Sicily Channel Seamounts

Numerous volcanic centres occur on the seafloor of the Sicily Channel (Fig. 8.1). Calanchi et al. (1989) recognised at least ten recent submarine volcanoes of various dimensions, mostly located along NW-SE regional faults. Some of these volcanoes have erupted during historical times others are covered by undisturbed Pliocene-Quaternary sediments and have been detected by seismic profiles and magnetic survey (Allan and Morelli 1971). 

The Banco Senza Nome Nameless Bank) is a pinnacle rising to about 80 m below sea level from a high probably made of sedimentary rocks (Bec-caluva et al. 1981). K/Ar isochrone dating on dredged samples gave an age of 9.5 Ma (Beccaluva et al. 1981). 

The Bannock seamount is located between the Island of Malta and the Pantelleria graben. It rises from a depth of about 1 km reaching 230 m below sea level. In spite of its conical shape, there are doubts about the volcanic nature of this seamount, since no magnetic anomalies have been detected. 

Three seamounts Linosa 1, Linosa 2 and Linosa 3) have been found north of Linosa island. Little is known about these cones and the volcanic nature of the northernmost centre (Linosa 3) is dubious. 

Finally, the most recent centre in the Sicily Channel is the Foerstner volcano sited about 5 km north-west of Pantelleria. This is reported to have erupted in October 1881. The eruption lasted about a week, but was not observed by any scientist and descriptions are based on fishermen accounts (Washington 1909). 

---

Sicily (7 Ma to Present) Etna (0.5-Present), Iblei (7-1.5), U-stica (0.75-0.13), Pantelleria (0.3-0.005), Linosa (1-0.5), Sicily Channel seamounts - Stratovolcanoes, diatremes, small plateaux, etc. formed of tholeiitic and Na-alkaline rocks (basanite, hawaiite, trachyte, peralkaline trachyte and rhyolite). 

Fig. 8.16. TAS classification diagrams of Linosa and Sicily Channel seamounts. The dashed line is the boundary between subalkaline and alkaline fields of Irvine and Baragar (1971). Data on seamounts have been recalculated on water-free basis.

Trace element abundances of rocks dredged from the Sicily Channel seamounts are scarce (Beccaluva et al. 1981 Calanchi et al. 1989). They show variable concentrations, with incompatible element abundances increasing from tholeiitic to alkaline basalts and basanites (Fig. 8.17). Mantle normalised incompatible elements define bell-shaped patterns (not shown), which resemble those for the exposed rocks in the Sicily Channel. 

Flegrei and Ischia) and continues in the Aeolian islands, in eastern Sicily (Etna), and along the Sicily Channel. Young volcanism in Sardinia has ages of about 5 to 0.1 Ma. Several Pliocene to active seamounts occur on the Tyrrhenian Sea floor. 

The volcanoes of the Sicily Channel (Linosa and Pantelleria and a number of seamounts Miocene to present in age) are mainly located along ex-... 

---