Chicxulub impact crater

Article By:

Gulick, Sean P. S. Institute for Geophysics, Jackson School of Geosciences, University of Texas, Austin, Texas.

Morgan, Joanna V. Faculty of Engineering, Department of Earth Science and Engineering, Imperial College London, London, United Kingdom.

Last reviewed:November 2019

DOI:https://doi.org/10.1036/1097-8542.129760

The now-buried remains of a large asteroid impact that occurred approximately 66 million years ago off the Yucatán Peninsula in Mexico, causing mass extinction on a global scale. Measuring approximately 200 km (124 mi) in diameter, the Chicxulub (pronounced CHIK-shoo-loob) impact crater (Fig. 1) is unique. It is the only known terrestrial impact structure that has been linked directly to a mass extinction event, and the only terrestrial impact with a global layer of ejecta (sediment material that is forced out of the Earth as a result of an asteroid impact, volcano discharges, or other explosions). Of the three largest impact structures on Earth, Chicxulub is the best preserved. Chicxulub is also the only known terrestrial impact structure with an intact, unequivocal topographic peak ring. Chicxulub's role in the Cretaceous–Paleogene (K–Pg) mass extinction [formerly called the Cretaceous–Tertiary (K–T) mass extinction] and its exceptional state of preservation make it an important natural laboratory for the study of (1) large impact crater formation on Earth and other planets, and (2) the effects of large impacts on the Earth's environment and ecology. See also: Asteroid; Impact; Mass extinctions; Paleoecology; Sedimentology

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