Sulfate isotope compositions (δ34S, δ18O) and strontium isotopic ratios (87Sr/86Sr) of Triassic evaporites in the Betic Cordillera (SE Spain)

Abstract

Sulfate isotope compositions (δ34S and δ18O) and strontium isotope ratios (87Sr/86Sr) of Triassic evaporites in the Betic Cordillera are addressed for the first time in the present work. Isotope values have been determined in gypsum and anhydrite samples of the Germanic-type facies (Buntsandstein, Muschelkalk and Keuper) coming from different outcrops spanning the complete Triassic Period and corresponding to both the Internal Zones and the External (Prebetic, Subbetic) Zones of this chain. More precise age assignments and stratigraphic controls are often obscured because of the intense halokinetic and tectonic deformation occurred during the Alpine Orogeny in the Betic Cordillera. Isotope values of Triassic sulfates obtained in the present study range between 12.5 and 16.6 ‰ for δ34S, between 8.9 and 16.9 ‰ for δ18O, and between 0.707615 and 0.708114 for 87Sr/86Sr. These values, as a whole, are in agreement with those of worldwide Triassic marine evaporites.