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°C) to 1142°C (±15°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.