Interacciones bióticas en la neoformación de minerales en lagunas salinas y alcalinas, con énfasis en los minerales de la arcilla

Abstract

The presented PhD Thesis has focused on the study of biotic interactions in the neoformation of minerals within microbial mats in two wetlands. In all the lakes microbial mats proliferate in different stages of lithification. Emphasis has been placed on the analysis of clay minerals and associated carbonates and sulfates. Two lake systems were selected for this study. One lake system is formed by El Longar, Altillo Grande and Altillo Chica lakes. It is located south of Lillo (Toledo, Guadiana Basin), it has a hypersaline character and hydrochemical composition of Mg2 + - (Na +) - (Ca2+) - SO42 - -(Cl-). El Longar lake has been studied in more detail, as it is the only one of the three which is a permanent lake and contains more evolved microbial mats. These three lakes share the same clay mineral assemblage since they have similar drainage basins and hydrochemistry. The second lake system (Cuenca del Duero) includes the Caballo Alba, Las Eras and Bodón Blanco lakes and extends between the towns of Coca (Segovia) and Olmedo (Valladolid). These are alkaline, soda-lakes and have a Na+ -Cl - -SO42- - HCO3- hydrochemistry. They present differences in the smectites content attributed to their different source areas and hydrochemical composition. This study has focused on Caballo Alba, which contains a higher proportion of smectites...