The estimated size of the magma reservoir under this corner of the Andes, the largest known in Earth's continental crust. It heats the water at Puritama.
The year-round warmth of the Puritama pools, included in every Full Experience Program beginning August 1.
The altitude of Piedras Rojas, our newest excursion, where iron-red rock meets a turquoise lagoon on the Andean Altiplano.
Two New Doors into the Alien Landscape
In short: Beginning August 1, the Puritama Hot Springs excursion is included in every Full Experience Program at Nayara Alto Atacama, and Piedras Rojas joins our collection of desert journeys. One is a geothermal river canyon at 3,500 meters. The other is an iron-red shoreline beside a turquoise lagoon at 4,000. Both are powered by the same force: one of the largest bodies of magma ever detected in Earth's crust, working quietly beneath the driest desert on the planet.
In the previous chapters we explored what makes these the clearest night skies on Earth, Rainbow Valley, and the terrain NASA borrows to rehearse for Mars.
This chapter goes underneath it. Two new excursions now open the desert's inner workings to our guests, and each one is a lesson in how this place was made. Puritama is what the heat under the Atacama does to water. Piedras Rojas is what time does to stone. Read them together and you hold the whole story of the driest desert on Earth in two afternoons.
The Engine Under the Desert
The Atacama looks still. It is anything but. Offshore, the floor of the Pacific, the Nazca plate, is diving beneath South America, and as it sinks it sweats. Water driven off the descending slab melts the rock above it, and that melt has been pooling under this corner of the Andes for millions of years. When geophysicists imaged the region with seismic waves, they found a body of magma and crystal mush on the order of half a million cubic kilometers, the Altiplano Puna Magma Body, the largest known reservoir of its kind in Earth's continental crust.
That reservoir is the engine of everything a guest sees here. It built the volcanoes on the horizon, Licancabur among them, standing 5,916 meters over San Pedro. Its ancient eruptions laid down the vast sheets of welded ash, called ignimbrite, that the desert's canyons are carved through. And its heat still rises today, boiling the groundwater at El Tatio into one of the highest geyser fields on Earth, and, a little farther south and a little more gently, warming a river.
That river is Puritama. The desert looks dormant. Under it, the planet is wide awake.
Puritama: The Warm River in the Canyon
About half an hour into the hills above San Pedro, the desert does something it is not supposed to do. A canyon opens in the ignimbrite, and at the bottom of it runs a river that is warm. The Rio Puritama emerges from the ground already heated by the volcanic system below, and at roughly 3,500 meters it steps down the canyon through a chain of clear pools, holding between 28 and 33 degrees Celsius all year, in a place where the nights can fall below freezing.
The water was never a secret. In Kunza, the old language of the Lickanantay people of this desert, puri means water, and these pools have been a place of bathing and healing for the communities of the Atacama for far longer than there have been visitors to share them with. The springs are stewarded today in partnership with those communities, so that the oldest spa in the desert benefits the people who found it first.
The canyon itself is its own small climate. Sheltered from the wind, watered year round, it grows a ribbon of giant grasses and native green through country that is otherwise bare rock, and the birds of the desert concentrate here the way everything in the Atacama concentrates around water. Beginning August 1, the Puritama excursion is included in every Full Experience Program, with our guides handling the journey, the timing, and the towels.
The pools of Puritama, held between 28 and 33 degrees by the volcanic system below.
What the Water Carries
On its way up from the deep, the water at Puritama does some shopping. It moves through hot volcanic rock and dissolves what it touches, arriving at the surface carrying sodium, calcium, magnesium, boron, and silica, the mineral signature of the Andes themselves. This is the same chemistry that has drawn people to thermal springs on every continent, and the experience of it is older than any study of it.
The studies exist, though, and they point the same direction the body already knows. Warm immersion widens the blood vessels and eases circulation. Buoyancy takes the load off joints that carry you through a day of desert hiking. Heat relaxes muscle, and time in warm mineral water is associated with a calmer stress response and easier sleep. None of it requires belief. It requires twenty minutes and a place to leave your robe.
At altitude, after a morning on the trails, the effect is not subtle. Puritama is the desert offering back what the desert takes out of you.
Piedras Rojas: The Color of Deep Time
South of San Pedro, past the village of Socaire, the road climbs above 4,000 meters onto the Altiplano, the great high plateau of the Andes, second in extent only to Tibet. On the way it passes the twin lagoons of Miscanti and Miniques, born roughly a million years ago when lava flows sealed the basin and the mountain runoff had nowhere left to go. Then the land opens onto the Salar de Aguas Calientes, and the shoreline turns the color of rust.
It is rust, in the most literal sense. The rocks of Piedras Rojas are iron-rich volcanic stone, and over immense stretches of time the iron in them has oxidized, the same slow chemistry that reddens an old nail, painted across an entire landscape. Beside them lies a lagoon of impossible turquoise, its color set by dissolved minerals and the scattering of high-altitude light, and beyond that the white crust of the salt flat. Red stone, blue water, white salt, and behind it all the dark cones of the volcanoes that made everything you are standing on.
Flamingos work the lagoons of this altiplano, three species of them, though the birds keep their own schedule and no honest guide promises them. What can be promised is the silence. At this altitude, on a windless afternoon, it is complete.
Why the Driest Desert on Earth
Both excursions owe their drama to an absence. The Atacama is the driest non-polar desert on the planet because it is robbed from both sides at once. To the east, the wall of the Andes wrings out every storm that tries to arrive from the Amazon. To the west, the cold Humboldt Current chills the Pacific air until it cannot hold rain, and the coastal range blocks what little fog gets through. Caught in that double shadow, the desert's core has stayed dry for millions of years, by many estimates longer than any other place on Earth.
The dryness is why NASA comes here to test instruments bound for Mars, why the night sky above the lodge is clear enough to have drawn the world's great observatories, and why a warm river in a green canyon feels less like an excursion and more like a miracle with a trailhead. In the Atacama, water is not scenery. It is the whole event.
Explore the Full Atacama Series
- Understanding the Atacama Desert
- The Oasis Advantage
- Stargazing in the Atacama
- Romance in the Desert
- Atacama and Mars
Frequently Asked Questions
When is the Puritama Hot Springs excursion included at Nayara Alto Atacama?+
How warm are the Puritama pools?+
Why are the rocks at Piedras Rojas red?+
How high is Piedras Rojas, and should I worry about altitude?+
What heats the water in the Atacama?+
- Smithsonian Global Volcanism Program: the volcanoes of the Central Andes
- Earth and Planetary Science Letters: seismic imaging of the Altiplano Puna Magma Body
- NASA Astrobiology: the Atacama as a Mars analog
- Exploring an Alien Landscape from the Lap of Luxury: part one of the series
The Desert, From the Inside
A warm river in a canyon, a red shoreline at 4,000 meters, and a lodge built to disappear into the valley between them.
