How cenotes were formed ?

Cenotes in Yucatan, most along the Rivieramaya (in west caribbean coast of the Yucatán Peninsula within the state of Quintana Roo), attract a lot of divers for their unique beauty. It’s absolutly a “must do” if you plan diving in Playa del Carmen area. But how  such a unique ecosystem has been formed ?

Yucatan cenotes were underwater

About 65,000,000 years ago, the Yucatan peninsula was covered by the ocean ( Cenozoic Era ).

As a result, the calcium-rich remains of marine plants, algae, mineral
and animals accumulated and sedimented over geological time and formed into a layers. Time, pressure and temperature solidified these sediments into a rock material named limestone.

The Ice age

During the ice age, the level of the ocean dropped and left many reefs and their dependent marine life dead. Many fossils revealed this history. You can observe them during a dive.


Cenotes in yucatan today

At the end of the ice era, the global climate got warmer, glaciers retreated and water level rose again, filling the caves with clear fresh water leaving them as they are today: magnificent!!

The cenotes provide access to extensive underwater cave systems, such as Sistema Ox Bel Ha, Sistema Sac Actun/Sistema Nohoch Nah Chich and Sistema Dos Ojos which are the three longest underwater caves in the world.

The volume of water drainage is so great that it can not exist on the surface. All water is highly  filtered through the soft, porous limestone and flows underground.

The evolution of cave passageways, which form or exist below the water table is known as the phreatic zone. The water moves through the passageways (pores) vertically and horizontally from higher pressure  to lower pressure.

We don’t know for sure when the water has reached its present level.

Most of scientists agree around this number : about 1,000 years ago.

However, we can affirm thanks to objects dated with carbon, that human beings have been visiting thoses caves over 9,000 years ago. Remains of differents animals (jaguar, mammoth…) have been found, even remains of  humans skeletons.

Obviously, it’s our and your responsibility as divers to respect and protect those amazing remains of the past. Cenotes in yucatan, in particular in Rivieramaya really are offering a spectacular “show”. But this eco system is really fragile, Let’s protect it. 

Our recommandations are :

  • respect the nature, all flora and fauna
  • do not use suntan lotions and mosquito repelent before swiming
  • do not touch any stalactite/stalagmite formations
  • follow all the standards that your guide recommend (even if you are a very well trained/certified diver).

The rules of cenotes conservations are very strict and nothing can be touched or removed.

Only pictures allowed !!