Options
Voloschina, Marija
Loading...
Preferred name
Voloschina, Marija
2 results
Now showing 1 - 2 of 2
- PublicationOpen AccessExplosive eruptions at Stromboli volcano (Italy): a comprehensive geochemical view on magma sources and intensity range(2023-05-05)
; ; ; ; ; ; ; ; ; ; ; ; ; A comprehensive understanding of the processes that occur during magmatic storage and pre-eruptive ascent—and of their associated timescales—is critical to identifying potential precursory signals, and to developing robust volcano early-warning systems. Stromboli’s persistent activity comprises continuous degassing and explosive activity that ranges from hourly, low-intensity “normal” activity to occasional, more violent, paroxysmal activity. While the magma source processes that drive normal and paroxysmal activity are reasonably constrained, eruptive activity intermediate in magnitude and intensity (i.e., major explosions) remains elusive in terms of classification, source region, and pre-eruptive timescales. Here, we investigate the 19 July 2020 major explosion that geophysical parameters place at the upper limit of the major explosions field, close to small-scale paroxysms such as the 2003 and 2007 events. The geochemical signatures of matrix glass, olivine, melt inclusions, and embayments—integrated with gas measurements—highlight important differences in eruption source, ascent behaviour, and pre-eruptive timescales of the studied event when compared to paroxysms. Melt inclusion volatile contents identify that magma rise begins from a slightly shallower source (~9.5 km below sea level, b.s.l.) than for paroxysms (11.4 km b.s.l.), with the activation of a shallower ponding zone at 5–6 km b.s.l.. This, in combination with intermediate matrix glass compositions, suggests complex ascent behaviour, characterised by CO2 buffering in the deep ponding region and magma self-mixing in the shallower zone. Fe–Mg-diffusion modelling in olivine indicates a system perturbation start- ing ~20–25 days before eruption onset, in agreement with the timescale of volcanic gas CO2/SO2 ratio changes observed in the plume, and significantly shorter than that observed prior to paroxysms (~4 months). The geochemical dataset provides insights into the processes controlling the steady-state conditions and the broad spectra in eruption magnitude and intensity at Stromboli and bears important implications for eruption forecasting.46 19 - PublicationRestrictedMagmatic reactivation of the Campi Flegrei volcanic system: insights from the Baia–Fondi di Baia eruption(2018)
; ; ; ; ; ; ; ; ; ; ; ; ;; ;; ; ; ;; ;The Baia–Fondi di Baia was a multi-stage, small-scale eruption which occurred in the western part of the Campi Flegrei caldera at 9525–9696 BP, marking the onset of Epoch 2 of post-Neapolitan Yellow Tuff volcanism. The eruption was characterized by a complex series of events related to two distinct eruptive episodes (Baia and Fondi di Baia) separated by a short time interval, and each characterized by several eruptive phases. Mineralogical, geochemical (major, and trace elements on whole rocks, major and volatile elements on matrix glasses, and melt inclusions), and Sr isotope characterization of the tephra material sampled along the entire sequence was carried out in order to constrain magmatic evolution and dynamics of the feeding system. Three main compositional groups were identified in matrix glasses and interpreted as representative of different magma bodies: (i) a trachyte (SiO2 60.3–64.7 wt.%), which is volumetrically predominant; (ii) a tephriphonolite-latite (SiO2: 55.1–57.9 wt.%); and (iii) an intermediate magma group between phonolite and trachyte compositions. This wide compositional heterogeneity contrasts with the narrow variability recognized in the bulk-rock compositions, which are all trachytic. Mineral, melt inclusions, and Sr isotope data suggest that the trachytic magma possibly derived from the Campanian Ignimbrite reservoir located at 6–9 km depth. Volatile content in matrix glass indicates a storage depth of at least 6 km for the tephriphonolite-latitic magma. The intermediate magma is interpreted as being derived from a remelting and assimilation process of a partially crystallized trachytic body (crystal mush) by the hotter tephriphonolite-latitic magma. As the tephriphonolite-latite was erupted together with the trachyte from the beginning of the eruption, we suggest that the ascent of this magma played a fundamental role in triggering the eruption. Upwards through the tephra sequence, we observed a progressive increase of the tephriphonolite-latitic and intermediate phonolite-trachytic components. The presence of banded clasts characterized by different compositions is also indicative of syn-eruptive mingling during the final phases of the eruption.257 6