Utilization of instrumental neutron activation analysis (INAA) for geochemical behaviour study of major and trace elements in Bouregreg river basin (Morocco)

The Bouregreg river basin is located in the Moroccan Central Massif which consists mainly of Palaeozoic formations that were subject to the Hercynian orogeny. This study documents the background geochemistry and hydrochemistry of the Bouregreg river basin, focusing on the distribution of major and trace elements. Rock samples were collected at nine locations along the Bouregreg River and its tributaries in the winter of 2005. Major (Al, Fe, Mn, Na, K and Ti) and trace (Rb, Cs, Sr, Sc, Ba, Cr, V, Co, Ni, Zn, As, Sb, La, Ce, Nd, Sm, Tb, Dy, Yb, Lu, Hf, Ta, Mo, Th and U) elements were analysed using instrumental neutron activation analysis. Data show that most of the geochemistry and hydrochemistry are related to regional and local geology. The geochemical heritage of geological environment in the Bouregreg river basin is very important, that results from the more compatible behaviour and the inertia of some elements during the weathering (3d transition elements (Co, Ni, Cr,…), interne transition elements f (lanthanides, Zr, Hf, Nb, Ta,…)). The geochemical homogeneity of the basin shows also heritage during the crustal accretion (magmatism-metamorphism-sedimentation) and the typology of this continental area is the same that the upper continental crust. Some anomalously high heavy metal analyses, particularly for As and Sb, may be related to anthropogenic activities.