The famous cenotes of Yucatan are the entrances to the largest underwater cave system in the world and in Mayan religion entrance to the underworld. They offer not only remains of ancient cultures and long extinguished creatures, but also amazing cavern and cave diving experiences. In millions of years nature created beautiful chambers, rich decorated with dripstones. Chrystal clear ponds invite to refresh and provide the most important thing for life: water!
In this small serial of articles I will show the history of the cenotes. It starts with the meteor impact 66 millions years ago to its exploration by divers nowadays.
The birth of the Cenotes
Everything started with a shock event: The Chicxulub event, impact of a massive meteor.
66 Million years ago the Gulf of Mexico and the Caribbean were one shallow tropical ocean, thus full of coral reefs. Then a huge meteor smashed into it, the center of the impact was were today the city of Chicxulub is placed. Hence the name. This meteor was also responsible for the mass extinguishing of life which ended the era of the dinosaurs.
The impact was like an object falling into water, just on a much larger scale: First the impact creates a hole. When the hole is too deep and the surface tension of the water can´t hold it anymore, the wall is collapsing. This creates a fountain that splashes up and falls back. Both, impact and the fountain create shockwaves that move away from the center in circles.
In case of a meteor impact the earth crust reacts like the water, just the shockwaves freeze in their position after the energy left.
How the meteor impact is connected to the Cenotes
Because of the shockwaves of the Chicxulub impact remained many cracks in the limestone of the reef.
Chicxulub crater. Credit D. VAN RAVENSWAAY / SCIENCE PHOTO LIBRARY
In millions of following years the impact area was still underwater. After recovered from the shock, the reefs continued growing, covering the cracks.
Around 10 million years ago due to tectonic movements, Yucatan peninsula was lifted above sealevel. Now rainwater started working on the limestone: Its acids dissolved the minerals, extended the cracks and holes and decorated it with dripstones. This process reached greater depth when the sea level was very low during the ice ages, because a lot of water was frozen in huge glaciers.
In warmer periods sea level was rising and the caves were filled with water. Hence during these periods no dripstones were formed.
The Cenotes bring life to Yucatan
In the caves which were created by the cracks and the ages with rain water, fresh water was accumulating. Due to its lesser density, fresh water stays seperated from salt water. The border between the upper, fresh water layer and the lower salt water layer is called halocline. Because of this effect life at the surface could profit from fresh water reserves. Due to the caves it was protected from the sun and plants could reach it with their roots.
From time to time the ceiling of a cave became instable and collapsed. Hence an opening to the surface was created and animals had access to fresh water as well. Therefore many remains can be found today in the caves of Yucatan peninsula. These entrences to the cave system are called “Cenotes”. This comes from the Mayan word “dzonot” which means sacred spring.
Prehistoric giant sloth in Sistema Sac Actun
Human life arrives in the Americas
The first human seddlers on the american continent came from asia. Then they moved southwards to more gentle climate. The oldest remains of a human skeleton have been found in a Cenote. “Naia” was a young woman that died when she tried to climb down a wall to reach the water and fell. She lived around 13000-12000 BC and was found in the cave Hoyo Negro. This is a large and deep chamber of the cave system Aktun Hu. Also sabertooth, mammoth and other prehistoric animals can be found down there.
Cenotes today
If you want to explore the cenotes of Yucatan peninsula, the best way is underwater. Before you can dive into the mystical mayan underworld you need to become a certified scuba diver. A basic Open water certification is enough to explore the cavern part of the cave systems together with a guide. Cavern is the part of a cave that has a maximum horizontal distance of 30m to the entrance and mostly natural light.
For diving in the cave section, so more than 30m away from the entrance, special training and equipment is necessary.
But many Cenotes offer also dry sections, which means you can walk inside to watch the formations. Another option to explore Cenotes is snorkelling, especially in Dos Ojos many beautiful decorated chambers can be reached without diving.
But no matter which way you will choose, it will be a lifetime experience!
Well done to the author. A wonderful article.