Abstract:
New observations about the very slow present-day evolution of karstic phenomena in the Cordillera de la Sal (Atacama, Chile) - A second visit to the salt diapir in the Cordillera de la Sal, on the western margin of the Salar de Atacama was conducted 9 years after the first one. We noticed practically no change in the landscape morphology in that very arid region. A stainless steel piton driven at the base of a small cliff of rock salt was used to measure the salt dissolution rate. It did not show any extra thickness loss. A new passage system, partly underground, was discovered and mapped. Several swallow holes were observed, most of them half-filled with eolian sand. Undoubtedly they become active as soon as enough rain is collected at the surface. The underground water flows probably in the direction of the Salar in order to feed the water-table in the post evaporitic sediments, following the prominently N 140o oriented fracture system of the Cordillera de la Sal. Under the present climatic conditions, which are hyper-arid, observations on a time scale longer than the decade are essential to see changes in morphology.