World 🢖 North America 🢖 Mexico 🢖 Tamaulipas

Sinkholes 🢔 Caves 🢔 Geological wonders 🢔 Categories of wonders


Poza del Caracol, Sistema Zacaton

WorldBlue  In short


ne of the prominent features of the unique Sistema Zacatón is Poza del Caracol – small, very deep sinkhole which is not fully explored this far.

3.8 out of 10 stars 38.3%

GPS coordinates
22.9938 N 98.1638 W
Location, address
North America, Mexico, Tamaulipas, southern part of the state, 12 km north-west from Aldama town
Full depth not reached, measured up to 114 m depth

Map of the site

Travelers' Map is loading...
If you see this after your page is loaded completely, leafletJS files are missing.

WorldYellow In detail

Sistema Zacatón is an area with incredible characteristics unparalleled in the world. In total area contains some 20 unusual features – sinkholes, caves, springs created by deep groundwater heated by volcanic processes. Karstification processes here continue today as well – acidic groundwater continues to strip away the limestone and deposits it in unusual travertine formations.

Poza el Caracol

Poza del Caracol belongs to the central, most interesting group of these karst formations. The formation of this sinkhole continues up to this day – vertical cliffs around it often have landslides. El Caracol has not been fully investigated – it has been dived up to 114 m depth. It contains a passage that leads in the direction of the neighboring El Zacatón but most likely does not reach it.

Acidic water in this sinkhole has the highest level of dissolved hydrogen sulfide if compared with neighboring sinkholes. Content of hydrogen sulfide fluctuated in the pool daily – this may be explained by microbial activity. Travertine walls here are entirely covered with purple, red, and green biomats.

Temperature of water in El Caracol is 30° C, acidity – 6.9 pH. Water temperature in the sinkhole is remarkably similar to the temperature in nearby El Zacatón although both caves do not have a direct connection.

WorldYellow Linked articles

Great Blue Hole, Belize
Great Blue Hole / Eric Pheterson, Flickr / CC BY 2.0


This category includes outstanding sinkholes – large natural depressions or holes, which for most the part represent collapsed caves.

The lake of acid in Ijen Crater, Indonesia
The lake of acid in Ijen Crater / © CEphoto, Uwe Aranas, Wikimedia Commons

Lakes and streams

There are many factors that can make lakes, sea bays, or rivers unusual. Some lakes have unusual chemical properties and even do not contain water at all – such as lava lakes. Others may have unusual animals living in them or… legends about such animals.

El Castillo pyramid, Chichen Itza
El Castillo pyramid, Chichen Itza / , Flickr / CC BY 2.0

Wonders of Mexico

Few countries in the world can offer such an array of unique and astounding attractions as Mexico.

The area of this country was the cradle of several highly developed indigenous civilizations and some regions in the country are dotted with remnants of ancient cities with temples, palaces, and pyramids.

WorldYellow Recommended books

Hypogene Karst Regions and Caves of the World

This book illustrates the diversity of hypogene speleogenetic processes and void-conduit patterns depending on variations of the geological environments by presenting regional and cave-specific case studies. The cases include both well-known and newly recognized hypogene karst regions and caves of the world. They all focus on geological, hydrogeological, geodynamical, and evolutionary contexts of hypogene speleogenesis.

Encyclopedia of Caves and Karst Science

The Encyclopedia of Caves and Karst Science contains 350 alphabetically arranged entries. The topics include cave and karst geoscience, cave archaeology and human use of caves, art in caves, hydrology and groundwater, cave and karst history, and conservation and management. The Encyclopedia is extensively illustrated with photographs, maps, diagrams, and tables, and has thematic content lists and a comprehensive index to facilitate searching and browsing.

0 0 votes
Article Rating
Notify of

Inline Feedbacks
View all comments