New Inferences on Magma Dynamics in Melilitite-Carbonatite Volcanoes: The Case Study of Mt. Vulture (Southern Italy)
This study provides the first micro-thermometric data of fluid inclusions (FIs) in mafic loose (disaggregated) xenocrysts and ultramafic xenoliths in explosive products of the melilitite-carbonatite Mt. Vulture volcano (southern Italy). Pure CO2 late stage FIs hosted in rock-forming minerals of wehrlite xenoliths and clinopyroxene xenocrysts were trapped at the local crust-mantle boundary (32 km). In contrast, trapping pressures within the loose olivine xenocrysts are from 3.2 to 4.5 kbar (8–13 km). Considering the ongoing degassing of mantle-derived CO2 rich gases, together with seismic evidences of the presence of low amount of melts at depth, and the tectonic control of the past volcanic…
Temporal evolution of the Fogo Volcano magma storage system (Cape Verde Archipelago): a fluid inclusions perspective
The architecture of the magma storage system underneath Fogo Volcano (Cape Verde Archipelago) is characterised using novel fluid inclusion results from fifteen basanites, spanning the last 120 thousand years of volcanic activity, and encompassing a major flank collapse event at -73 ka. Fluid inclusions, hosted in olivine and clinopyroxene, are made of pure CO2, and based on their textural characteristics, are distinguished in early (Type I) and late (Type II) stage. Inclusions homogenize to a liquid phase in the 2.8 to 30.8 degrees C temperature range. Densities values, recalculated assuming an original 10% H2O content at the time of trapping, range from 543 to 952 kg center dot m(-3), and …
Microthermometry of fluid inclusions in calcite from Fuerteventura carbonatites: composition and formation conditions
The petrographic analysis in calcite minerals in carbonatitic dykes from Fuerteventura Basal Complex (Ajuy, Punta de la Nao) shows the presence of isolated primary fluid inclusions, corroborating their magmatic origin instead of a late-stage origin. Micro-thermometric studies in calcite show a restricted range of apparent eutectic temperature (Te*= -21.7 – -21.0 °C) and final ice melting temperatures (Tim= -3.2 – -2.1. °C). Homogenization temperatures and pressures are in the range of 140-210 °C and 4-16 bars respectively. Our results suggest the binary NaCl-H2O system as a characterizing chemical system in studied fluid inclusions, with the presence of low salinity fluids (≈ 5 wt. % NaCleq…
The fumarolic CO2 output from Pico do Fogo volcano (Cape Verde)
The Pico do Fogo volcano, in the Cape Verde Archipelago off the western coasts of Africa, has been the most active volcano in the Macaronesia region in the Central Atlantic, with at least 27 eruptions during the last 500 years. Between eruptions fumarolic activity has been persisting in its summit crater, but limited information exists for the chemistry and output of these gas emissions. Here, we use the results acquired during a field survey in February 2019 to quantify the quiescent summit fumaroles' volatile output for the first time. By combining measurements of the fumarole compositions (using both a portable Multi-GAS and direct sampling of the hottest fumarole) and of the SO2 flux (u…
Micro-thermometry and minerochemical composition of ultramafic xenoliths and minerals from Mt. Vulture volcano (southern Italy)
Here minerochemical composition and micro-thermometric data of ultramafic xenoliths (wehrlite) and loose xenocrysts (olivine and Cr-diopside) from the last melilitite-carbonatite explosive volcanic activity of Mt. Vulture volcano. In addition, some geometrical parameters of pelletal lapilli are reported.