| | The destroyer Chicxulub, the gift that keeps on giving.
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Chicxulub crater
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For the town and municipality, see Chicxulub, Yucatán.
Chicxulub crater
Location of Chicxulub crater, Mexico
Imaging from NASA's Shuttle Radar Topography Mission STS-99 reveals part of the 180 km (110 mi)-diameter ring of the crater. The numerous sinkholes clustered around the trough of the crater suggest a prehistoric oceanic basin in the depression left by the impact. [1]
The Chicxulub crater ( /'t?i?k??lu?b/; Mayan pronunciation: [t?'ik?ulu?]) is an impact crater buried underneath the Yucatán Peninsula in Mexico. [2] Its center is located near the town of Chicxulub, after which the crater is named. [3] The date of the Chicxulub impactor, which created it, coincides precisely with the Cretaceous–Paleogene boundary (K–Pg boundary). [4] The crater is more than 180 kilometers (110 miles) in diameter and 20 km (12 mi) in depth, making the feature the second 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. [5] [6] 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 19 kyr of each other, or almost exactly the same within experimental error. [7] |
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