La caldera (SPA-ENG)

The boiler

In the Andean Patagonian region, specifically in the province of Chubut, Argentina, near the town of Gualjaina, there is an area that is difficult to access but marvelous for the eyes and the other senses. It is an ancient geological formation, a huge volcano that became extinct millions of years ago and was named La Caldera.

I mentioned that it is not easily accessible, as it is accessed via rural, secondary, and provincial roads, all of which are made of dirt and stone. It is almost essential to have the services of a guide and a special all-wheel-drive vehicle to enjoy everything it has to offer.

This entire area corresponds to Miocene geological formations, which places the Caldera between 5 and 23 million years old, although our guide, the only certified one in all of Gualjaina, mentioned 60 million years; it's something I'll ask him about the next time I'm in the area, something that happens quite frequently, since there are some good fishing spots there and I'm a flyfishing enthusiast. Add to that the fact that my son and his family live just 100 kilometers away, and I'll surely be visiting the region again soon.

The term used to describe this entire vast region refers to the large depression formed when magma spilled out, causing the collapse of the volcano's summit. In this case, the volcano was so large that the edges of the volcanic neck are invisible except from the air. For everyone's peace of mind, it's extinct, so all activity ceased millions of years ago.

Barely beginning the walk, the guide's narrative explains what we're seeing. Being geological novices, it's impossible to understand what we're seeing. These are rock formations, and the information is somewhat overwhelming: rhyolites, basalts, andesites, different types of rocks that correspond to chaotic periods, precisely when the Andes mountain ranges in South America and the Betic and Rif mountain ranges in Europe were formed. The only way to preserve the information is by recording the explanations. Luckily, we thought of doing so, and today I can convey a few concepts, even non-academic but purposeful, about the experience.

We observe a landscape that I imagine to be lunar, although Jorge, the guide, quickly puts us in context: most of the various visible structures are eroded volcanic cones, lava domes, and pyroclastic deposits. Wind, river, and gravitational erosion shaped what we see now. Harder rock formations emerged, and softer ones folded and disappeared. We now see the more hidden inner layers of the ancient volcano.

We see domes of vitrified rocks, where no matter how steep the slope, it doesn't affect balance. There's no chance of slipping. Shoes grip the ground as if they had suction cups. You have to be careful; it's glass, and scraping your skin can cause injury.

In another area, we see enormous rock formations that rise straight, somewhat like cliffs. This is the ideal habitat for the chinchillón, a friendly little animal similar to the vizcacha, although reserved and shy. It likes these steep, high places, difficult to observe due to its fur, which resembles that of the rocks it inhabits. However, there are some photographs, perhaps not as clear as they should be.

At some point during the walk, we approached an area of ​​petrified trees. Unfortunately, it's not a protected area, and according to Jorge, many unscrupulous visitors take pieces as souvenirs.

Erosion shapes the rocks, and the game of imagining people, animals, and objects takes over, recalling another, much more famous place called the Enchanted Valley, on the way to the tourist city of Bariloche. There, we see whimsical formations, each of which we quickly name according to what our vision and imagination suggest: alien skulls, the guardian of the entrance to the underworld, the sea lion and the bear's head, the Templar, and many other forms we've given names we've since forgotten.

The current relief bears no resemblance to that of the period when the enormous volcano was active. Now we have well-defined areas between elevated plateaus, canyons, gorges, and low, rounded hills. The vegetation is typical of the Patagonian steppe. We find yaretas, a rounded shrub that can be confused with moss attached to rocks; coirones, thin, elongated plants similar to straw; and other shrubs whose names I don't recall but with similar characteristics: low and adapted to the arid, dry climate that prevails in the region.

We also have a few streams and springs that generally dry up in the summer, although there are a couple of rivers, the Gualjaina River basin and its confluence with the Chubut River, where large trout are abundant.

More surprises await us at the end of the tour. First, the Cañadón de la Buitrera, a gorge approximately 3 km long with high walls that can reach 100 meters. In addition to preserving some cave paintings from the Mapuche and Tehuelche indigenous cultures, it is an ideal area for rock climbing and rappelling. Hiking, wildlife watching, and photography are also ideal activities.

It all culminates at Piedra Parada, a gigantic mass of stone, primarily rhyolite, although it also contains remains of other igneous rocks. It is 240 meters high with a diameter of 100 meters. According to the guide, it is a solidified remnant of a volcanic vent.

Some might say it's a geological paradise, although we, without being part of that segment of science, also enjoyed simpler things like the landscapes, the flora and fauna, and the various rock formations.

Almost 6 hours of travel that went by very quickly; time is not a significant variable when the magnificence of nature occupies all our senses.