CO2-Rich Xenoliths at Mt. Vulture Volcano (Southern Italy): New Constraints on the Volcano Plumbing System

This study provides new mineral chemistry data together with micro-thermometric measurements on fluid inclusions hosted in ultramafic xenoliths (lherzolite, wehrlite, and dunite) brought to the surface by the last Mt. Vulture volcano activity (140 ka; southern Italy), and fed by melilitite-carbonatite magmas. Petrographic evidence and mineralogical compositions of Mt. Vulture xenoliths are consistent with an origin in the upper mantle. Fluid inclusions in rock-forming minerals of lherzolite and wehrlite xenoliths are CO2-dominated. The equilibrium temperature calculated by geothermometric estimates ranges from 1039 C (+/- 36 degrees C) to 1142 degrees C (+/- 15 degrees C), and entrapment pressures of fluid inclusions with post-trapping re-equilibration correspond to the local crust-mantle boundary (32 km depth), and to a shallow reservoir located at 12-14 km depth. These results contribute to constrain the origin of these xenoliths and the depth of storage of magmas erupted from Mt. Vulture, where carbonatite-like metasomatism and mantle-derived CO2 degassing occur.