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The unconfined aquifer of coastal Chaouia is an example of groundwater resources subjected to intensive withdrawals in Morocco. In this study, we focus on the salinization of groundwater in coastal aquifers, by physic-chemical analysis of 39 groundwater samples collected from wells during May 2011. The hydrochemical results show two facies types, the first is chloride-sodium, caracterizing the wells in the coastal fringe; the second is chloride bicarbonate-calcium characterizing waters exploited in marly limestone of the Cretaceous. The marine influence (aerosols and seawater intrusion), aquifer rock dissolution/precipitation and infiltration of irrigation water are among the causes of the increase in the salinity of groundwater, in addition to the excessive exploitation of groundwater in the study area.EDITEUR Z.W. KundzewiczEDITEUR ASSOCIÉ M. Besbes [ABSTRACT FROM AUTHOR]

The seismic reflection studies carried in the Essaouira Basin, intermediate zone between the High Atlas and the Atlantic Margin, show the presence of halokinetic structures that played a significant role in the evolution of the basin. Salt dynamics was controlled by the Atlantic rifting and the Atlasic orogen. These tectonic controls and the margin segmentation are responsible for the diachronism of salt movement. Halokinesis varied in time and space in the basin and was more active offshore, where autochtonous and allochtonous salt layers are present. To cite this article: K. Mehdi et al., C. R. Geoscience 336 (2004). [Copyright &y& Elsevier]

Abstract: The recent discovery of emerged and lifted lagunal deposits near the Moulay Bouselham lagoon (North Moroccan Atlantic coast), up to 32m above sea level, requires a new model to explain the evolution of this ecosystem. All the studies on these deposits seem to indicate that we are dealing with very recent lagoonal levels. The main problem is to explain the altitude of these deposits. Likely explanations are a historical tsunami, tempest, and/or a very strong neotectonics in this area. We choose the later hypothesis because it matches the occurrence of an argilokinetic tectonic in front of the North Atlantic Moroccan margin. In this tectonic context, results of 14C analysis data, i.e. 2400±250 BP for one outcrop and 2170±215 BP for a value in a core taken in the lagoon, we obtain a rate of uplift of about 14mm/yr. Therefore, this region corresponds to an important tectonic junction between the stable Meseta to the south, the Rifian domain to the north and the accretionary prism, in relation with the subduction of the Atlantic crust under the African and European plates to the west. Moreover, in front of the studied site, many mud volcanoes have been observed in the Gulf of Cadiz, near the Moroccan margin. [Copyright &y& Elsevier]