The analysis of the grain size fraction fine than 63μm of the beach and dune sediments between Espinho and Torreira shows that this component of the sedimentará spectrum decreases from the beach face towards the dune. The mineral composition consists mainly of K-feldspar, plagioclase and illite. Anhydrite, opal C/CT, kaolinite and dolomite are minor components. Quartz is directly correlated with dolomite and anhydrite; whereas halite is directly correlated with zeolites, kaolinite, illite and chlorite. These associations allowed the establishment of the mineralogical index (An+Do+Qz) / (H+Ze+K+I+CI) found to be interesting as a discriminating tool of depositional enviromnents.
