The origin of salt
During the Triassic period (between 251 and 208 million years ago), at a time when all continents were united into one land mass called Pangea, the Añana Salt Flats were submerged under a great ocean. The evaporation of the water caused the deposition of large layers of evaporites that, over time, were covered by other layers.
The presence of salt in Añana is explained by the geological phenomenon known as Diapir. In general, this consists in the ascent to the surface of older materials due to their lower density, just the same as an air bubble immersed in a liquid moves to the surface. This particular process began, in the present case, about 220 million years ago, when the evaporitic rocks of the Triassic period in Keuper facies - located about 5 km deep - began to ascend to the surface, dragging the materials that characterise a salt landscape: carniola, ophite, limestone, loam, clay... This process is still taking place.
Rainwater falling on the Diapir first makes its way through the upper strata of rock and then the salt layers, that then rise to the surface in the shape of hypersaline springs. All the springs that exist in Añana provide an average flow of 3 litres per second, with an average salinity level of over 250 grams per litre.
The water system related to the Diapir also features Arreo Lake, whose waters, due to its location in a closed basin above evaporites, is mostly saline. Both the lake and the Añana Salt Flats contain deposits with significant paleoenvironmental and paleoclimatic information, as well as a biodiversity that is typical of wetlands, which has led to the need to preserve them by including them in the RAMSAR list of wetlands of international importance.
Añanako Gatz Harana Fundazioa - Fundación Valle Salado de Añana - 01426 - Gesaltza-Añana / Salinas de Añana - Araba / Álava - 945 35 14 13 - firstname.lastname@example.org