Ephemeral carbonate melts in the upper mantle: carbonate-silicate immiscibility in microveins and iinclusions within spinel peridotite

Carbonate droplets containing mafic silicate glass ± C

Melt inclusion: methods, applications and problem: Silica-rich melts in quartz xenoliths from Vulcano islands and their bearing on processes of crustal melting and crust-magma interaction in the Aeolian Arc, Italy

Silica-rich melts in quartz xenoliths from Vulcano islands and their bearing on processes of crustal melting and crust-magma interaction in the Aeolian Arc, Italy Proceedings of workshop Melt inclusion: methods, applications and problem. Napoli, Italy, September 2002, p. 71-7

Relationships between magmatism and lithosphere-asthenosphere structure in the western Mediterranean and implications for geodynamics

Shear-wave (VS) tomography along transects across the Western- Central Mediterranean area reveals heterogeneous lateral and vertical physical characteristics in the lithosphere-asthenosphere system (LAS). A 50 km thick low velocity layer (LVL), with VS 3c 4.0\u20134.2 km/sec, typical of low rigidity fluid-bearing mantle material, is observed at a depth of about 70\u2013120 km from offshore Provence, to Sardinia and the Central Tyrrhenian Sea. This LVL, enclosed between higher velocity mantle rocks, rises to a depth of less than 30 km below the recent and active volcanoes of Central Italy and the Southern Tyrrhenian Sea, where a maximum in the heath flow is observed. The LVL is absent beneath Southeastern France and the northern border of the African foreland. In the Balearic Sea-Sardinia-Central Tyrrhenian section, the depth of LVL corresponds to pressure conditions of minimum temperature of peridotite+CO2+H2 O solidus, consistent with conditions where fluid loss from the slab and mantle flow over the subducting plate favor significant melt gen- eration above steep, west-dipping subduction zones. It is suggested that LVLin the Balearic-Tyrrhenian domains is the result of mantle contamination and melting left behind by the eastward retreating Adriatic-Ionian subducting plates from Oligo-Miocene to present. This layer also marks a discontinuity between the lithospere and underlying mantle behind the subduction zone, favoring detachment and westward drift of the lithosphere, and consequent opening of backarc basins. These data support the hypothesis that the orogenic Oligocene to Quater- nary volcanism in the Western Mediterranean area is the effect of shallow mantle processes, and argue against the presence of deep mantle plumes. A shallow-mantle origin is also suggested for the EM1-type Plio-Quaternary anorogenic magmatism in Sardinia and for the FOZO-DMM-type magmatism on the northern margin of the African foreland