Zacatón

Zacatón is a thermal water-filled sinkhole belonging to the Zacatón system – a group of unusual karst features located in Aldama Municipality near the Sierra de Tamaulipas in the northeastern state of Tamaulipas, Mexico. At a total depth of 339 meters (1, 112 ft), it is one of the deepest known water-filled sinkholes in the world. Using an autonomous robot, the underwater portion of Zacatón has been measured to be 319 meters (1, 047 ft) deep (a 20 m or 66 ft difference between the rim of cliff and surface of water adds to the total depth). Zacatón is the only sinkhole of the five located in Rancho La Azufrosa to have any noticeable water flow. The name Zacatón comes from the free-floating islands of zacate grass which move around on the surface with the wind. Scrapings from the rock walls beneath the surface yielded at least three new phyla of bacteria.

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