres (25 mi).

Stishovite

Stishovite is an extremely hard, dense tetragonal form (polymorph) of silicon dioxide. It is very rare on the Earth's surface, however, it may be a predominant form of silicon dioxide in the Earth, especially in the lower mantle.Stishovite was named after Sergey M. Stishov, a Russian high-pressure physicist who first synthesized the mineral in 1961. It was discovered in Meteor Crater in 1962 by Edward C. T. Chao.Unlike other silica polymorphs, the crystal structure of stishovite resembles that of rutile (TiO2). The silicon in stishovite adopts an octahedral coordination geometry, being bound to six oxides. Similarly, the oxides are three-connected, unlike low-pressure forms of SiO2. In most silicates, silicon is tetrahedral, being bound to four oxides. It was long considered the hardest known oxide (~30 GPa Vickers); however, boron suboxide has been discovered in 2002 to be much harder. At normal temperature and pressure, stishovite is metastable.

Stishovite can be separated from quartz by applying hydrogen fluoride (HF); unlike quartz, stishovite will not react.

Winslow (crater)

Winslow is an impact crater on Mars, located in the Iapygia quadrangle at -3.74°S latitude and 59.16°E longitude. It measures 1.08 kilometres (0.67 mi) in diameter and was named after Winslow, Arizona, a town just east of Meteor Crater, which has a similar size and resembles Winslow crater. The two craters also have similar infrared characteristics.

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