Coordinates: 21°24′N, 89°31′W Map of Earth showing lines of latitude (horizontally) and longitude (vertically), Eckert VI projection; large version (pdf, 1. ...

Radar topography reveals the 180 kilometer (112 mile) wide ring of the crater (image courtesy NASA/JPL-Caltech)

Chicxulub Crater (IPA: /tʃikʃu'lub/) (cheek-shoo-LOOB) is an ancient impact crater buried underneath the Yucatán Peninsula, with its center located approximately underneath the town of Chicxulub, Yucatán, Mexico. Download high resolution version (715x799, 118 KB)Radar topography (color corresponds to height) of the Yucatán peninsula, revealing the Chicxulub Crater. ... Download high resolution version (715x799, 118 KB)Radar topography (color corresponds to height) of the Yucatán peninsula, revealing the Chicxulub Crater. ... Articles with similar titles include the NATO phonetic alphabet, which has also informally been called the “International Phonetic Alphabet”. For information on how to read IPA transcriptions of English words, see IPA chart for English. ... Tycho crater on Earths moon. ... The Yucatán peninsula as seen from space The Yucatán Peninsula separates the Caribbean Sea from the Gulf of Mexico. ... Chicxulub (pronounced as CHEEK-shoe-lube) is a town in the state of Yucatán, Mexico, located at 21°14′ N 89°51′ W In 2000 the town had a population of about 3,400 people. ... Yucatán is the name of one of the 31 states of Mexico, located on the north of the Yucatán Peninsula. ...

Investigations suggest that this impact structure is dated from the late Cretaceous Period, about 65 million years ago. Thus the meteorite associated with the crater is implicated in causing the extinction of the dinosaurs as suggested by the K-T boundary. The Cretaceous Period is one of the major divisions of the geologic timescale, reaching from the end of the Jurassic Period (i. ... A geologic period is a subdivision of geologic time that divides an era into smaller timeframes. ... Mega-annum, usually abbreviated as Ma, is a unit of time equal to one million years. ... Orders & Suborders Saurischia Sauropodomorpha Theropoda Ornithischia Thyreophora Ornithopoda Marginocephalia Dinosaurs were vertebrate animals that dominated the terrestrial ecosystem for over 160 million years, first appearing approximately 230 million years ago. ... Badlands near Drumheller, Alberta where erosion has exposed the KT boundary. ...

Impact specifics

The meteorite's estimated size was about 10 km (6 mi) in diameter, releasing an estimated 500 zettajoules (5.0×10²³ joules) of energy, approximately 100 teratons of TNT,^[1] on impact. By contrast, the most powerful man-made explosive device ever detonated, the Tsar Bomba or Emperor Bomb, had a yield of only 50 megatons, which would make this impact 2,000,000 times more powerful than the Tsar Bomba. Willamette Meteorite A meteorite is a natural object originating in outer space that survives an impact with the Earths surface without being destroyed. ... Zetta (symbol Z) is a SI prefix in the SI (system of units) denoting 1021 or 1 000 000 000 000 000 000 000. ... The joule (IPA pronunciation: or ) (symbol: J) is the SI unit of energy. ... The joule (IPA pronunciation: or ) (symbol: J) is the SI unit of energy. ... A teraton is equal to 1,000 gigatons. ... R-phrases S-phrases Related Compounds Related compounds picric acid hexanitrobenzene Except where noted otherwise, data are given for materials in their standard state (at 25 Â°C, 100 kPa) Infobox disclaimer and references Trinitrotoluene (TNT) is a chemical compound with the formula C6H2(NO2)3CH3. ... A Tsar Bomba-type casing on display at Chelyabinsk-70 . ... // The explosive yield of a nuclear weapon is the amount of energy discharged when the weapon is detonated, expressed usually in the equivalent mass of trinitrotoluene (TNT), either in kilotons (thousands of tons of TNT) or megatons (million of tons of TNT), but sometimes also in terajoules (1 kiloton of... A megaton or megatonne is a unit of mass equal to 1,000,000 metric tons, i. ...

The impact would have caused some of the largest megatsunamis in Earth's history. These would have spread in all directions, hitting the Caribbean island of Cuba especially hard. The emission of dust and particles caused environmental changes close to a nuclear winter, during which the surface of the Earth was totally covered by a cloud of dust for several years. (Pope, et al., 1997) Megatsunami (often hyphenated as mega-tsunami, also known as iminami or “wave of purification”) is an informal term used mostly by popular media and popular scientific societies to describe a very large tsunami wave beyond the typical size reached by most tsunamis (usually around 10 metres). ... Nuclear winter is a hypothetical global climate condition that is predicted to be a possible outcome of a large-scale nuclear war. ...

Extinction of the dinosaurs

This timing is in good agreement with the theory postulated by the late physicist Luis Alvarez and his son, geologist Walter Alvarez, for the extinction of the dinosaurs. The Alvarezes, at the time both faculty at the University of California, Berkeley, postulated that the extinction of the dinosaurs, roughly contemporaneous with the K-T boundary, could have been caused by the impact of just such a large meteorite. This theory is now widely, though not universally, accepted by the scientific community.^[2] ... Portrait of Luis Alvarez Luis Walter Alvarez (June 13, 1911 – September 1, 1988) of San Francisco, California, USA, was a famed physicist of Spanish descent, who worked at the University of California, Berkeley. ... the are cool The Geologist by Carl Spitzweg A geologist is a contributor to the science of geology, studying the physical structure and processes of the Earth and planets of the solar system (see planetary geology). ... Walter Alvarez (born 1940), son of Nobel Prize winner Luis Alvarez, is a professor in the geology and geophysics department at the University of California, Berkeley. ... Orders & Suborders Saurischia Sauropodomorpha Theropoda Ornithischia Thyreophora Ornithopoda Marginocephalia Dinosaurs were vertebrate animals that dominated the terrestrial ecosystem for over 160 million years, first appearing approximately 230 million years ago. ... The University of California, Berkeley (also known as Cal, UC Berkeley, UCB, or simply Berkeley) is a prestigious, public, coeducational university situated in the foothills of Berkeley, California to the east of San Francisco Bay, overlooking the Golden Gate and its bridge. ... Badlands near Drumheller, Alberta where erosion has exposed the KT boundary. ... This article or section does not adequately cite its references or sources. ...

The main evidence is a widespread, thin layer of clay present in this geological boundary across the world. In the late 1970s, the Alvarezes and colleagues reported^[3] that it contained an abnormally high concentration of iridium – 6 parts per billion by weight or more compared to 0.4^[4] for the Earth's crust as a whole. Meteorites can contain around 470 parts per billion^[5] of this element. It was hypothesised that the iridium was spread into the atmosphere when the meteorite was vapourised and settled across the Earth's surface amongst other material thrown up by the impact, producing the relatively iridium-rich layer of clay.^[6] The 1970s decade refers to the years from 1970 to 1979, In the Western world, the focus shifted from the social activism of the sixties to social activities for ones own pleasure, save for environmentalism, which continued in a very visible way. ... General Name, Symbol, Number iridium, Ir, 77 Chemical series transition metals Group, Period, Block 9, 6, d Appearance silvery white Atomic mass 192. ...

Discovery

Clues in Haitian rock

In early 1990, Alan R. Hildebrand, a graduate student at the University of Arizona, visited a small mountain village named Beloc in Haiti. He was investigating certain K-T deposits that include thick, jumbled deposits of coarse rock fragments, which were apparently scoured up from one location and deposited elsewhere by a kilometers-high tsunami that most likely resulted from an Earth impact. Such deposits occur in many locations but seem to be concentrated in the Caribbean Basin. MCMXC redirects here; for the Enigma album, see MCMXC a. ... The University of Arizona (UA or U of A) is a land-grant and space-grant public institution of higher education and research located in Tucson, Arizona, United States. ... The tsunami that struck Malé in the Maldives on December 26, 2004. ... The Caribbean basin is generally defined as the area running from Florida westward along the Gulf coast, then south along the Mexican coast through Central America and then eastward across the northern coast of South America. ...

Hildebrand found a greenish brown coloured clay with an excess of iridium and containing shocked quartz grains and small beads of weathered glass that appeared to be tektites. He and his faculty adviser, William V. Boynton, published the results of the research in the scientific press, suggesting that the deposits were the result of an Earth impact and that the impact could not have been more than 1,000 kilometers (620 mi) away. General Name, Symbol, Number iridium, Ir, 77 Chemical series transition metals Group, Period, Block 9, 6, d Appearance silvery white Atomic mass 192. ... Shocked quartz is a form of quartz that has a microscopic structure that is different from normal quartz. ... Glass can be made transparent and flat, or into other shapes and colors as shown in this sphere from the Verrerie of Brehat in Brittany. ... A tektite Tektites (from Greek tektos, molten) are natural glass objects, up to a few centimeters in size, which — according to most scientists — have been formed by the impact of large meteorites on Earths surface, although a few researchers favor an origin from the Moon as volcanic ejecta. ...

However, no crater was known to exist in the Caribbean basin. Hildebrand and Boynton also reported their findings to an international geological conference, sparking substantial interest.

Evidence pointed to possible crater sites off the north coast of Colombia or near the western tip of Cuba. Then Carlos Byars, a reporter for the Houston Chronicle, contacted Hildebrand and told him that a geophysicist named Glen Penfield had discovered what might be the impact crater in 1978, buried under the northern Yucatán Peninsula. The Houston Chronicle is a daily newspaper in Houston, Texas, United States. ... 1978 (MCMLXXVIII) was a common year starting on Sunday. ... The Yucatán peninsula as seen from space The Yucatán Peninsula separates the Caribbean Sea from the Gulf of Mexico. ...

Discovery of "arc"

In that year, Penfield had been working for Petroleos Mexicanos (PEMEX, the Mexican state-owned oil company) as a staff member for an airborne magnetic survey of the Yucatán Peninsula. When Penfield examined the survey data, he found a huge underground "arc", with its ends pointing south, in the Caribbean off the Yucatan that was inconsistent with the region's geology. A Pemex gas station in Puerto Vallarta Petróleos Mexicanos (PEMEX) is Mexicos state-owned, nationalized petroleum company. ...

Penfield then obtained a gravity map of the Yucatan that had been made in the 1960s. He found another arc, but this one was on the Yucatan itself, and its ends pointed north. He matched up the two maps and found that the two arcs joined up in a circle, 180 kilometers (112 miles) wide, with its center at the village of Puerto Chicxulub. The 1960s decade refers to the years from January 1, 1960 to December 31, 1969, inclusive. ... Chicxulub is a town in the state of Yucatán, Mexico, located at 21. ...

Although PEMEX would not allow him to release specific data, the company did allow him and PEMEX official Antonio Camargo to present their results at a geological conference in 1981. The conference was under-attended in that year, ironically because most geologists were attending a workshop on Earth impacts, and their report attracted very little attention, though it did get back to Byars. 1981 (MCMLXXXI) was a common year starting on Thursday of the Gregorian calendar. ...

Penfield knew that PEMEX had drilled exploratory wells in the region in 1951. One of the wells had bored into a thick layer of andesite about 1.3 kilometers (4,200 ft) down. Such a structure could have resulted from the intense heat and pressures of an Earth impact, but at the time of the borings it had been written off as a "volcanic dome", even though such a feature was out of place in the geology of the region. 1951 (MCMLI) was a common year starting on Monday; see its calendar. ... A sample of andesite (dark groundmass) with amygdaloidal vesicules filled with zeolite. ... A volcanic dome is a volcanic feature formed by the extrusion of extremely viscous lava. ...

Corellation of data

After Hildebrand got in touch with Penfield, the two men were able to locate two separate samples from the wells drilled by PEMEX in 1951. Analysis of the samples clearly showed shock-metamorphic materials. Studies by other geologists of the debris found in Haiti at Beloc also showed it to be clearly the result of an impact. 1951 (MCMLI) was a common year starting on Monday; see its calendar. ...

Satellite surveys

In 1996, a team of California researchers, including Kevin O. Pope, Adriana Ocampo, and Charles Duller, conducted a survey of satellite images of the region. They found that there was a ring of sinkholes centered on Puerto Chicxulub that matched the ring Penfield had found in his data. The sinkholes were likely caused by subsidence of the crater's wall. (Pope, et al., 1996) 1996 (MCMXCVI) was a leap year starting on Monday of the Gregorian calendar, and was designated the International Year for the Eradication of Poverty. ... Dr. Kevin O. Pope is the former NASA archaeologist and founder of Geo Eco Arch Research who helped connect the Chicxulub Crater to the Cretaceous-Tertiary extinction event. ... Devils Hole near Hawthorne, Florida Sinkholes, also known as sinks, shakeholes or dolina (in the Slovene language dolina means valleys), and cenotes, are formed by the collapse of cave roofs and are a feature of landscapes that are based on limestone bedrock. ... A road destroyed by subsidence and shear. ...

Further studies have reinforced the consensus. Indeed, some evidence has accumulated that the actual crater is 300 kilometers (186 miles) wide, and the 180 kilometer ring is just an inner wall. (Sharpton & Marin, 1997)

Multiple impact theory

See also: Roche limit

In recent years, several other craters of around the same age as Chicxulub have been discovered, all between latitudes 20°N and 70°N. Examples include the Silverpit crater in the United Kingdom, and the Boltysh crater in Ukraine, both much smaller than Chicxulub but likely to have been caused by objects many tens of metres across striking the Earth. This has led to the hypothesis that the Chicxulub impact may have been only one of several impacts that happened all at the same time. Another possible crater thought to have been formed at the same time is the Shiva crater, though the structure's status as a crater is contested. The Roche limit, sometimes referred to as the Roche radius, is the distance within which a celestial body held together only by its own gravity will disintegrate due to a second celestial bodys tidal forces exceeding the first bodys gravitational self-attraction. ... Approximate location of the Silverpit crater The Silverpit crater is a sub-sea structure under the North Sea off the coast of the United Kingdom. ... Location of the Boltysh Crater The Boltysh Crater is an impact crater in Ukraine. ... The Shiva Crater is located in the Indian Ocean west of India. ...

The collision of Comet Shoemaker-Levy 9 with Jupiter in 1994 proved that gravitational interactions can fragment a comet, giving rise to many impacts over a period of a few days if the comet should collide with a planet. Comets frequently undergo gravitational interactions with the gas giants, and similar disruptions and collisions are very likely to have occurred in the past. This scenario may have occurred on Earth 65 million years ago. Hubble Space Telescope image of Comet Shoemaker-Levy 9, taken on May 17, 1994. ... 1994 (MCMXCIV) was a common year starting on Saturday of the Gregorian calendar, and was designated as the International Year of the Family and the International Year of the Sport and the Olympic Ideal by United Nations. ...

In late 2006, Ken MacLeod, a geology professor from the University of Missouri–Columbia, completed an analysis of sediment below the ocean's surface bolstering the single-impact theory. MacLeod conducted his analysis approximately 4,500 kilometers (2,800 mi) from the Chicxulub Crater to control for possible changes in soil composition at the impact site while still close enough to be affected by the impact. The analysis revealed there was only one layer of impact debris in the sediment, indicating only one impact. Reuters quoted Multiple Impact proponent Gerta Keller as saying, "Unfortunately, these claims are rather hyper-inflated and do not withstand close examination." For the Manfred Mann album, see 2006 (album). ... This article includes a list of works cited but its sources remain unclear because it lacks in-text citations. ... The University of Missouri–Columbia is a public land-grant university and is Missouris largest university and public research institution. ... Sediment is any particulate matter that can be transported by fluid flow and which eventually is deposited as a layer of solid particles on the bed or bottom of a body of water or other liquid. ... There are very few or no other articles that link to this one. ...

See also

• Cretaceous-Tertiary extinction event
• Permian-Triassic extinction event
• Wilkes Land crater

Badlands near Drumheller, Alberta where erosion has exposed the KT boundary. ... The Permian-Triassic (P-T or PT) extinction event, sometimes informally called the Great Dying, was an extinction event that occurred approximately 251 million years ago (mya), forming the boundary between the Permian and Triassic geologic periods. ... Map of Antarctica, with Wilkes Land slightly to the right The Wilkes Land crater is a proposed name for a 300 mile (500 km) -wide geological feature, located in Wilkes Land, Antarctica, and centered at , that has been explained as an impact crater. ...

References

• Pope KO, Baines KH, Ocampo AC, Ivanov BA (1997). "Energy, volatile production, and climatic effects of the Chicxulub Cretaceous/Tertiary impact". Journal of Geophysical Research 102 (E9): 21645-64. PMID 11541145. 
• Pope KO, Ocampo AC, Kinsland GL, Smith R (1996). "Surface expression of the Chicxulub crater". Geology 24 (6): 527-30. PMID 11539331. 
• Rojas-Consuegra, R., M. A. Iturralde-Vinent, C. Díaz-Otero y D. García-Delgado (2005). "Significación paleogeográfica de la brecha basal del Límite K/T en Loma Dos Hermanas (Loma Capiro), en Santa Clara, provincia de Villa Clara. I Convención Cubana de Ciencias de la Tierra.". GEOCIENCIAS 8 (6): 1-9. ISBN 959-7117-03-7. 
• Sharpton VL, Marin LE (1997). "The Cretaceous-Tertiary impact crater and the cosmic projectile that produced it". Annals of the New York Academy of Sciences 822: 353-80. PMID 11543120. 
• Single Massive Asteroid Wiped Out Dinosaurs Reuters, December 1, 2006
• The Chixulub Debate

Geology is a publication of the Geological Society of America. ...

External links

• Chicxulub
• Mystery of the Chicxulub Crater by Robert Roy Britt
• Chicxulub impact predates the K-T boundary mass extinction
• Satellite image of the region (from Google Maps)
• NASA JPL: "A 'Smoking Gun' for Dinosaur Extinction", March 6, 2003
• Chicxulub, Crater of Doom