Geodynamic significance of the Aeolian volcanism (Southern Tyrrhenian Sea, Italy) in light of structural, seismological, and geochemical data

Abstract

[1] The Aeolian volcanoes are located between the Southern Tyrrhenian Sea back arc and the Calabrian Arc forearc region. Structural, geochemical and seismological data indicate that the early phases of volcanic activity (1.3 Myr) developed in the western sector along WNW-ESE tear faults controlling the southeastward migration of the forearc -back arc system. This magmatism ceased when delamination processes affected the Calabrian Arc. At 0.8 Myr, the volcanism migrated southeastward and concentrated on the ''new'' formed NNW-SSE tear faults related to the postsubduction extensional strain. The compressive strain deduced by focal mechanism of earthquakes in the western sector explains the volcanism ending. The still active volcanism in the central and eastern sectors develops on a NNW-SSE striking lithospheric discontinuity that crosses the ring-shaped volcanic belt. Moho upwelling occurs in the area of active volcanism. Fault-slip data and focal mechanisms from M > 5 earthquakes indicate that the NNW-SSE discontinuity moves in response to an oblique (strikeslip/normal) stress related to a WNW-ESE extension. This direction of extension is consistent with that of the forearc region, where thrust-type events are lacking and the last compressive phases occurred during Pliocene. The later phases of the Aeolian volcanism are related to the melting of shallower source(s) consistent with a continental rift magmatism. The Aeolian Islands represent a postcollisional, rift-type volcanism emplaced in an older collision zone.

Oxygen Isotopic Variations in the Clinopyroxene from the Filicudi Volcanic Rocks (Aeolian Islands, Italy): Implications for Open-System Magma Evolution

“…These characteristics suggest that an oceanic type crust was subducted beneath the western branch of the Aeolian Arc. Our conclusions are inconsistent with Doglioni TN 2001 [47] who suggests that a continental type crust is subducting beneath the western Aeolian Arc, but agree with De Astis T 2003 [48] who suggests oceanic crust subduction.…”

Radon mapping, automatic measurements and extremely high 222Rn emissions during the 2002–2007 eruptive scenarios at Stromboli volcano

“…Its cone is built on a NE-SE normal fault with a moderate oblique component: the Stromboli-Panarea (SA) alignment. This structure is connected to the NNW-SSW trending Tindari-Letojanni fault that crosscuts eastern Sicily and the southern Tyrrhenian region (cf., De Astis et al, 2003;Acocella and Neri, 2009). The volcano rises 924 m above sea level and was built during the last 100 kyr (Gillot and Keller, 1993) with its submerged part reaching a depth of about 2,000 m below sea level.…”

Structural features of Panarea volcano in the frame of the Aeolian Arc (Italy): Implications for the 2002–2003 unrest

“…A lack of deep seismicity (>20 km) in the western arc suggests active subduction in the eastern sector only (De Astis et al, 2003, and references therein). While the western arc undergoes predominant compression (De Astis et al, 2003), the eastern arc undergoes predominant extension (De Astis et al, 2003;Neri et al, 2005;Billi et al, 2006).…”

“…1a). Volcanism occurred between 1.3 Ma and 3040 years in the western arc, from 0.8 Ma to present in the eastern-central arc (De Astis et al, 2003, and references therein), with documented coeval unrests, such as in [2002][2003] (degassing at Panarea and effusive eruption at Stromboli). A lack of deep seismicity (>20 km) in the western arc suggests active subduction in the eastern sector only (De Astis et al, 2003, and references therein).…”