ABSTRACT
The study’s objective was to identify the source of salts and the controls and mechanism of their distribution in a sedimentary basin with a coupled gravity-driven and over-pressured flow regime. The generalised salinisation and flow model was built up based on multidisciplinary data interpretation in the Duna-Tisza Interfluve, Hungary. In the basin a gravity-driven flow regime characterised by (Ca, Mg)-(HCO3)2-type water is perched hydraulically upon an over-pressured saline flow regime. The salt for the surface salinisation originates partly from the NaCl-type groundwater of the Pre-Neogene basement and the deep-basin sediments, and in addition from the NaHCO3-type water of the Neogene sequence. These saline waters mix and ascend due to tectonically controlled overpressure close to the surface. The Cl− as a conservative element traces the appearance of this deep saline water in the near surface. The salinisation pattern on the surface is controlled by the salt-distributing effect of the fresh, shallow gravity flow-systems, which contacts the ascending saline groundwater by diffusion.
