Evaporitic traces in the Upper Albian of Bi Haizpeak / Dos Hermanas (Aralar, Nafarroa): palaeotectonic implications

Abstract

Pétrographie analysis of a thin (50 cm) bed from the Upper Albian Bi Haizpeak/Dos Hermanas (Aralar) unit, has shown signs and traces of evaporitic minerals. These features mainly consist of gypsum inclusions, micritic feplacements of gypsum crystals, and authigenic quartz cristals with anhidrite and gypsum inclusions. This is the first reference to Albian evaporites in the Basque-Cantabrian Basin, wihch, on the other hand, were formed in a general humid climate. We attribute these sulphate minerals to anomalous sedimentary conditions, related to a pulse of local ascension ofKeuper salt through synsedimentary fault

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