Inwersja hydrochemiczna i wiekowa wód podziemnych na obszarze GZWP nr 401 (Zbiornik Niecka Łódzka)

The area of Łódź basin is presented in the hydrogeology literature as an area where hydrogeochemical vertical inversion and age vertical inversion between Upper Cretaceous aquifer and Lower Cretaceous aquifer occur. This article describes new facts and research results which will allow to verify the well-known fact about inversion presented above. Furthermore, the presented research results help to form a thesis about groundwater recharge and groundwater discharge of Early Cretaceous aquifer which creates MGB No. 401 (Łódź Basin).