Geochemical and Sr-Isotopic Study of Clinopyroxenes from Somma-Vesuvius Lavas: Inferences for Magmatic Processes and Eruptive Behavior

Abstract

Somma-Vesuvius is one of the most dangerous active Italian volcanoes, due to the explosive character of its activity and because it is surrounded by an intensely urbanized area. For mitigating the volcanic risks, it is important to define how the Somma-Vesuvius magmatic system worked during the past activity and what processes took place. A continuous coring borehole drilled at Camaldoli della Torre, along the southern slopes of Somma-Vesuvius, allowed reconstructing its volcanic and magmatic history in a previous study. In this work, the wide range of chemical (Mg# = 92–69) and isotopic (87Sr/86Sr = 0.70781–0.70681) compositions, collected on single clinopyroxene crystals separated from selected lava flow units of the Camaldoli della Torre sequence, have been integrated with the already available bulk geochemical and Sr-isotopic data. The detected chemical and isotopic signatures and their variation through time allow us to better constrain the behavior of the volcano magmatic feeding system, highlighting that mixing and/or assimilation processes occurred before a significant change in the eruptive dynamics at Somma-Vesuvius during a period of polycyclic caldera formation, starting with the Pomici di Base Plinian eruption (ca. 22 ka).

Editorial for the Special Issue “Minerals of Alkaline Igneous Rocks: Chemical and Isotopic Features as Tracers of Magmatic Processes”

“…Di Renzo et al [23] present a detailed study on the clinopyroxenes of lavas of variable ages from Somma-Vesuvius, one of the most well-known volcanoes of Southern Italy. In particular, several single clinopyroxene crystals collected from three lava flows cored in a deep borehole on a flank of the volcano were analyzed using an electron microprobe for major elements and by thermal ionization mass spectrometry for the Sr-isotopic composition.…”

“…22 ka). The study of Di Renzo et al [23] illustrated how minerals of igneous rocks may help to improve the knowledge of the past behavior of a dangerous volcano, with the aim of mitigating the volcanic risk in case of the renewal of volcanic activity.…”