Thursday, 23 June 2016

San Pedro de Atacama; an astonishing part of the world. Part 1, Deep Desert.

The far north of Chile is some 4,500km from the cold wet windy south - but in some ways it feels even further. The mighty Atacama Desert is unlike anywhere else on earth, though near to the sea it has similarities with the Namib of south-western Africa, centred on Namibia (which takes its name from the desert). Both have a cold current - the Humboldt in the case of the Atacama - hard on-shore, which doesn't give rise to moisture-bearing air masses. (On the west coast of Australia the desert also comes to the coast, but it isn't as arid and is vegetated.) What makes the Atacama unique however is the fact that it rises to over 4,500 metres above sea level (masl) across substantial areas in the Andes, though some people would technically exclude the arid Andean slopes from the definition of the desert. The Andes exacerbate the aridity by intercepting clouds moving west from the Atlantic across the Amazon basin.
A typical Atacama scene near San Pedro de Atacama.
There is no vegetation at all across vast expanses of the desert; in this area for instance the annual
rainfall is just 40mm, half of which is expected in January.
The three winter months (June to August) average exactly zero...
And there is something surreal about the backdrop of snowy peaks.
Most visitors are likely to fly into Calama on the Rio Loa, then drive the 100km south to San Pedro. Calama exists solely to support the world's largest copper mine, Chuquicamata, and unless you have business there, there is really no reason to linger. San Pedro is a much pleasanter town of some 5,000 people, built at 2400masl (a comfortable altitude for most people) on an oasis which is based on an aquifer originating in the high Andes and nearing the surface in the dry bed of the Rio Grande. It was inhabited at least 3000 years ago when it acted as a rest stop on the trading route to the highlands. It has been described as ‘the gringo gathering point of northern Chile’ and the main streets comprise mostly bars and souvenir shops - I am not surprised to find that I don't have any photos of it. However, we don't go there for its own sake, but as a base to explore the surrounding desert.
The arrow indicates the approximate position of San Pedro de Atacama,
at 2,400 metres above sea level on the Atacama Plateau.
The unvegetated expanses are hard to comprehend at first, even to someone like me who has spent quite a bit of time in deserts - I've always known that there are 'deserts and deserts', but I think you have to really experience the Atacama to appreciate the truth of that.

It seems extraordinary that people have been present in this harsh landscape for many centuries, but as mentioned above oases like San Pedro have long enabled trade routes to pass through the Atacama. And when the Inca Empire pushed south into Chile, their famed roads which took traders and messengers throughout the empire pushed even through the forbidding Atacama.
Inca Road, marked with rocks (for scores of kilometres) near San Pedro. There was no need to seal roads here
(unlike the amazing paved roads through the Andes, such as the Inca Track near Machu Picchu), but
they did need to be clearly defined. I muse on whether it would be worse to be an Inca runner here,
or in the high cold mountains.
The ever-present mountains are another remarkable aspect - and the Andes are still growing as the Nazca Plate (under the Pacific Ocean) shoves its way under the South American Plate, and the volcanoes are either potentially or actually still active. 

Sunrise through a haze of mist - it's hard to imagine there could be moisture in the air - from San Pedro.

Volcano Lascar.

Volcano Lascar from a different angle - with smoke wafting from the crater.
And in that last photo something different appears - vegetation, even trees! Tamarugo is a pea, Prosopis tamarugo, which remarkably can grow in the total absence of rain, relying on dew and deep tap roots into water tables.
Tamarugo - old tree (above) and close-up (below).

Partially excavated Tamarugo root, Pampa de Tamarugo NR (further north in Chile).
Various species of chenopods (or saltbushes) grow as an understorey to the Tamarugo, or on their own. 
Tamarugo woodland and chenopods, west of San Pedro.
As you might expect, wildlife isn't obvious, but it certainly exists, especially near settlements, which are associated with oases. 
Female Greenish Yellow-finch Sicalis olivascens, Socaire.
Yellow-finches are now understood to be tanagers; this species occurs in flocks in the Andes.

Great Thrush Turdus fuscater, another high country species, though this one is more often encountered
in wetter habitats. It is well-adapted to urban living.
Guanacos Lama guanicoe, above and below, west of San Pedro.
They are far less common than in past times, and nowhere near as abundant in the
north as they are in the far south. More on them here.

There is in fact one habitat in this part of the Atacama which hosts a wealth of wildlife, but that's the topic of next week's posting.

Most visitors come for the desert scenery, and a tour of the Valle de la Luna (the Valley of the Moon) is on everyone's itinerary - and for good reason! It compromises a huge amphitheatre with jagged rock formations, and vast areas of gleaming salt from a long-gone age when there were lakes here; now no rain has fallen here in the time of a European presence. Here are just a few of very many images that I could have offered you.

Close-up of the salt surface. It can be near-blinding in the full sun.

A typical scene from within the amphitheatre, looking out to the Andes beyond.

Salt-crusted rocks come in a variety of forms, from massive domes...

... to strange twisted remnants of outcrops. This one is known as Las Tres Marias.
A striking juxtaposition of red sand dune and salt field, which resonates with an Australian.

A panorama incorporating some of the above themes.
Many of these tours are timed to end at sunset, absorbed from an extensive lookout area along cliff tops looking out across the plains to the Andes through more than 180 degrees. These photos don't need explanations. They are offered in chronological order, taken over a period of 17 minutes.

The Atacama is a grand and magnificent adornment to the world, and the San Pedro area is as good an introduction to it as any. And next week I shall conclude this visit to it with a look at two very different and unexpected features - lakes!



Juan Cardenas said...

Muchas gracias Amigo, great post and Fantastic photos!! Your motivation, entushiasm and passion for your job is brilliant, I love every comment you make because it makes me smile, remember and feel the adventure and love for what you do!! Love traveling with you, learning, sharing, living and knowing. Love you MATE!!

Ian Fraser said...

Ah Juanito, mi amigo y mate! You've shown me so many wonderful things in your part of the world. Let's do it again soon!!