Lima Fault

The identification of the staggering of the coastal platforms in Viana do Castelo was carried out by Carvalhido R. (2012) using detailed cartography of the structural alignments and hydrodynamic geoforms, namely potholes and basal notch shapes (sapas or notches). This study allowed to identify 5 levels of preserved rock platforms above the current one (Platform VI): Plat. I (18 m), Plat. II (13 m), Plat. III (8 m), Plat. IV.1 (4.5-5.5 m), Plat. IV.2 (2.0-3.5 m) and Plat. V (0.2-1.7 m) and it was found that the width of the coastal platforms is uneven in the different coastal sectors where they are preserved and that there are variations in relation to the reference altimetric interval values, with a maximum expression of 100 cm between Montedor (LNM Alcantilado de Montedor) and Cabedelo (LNM Ribeira da Anha).

In this LNM two coastal platforms are preserved above the current one and which were interpreted as Eemian levels (MIS5e): Platform IV (3.9-4.5 m, sapa at 4.5 m) and Platform V (2.1-2.8 m). The Forte do Cão Conglomerates and Sands are preserved approximately 100 cm below the same terrace level identified in Gelfa (+2.00) (Caminha municipality). This unit testifies to a high energy beach level, installed during MIS5e and constitutes the only record of this environment known in the municipality of Viana do Castelo. These observations corroborate the effect of regional subsidence of the Lima-south compartment, with reference to the coastal sector of Montedor, which will have suffered vertical deformation at a rate of about 0.008 mm / a above that seen in the south of Lima. This phenomenon was attributed to the inverse component of the probable failures ENE-WSW (Lima and Pêgo), already somewhat out of tune with the current WNW-ESE tension field (Ribeiro et al., 1996), which is why it is very low (in Carvalhido, 2012 )