Tatio Lower Field Mudpots

The Tatio Lower Field mudpots are a collection of geothermal vents located in the Andes mountains of Chile’s Atacama Desert. They sit below the main geyser basin of the El Tatio geothermal field. This area is situated at an extreme altitude of over 4,200 meters (13,700 feet) above sea level.

The El Tatio mudpots and geysers are best viewed between 6:00 AM and 7:00 AM, just after sunrise. The frigid early morning desert air causes the hot, pressurized steam to condense into massive, highly visible white plumes. Once the desert sun heats up the ambient air later in the morning, the thermal activity becomes much harder to see.

The high altitude of the Atacama Desert causes water to boil at a lower temperature than at sea level, making the thermal activity look much more violent than it actually is. Combined with subsurface volcanic heat, the lowered atmospheric pressure allows the mineral-rich mud to bubble intensely. The harsh, high-elevation climate also restricts the type of vegetation that can grow around the vents.

The varying colors—ranging from pale grey to warm ochre—are caused by the different types of volcanic rock and minerals being dissolved by the superheated groundwater. Iron oxidation in the mud creates the reddish and ochre hues, while high concentrations of silica and volcanic ash result in greyish tones. As the runoff cools, these minerals precipitate and stain the surrounding soil.