Marine and Freshwater Research Marine and Freshwater Research Society
Advances in the aquatic sciences

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Isotopic and geochemical methods for studying Water-rock interaction and recharge mode. Application to the Cenomanian-Turonian and Plio-quaternary aquifer of Essaouira Basin, Morocco

Mohammed Bahir , Salah Ouhamdouch , Paulà Maria Carreira

Abstract

The study of the Cenomano-Turonian and Plio-Quaternary aquifers of Essaouira basin (Western Morocco), based on the interpretation of geochemical (major elements) and isotopic (18O, 2H, 13C and 14C) data, has aided the understanding of the hydrodynamics of these aquifers, which is greatly influenced by tectonics. Hydrochemical characteristics based on the bivariate diagrams of major (Cl-, SO42-, NO3-, HCO3-, Na+, Mg2+, K+ and Ca2+) and electrical conductivity and mineral saturation indices indicate that the origins of groundwater mineralization is the result of: (i) evaporite dissolution (ii) cation exchange reactions (iii) and evaporation processes. Radiogenic isotopes (3H and 14C) have highlighted the presence of significant recent recharge in the Eastern part of the basin with groundwater moving according to the general flow path (SE–NW). Stable isotopes data from the Essaouira basin, plots along the Global Meteoric Water Line (GMWL) and below the Local Meteoric Water Line (LMWL). This suggest that groundwater has been recharged under several different climate regimes.

MF17370  Accepted 17 January 2018

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