The Many Marvels Of Chile’s Atacama Desert

El Tatio Geyser Field, Atacama, Chile
El Tatio Geyser Field

Oscar, the guide, has his watch ready.  He stares at it intently, then lifts his eyes to the crowd.

“Twenty seconds.”

The visitors are still bleary-eyed from the early hour (6:30 a.m., departure time 4:30), but the sun just now clearing the snow-dappled peaks is gradually dispelling the sleepiness.  One girl taps at a smoking puddle with the tip of her Vans.  A mood of expectancy fills the air—as does the reek of sulfur.

“Five, four, three…and go!”

Right on cue, the geyser named El Jefe lets loose, unleashing a stream of boiling spray topped by a plume of white vapor that unfurls through the early-morning glare.  Every 132 seconds it does this, just as it’s been doing for thousands of years.

Not that the show’s captive audience seems to mind the monotony.  For each of the 655 performances that El Jefe gives daily, it’s applauded by 80 of its brethren, who whistle, hiss, spurt, and gush their approval to the cloudless skies overhead.  This gathering of terrestrial hydraulics collectively makes El Tatio, the geyser field in northern Chile’s Atacama Desert where El Jefe is located, the largest in the southern hemisphere.  A veritable symphony of steam.

El Tatio is just one of many marvels on display in the Atacama.  Covering some 54,000 square miles and receiving just 0.3 millimeters of rainfall per year, the desert is down in the record books for being the driest place on earth.  To those who visit, however, the extreme statistics take a back seat to its hypnotic, soul-stirring beauty, as well as the glimpse it offers, through the abyss of geological time, of Earth’s innermost secrets.  It’s a place of Martian landscapes and eerie ghost towns, vast salt flats and tiny microclimates, minerals and mummies.

It’s a place where one confronts nature at its most sublime.

As novelist Paul Bowles once wrote of the Sahara: “in the desert one is in the midst of something that is absolute…and the absolute has no price.”

Moon Valley, Atacama, Chile
Moon Valley

Absolute Desert

Many rains ago—so begins a Mapuche legend still told in parts of the Atacama—two giant serpents waged a fierce battle for dominion over the earth.  Kai-Kai, the more aggressive, was the spirit that inhabited the waters.  In his rage he sought to destroy humans for their neglect by creating a deluge with his tail.  This angered Tren-Tren, the spirit of the land, who responded by elevating the mountains above the flood and bearing men and women to safety on his back (the stragglers he transformed into birds or fish).

After a seismic but inconclusive face-off, the serpents made a truce.  Earth and ocean would retire to their proper places.  But the mountains had been pushed up permanently, and the waters had left their mark upon the boundless sands.

As it turns out, the Mapuche basically had it right.  As scientists today investigate why the Atacama is so much drier than anyplace else on the planet, what they’ve found has served to confirm the ancient memories preserved in the legend.

Plate tectonics are the key.  Some 150 million years ago, the Atacama was completely under water, a fact attested to by the gypsum deposits scattered over its valleys.  (Gypsum is a rock that only exists in the ocean in a dissolved state; it solidifies when the waters recede.)  At some point the Pacific Coastal Plate, whose edge once lay off the western coast of South America, began moving east, burrowing under the continental shelf and in the process pushing up both the Atacama region and the long spine of the Andes, causing it to shed its water.  This created the altiplano—high plain—on which the Atacama lies, at an altitude of some two miles above sea level.

Hence the Mapuche legend: desert sands rising from roiling waters.

But that wasn’t all.  Plate tectonics also engendered two further conditions that make the Atacama the bone-dry place it is today.  The first is the barrier of the Andes.  The great cordillera lies just to the east of the Atacama, blocking all the moisture that would otherwise flow westward from the Amazon region in an effect scientists call a “rain shadow,” a dry area on the leeward side of a mountain.  When the shifting plates erected the great mountain chain, they effectively sealed the Atacama’s parched fate.

Equally important is the Humboldt Current.  In the titanic slip-and-slide of the Earth’s crust all those millions of years ago, a gap opened between Antarctica and South America, through which cold water began to flow north.  That stream of icy water—named after its discoverer, the 19th-century naturalist Alexander von Humboldt—cools the oceans along South America’s west coast, preventing evaporation.  When a hot-air mass from off the land immobilizes this cold water under a high-pressure ceiling, bingo: no rainfall.

The upshot?  There are places in the Atacama that haven’t seen rain for 40 million years.  An “absolute desert,” as scientists say.

Flamingos, Atacama, Chile

Martians and Microclimates

So is the Atacama utterly inhospitable to living things?  A barren waste, like Mars?

Not exactly.

While it’s true the desert’s rust-streaked hills have an extraterrestrial aspect (they’ve been used by NASA scientists to test Mars space probes), the vagaries of the Chilean landscape mean that in certain parts, at least, life is surprisingly abundant.

Take, for example, the slopes moistened by the camanchaca, a coastal fog that rises from the sea.  Here the Pacific vapor provides enough humidity to create a tiny but lush rainforest in the midst of the badlands.  In this dripping, glade-like world, lizards scurry on the forest floor amidst air that savors of humus.

Meanwhile, farther east, the humidity of the Amazon rises to the Andean peaks that overlook the Atacama, creating streams that irrigate small green patches called bofedales, used by Aymara herdsmen for grazing their flocks.  These streams flow downward to the sea, leveling off into basins where they’re dried out into large salt pans.  The largest and most famous is the Salar de Atacama, home to pink algae, which are fed upon by tiny brine animals.  These in turn are devoured by flamingos, who absorb the keratin pigment from the algae, giving them their pink color.  Some Chilean flamingos even stamp the water in a kind of flamenco-like dance to stir up brine shrimp and fly larvae from the bottom.

Other species have also found their niche in the Atacama.  Guanacos, vicunas, viscachas (which resemble chinchillas), hummingbirds, South American gray foxes, and Darwin’s leaf-eared mice can all be spotted, even as Humboldt penguins and sea lions bob in the waters off the coast.  Ample testimony, all, to nature’s resourcefulness.

Cerro Unita's Geoglyph, Atacama, Chile
Cerro Unita’s Geoglyph (Photo Credit: Sznegra)

Human Traces

At Cerro Unita, on a low hillside near a looping dirt road, a giant is resting.

His arms are bent at the elbows, as though making to stretch and shake off his long slumber, but for some 1,000 years, he’s never quite made it.  Even now, his image continues to gaze up blankly at the sky, as though longing to return to some otherworldly home.

Cerro Unita’s geoglyph, formed by displacing the stones on the desert’s topsoil, is just one reminder that humans too inhabit the Atacama.  At 390 feet, the world’s largest anthropomorphic figure probably represents a deity of some sort, but there are other figures, especially at Chug Chug some 500 miles away, whose designs include llama caravans, lizards, shepherds, and geometric figures.  Archaeologists today speculate that these etchings were intended as markers for nomads as they made their way across the desert wastes.

Even more eerie are the ghost towns that dot the plains.  In the late 19th century, the discovery of vast deposits of nitrates made the Atacama a boom territory.  Seemingly overnight, the so-called “nitrate pampa” sprouted some 80 oficinas, ramshackle mining towns built to cash in on the desert’s bonanza.  When the crash came in the 1930s due to the development of synthetic nitrates, the towns were abandoned, but the empty worker barracks, rusting trains, dead machinery, and vast fields of crosses in the improvised cemeteries remain, a disquieting sermon on impermanence.  On one 70-mile stretch of Chile’s Route 25, the skeletons of 20 different towns rustle in the wind.

The last word on disquiet, however, is had by the Chinchorro mummies, the oldest human specimens on earth.  Dating back as far as 5000 B.C., the remains from this seaside community of hunter-gatherers are still being unearthed by archaeologists today, and include—heartbreakingly—fetuses interred with their mothers.  On display in the museum at the University of Tarapaca in Arica, they serve as yet another window the Atacama provides on the long corridor of our earthly origins.

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