Evolución diagenética de la plataforma carbonatada Aptiense superior del sector Benicàssim-Orpesa. Cuenca del Maestrat. Cadena Ibérica

Abstract

The upper Aptian carbonate platform of Benicàssim-Orpesa area contains reefal facies that are affected by a complex diagenetic evolution including: (1) Calcite 1, (2) Calcite 2, (3) Calcite 3, (4) Silica and dolomite, and (5) Dedolomite and Calcite 4. Cc1 with low Fe content indicates an early marine environment in which the replacement of the coral walls occurred together with precipitation of this cement in the primary porosity. Cc2 with high Fe content and cross-cutting mosaic geometries are interpreted as indicative of a sea level drop resulting in the alteration of the corals in a meteoric-phreatic environment and the formation of dissolution cavities. Cc3 with low Fe and high Sr content indicates a new episode of marine influence probably related with a sea level rise and resulting in the precipitation of this cement in the secondary porosity. Silica precipitated contemporaneously to dolomite rhombohedra crystals. The later Cc4, with high Fe and low Sr content, also precipitated in a meteoric-phreatic environment, probably coetaneous to dedolomitization. Finally, saddle dolomite occurs with no obser ved relation with the other diagenetic products, and probably precipitated in a late and deep event