Seawater intrusion and associated processes in a small coastal complex aquifer (Castell de Ferro, Spain)

An attempt to identify the hydrogeochemical processes that accompany current or past intrusion of seawater in the Castell de Ferro coastal aquifer (SE Spain) was made using ionic deltas, ionic ratios and saturation indices. Alluvial and coastal Quaternary sediments and Triassic marbles constitute this complex aquifer. Cation exchange, dolomitization, and calcite dissolution were identified as operating in the aquifer. The cation exchange processes in the detrital materials are different from those in the marbles. In addition, it was determined that while the processes of marine intrusion associated with periods of low groundwater levels still persist in the detrital aquifer, in the carbonate sector the flushing process characteristic of wetter conditions has begun. (C) 2004 Elsevier Ltd. All rights reserved.