New Inferences on Magma Dynamics in Melilitite-Carbonatite Volcanoes:
The Case Study of Mt. Vulture (Southern Italy)
Abstract
This study provides the first micro-thermometric data of fluid
inclusions in mafic loose xenocrysts and ultramafic xenoliths in
explosive products of the melilitite-carbonatite Mt. Vulture volcano
(southern Italy). We found within ultramafic xenoliths
CO2-dominated fluid inclusions with trapping pressures
between 8.5 and 8.9 kbar, corresponding to a depth of 26-27 km, in
proximity of the local crust-mantle boundary. In contrast, trapping
pressures within the loose xenocrysts are up to 2.8 and 3.2 kbar (8-9
km). We estimated an ascent rate of the latest 141 ka old
melilititic-carbonatitic magmas from the Moho depth to the surface in
the range of few hours. Considering the ongoing degassing of
mantle-derived CO2 rich gases at Mt. Vulture, together
with geophysical evidences of the presence of low amount of melts at
depth, and the tectonic control of the past volcanic activity, our study
opens new perspective about the hazardous nature of the “quiescent”
melilitite-carbonatite volcanoes.