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Cenote facts for kids

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Bolonchen Cenote Catherwood
Cenote at Bolonchen, Mexico, used as source of water, 1842.

A cenote is a natural pit, or sinkhole, resulting from the collapse of limestone bedrock that exposes groundwater underneath. Especially associated with the Yucatán Peninsula of Mexico, cenotes were sometimes used by the ancient Maya for sacrificial offerings.

The term derives from a word used by the low-land Yucatec Maya — ts'onot — to refer to any location with accessible groundwater. Cenotes are common geological forms in low latitude regions, particularly on islands, coastlines, and platforms with young post-Paleozoic limestones that have little soil development.

Definition and description

Cenotes are surface connections to subterranean water bodies. While the best-known cenotes are large open water pools measuring tens of meters in diameter, such as those at Chichén Itzá in Mexico, the greatest number of cenotes are smaller sheltered sites and do not necessarily have any surface exposed water. The term cenote has also been used to describe similar karst features in other countries such as Cuba and Australia, in addition to the more generic term of sinkholes.

Cenote water is often very clear, as the water comes from rain water filtering slowly through the ground, and therefore contains very little suspended particulate matter. The groundwater flow rate within a cenote may be very slow. In many cases, cenotes are areas where sections of cave roof have collapsed revealing an underlying cave system, and the water flow rates may be much faster: up to 10 kilometers (6 mi) per day. Cenotes around the world attract cave divers who have documented extensive flooded cave systems through them, some of which have been explored for lengths of 100 km (62 mi) or more.

Geology and hydrology

Cenote en Chichén Itzá, Yucatán, México
The Ik Kil Cenote in Yucatán, Mexico.
Cenote in valladolid mexico (21362599476)
Cenote in Valladolid

Formation

Cenotes are formed by dissolution of rock and the resulting subsurface void, which may or may not be linked to an active cave system, and the subsequent structural collapse. Rock that falls into the water below is slowly removed by further dissolution, creating space for more collapse blocks. The rate of collapse increases during periods when the water table is below the ceiling of the void, since the rock ceiling is no longer buoyantly supported by the water in the void.

Cenotes may be fully collapsed creating an open water pool, or partially collapsed with some portion of a rock overhanging above the water. The stereotypical cenotes often resemble small circular ponds, measuring some tens of meters in diameter with sheer drops at the edges. Most cenotes, however, require some degree of stooping or crawling to access the water.

Types

Yucatan chix crater
Radar topography reveals the 180 km (110 mi) ring of the crater; clustered around the crater's trough are numerous sinkholes, suggesting a prehistoric oceanic basin in the depression left by the impact (Image courtesy NASA/JPL-Caltech).

In 1936, a simple morphometry-based classification system for cenotes was presented.

  • Cenotes-cántaro (Jug or pit cenotes) are those with a surface connection narrower than the diameter of the water body;
  • Cenotes-cilíndricos (Cylinder cenotes) are those with strictly vertical walls;
  • Cenotes-aguadas (Basin cenotes) are those with shallow water basins; and
  • grutas (Cave cenotes) are those having a horizontal entrance with dry sections.

The classification scheme was based on morphometric observations above the water table, and therefore incompletely reflects the processes by which the cenotes formed and the inherent hydrogeochemical relationship with the underlying flooded cave networks, which were only discovered in the 1980s and onwards with the initiation of cave diving exploration.

Definition and description

Cenote swimming
Cenote in Quintana Roo

Cenotes are surface connections to underground water bodies. While the most well-known cenotes are large open water pools measuring tens of metres in diameter, such as those at Chichén Itzá, most cenotes are smaller sheltered sites and do not necessarily have any surface exposed water. The term cenote has also been used to describe similar karst features in other countries such as Cuba and Australia, in addition to the more generic term of sinkholes.

Cenote water is often very clear, as the water comes from rain water infiltrating slowly through the ground. The groundwater flow rate within a cenote may be very slow at velocities ranging from 1 to 1000 meters per year. Cenotes around the world attract cave divers. They have explored extensive flooded cave systems, some of which have been investigated for 100 kilometers or more.

Cave diving

Cenotes have attracted cave divers and there are organized efforts to explore and map these underwater systems. The Quintana Roo Speleological Survey maintains a list of the longest and deepest water filled and dry caves within the state boundaries.

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