Peloides de glauconita y apatito en sedimentos carbonatados mesozoicos del sector oriental de la Zona Subbética (provincia de Alicante)

Abstract

Glauconite and apatite peloids occur in jurassic and cretaceous bioclast-bearing carbonate rocks from the Algayat-Crevillente Unit (Subbetic Zone). The size and the morphology of peloids are controlled by the bioclasts. Interna1 texture commonly evidence that the glauconite forh nuclei surrounded by apatite. K content is elevated in both stratigraphic positions but higher in the cretaceous glauconites than the jurassic glauconites. Textural and chemical evidence indicate a model of glauconitization with two steps: an early dissolution-crystallization process and a further process of K-enrichment. Low K-content in jurassic glauconites can be explained by the calcitic early diagenetic cementation which stops the second step of glauconitization, while the low Fe content of this glauconites could be a later effect due to a deeper burial diagenesis.