Tectonic, volcanic and hydrothermal features of a submarine portion of the Aeolian arc (Tyrrhenian Sea)

Multibeam, side-scan sonar, remotely operated vehicle and bottom sampling data have been acquired over a sector of the Aeolian are to assess its volcano-tectonic characteristics and hydrothermal mineralization potential. In this paper we report a description of the areas where major tectonic, volcanic and hydrothermal activity has been observed. There areas are the Basiluzzo area, the Secca dei Pesci area, the southwestern Panarea platform, the Secca del Capo highs, the offshore area between Salina and Lipari, and the eastern slope of Vulcano. The study region lies at the junction of two major E-W and NE-SW trending tectonic lineaments through which the extensional faulting of the Calabrian and Sicilian margins, leading to the formation of the Tyrrhenian back-arc sea, took place. The recent tectonics of the study area, dominated by NE-SW and E-W trending extensional structures, appears to be still controlled by the processes which have originated the Tyrrhenian back-arc opening. Many newly discovered recent Volcanic features have been observed, e.g.: (1) three pairs of volcanic cones aligned along NE-SW tectonic lineaments in the offshore between Salina and Lipari; (2) a field of fresh, tube and pillow lavas in the eastern offshore of Vulcano; (3) outcrops of fresh volcanic rocks in the Panarea platform, in particular around Basiluzzo islet, suggesting recent volcanic activity. Two types of hydrothermal mineralization were sampled, i.e. sediment-hosted sulphide deposits, and Fe-rich crusts and sediments. The polymetallic sulphide deposits were sampled in a depression south of Basiluzzo islet, for which area a kuroko-type hydrothermal system reaching high-temperature black ore deposition is suggested. In the other sectors of the study area, however, circulation is thought to have originated the Fe-rich tetsusekiei-type samples. (C) 1997 Elsevier Science B.V.