The Chicxulub crater is an impact crater located near the town of Chicxulub on the Yucatán Peninsula in Mexico. It has a diameter of 180 km and was discovered in the 1970s by Antonio Camargo and Glenn Penfield. Since then, it has been studied by numerous scientists working for the Mexican state-owned oil company, Petróleos Mexicanos, in search of oil deposits. It is the third largest impact crater in the world.
In this article we will tell you all about the characteristics and importance of the Chicxulub crater.
History
The crater is located near the city of Chicxulub on the Yucatán Peninsula in Mexico, at 19° 18′ south latitude and 127° 46′ east longitude. With a diameter of 180 meters and a depth of about 900 meters, it is the third largest impact crater on Earth. According to surveys, the first indications of this crater date back to the 1960s, noted Jaime Urrutia Fucugauchi, a researcher at the Institute of Geophysics of the National Autonomous University of Mexico (UNAM), who stated that after exploring the subsurface of the Gulf of Mexico, certain gravitational anomalies were detected in the carbonate layer of the Yucatán Peninsula.
Unlike common geological structures that have irregular shapes, the images appear as circular and concentric patterns. Despite its size, it was not discovered until 1970 by geophysicists Antonio Camargo and Glenn Penfield during an oil survey.
Penfield examined the data collected in northern Yucatán and found a remarkably symmetrical underground arc in the 70-kilometer-diameter ring . Geophysicists obtained gravity signature maps of the peninsula made in the 1960s.
Penfield found another arch, although this one was located on the Yucatan peninsula with its apex pointing north. Comparing the two maps, he found that two arcs (the one on the 1960s map and the one he found) formed a circle 180 kilometers in diameter with its center very close to the town of Chicxulub.
Situation of the Chicxulub crater
Geophysicists are almost certain that this strange geophysical feature of the Yucatán Peninsula was caused by a cataclysm at some point in Earth's geological history, dating back to the late Cretaceous period, about 65 million years ago . The meteorite is estimated to be about 10 kilometers in diameter, so when it struck, it formed a crater with a diameter of 180 kilometers, releasing an estimated 4,3 × 10²³ joules of energy, equivalent to about 191.793 gigatons of TNT (dynamite) during the impact.
The impact triggered a massive tsunami that swept across the island of Cuba. The resulting emissions of dust and particles caused environmental changes that completely covered the Earth's surface with dust clouds, which could be related to the extinction of the dinosaurs, as mentioned in the study on the role of asteroid impacts in their extinction.
This sequence coincides with the hypothesis of American physicist Luis Walter Alvarez and his son, geologist Walter Alvarez, regarding the extinction of the dinosaurs, who believe it could have been caused by a meteorite of this size. This theory is widely accepted by the scientific community and has been explored in multiple studies on the subject.
The main evidence is a thin, scattered layer of iridium at this geological boundary worldwide. Iridium is a rare metal on Earth but abundant in meteorites. This effect is believed to be part or all of the cause of the extinction event between the Cretaceous and Tertiary periods.
The crater has been the subject of geochemical studies, core analysis, electron microscopy and stratigraphy, among others, which have led to strong hypotheses, including that the projectile must have been about 10 kilometers in diameter and penetrated the Earth's stratigraphic peninsula at a speed of 10 kilometers per second.
It must have been a high-speed collision, because that's the only way to explain what remains of the material, and there is evidence that the high temperature and pressure of the impact caused the melting. Furthermore, this event may have triggered a megatsunami that changed the regional landscape and had global consequences, which you can see in more detail in our article on megatsunamis.
Key features
The crater is well preserved, the complexity is that it is not a bowl, but a different one, which can be described as a series of concentric rings, the perfect analogy is to think of it as throwing a stone into water and the ring and the central convex, known in geophysics as elevation of the central structure.
It is covered by 2 to 3 kilometers of sediment, which undoubtedly helps to protect it, even though it is underwater, which has been confirmed by gravity measurements made by the oceanographic vessel Maurice Ewing.
After analyzing the crater's structure, we know it has four layers that reflect the continuum of events that took place: the bottom layer before the collision contains microfossils typical of the Cretaceous period; then comes the layer of material ejected during the collision; above that is the layer formed by the remnants of the fireball; and finally, the sediment that accumulated after the disaster. This highlights the importance of studying the Chicxulub crater for understanding Earth's stratigraphy.
The fossils in the first and last layers are different, indicating that the species has changed. Furthermore, between the pyrosphere layer and the corresponding layer in the Cenozoic, there is a space without fossil remains, called the "empty sea layer," which is a sign of marine time, highlighting the importance of the crater in geological history.
Mysteries of the Chicxulub Crater
Many of the mysteries of the Chicxulub Crater remain buried. Mexico has asked UNESCO to recognize the crater. There is very little that tourists can see because the impact is from a long time ago.
Tourists visit one of the few remaining vestiges of geological formations—impressive cenotes where you can swim among fish and dangling tree roots— but they don't realize that these geological features exist only because they are made of soft limestone . Ocampo has visited the site several times, but he believes few people understand its significance. It is a unique place on our planet, a testament to Earth's geological history. It truly is, and it should be preserved as a World Heritage Site.
