In South Transdanubia (Hungary) there are remarkable geothermal and hydrocarbon resources. Besides the sedimentary basin, the area also includes the Villány Thermal Karst. The karst area is characterized by natural thermal water discharge at the boundary of outcropping carbonate hills and the sedimentary basin, which established the thermal water exploration of Hungary in 1866. These regional discharge areas are favourable sites of hypogenic caves as well. These geofluid systems and groundwater related phenomena are usually investigated separately and their interactions are just neglected. The aim of this study was to give all these resources and phenomena a common framework applying the dynamic system approach and complete the regional hydraulic and hydro-geochemical assessment of the area. During the measured data based hydraulic assessment pressure-elevation (p(z)) profiles, tomographic fluid potential maps and hydraulic cross sections had been constructed to determine the vertical and horizontal fluid flow conditions. The hydrochemical study (concentration- and temperature-elevation profiles, concentration map series) helped to understand the geofluid systems more accurately. Local scale studies focused on groundwater related phenomena: on the research of a spring lake and a hypogenic cave. With geophysical measurements the local geological build-up of the spring lake was explored. Time series of physico-chemical parameters of the spring and in the cave help to understand the local scale dynamics of the system which was verified by numerical simulation. In-situ experiment using carbonate rock slices combined with continuous recording of the physico-chemical parameters reported on the recent processes in the cave.
The National Research, Development and Innovation Fund has provided financial support to the research under the grant agreement no. PD 116227.