GEOMETRIES IN SODIUM CHLORIDE

April 27, 2017 SouthAmerica

The Salares de Mares in the Cusco Province of Peru comprise an impressive array of salt water evaporative ponds that have been in continual use since the times of the Incas. It is one of the satellite attractions for tourists doing the Cusco circuit, taking about one hour’s ride to the north of the city to a tributary steep canyon overlooking the Sacred Valley of Urubamba. The salt waters originate oddly enough from a cold water saline spring. This is truly geologically rare, and in fact upon first visiting Salares de Mares it was the first time in 30 years as a geologist I have ever come across something like it. Later I have read about descriptions of numerous saline springs surrounding Bogota in Colombia, with the salt being derived from a Cretaceous aged formation. Of course, at the Salares de Mares site, after paying the nominal entrance fee and strolling about taking pictures of the process, there is no explanation by the operators on the nature of the spring, except that the water is partitioned for distribution to the various families that have long traditional claims for its use.

https://www.southamericatotheworld.com/ — Salares de Mares – Peru

What is the source of the salt? From some regional geology that I have read about over the years, and have seen firsthand in select areas, the Triassic-Jurassic formations that once constituted a marine platform limestone shelf locally contain evaporate deposits. A few of these thin horizons form gypsum beds that are extracted in many locations in Peru in an artisanal manner. Whether or not the Salares de Mares spring water moving underground along a similar narrow beds stripping out the salt as it goes, or if it has subterranean plumbing that has intersected a much larger buried salt dome can only be pondered. Just the same, the long use of the salt water has built up impressive deposits along the thin walled evaporative tanks where workers manually crush and sieve the halite crystals to dry out and sell at market for about 4 to 5 Soles per kilo. Photographs of yesterday and those of the future will apply themselves in composing subsets of the sodium motifs, just as I have duly taken my turn in visual extraction.