The Chicxulub crater (//; Mayan pronunciation: [tʃʼikʃuluɓ]) is an impact crater buried underneath the Yucatán Peninsula in Mexico. Its center is located near the town of Chicxulub, after which the crater is named. The date of the Chicxulub impactor, which created it, coincides precisely with the Cretaceous–Paleogene boundary (K–Pg boundary). The crater is more than 180 kilometers (110 miles) in diameter and 20 km (12 mi) in depth, making the feature one of the largest confirmed impact structures on Earth; the impacting bolide that formed the crater was at least 10 km (6 mi) in diameter.
The crater was discovered by Antonio Camargo and Glen Penfield, geophysicists who had been looking for petroleum in the Yucatán during the late 1970s. Penfield was initially unable to obtain evidence that the geological feature was a crater, and gave up his search. Through contact with Alan Hildebrand, Penfield obtained samples that suggested it was an impact feature. Evidence for the impact origin of the crater includes shocked quartz, a gravity anomaly, and tektites in surrounding areas.
The age of the rocks marked by the impact shows that this impact structure dates from roughly 66 million years ago, the end of the Cretaceous period, and the start of the Paleogene period. It coincides with the K-Pg boundary, the geological boundary between the Cretaceous and Paleogene. The impact associated with the crater is thus implicated in the Cretaceous–Paleogene extinction event, including the worldwide extinction of non-avian dinosaurs. This conclusion has been the source of controversy. In March 2010, 41 experts from many countries reviewed the available evidence: 20 years' worth of data spanning a variety of fields. They concluded that the impact at Chicxulub triggered the mass extinctions at the K–Pg boundary. In 2013 a study compared isotopes in impact glass from the Chicxulub impact with the same isotopes in ash from the boundary where the extinction event occurred in the fossil record; the study concluded that the impact glasses were dated at 66.038 ± 0.049 Ma, and the deposits immediately above the discontinuity in the geological and fossil record was dated to 66.019 ± 0.021 Ma, the two dates being within 32 kyr of each other, or almost exactly the same within experimental error.
In 1978, geophysicists Antonio Camargo and Glen Penfield were working for the Mexican state-owned oil company Petróleos Mexicanos, or Pemex, as part of an airborne magnetic survey of the Gulf of Mexico north of the Yucatán peninsula. Penfield's job was to use geophysical data to scout possible locations for oil drilling. In the data, Penfield found a huge underwater arc with "extraordinary symmetry" in a ring 70 km (40 mi) across. He then obtained a gravity map of the Yucatán made in the 1960s. A decade earlier, the same map suggested an impact feature to contractor Robert Baltosser, but he was forbidden to publicize his conclusion by Pemex corporate policy of the time. Penfield found another arc on the peninsula itself, the ends of which pointed northward. Comparing the two maps, he found the separate arcs formed a circle, 180 km (110 mi) wide, centered near the Yucatán village Chicxulub; he felt certain the shape had been created by a cataclysmic event in geologic history.
Pemex disallowed release of specific data but let Penfield and company official Antonio Camargo present their results at the 1981 Society of Exploration Geophysicists conference. That year's conference was underattended and their report attracted scant attention. Coincidentally, many experts in impact craters and the K–Pg boundary were attending a separate conference on Earth impacts. Although Penfield had plenty of geophysical data sets, he had no rock cores or other physical evidence of an impact.
He knew Pemex had drilled exploratory wells in the region. In 1951, one bored into what was described as a thick layer of andesite about 1.3 kilometres (4,300 ft) down. This layer could have resulted from the intense heat and pressure of an Earth impact, but at the time of the borings it was dismissed as a lava dome — a feature uncharacteristic of the region's geology. Penfield tried to secure site samples, but was told such samples had been lost or destroyed. When attempts at returning to the drill sites and looking for rocks proved fruitless, Penfield abandoned his search, published his findings and returned to his Pemex work.
At the same time, scientist Luis Walter Alvarez put forth his hypothesis that a large extraterrestrial body had struck Earth and, unaware of Penfield's discovery, in 1981 University of Arizona graduate student Alan R. Hildebrand and faculty adviser William V. Boynton published a draft Earth-impact theory and sought a candidate crater. Their evidence included greenish-brown clay with surplus iridium containing shocked quartz grains and small weathered glass beads that looked to be tektites. Thick, jumbled deposits of coarse rock fragments were also present, thought to have been scoured from one place and deposited elsewhere by a kilometers-high tsunami resulting from an Earth impact. Such deposits occur in many locations but seem concentrated in the Caribbean basin at the K–Pg boundary. So when Haitian professor Florentine Morás discovered what he thought to be evidence of an ancient volcano on Haiti, Hildebrand suggested it could be a telltale feature of a nearby impact. Tests on samples retrieved from the K–Pg boundary revealed more tektite glass, formed only in the heat of asteroid impacts and high-yield nuclear detonations.
In 1990, Houston Chronicle reporter Carlos Byars told Hildebrand of Penfield's earlier discovery of a possible impact crater. Hildebrand contacted Penfield in April 1990 and the pair soon secured two drill samples from the Pemex wells, stored in New Orleans. Hildebrand's team tested the samples, which clearly showed shock-metamorphic materials.
A team of California researchers including Kevin Pope, Adriana Ocampo, and Charles Duller, surveying regional satellite images in 1996, found a cenote (sinkhole) ring centered on Chicxulub that matched the one Penfield saw earlier; the sinkholes were thought to be caused by subsidence of the impact crater wall. More recent evidence suggests the actual crater is 300 km (190 mi) wide, and the 180 km ring is in fact an inner wall of it.
The Chicxulub impactor had an estimated diameter of 10 km (6.2 mi) or larger, and delivered an estimated energy equivalent of 240,000 gigatons of TNT (1.0×1024 J). By contrast, the most powerful man-made explosive device ever detonated, the Tsar Bomba, had a yield of only 50 megatons of TNT (2.1×1017 J), making the Chicxulub impact almost 5 million times more powerful. Even the most energetic known volcanic eruption, which released an estimated energy equivalent of approximately 240 gigatons of TNT (1.0×1021 J) and created the La Garita Caldera, delivered only 0.1% of the energy of the Chicxulub impact.
The impact would have caused some of the largest megatsunamis in Earth's history. A cloud of super-heated dust, ash and steam would have spread from the crater as the impactor burrowed underground in less than a second. Excavated material along with pieces of the impactor, ejected out of the atmosphere by the blast, would have been heated to incandescence upon re-entry, broiling the Earth's surface and possibly igniting wildfires; meanwhile, colossal shock waves would have triggered global earthquakes and volcanic eruptions. The emission of dust and particles could have covered the entire surface of the Earth for several years, possibly a decade, creating a harsh environment for living things. The shock production of carbon dioxide caused by the destruction of carbonate rocks would have led to a sudden greenhouse effect. Over a longer period, sunlight would have been blocked from reaching the surface of the Earth by the dust particles in the atmosphere, cooling the surface dramatically. Photosynthesis by plants would also have been interrupted, affecting the entire food chain. A model of the event developed by Lomax et al. (2001) suggests that net primary productivity (NPP) rates may have increased to higher than pre-impact levels over the long term because of the high carbon dioxide concentrations. A long-term effect of the impact was the creation of the sedimentary basin which "ultimately produced favorable conditions for human settlement in a region where surface water is scarce."
In February 2008, a team of researchers led by Sean Gulick at the University of Texas at Austin's Jackson School of Geosciences used seismic images of the crater to determine that the impactor landed in deeper water than was previously assumed. They argued that this would have resulted in increased sulfate aerosols in the atmosphere. According to the press release, that "could have made the impact deadlier in two ways: by altering climate (sulfate aerosols in the upper atmosphere can have a cooling effect) and by generating acid rain (water vapor can help to flush the lower atmosphere of sulfate aerosols, causing acid rain)."
Geology and morphology
In their 1991 paper, Hildebrand, Penfield, and company described the geology and composition of the impact feature. The rocks above the impact feature are layers of marl and limestone reaching to a depth of almost 1,000 m (3,300 ft). These rocks date back as far as the Paleocene. Below these layers lie more than 500 m (1,600 ft) of andesite glass and breccia. These andesitic igneous rocks were only found within the supposed impact feature, as is shocked quartz. The K–Pg boundary inside the feature is depressed to 600 to 1,100 m (2,000 to 3,600 ft) compared with the normal depth of about 500 m (1,600 ft) measured 5 km (3 mi) away from the impact feature. Along the edge of the crater are clusters of cenotes or sinkholes, which suggest that there was a water basin inside the feature during the Neogene period, after the impact. The groundwater of such a basin would have dissolved the limestone and created the caves and cenotes beneath the surface. The paper also noted that the crater seemed to be a good candidate source for the tektites reported at Haiti.
Astronomical origin of asteroid
In September 2007, a report published in Nature proposed an origin for the asteroid that created the Chicxulub Crater. The authors, William F. Bottke, David Vokrouhlický, and David Nesvorný, argued that a collision in the asteroid belt 160 million years ago resulted in the Baptistina family of asteroids, the largest surviving member of which is 298 Baptistina. They proposed that the "Chicxulub asteroid" was also a member of this group. The connection between Chicxulub and Baptistina is supported by the large amount of carbonaceous material present in microscopic fragments of the impactor, suggesting the impactor was a member of a rare class of asteroids called carbonaceous chondrites, like Baptistina. According to Bottke, the Chicxulub impactor was a fragment of a much larger parent body about 170 km (106 mi) across, with the other impacting body being around 60 km (37 mi) in diameter. In 2011, new data from the Wide-field Infrared Survey Explorer revised the date of the collision which created the Baptistina family to about 80 million years ago. This makes an asteroid from this family highly improbable to be the asteroid that created the Chicxulub Crater, as typically the process of resonance and collision of an asteroid takes many tens of millions of years. In 2010, another hypothesis was offered which implicated the newly discovered asteroid P/2010 A2, a member of the Flora family of asteroids, as a possible remnant cohort of the K/Pg impactor.
Chicxulub and mass extinction
The Chicxulub Crater lends support to the theory postulated by the late physicist Luis Alvarez and his son, geologist Walter Alvarez, that the extinction of numerous animal and plant groups, including non-avian dinosaurs, may have resulted from a bolide impact (the Cretaceous–Paleogene extinction event). Luis and Walter Alvarez, at the time both faculty members at the University of California, Berkeley, postulated that this enormous extinction event, which was roughly contemporaneous with the postulated date of formation for the Chicxulub crater, could have been caused by just such a large impact. This theory is now widely accepted by the scientific community. Some critics, including paleontologist Robert Bakker, argue that such an impact would have killed frogs as well as dinosaurs, yet the frogs survived the extinction event. Gerta Keller of Princeton University argues that recent core samples from Chicxulub prove the impact occurred about 300,000 years before the mass extinction, and thus could not have been the causal factor. However, this conclusion is unsupported� by radioactive dating and sedimentology.
The main evidence of such an impact, besides the crater itself, is contained in a thin layer of clay present in the K–Pg boundary across the world. In the late 1970s, the Alvarezes and colleagues reported that it contained an abnormally high concentration of iridium. Iridium levels in this layer reached 6 parts per billion by weight or more compared to 0.4 for the Earth's crust as a whole; in comparison, meteorites can contain around 470 parts per billion of this element. It was hypothesized that the iridium was spread into the atmosphere when the impactor was vaporized and settled across the Earth's surface amongst other material thrown up by the impact, producing the layer of iridium-enriched clay.
Multiple impact theory
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 disputed Silverpit crater in the North Sea and the Boltysh crater in Ukraine. Both are much smaller than Chicxulub, but are likely to have been caused by objects many tens of meters across striking the Earth. This has led to the hypothesis that the Chicxulub impact may have been only one of several impacts that happened nearly at the same time. Another possible crater thought to have been formed at the same time is the larger Shiva crater, though the structure's status as a crater is contested.
The collision of Comet Shoemaker–Levy 9 with Jupiter in 1994 demonstrated 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 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 at the end of the Cretaceous, though Shiva and the Chicxulub craters might have been formed 300,000 years apart.
In late 2006, Ken MacLeod, a geology professor from the University of Missouri, completed an analysis of sediment below the ocean's surface, bolstering the single-impact theory. MacLeod conducted his analysis approximately 4,500 kilometres (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, which indicated there was only one impact. Multiple-impact proponents such as Gerta Keller regard the results as "rather hyper-inflated" and do not agree with the conclusion of MacLeod's analysis, arguing that there might only be gaps of hours to days between impacts in a multiple-impact scenario (cf. Shoemaker-Levy 9) which would not leave a detectable gap in deposits.
In 2016, planned exploration will get the first offshore samples from the peak ring, rough circular hills that form around the center of large impacts, like the rings on craters on the Moon, to determine how the peak ring formed. Chicxulub is the only Earth crater with a remaining impact peak ring.
- "PIA03379: Shaded Relief with Height as Color, Yucatan Peninsula, Mexico". Shuttle Radar Topography Mission. NASA. Retrieved 28 October 2010.
- "Chicxulub". Earth Impact Database. University of New Brunswick. Retrieved 2008-12-30.
- Renne et al.
- Schulte, et al.
- Time Scales of Critical Events Around the Cretaceous-Paleogene Boundary - Renne et al
- Verschuur, 20–21.
- Verschuur, 20.
- Hildebrand, Penfield, et al.
- Hildebrand interview: 'Similar deposits of rubble occur all across the southern coast of North America [...] indicate that something extraordinary happened here.'
- Frankel, 50.
- Hildebrand interview.
- Pope, Baines, et al.
- Sharpton & Marin.
- BBC News – Dinosaur extinction: Scientists estimate 'most accurate' date
- Hildebrand et al., (1998). "Mapping Chicxulub crater structure with gravity and seismic reflection data". The Geological Society.
- Adamsky and Smirnov, 19.
- Mason, et al.
- Melosh, interview.
- Melosh. "On the ground, you would feel an effect similar to an oven on broil, lasting for about an hour [...] causing global forest fires."
- Hildebrand, Penfield, et al.; 5.
- Pope, Ocampo, et al.
- Lomax, B.; Beerling D.; Upchurch Jr G.; Otto-Bliesner B. (2001). "Rapid (10-yr) recovery of terrestrial productivity in a simulation study of the terminal Cretaceous impact event". Earth and Planetary Science Letters 192 (2): 137–144. Bibcode:2001E&PSL.192..137L. doi:10.1016/S0012-821X(01)00447-2. Retrieved 8 May 2010.
- Winemiller, Terance L. (2007), The Chicxulub Meteor Impact and Ancient Locational Decisions On the Yucatán Peninsula, Mexico: the Application of Remote Sensing, GIS, and GPS in Settlement Pattern Studies (PDF), Tampa, Florida: American Society for Photogrammetry and Remote Sensing, retrieved 2 October 2012
- Marc Airhart (January 1, 2008). "Seismic Images Show Dinosaur-Killing Meteor Made Bigger Splash".
- Hildebrand, Penfield, et al.; 1.
- Hildebrand, Penfield, et al.; 3.
- Hildebrand, Penfield, et al.; 4.
- "Meteor Impact Site – Earth: The biography". National Geographic. 11 Jul 2008. Retrieved 19 Aug 2015.
- Kring, "Discovering the Crater".
- Bottke, Vokrouhlicky, Nesvorny.
- Plotner, Tammy (2011). "Did Asteroid Baptistina Kill the Dinosaurs? Think other WISE...". Universe Today. Retrieved 2011-09-19.
- "Smashed asteroids may be related to dinosaur killer" Reuters, Feb. 2, 2010
- Alvarez, W. interview.
- Kring, "Environment Consequences".
- Keller, et al.
- Web Elements.
- Riddle, Dawne (December 2009). "Silverpit "not crater"". Geological Society of London. Retrieved 10 April 2013.
- Stewart, Allen.
- Kelley, Gurov.
- Mullen, "Multiple Impacts".
- "Mass extinctions: I am become Death, destroyer of worlds". The Economist. 2009-10-22. Retrieved 2009-10-24.
- Mullen, "Shiva".
- "Physics World". live.iop-pp01.agh.sleek.net. Retrieved 2015-09-23.
- Adamsky, Viktor; Smirnov, Yuri (1994). "Moscow's Biggest Bomb: the 50-Megaton Test of October 1961" (PDF). Cold War International History Project Bulletin (4): 3, 19–21. Archived from the original (PDF) on 2000-08-26.
- Alvarez, W.; Alvarez, L.W.; Asaro, F.; Michel, H.V. (1979). "Anomalous iridium levels at the Cretaceous/Tertiary boundary at Gubbio, Italy: Negative results of tests for a supernova origin". In Christensen, W.K.; Birkelund, T. Cretaceous/Tertiary Boundary Events Symposium 2. University of Copenhagen. p. 69.
- Bates, Robin (series producer), Chesmar, Terri and Baniewicz, Rich (associate producers) (1992). The Dinosaurs! Episode 4: "Death of the Dinosaur" (TV-series). PBS Video, WHYY-TV.
- Bakker, Robert T. Interview: The Dinosaurs: Death of the Dinosaur. 1990, WHYY.
- Hildebrand, Alan. Interview: The Dinosaurs: Death of the Dinosaur. 1992, WHYY.
- Melosh, Gene. Interview: The Dinosaurs: Death of the Dinosaur. 1992, (1990): WHYY.
- Moras, Florentine. Interview: The Dinosaurs: Death of the Dinosaur. 1992, (filmed 1990): WHYY.
- Penfield, Glen. Interview: The Dinosaurs: Death of the Dinosaur. 1992, WHYY.
- Bottke, W.F.; Vokrouhlicky, D.; Nesvorny, D. (September 2007). "An asteroid breakup 160 Myr ago as the probable source of the K/T impactor" (PDF). Nature 449 (7158): 23–25. Bibcode:2007Natur.449...48B. doi:10.1038/nature06070. PMID 17805288. Retrieved 2007-10-03.
- Bralower, Timothy J.; Paull, Charles K.; Leckie, R. Mark (April 1998). "The Cretaceous–Tertiary boundary cocktail: Chicxulub impact triggers margin collapse and extensive sediment gravity flows" (PDF). Geology 26 (4): 331–334. Bibcode:1998Geo....26..331B. doi:10.1130/0091-7613(1998)026<0331:tctbcc>2.3.co;2. Retrieved 2007-09-25.
- Covey, C; et al. (1994). "Global climatic effects of atmospheric dust from an asteroid or comet impact on Earth". Global and Planetary Change 9 (3–4): 263. Bibcode:1994GPC.....9..263C. doi:10.1016/0921-8181(94)90020-5.
- Dunham, Will (2006-11-30). "Single massive asteroid wiped out dinosaurs: study". physadvice.net. Retrieved 2007-09-29.
- Frankel, Charles (1999). The End of the Dinosaurs: Chicxulub Crater and Mass Extinctions. Cambridge University Press. p. 236. ISBN 0-521-47447-7.
- Grieve, R. (1975). "Petrology and Chemistry of the Impact Melt at Mistastin Lake Crater". Geological Society of America Bulletin 86 (12): 1617–1629. Bibcode:1975GSAB...86.1617G. doi:10.1130/0016-7606(1975)86<1617:PACOTI>2.0.CO;2.
- Hildebrand, Alan R.; Penfield, Glen T.; Kring, David A.; Pilkington, Mark; Zanoguera, Antonio Camargo; Jacobsen, Stein B.; Boynton, William V. (September 1991). "Chicxulub Crater; a possible Cretaceous/Tertiary boundary impact crater on the Yucatan Peninsula, Mexico". Geology 19 (9): 867–871. Bibcode:1991Geo....19..867H. doi:10.1130/0091-7613(1991)019<0867:CCAPCT>2.3.CO;2.
- Ingham, Richard (2007-09-05). "Traced: The asteroid breakup that wiped out the dinosaurs". AFP. Google News. Retrieved 2007-09-27.
- Keller, Gerta; Adatte, Thierry; Berner, Zsolt; Harting, Markus; Baum, Gerald; Prauss, Michael; Tantawy, Abdel; Stueben, Doris (2007). "Chicxulub impact predates K–T boundary: New evidence from Brazos, Texas" (PDF). Earth and Planetary Science Letters 255 (3–4): 1–18. Bibcode:2007E&PSL.255..339K. doi:10.1016/j.epsl.2006.12.026. Retrieved 2007-09-25.
- Kelley, Simon P.; Gurov, Eugene (2002). "The Boltysh, another end-Cretaceous impact". Meteoritics & Planetary Science 37 (8): 1031–1043. Bibcode:2002M&PS...37.1031K. doi:10.1111/j.1945-5100.2002.tb00875.x.
- Kring, David A. (2003). "Environmental consequences of impact cratering events as a function of ambient conditions on Earth". Astrobiology 3 (1): 133–152. Bibcode:2003AsBio...3..133K. doi:10.1089/153110703321632471. PMID 12809133.
- Kring, David A. "Discovering the Crater". lpl.arizona.edu. Archived from the original on October 10, 2007. Retrieved 2007-10-12.
- Mason, Ben G.; Pyle, David M.; Oppenheimer, Clive (2004). "The size and frequency of the largest explosive eruptions on Earth". Bulletin of Volcanology 66 (8): 735–748. Bibcode:2004BVol...66..735M. doi:10.1007/s00445-004-0355-9.
- Mason, Moya K. (2007). "In Search of a Key Paper". moyak.com. Retrieved 2009-04-03.
- Mayell, Hillary (2005-05-15). "Asteroid Rained Glass Over Entire Earth, Scientists Say". National Geographic News. Retrieved 2007-10-01.
- Mullen, Leslie (2004-11-04). "Deep Impact – Shiva: Another K–T Impact?". Astrobiology Magazine. Retrieved 2007-09-29.
- Mullen, Leslie (2004-10-21). "Did Multiple Impacts Pummel Earth 35 Million Years Ago?". spacedaily.com. Retrieved 2007-09-29.
- Perlman, David (2007-09-06). "Scientists say they know where dinosaur-killing asteroid came from". San Francisco Chronicle. Retrieved 2007-10-03.
- 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): 245–64. Bibcode:1997JGR...10221645P. doi:10.1029/97JE01743. PMID 11541145.
- Pope KO; Ocampo AC; Kinsland GL; Smith R (1996). "Surface expression of the Chicxulub crater". Geology 24 (6): 527–30. Bibcode:1996Geo....24..527P. doi:10.1130/0091-7613(1996)024<0527:SEOTCC>2.3.CO;2. PMID 11539331.
- Qivx Inc. (2003). "Periodic Table: Properties of Iridium". qivx.com. Archived from the original on 2007-09-28. Retrieved 2007-09-25.
- Renne, PR; Ludwig, KR; Karner, DB (2000). "Progress and challenges in geochronology". Science Progress 83: 107–121. PMID 10800377.
- Rincon, Paul (2010-03-04). "Dinosaur extinction link to crater confirmed". BBC. Retrieved 2010-03-05.
- Rojas-Consuegra, R.; M. A. Iturralde-Vinent; C. Díaz-Otero & D. García-Delgado (2005). "Significación paleogeográfica de la brecha basal del Límite K/T en Loma Dos Hermanas (Loma del 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.
- Peter Schulte; Laia Alegret; Ignacio Arenillas; José A. Arz; Penny J. Barton; Paul R. Bown; Timothy J. Bralower; Gail L. Christeson; et al. (5 March 2010). "The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundary". Science (AAAS) 327 (5970): 1214–1218. Bibcode:2010Sci...327.1214S. doi:10.1126/science.1177265. ISSN 1095-9203. PMID 20203042. Retrieved 5 March 2010.
- 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. Bibcode:1997NYASA.822..353S. doi:10.1111/j.1749-6632.1997.tb48351.x. PMID 11543120.
- Stewart, S. A.; Allen, P.J. (2005). "3D seismic reflection mapping of the Silverpit multi-ringed crater, North Sea". Geological Society of America Bulletin 117 (3): 354–368. Bibcode:2005GSAB..117..354S. doi:10.1130/B25591.1.
- Stewart S. A.; Allen P. J. (2002). "A 20-km-diameter multi-ringed impact structure in the North Sea". Nature 418 (6897): 520–3. Bibcode:2002Natur.418..520S. doi:10.1038/nature00914. PMID 12152076.
- Than, Ker (2006-11-28). "Study: Single Meteorite Impact Killed Dinosaurs". livescience.com. Retrieved 2007-09-29.
- Verschuur; Gerrit L. (1996). Impact!: The Threat of Comets and Asteroids. Oxford University Press (U.S.). ISBN 0-19-511919-3.
- Web Elements (2007). "Geological Abundances". webelements.com. Retrieved 2007-09-26.
- Weinreb, David B. (March 2002). "Catastrophic Events in the History of Life: Toward a New Understanding of Mass Extinctions in the Fossil Record – Part I". jyi.org. Retrieved 2007-10-03.
- Weisstein, Eric W. (2007). "Eric Weisstein's World of Physics – Roche Limit". scienceworld.wolfram.com. Retrieved September 5, 2007.
- Renne; et al. "Impact and Extinction".
Schute, P., Alegret, L., Arenillas, I., Arz, J. A., Barton, P. J., Brown, P.R., et al. (2010). The Chicxulub Asteroid Impact and Mass Extinction at the Cretaceous-Paleogene Boundary. Science, 1214 (3970).
|Wikimedia Commons has media related to Chicxulub crater.|
- Numerous sinkholes (Cenotes) marked around Chicxulub crater. Opens in Google Earth
- NASA JPL: "A 'Smoking Gun' for Dinosaur Extinction", March 6, 2003
- Chicxulub: Variations in the magnitude of the gravity field at sea level image. (Lunar and Planetary Institute, USRA)
- Chicxulub, Crater of Doom
- Doubts On Dinosaurs – Scientific American.