Simplified geological map of the Port-Béni coastal foreshore and sampling locations. Microgranodiorites 1 and 2: porphyritic Pleubian microgranodiorite, phenocryst-rich and phenocryst-poorer facies, respectively. Doleritic dykes: 1 to 3, compositional groups from Lees et al. (1991) and Roach et al. (1992); 0, undifferentiated from any of these groups; 1, spilites and “albitophyres d’Er” (Auvray et al., 1976; Auvray, 1979); 2 and 3, Trieux dolerites, Talbert and Launay dolerites (Lahaye et al., 1995), respectively. Numbers also underline relative chronologies. Note that only two structural groups of doleritic dykes can be identified on the map (see text).