δ34S, δ18O, and δ2H-δ18O as an Approach for Settling the Question of Groundwater Salinization in Neogene Basins: The North of Morocco in Focus

Abstract

Neogene plains around the Mediterranean basin are characterized by considerable groundwater salinization. Some studies have misidentified seawater intrusion as the main source of salinity. Across northern Morocco, we gathered δ18OSO4 and δ34SSO4 data from coastal and inland aquifers, Messinian marls, and volcanic products. Differences in the isotopic composition between Messinian marls and some groundwater in all aquifer samples indicate that salinization in groundwater is a consequence of dissolution of Messinian evaporite deposits; nevertheless, modern agriculture and wastewater strongly influence depletion in levels of δ34SSO4. Our novel approach enables effective investigation of processes governing salinity in Neogene basins to support more informed water resource management and governance.