In an interesting coincidence, during our visit to San Pedro de Atacama and its Salt Flats, I was reading a book about the history of salt. I picked up Salt, A World History by Mark Karlansky in Auckland airport during one of our long sojourns there. A cover as umpromising as that, I reasoned, was sure to hide an excellent book. Only a publisher who was very confidant of their author's ability to truely facinate the reader would risk their money on 450 pages of a book like that. (The same auther has a track record - a biography of the cod. As in fish. Seriously.)
But usually the simplest explanation is the correct one. A book about salt is, well, hard to swallow. I'm on page 256 now, and I feel like my brain has been pickled in brine. I have been almost entirely leached of my will to read. On the bright side, the book did help somewhat with my Santiago insomnia. And I have learned a few things, though painfully (like, not to buy the book about cod).
Why is the sea salty?
I'm very comfortable with the answer "I don't know" to most questions that anyone, especially my daughters, might put to me. I like the ring of it. I like its simplicity. And it suits me. But the nature of my children is to abhor this vacuum. When given the choice between idle and ill-founded conjecture on one hand, and the honest admission of ignorance on the other, Nina and Sara generally opt for the former. In face, in the absence of an answer to a question like "Why is the sea salty?" they are capable of constructing a complete mytholigical edifice involving princesses and tyrannical kings (who knows why, but hard-done-by princesses and tyrant kings feature regularly in their stories...)
But the answer to the above question was answered for us in, of all places, the desert. When you visit the Salar de Atacama despite being in one of the driest places on Earth you'll find salty lagoons with shrimps swimming in them, and three different species of flamingo that feed on the shrimp. Around the lagoons there is nothing but jagged salt-encrusted plains. Around the salt there is only the rocks and dust of the desert. And all of this is enclosed by the Andes on one side and the Cordillera de la Sal (yes, salt) on the other. Where does the water, and the salt come from?
I don't know.
Just kidding. Force of habit. It's meltwater from the Andean snow peaks. It flows downward like a river, but under the surface of the ground. Like any river, it carries along with it the minerals of the soil through which it runs. But this river never gets even close to the sea. It hits the high plains between the two mountain ranges, where the impermeable rock pushes it to the surface. 96% of the water evaporates, depositing the salt crystals in ever-growing clumps. The remaining 4% creates the lagoons.
The effect that this produces is best told with pictures - Letizia's of course. Looked at closely, the Salt Flats aren't really flat at all. The surface looks like badly-ploughed earth, sprinkled with snow. And when the sun goes down, the colour of the salt, and the reflection of the reddening mountains and volcano in the lagoon outdoes even Uluru. Even without the champagne.
What's that? Oh - what does make the sea salty? Well, just allow a river to reach the sea (many do, apparently) and the same process of surface evaporation, carried on over eons, makes for a salty sea. Well that's one explanation. Another one is that the evil king, punishing his two poor innocent daughters for not eating their dinner, makes them fill the sea with the kingdom's salt, teaspoon by teaspoon.