Geochemical analysis by means of XRF and ICP|AES was carried out on 35 selected samples. Major and trace elements were determined. They were: CaCO-3, P-2O-5, Fe-2O-3, TiO-2, SiO-2, Al-2O-3, CaO, K-2O, MnO, Rb, Cs, Ga, Zr, Ta, Nb, Sr, Ba, Cr, Ni, Zn, Pb, Cu, V and B. The country rocks studied were of sandy|muddy lithofacies, belonging to a typical tide marine transgressive heterolithic succession of Middle Miocene age. They are called the Ituzaingó Formation. The formation outcrops in northeastern Argentina on the left of the Paraná River Valley. The depositional setting largely depends on the outstanding internal structures and textures (i.e., herringbone cross stratification, tidal bundles, reactivation surfaces). In the study area, loessial friable sediment was used as geochemical background because it overlies shallow marine sediments. The results show significant differences. Boron is absent in loessial sediments. On the other hand, several trace elements such as vanadium and chromium are concentrated in the shallow marine sediments. These results may be useful to discern uncertain beds in the area studied.
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