Put simply, a cenote is an above-ground entrance to a subterranean network of caves that have (usually) filled with water. The Mexican peninsula of Yucatan contains many cenotes; apart from being beautiful, they are historically significant, having been noticed, used, and appreciated since the first appearance of human civilization in Mesoamerica.
Classifying Cenotes
Since 1936, cenotes have been classified into several distinct types based on their physical appearance. Pit (or jug) cenotes are perhaps the most typical, simply described as openings in the ground which connect the surface with a subterranean region larger than their circumference. Cylinder cenotes are similar in shape, but have longer passages to the underground with steep, vertical walls. Basin cenotes, as their name suggests, contain a shallow basin of water at their terminus. Cave cenotes are the most unlike the other kinds, with horizontal, rather than vertical, entrances, which usually remain dry.
The Making of Cenotes
Cenotes are formed by natural processes of weathering and the dissolution of rock in water. With the help of abrasive forces like rain, wind, and gravity, the surface region above an underground void gradually wears away, until an opening appears. Sometimes, the stability of the entire roof structure is affected by the cenote beginning to form, and it collapses, leaving a wide circular entrance to the caves beneath.
Cenotes usually form more rapidly when the depressions they begin as are not completely filled with water, as the motion of a smaller portion of liquid is more rapidly aided by surface forces, resulting in a more rapid degradation of the rock beneath. Saltwater, being more abrasive, generally forms cenotes more quickly than fresh water does.
Some cenotes don't completely collapse inward; these partially collapsed cenotes will often have a rocky ledge or overhang, forcing anyone who wishes to enter the caves to crawl under them in order to access the underground water source below.
Connected Cenotes
The Yucatan is also the location of a huge, partially submerged crater, called the Chicxulub crater, which was created by an asteroid strike about 65 million years ago, and is suspected to be one of the major events that resulted in the extinction of the dinosaurs. A ring of cenotes is arranged on the circular rim of the section of crater which lies on land.
These cenotes can extend to a depth of greater than 100 meters below the surface, where fresh groundwater and rainwater accumulates; thus, the water contained within the underground caves is remarkably clear and pure. Many of these cenotes are interconnected, making for passageways that support an underground river which can be used (and historically has been important) for transportation or recreation. This is especially significant in the Yucatan, which suffers from a dearth of natural lakes and rivers, the only major water source (the Gulf) being saltwater and unsuitable for supporting human or plant life. The currents that carry these subterranean natural canals from cenote to cenote can be quite rapid, usually more so when the roof of the cenote above has not completely collapsed.
Because of their abundance and usefulness as a freshwater source, these cenotes were extremely important to the earliest Mesoamericans, who used them variously as sources for drinking water, irrigation, and rapid transit of men and materials. Few doubt that the ancient Maya would have been able to develop such colossal cities without enlisting the aid of these cenotes to support the villages and farms which aided in their construction and sustenance.
For all these reasons, the cenotes of the Yucatan continue to be visited, explored, enjoyed, and admired; a refreshing spot for tourists, and ancient source of live-giving water, and a continuing pillar of the region's environmental health.
Classifying Cenotes
Since 1936, cenotes have been classified into several distinct types based on their physical appearance. Pit (or jug) cenotes are perhaps the most typical, simply described as openings in the ground which connect the surface with a subterranean region larger than their circumference. Cylinder cenotes are similar in shape, but have longer passages to the underground with steep, vertical walls. Basin cenotes, as their name suggests, contain a shallow basin of water at their terminus. Cave cenotes are the most unlike the other kinds, with horizontal, rather than vertical, entrances, which usually remain dry.
The Making of Cenotes
Cenotes are formed by natural processes of weathering and the dissolution of rock in water. With the help of abrasive forces like rain, wind, and gravity, the surface region above an underground void gradually wears away, until an opening appears. Sometimes, the stability of the entire roof structure is affected by the cenote beginning to form, and it collapses, leaving a wide circular entrance to the caves beneath.
Cenotes usually form more rapidly when the depressions they begin as are not completely filled with water, as the motion of a smaller portion of liquid is more rapidly aided by surface forces, resulting in a more rapid degradation of the rock beneath. Saltwater, being more abrasive, generally forms cenotes more quickly than fresh water does.
Some cenotes don't completely collapse inward; these partially collapsed cenotes will often have a rocky ledge or overhang, forcing anyone who wishes to enter the caves to crawl under them in order to access the underground water source below.
Connected Cenotes
The Yucatan is also the location of a huge, partially submerged crater, called the Chicxulub crater, which was created by an asteroid strike about 65 million years ago, and is suspected to be one of the major events that resulted in the extinction of the dinosaurs. A ring of cenotes is arranged on the circular rim of the section of crater which lies on land.
These cenotes can extend to a depth of greater than 100 meters below the surface, where fresh groundwater and rainwater accumulates; thus, the water contained within the underground caves is remarkably clear and pure. Many of these cenotes are interconnected, making for passageways that support an underground river which can be used (and historically has been important) for transportation or recreation. This is especially significant in the Yucatan, which suffers from a dearth of natural lakes and rivers, the only major water source (the Gulf) being saltwater and unsuitable for supporting human or plant life. The currents that carry these subterranean natural canals from cenote to cenote can be quite rapid, usually more so when the roof of the cenote above has not completely collapsed.
Because of their abundance and usefulness as a freshwater source, these cenotes were extremely important to the earliest Mesoamericans, who used them variously as sources for drinking water, irrigation, and rapid transit of men and materials. Few doubt that the ancient Maya would have been able to develop such colossal cities without enlisting the aid of these cenotes to support the villages and farms which aided in their construction and sustenance.
For all these reasons, the cenotes of the Yucatan continue to be visited, explored, enjoyed, and admired; a refreshing spot for tourists, and ancient source of live-giving water, and a continuing pillar of the region's environmental health.
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