Evaporitic carbonates in the pre salt of Santos Basin: Genesis and tectonic implications – A reply

Pietzsch (2021) commented about the clumped isotope and strontium isotopic ratios published in Farias et al. (2019), suggesting in their interpretation that clumped isotopes of the Barra Velha Formation may require consideration of non-equilibrium isotopic effects or isotopic reordering, and that 87Sr/86Sr data do not support leaching predominantly basalts or originating from interaction with the mantle as in the geochemical model proposed in our paper. In our reply to Pietzsch's comment, we emphasize that we agree with other possibilities of interpretation based on the clumped isotope data, while we clarify our geochemical model and correct an erroneous interpretation included in Pietzsch (2021), who suggested the influence of mantle serpentinization fluids in the model. Lastly, we propose here an alternative interpretation of radiogenic 87Sr/86Sr data in pre-salt carbonates, not previously considered by Pietzsch (2021), indicating the increasing strontium isotopic ratio in fluids as a result of the infiltration of marine waters in continental aquifers.