File(s) not publicly available
Fluid inclusion evidence of second immiscibility within magmatic fluids (79AD eruption of Mt. Vesuvius)
journal contributionposted on 2023-05-16, 17:41 authored by Fulignati, P, Vadim KamenetskyVadim Kamenetsky, Marianelli, P, Sbrana, A
Foid-bearing syenite cognate xenoliths represent fragments of the upper peripheral parts of the K-phonolitic portions of the 79 AD magma chamber, wrenched during the explosive eruption. Abundant multiphase fluid inclusions are hosted within K-feldspar and coexist with rare silicate melt inclusions. This gives evidence to the exsolution of a magmatic volatile-rich phase from the peripheral parts of the silicate magma chamber. The characterization of daughter mineral assemblage of these fluid inclusions, by SEM-EDS and Raman spectroscopy, indicates two ubiquitous main components: Na-K chlorides (halite + sylvite) and Na-Ca carbonates (calcite Â± nahcolite). Microthermometric experiments indicate nearly magmatic trapping temperatures (760Â°C to 830Â°C) of the homogeneous chloride-carbonate liquid. Cooling of such liquid produces two immiscible melt phases (chlorides and carbonates) at 455-435Â°C. This suggests that a hypersaline-carbonate fluid, exsolved from the silicate magma, can further experience another unmixing event that would occur in essentially Â«post-magmaticÂ» environment.
Publication titlePeriodico di Mineralogia
Department/SchoolSchool of Natural Sciences
Place of publicationRome, Italy