Geology and Hydrochemistry of the Deep Sandstone Aquifers of Jordan

Abstract

The deep sandstone aquifer complex of Jordan consists of hundreds of meters of Paleozoic to Lower Cretaceous sandstones that extend from the Saudi Arabian border in the south up to northern Jordan. In the south, this aquifer is known as the Disi Aquifer and is near the surface, well understood and heavily exploited. Toward the north, thick accumulations of later Mesozoic and Cenozoic sedimentary sequences cover the complex. The depth of the aquifer in this area makes it less viable as a water resource. Thus, little is known about its origin, movement and chemical evolution. A number of exploration and production wells have penetrated this aquifer throughout central and northern Jordan. The data from these wells can help to draw a reasonable understanding about this aquifer and its water. Most of the aquifer is under artesian pressure, and the piezometric head data point to a general flow north with drainage of the aquifer into the Dead Sea Rift Basin. Stable isotopes show that the water differs from modern meteoric water in the region and thus is possibly Late Pleistocene in age. The water is slightly brackish, and according to Jordanian Standards, it can be used for drinking under certain conditions. Geochemical modeling shows that here is no evidence that the salinity is primarily the result of prolonged water–rock interactions, but more likely the result of mixing with possibly trapped connate water throughout the complex.