BackgroundUstica, the subaerial expression of a large submerged volcanic complex about 30 km wide, is formed mostly of lava flows, with minor hydrovolcanic products. Initial activity produced mostly pillow lavas, hyaloclastites, and breccias, having begun underwater. This was followed by effusive and hydromagmatic explosive activity, from two main volcanic centers: Monte Guardia dei Turchi (500 ka) and Monte Costa del Fallo (Peccerillo, 2005; Guest et al., 2003). These eruptions produced lavas, domes, basaltic scoria, pumice, and lapilli (Guest et al., 2003). This predominantly mafic activity was followed by a trachytic explosion and dome emplacement at about 424 ka (Peccerillo, 2005; Guest et al., 2003). One of the youngest eruptions on the island was a Surtseyan eruption, which produced extensive tuff deposits and formed the Falconiera pyroclastic cone (Guest et al., 2003). The volcanics on the island are middle Pleistocene, about 750-130 ka (Romano & Sturiale, 1971; Peccerillo, 2005; Guest et al., 2003).
Smithsonian / GVP volcano information
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