Conceptual model for surface salinization in an overpressured and a superimposed gravity-flow field, Lake Kelemenszék area, HungaryModèle conceptuel d’une salinisation de surface dans un champ d’écoulement gravitaire sous pression avec flux surimposé, secteur du lac Kelemenszék, HongrieModelo conceptual para la salinización superficial en un campo de flujo por gravedad sobre presurizado y superpuesto, área del Lago Kelemenszék, Hungría匈牙利Kelemenszék湖区某承压和叠盖型重力流场地的地表盐碱化概念模型Modelo conceptual da salinização à superfície a partir de um fluxo sob pressão e de um fluxo gravítico sobreposto, na área do Lago Kelemenszék, Hungria

The Duna-Tisza Interfluve, Hungary, is characterized by patchy surface salinization. However, in the Duna Valley, salinized wetlands appear in a N–S trending continuous zone (Lake Kelemenszék area). The source of the salts is reported to be the overpressured NaCl-type water of the Pre-Neogene basement and the NaHCO3-type water of the Neogene sediments. This “basement and basin origin of salts” concept is based on the strong correlation between the regional distribution of surface salinization and the basinal flow pattern. This study, applying integrated methods, presents hydrogeological evidence for this theory and creates a conceptual model for the salinization. The model reflects that the basement water rises near to the surface through conductive faults crosscutting an extensive aquitard and aquifer. These faults ensure “shortcut”-type water exchange between the basement and the uppermost aquifer. This hydraulic setting generates chemical anomalies in this aquifer up to the surface, producing Na–HCO3–Cl-type water. This water causes extensive surface salinization in those discharge areas where the infiltrating freshwater does not superimpose the upwelling saline water. Where a freshwater lens is located above the ascending saline water, this fresh gravity-driven flow controls the surface distribution of salts, which results in saline patches.