Modelización de la hidroquímica y sedimentoquímica de una laguna tipo playa (Cl- So2-4 Mg2+ - Na+): La Laguna Grande de Quero (Toledo)

Abstract

The «Laguna Grande de Quero», is a saline pond located on the aluvial system from the Cigüela and Riansares rivers. The pond's underground impermeable materials are claystone with gypsum from the Triassic ages. On the next reliefs appears gypsiferous-detrital and calcareous materials from the Tertiary ages. A model have been created for the evaporative process, correcting the saline effect bearing in mind the climatic parameters; the conclusions obtained are coherents with the experimental data, which have been obtained in two experimental pools placed for the evaporative- concentration processes chasing. The experimental precipitation sequence obtained was: calcite + gypsum → bloedite + thenardite → bloedite → epsomite + halite. This sequence has been studied about saits generated on the air-brine interface. Moreover coincide with the foreseeable theoric sequence, according to Valyashko diagrams. In the natural environment appears facies and paragenesis associations coherents with the experimental data. During the evaporative process to specific gravity and concentration evolution graphics show a stagnancy period, «plateau effect», that it seams to coincide with a differential heating from the depth waters. The explanation of this effect can be related with the salts dissolution previously formed.