On the Yucatan Peninsula in Central America we can find interesting geological formations. We call them cenotes, and they are natural holes in the ground filled with fresh water.
Cenotes are formed by the dissolution of soil that is very permeable, so water is difficult to stay on the surface in the form of ordinary rivers and lakes. Rainwater quickly passes through the soil and collects underground where it melts limestone rocks. Occasionally the ground collapses and reveals a cave filled with water.
Cenotes are part of the vast, largely unexplored world of submerged caves in the Mexican underground. The Yucatan is home to two of the five largest cave systems in the world! The caves stretch endlessly forming underground rivers and lakes.
WHAT DO CENOTES HAVE TO DO WITH THE ASTEROID IMPACT THAT CHANGED LIFE ON OUR PLANET?
More than 66 million years ago, an asteroid (10-15 km in diameter) fell on Earth, more precisely in a place that is now called Chicxulub on the Yucatan Peninsula. This led to a chain of catastrophic events that led to the extinction of three-quarters of the animal and plant species on the planet. The impact altered the limestone sediments below the earth’s surface, making it more susceptible to erosion. That, mixed with the circulation of groundwater bouncing off the rim of the crater, creating a stronger current that washes away the weakened limestone, which over time created the ring of cenotes that runs along the edge of the Chicxulub crater. There are thousands of cenotes scattered throughout the Yucatan Peninsula in Mexico.
Many cenotes are hidden in the jungle and are very difficult to reach. Some are quite small, while others are large and a popular tourist attraction where you can swim and dive. There are also cenotes in other parts of the world, but they are not as popular as these in Mexico.
In the north and north-west of the Yucatan Peninsula, the cenotes generally overlie vertically extensive voids penetrating 50 to 100 m (160 to 330 ft) below the modern water table. However, very few of these cenotes appear to be connected with horizontally extensive underground river systems, with water flow through them being more likely dominated by aquifer matrix and fracture flows.
The stalactites and stalagmites that form inside the cenotes are true natural works of art. In many, holes in the ceiling allow the sunlight to filter into the cenotes, giving the scene a magical feeling. The cenotes of the Yucatan Peninsula are a true natural gift that should be seen by all, but keep in mind that they should be protected so that they are here for generations to come.
SOME FACTS:
There are about 7,000 cenotes in the Yucatan, and only 142 are available to visit, which means that 98% of the Yucatan cenotes are still unexplored.
Some cenotes in the Riviera Maya and Yucatan can go as deep as 10 to 40 meters.
Some of the most famous cenotes are: Ik-Kil, Oxman, Suytun, Chak-Mool, Kukulkan, Grand Cenote
Cenotes are around 66 million years old.
