These deep pools of crystal-clear water hold geological, paleontological, and biochemical mysteries. They are flooded caves called cenotes (pronounced suh-noh-tees), and they sketch the outline of a hidden landscape within Mexico’s Yucatán Peninsula: the rim of the Chicxulub crater.
In this clip from the BBC’s Earth: The Power of the Planet (2007), professional cave diving instructor Bernadette Carrión takes host Steve Backshall into one of these breathtaking subterranean caves. Northwestern’s Karst Geochemistry and Hydrogeology explains:
“The Maya people, who not only had knowledge of these manifestations of the land but used them daily as a source of water and farming, called them ts’ono’ot or d’zonot, which means ‘water deposit.'”
But most cenotes have yet to be explored as deeply as this. From the video:
“Fewer people have visited some of these drowned caverns than have stepped on the surface of the Moon. As divers have explored further, they’ve discovered the cenotes are actually part of a huge complex of tunnels and caves. In fact, when viewed from above, hundreds of cenotes can be seen scattered across the landscape.”
The crater they line, named Chicxulub after the nearby town, was formed around 66 million years ago by the dinosaur-killing asteroid that struck Earth. The impact left a scar on the Earth’s crust, “180 kilometers (110 miles) in diameter and 20 kilometers (12 miles) in depth.”
“It is the second largest confirmed impact structure on Earth, and the only one whose peak ring is intact and directly accessible for scientific research…
“The date of the impact coincides with the Cretaceous–Paleogene boundary (commonly known as the K–Pg or K–T boundary). It is now widely accepted that the resulting devastation and climate disruption was the cause of the Cretaceous–Paleogene extinction event, a mass extinction of 75% of plant and animal species on Earth, including all non-avian dinosaurs.”
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