2 - ELBA ISLAND - B - EASTERN ELBA

Abstract

The geology of the Elba Island is very interesting for its structural complexity, for the relationships between Mio- Pliocene magmatism and tectonics and for its location between Corsica and Northern Apennines. In fact, it is the southwesternmost outcrop of the Northern Apennines chain. The first tectono-sedimentary events come back to the Palaeozoic. In fact, in the Palaeozoic basement are clearly recorded the Hercynian and, probably, also the Caledonian events. The Alpine sedimentary succession began during the Triassic and its tectonic evolution begins in Late Cretaceous - Early Tertiary and goes on until Late Miocene - Pliocene. The compressive movements started with the consumption of the Mesozoic Western Tethys (Liguria-Piedmont Basin), went up to the collision of European (Corsica) and Adriatic (Tuscany Domain) margins (Abbate et al., 1980, Boccaletti et al., 1980; Bortolotti et al., 2001a), and terminated with the successive polyphase deformations, which originated the Apennine orogenic chain. Trevisan (1950), proposed a geological frame of the Elba I. which, successively slightly modified by Barberi et al. (1967; 1969), which has been the geological starting-point for all successive studies. This model divides the nappe pile of the Island into five Complexes. New stratigraphical and structural data modify this frame. The new scheme we propose (Bortolotti et al., 2001a), comprises nine tectonic units, built up of Tuscan (Adria continental margin), Ligurian and Liguria-Piedmont (Jurassic-Eocene oceanic domains) successions, piled up with a very complex frame. This frame is complicated by post-orogenic extensional events, that produced the thinning of the Tuscan crust that underlies the Elba Units, the uplift of the Moho and the birth and evolution of the Tyrrhenian Basin (Boccaletti et al., 1985; Bartole et al., 1991; Bartole, 1995 cum bibl.; Carmignani et al., 1995). To this phase is linked the emplacement of the monzogranitic bodies and the formation of ore deposits and skarns. These latter constitute one of the best known geological features of the Island (Marinelli, 1975; Serri et al., 1991; Tanelli, 1977; 1983 cum bibl.).