Tilcara & the Quebrada de Humahuaca

We live on a big rock.

That statement is both obvious and something I take for granted most of the time. I simply think about what’s under my feet as “the ground”, not as thousands of kilometers of solid (and molten) rock extending all the way to the planet’s iron-nickle core. I tend to think of the Earth as static, not as a dynamic place constantly being reshaped by powerful geological forces.

That is, until the evidence is right there in front of my face. Which has been happening a lot during this trip. Nowhere was it more evident than in the valley know as the Quebrada de Humahuaca and the little town of Tilcara, located in the far north-west of Argentina, astride the Tropic of Capricorn, just below Bolivia.

Tilcara is a bit off the beaten track, which makes it popular with backpackers, adventurers and urban refugees. (I think we fit somewhere in that spectrum). But there is still a strong indigenous presence, both in the faces of the people and day to day life. Many of the older (our age) people still speak Quechua, the language of the Inca Empire. Adobe and colonial buildings line the narrow, dusty streets. Farmers sell their produce beside the souvenir stalls in the market. Local families and tourists rub shoulders in the central square in the cool of the evening. Restaurants feature llama steaks and locro, a delicious, hardy stew. (I’m not sure exactly what’s in it, but I’ve never let that stop me).

There is archeological evidence of people living around Tilcara dating back 10,000 years, making it one of the oldest continuously inhabited places in Argentina. It certainly feels like one of those places where time has, if not stood still, at least slowed to a relaxed, reasonable pace.

It is a harsh, but vivid and in some ways almost magical landscape. The Quebrada de Humahuaca valley is bounded by steep mountains, cut by a network of dry, river-scoured canyons. What water there is, from snow melt in the high mountains and summer thunderstorms, feeds the trickle that is the Rio Grande in the valley bottom. Which, in turn supports a green ribbon of small-plot farms and pastures. At 2,300 meters (7,500 ft) it’s also home to some of the highest vineyards in the world, with cacti growing among the vines!

Above, the slopes are bare except for cactus and a few hardy shrubs that somehow survive under the merciless desert sun. Which leaves the geological structure exposed.

This landscape, and indeed all of western South America has been shaped by plate tectonics. Basically, part of the  crust underlying the Pacific Ocean (the Nazca Plate) is being shoved underneath South America. This results in earthquakes, volcanoes and the various ranges of the Andes Mountains. If you want to illustrate this for yourself, spread a tablecloth. Anchor one side, then push gently on the other side of it. The ripples and folds that result are similar to the mountains created when tectonic plates (sections of the Earth’s crust) run into each other. The geology is more complicated than your tablecloth, but it’s a good approximation.

The motion is slow by our standards – 7 to 10 cm per year (3 to 4 inches), but over millions of years it is enough to create the highest mountains in the world outside of the Himalayas.

Science aside, the Quebrada de Humahuaca is visually stunning. The Serrania de Hornocal, north of Tilcara is a jagged row of mountain ‘teeth’, displaying the spectacular colours of the various rock strata. Getting there is an adventure in itself – a winding gravel road that snakes up to the view point at 4,350 meters (14,300 ft) above sea level. At that altitude there is 40% less air. Both Liz and I, and our little rented Peugot felt the lack of oxygen. Not only did it struggle on the way up, the car didn’t want to start again after our stop. (It did on the third try, after an unspoken prayer).

Tectonics forms basins as well as mountains. This has resulted large salt flats, in areas where there is high evaporation and little drainage. The Salinas Grande, west of Tilcara is one of these. Visiting involves crossing another high mountain pass (4,150 meters). The road is paved, but it rises some 2,000 meters in just over 20 km. That might not sound like much, until you drive it. You need to give right-of-way to the trucks which take up both lanes on the hairpin turns. Mostly though I felt sorry for the truck drivers struggling on the way up in first and second gear, and trying not to burn out their brakes on the way down.

The blinding expanse of salt reminded us of the snow back home, but the heat and the sun, which felt like it was literally pressing down on us, said otherwise. It’s a striking and otherworldly environment. These days it’s a tourist destination, as well as a commercial salt mining operation. It’s relatively easy to reach by car, but I couldn’t help wondering at the settlers, the Inca and others before them who crossed these lands with only what water they could carry. And how many didn’t make it.

These days the Salinas are part of another challenge. These salt flats are rich in lithium, which is in high demand for car batteries and other electronics. The lithium is needed for many ‘green’ technologies, but the issue is complicated by indigenous land rights, water usage in an arid environment and other environmental factors. Buying an electric car, like Liz and I did, is all well and good, but there are other upstream and downstream factors to consider. I don’t pretend to have the answers.

As I travel I like to think about not just what is in front of me, but how did it get like that and what is the broader context. For me, those things add an extra layer of richness to the beautiful and startling world in which we live.

Here’s the link to more photos of the Tilcara area.