Wpływ neotektoniki na zmiany stosunków hydrogeologicznych Roztocza

Abstract

Autor dokonuje próby wykazania związków zachodzących między podnoszeniem się Roztocza a kształtowaniem się stosunków hydrogeologicznych. Podnoszenie się Roztocza wiąże się z ruchami neotektonicznymi powodującymi obniżanie się zwierciadła wód podziemnych. Podnoszenie to trwa przypuszczalnie od .sarmatu, a jego wpływ na obniżanie się zwierciadła wód można śledzić od początku holocenu na podstawie ewolucji sieci hydrograficzne.

THE INFLUENCE OF THE NEOTECTONICS ON CHANGES IN HYDROGEOLOGICAL CONDITIONS IN THE ROZTOCZE AREA

The analysis of hydrographic network of the Roztocze area has shown lowering of groundwater table during the Holocene. The lowering of groundwater table is not a companied by decrease of underground outflow index nor value of underground water flow as it has been shown by the results of hydrogeological studies.

The phenomenon of groundwater table lowering may be explained by the effects of neotectonic movements leading to a steady uplift of the Roztocze area. The paper presents an attempt to trace relationships between the uplift of that area and formation of hydrogeological regime. The uplift of the Roztocze area presumably continues since the Sarmatian. The resulting drop of groundwater table may be traced since the beginning of the Holocene. In these ,times the rate of uplift of the Roztocze was presumably equal 0.5 mm per year, that is 5 m during the whole period analysed, i.e. 10 000 years of the Holocene. A drop of groundwater table for about 40 m corresponds to that uplift (Figs. 3-4).

When the hydrogeological model of the Roztocze area (Fig. 1) is accepted it is possible to draw the following conclusion from the above data:

1. Uplifting of Roztocze rock massif results is opening of fissures in subsurficial ,zone as well as capillary or even subcapillary fissures existing at larger depths. The widening of fissures increases saturation zone water capacity magnifold.

2.Increase incapacity of Saturated zone as well as opening of deeper seated fissures lead to a gradual translocation of saturation zone downwards which takes place in equilibrium with the pattern of local drainage base.

3. Translocation of saturation zone does not disturb factors of hydrogeological and hydrological balances; therefore, despite of lowering of groundwater table neither decrease in flow values nor in output of water intakes are found.

In order to trace in detail the interdependances between uplift of the Roztocze area and lowering of ground water table is planned to construct two hydrological station for making stationary measurements.