Hydrochemistry and isotopic composition of the Nubian sandstone aquifers of Disi-Mudawwara area, South Jordan

The Nubian sandstones of Cambro-Ordovician age crop out in the southern desert of Jordan. It comprises varicolored fine grained sandstones, siltstones and shales. The water bearing strata consist of two groups. The Khreim group of Ordovician-Silurian age overlies one of the most important fresh water resource in the country, which is Rum group. The Rum group is of Cambro-Ordovician age and consisting mainly of white medium grained sandstone. Any feature development of the Rum group might accelerate the vertical leakage of the poor water quality from The Khreim group (upper aquifer) towards the Rum group (lower aquifer). Investigating and studying the origin and behaviour of the Khreim group is of great importance to deal with the vertical leakage of the upper aquifer. Therefore, the hydrochemical and isotopic compositions of the Khreim water have been investigated as well as that of the Rum. The water types and geneses of both aquifers have been identified, by using complete hydrochemical analyses and the T, D, and O18 analyses. However, the average tritium content indicates that the water of both aquifers is not recent. Saturation indices and species of the waters of the waters of the two aquifers, were calculated by using the program PHREEQE. In order to identify the origin of the Khreim water a mixing model between the water of the lower aquifer and that of the Khreim was applied to demonstrate the potential risk of leakage from the Khreim group. (author). 11 refs, 5 figs, 5 tabs