Fabricas diageneticas asociadas al paleokarst del techo de la Unidad Intermedia del Mioceno de la Cuenca de Madrid

Abstract

Carbonates and evaporites from the top of the Miocene Intermediate Unit of the Madrid Basin have set as host-rock for early karstification phenomena. The development of these karstic processes imply an important change in the depositional evolution of the basin. In these materials, complex diagenetic fabrics formed as a result of shallow meteoric diagenetic proceses have been recognized, being dedolomitization and calcitization of gypsums in the main diagenetic processes that affected the top of the Miocene Intermediate Unit. The high variability of diagenetic fabrics is thought to be mainly influenced by the original composition of sediments, the activity of microorganisms and the chemistry of diagenetic waters.