The evolution of a gypsum vein network in compressive tectonic settings: the Montsant anticlinorium case (NE Spain)

Abstract

The Montsant anticlinorium is part of the Pàndols-Cavalls-Montsant tectonic line situated in the southwestern area of the Catalan Coastal Ranges, adjacent to the contact with the Tertiary Ebro Basin. We have interpreted this Alpine structure as a triangular type I zone with two opposite faults. The centre of the anticlinorium is formed by middle Muschelkalk facies with intensively deformed gypsum layers and an intensively deformed zone with an associated framework of satin spar gypsum veins. A field structural analysis reveals that there are two sets of veins: one associated with a pre-folding stage (before the Alpine orogeny), and another one related to the development of the Montsant anticlinorium, and therefore syn-folding (and Alpine in age).