La porosidad en las areniscas triásicas (Rama Aragonesa de la Cordillera Ibérica)

Abstract

Triassic sandstone's porosity (Buntsandstein and Muschelkalk facies) from the Aragonesa Branch of the Iberian Range are studied, firstly at the sediment primary porosity calculation and secondly the porosity-reducing processes are analyzed. Processes creating secondary sandstone porosity can be established (dissolution and fracturing) by the textural and genetic caracterization of the sandstone's voids. The dissolution of potassium feldspar, carbonate cement and barite cement, is related with meteoric pore-water flow alloys to intramesozoic unconformities, Fracturing porosity is related to Iberian Range tertiary structuration. Finally, we concluded that the amount of the sandstone's secondary porosity depends mainly on the original composition of the sediments and also on the geochemical sedimentary environments that control the first diagenetic stages (eodiagenesis), This fact manifests itself in the amount and types of variating porosities along the stratigraphic section.