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My research focuses on reconstructing the pre- and syn-eruptive magmatic conditions and the timescales of magmatic processes by experimental investigations and by using the compositions and/or textures of mineral phases.
Current Research
4DVOLC: Magma storage and ascent in volcanic systems via time resolved HPHT x-ray tomographic experiments and numerical modelling of eruption dynamics
Twitter: @4Dvolc
2025. Linking eruptive style with pore network geometry in tephritic/basanitic tephra from the 2021 Tajogaite eruption (Canary Islands, Spain)
into magma ascent processes, due to their influence on magma permeability, outgassing efficiency and explosivity. Here, we used X-ray computed microtomography to investigate vesicle textures in tephra from the 2021 Tajogaite eruption (La Palma, Spain) and the relationship between these pore network parameters and eruptive style. We report a 3D dataset of pore network parameters for lapilli clasts collected throughout the eruption, associated with different eruptive styles (ash-rich jets, lava fountains, Strombolian activity). In clasts from Strombolian activity, the lower vesicle number density (VND) and tortuosity factor (m) suggests that there are fewer vesicles and that the channels which connect them are less tortuous than in clasts from fountain and ash-rich jet activity, favouring a lower degree of gas–melt coupling and thus, more efficient outgassing. Instead, for clasts of lava fountain and ash-rich jet activity, the higher VND and m suggest a higher number of vesicles connected by more tortuous channels, promoting some degree of gas–melt coupling and thus, less efficient outgassing. However, in clasts from ash-rich jets, the presence of narrower channels, as suggested by the lower throat-pore size ratio, favours a greater degree of gas–melt coupling with respect to fountain activity, leading to magma fragmentation. This work highlights the importance of textural and pore network analyses in understanding eruption dynamics, and provides a case study for investigating the interplay between pore network parameters, magma permeability and ascent dynamics for low-viscosity magmas.
Results and implications are presented in Bonechi et al. 2025, Bulletin of Volcanology
2025. Numerical Modeling Integrated With Field Observations and Analytical Data of the 2021 Cumbre Vieja Eruption Improves Understanding of Eruption Dynamics at Mafic Volcanoes
Abrupt transitions in eruptive style are common at mafic volcanoes, possibly leading to styles that potentially damage infrastructures and threaten the surrounding communities. During the 19th September–13th December 2021 Cumbre Vieja eruption (La Palma, Canary Islands), rapid changes in eruptive style were observed, from vigorous lava fountaining to sporadic intense ash columns, alongside continuous lava effusion, providing an ideal case study for investigation of the mechanisms underlying such transitions. We used a 1D steady‐state numerical model for magma ascent to study the driving processes behind the eruptive style transitions. The model considers the complex and non‐linear interdependence among the major processes occurring during magma ascents, such as temperature and viscosity evolution, non‐ideal gas behavior, outgassing, and disequilibria in crystallization and volatile exsolution. Input parameters of the simulations (inlet pressure and temperature, water and CO2 content, initial phenocrystal content) are constrained by analytical studies and empirical data. Simulation outputs are compared with field observations and analytical data. Results suggest that a change in the degree of coupling between gas and melt might have caused the eruptive style change. We hypothesize that a change in the conduit geometry triggered this shift. One possible explanation could be a shallow branching of the conduit, which leads to variable magma and gas partitioning between ramifications. Another possible cause could be the temporary partial collapse of the conduit walls near the surface, which might have generated an acceleration of magma, reducing volatile outgassing, increasing magmatic strain, and consequently triggering the observed transition to explosive activity.
Results and implications are presented in Biagioli et al. 2025, Journal of Geophysical Research: Solid Earth
2024. Direct observation of degassing during decompression of basaltic magma
Transitions in eruptive style during volcanic eruptions strongly depend on how easily gas and magma decouple during ascent. Stronger gas- melt coupling favors highly explosive eruptions, whereas weaker coupling promotes lava fountaining and lava flows. The mechanisms producing these transitions are still poorly understood because of a lack of direct observations of bubble dynamics undernatural magmatic conditions. Here, we combine x- ray radiography with a novel high- pressure/high- temperature apparatus to observe and quantify in real- time bubble growth and coalescence in basaltic magmas from 100 megapascals to surface. For low- viscosity magmas, bubbles coalesce and recover a spherical shape within 3 seconds, implying that, for lava fountaining activity, gas and melt remain coupled during the ascent up to the last hundred meters of the conduit. For higher- viscosity magmas, recovery times become longer, promoting connected bubble pathways. This apparatus opens frontiers in unraveling magmatic/volcanic processes, leading to improved hazard assessment and risk mitigation.
Results and implications are presented in Bonechi et al. 2024, Science Advances
2024. Magma residence time, ascent rate and eruptive style of the November ash-laden activity during the 2021 Tajogaite eruption (La Palma, Spain)
We combined compositional analyses, crystal size distributions and geothermobarometry of tephra erupted during the 2021 Tajogaite eruption (La Palma, Spain), focusing on samples collected in November 2021 associated with a period of abundant ash emission characteristic of the second half of the eruption (from October onwards). Magma erupted in November exhibits a more primitive basanitic composition than the earlier magma. Crystallization temperatures range between ~1100-1160 °C (H2O = 1-3 wt.%) for phenocrysts and microphenocrysts, with corresponding pressures indicating depths from ~10 to ~30 km. Crystal size distribution analysis reveals short (minutes) residence times for plagioclase. Finally, magma ascent velocities (~0.01-0.3 m/s) suggest acceleration and fragmentation in the shallowest part of the conduit. Our results suggest that the trigger of the November explosive activity can be attributed to complex feedback between gas emission rates, changes in conduit geometry, and magma ascent rate.
Results and implications are presented in Bonechi et al. 2024, Volcanica
Previous research
A list of research topics investigated so far is shown below:
phase equilibria in magmatic systems;
crystallization kinetics to reconstruct timescales of magmatic processes;
partitioning of major, minor and trace elements between minerals and melts;
ultrapotassic magmas of Colli Albani Volcanic District;
rheological properties of primitive alkaline magmas.
Phase equilibria in magmatic systems
2019. Effect of water on the phase relations of primitive K-basalts: implications for high pressure differentiation in the Campi Flegrei magmatic system
We documented H2O effect on the phase relations of a K-basaltic melt at pressure corresponding to the crust-mantle boundary beneath the Campania volcanic area. At H2O <2 wt%, extensive crystallization of clinopyroxene as liquidus phase results in a liquid line of descent reflecting the least differentiated natural products of Procida. At H2O >2 wt%, with the system still water-undersaturated, the co-saturation of clinopyroxene and olivine on the liquidus drives the differentiated melts toward shoshonitic compositions similar to the most primitive Campi Flegrei products. Instead, the experimental subalkaline liquids formed at water-saturated conditions could suggest the early stationing of old parental K-basalts at high pressure and water-saturated conditions. Our experiments highlights the effect that variable water contents might have had on the petrogenesis and degassing history of these magmas.
Results and implications are presented in Perinelli et al. 2019, Lithos
2017. Experimental constraints on amphibole stability in primitive alkaline and calc-alkaline magmas
We investigated the effects of alkalis on the stability of amphibole during the early stages of fractionation in alkaline/calc-alkaline magmas. Amphibole stability is achieved in the calc-alkaline composition at 1050 °C and >5 wt% H2O in the melt, while its crystallization is restricted at lower temperature (i.e. 1000 °C) in the alkaline composition. This is unexpected by virtue of the relatively high Na2O content in the experimental alkaline glasses, which is thought to favor amphibole crystallization under a wider range of physico-chemical conditions. Therefore, we interpreted amphibole crystallization in our experiments as being mostly controlled by the Na2O/K2O ratio of the residual melt rather than by its absolute sodium content.
Results and implications are presented in Bonechi et al. 2017, Periodico di Mineralogia
Crystallization kinetics to reconstruct timescales of magmatic processes
2021. High pressure experimental investigation of clinopyroxene dissolution in a K-basaltic melt
Dissolution of clinopyroxene (cpx) in a K-basaltic melt from the Campi Flegrei Volcanic District (Italy) has been investigated through dissolution and dissolution-crystallization experiments at high pressure and superliquidus temperature. In the dissolution-crystallization experiment, the formation of overgrowth rims accompanied by new cpx crystals suggests that the injection of recharge magmas in basaltic reservoir may lead to inverse or oscillatory zonation. The interaction between cpx and K-basaltic melt at ~1570 °C was studied by in situ radiography using synchrotron radiation combined with the Paris-Edinburgh press. The role of crystal dissolution in the estimation of magma residence times has been also tested for a natural magmatic system by interpolating the dissolution rates with the textural data of cpx phenocrysts from the Agnano-Monte Spina pyroclastic deposit at Campi Flegrei caldera (Campanian region, Italy). Results from calculations indicate that the time required for partial or complete resorption of phenocrysts varies from ~0.5 to ~40 h, and that the effect of crystal dissolution may be relevant to estimate magma residence times whether significant dissolution occurs during magma mixing processes.
Results and implications are presented in Bonechi et al. 2021, Chemical Geology
2020. Clinopyroxene growth rates: high-pressure investigation on a primitive alkaline basalt from the Campi Flegrei Volcanic District (south Italy)
Through this work, we have improved knowledge of crystallization kinetics of clinopyroxene in alkaline basaltic melts, providing new crystal growth rate data under high-pressure conditions. By comparing our clinopyroxene growth rate data with those available in the literature, we observe that viscosity, and the parameters that control it (temperature, water content and chemical composition), undercooling and cooling rate are the factors that most affect crystal growth rate. The experimental Cpx growth rate combined with data from CSD and thermobarometry of CFVD clinopyroxenes suggests that recharge by primitive magmas in the deep CFVD reservoirs occurs with a relatively high ascent rate, that is of paramount significance in terms of volcanic hazard.
Results and implications are presented in Bonechi et al. 2020, Bulletin of Volcanology
2020. Amphibole growth from a primitive alkaline basalt at 0.8 GPa: time-dependent compositional evolution, growth rate and competition with clinopyroxene
New amphibole growth rate data from this study improve knowledge of amphibole growth kinetics at high pressure. Comparison between amphibole and clinopyroxene growth rates provide evidence for the faster growth of amphibole with respect to coexisting clinopyroxene, which we surmise is due to chemical and structural similarities between these minerals that cause a “kinetic competition”. The calculated growth rates were used to investigate the crystallization process of natural products from Sardinia. Our findings may be useful to correctly interpret the textural features of amphibole-bearing mafic cumulates and rocks, and for a better constraining of the timescales of magmatic processes at upper mantle-lower crustal depths.
Results and implications are presented in Bonechi et al. 2020, Lithos
2020. Influence of pre-existing nuclei on the crystallization kinetics of primitive alkaline magmas: insights on the deep feeding system of the Campi Flegrei Volcanic District
This study provides constraints on the effect of pre-existing nuclei on clinopyroxene growth and nucleation rates. In particular, the growth rates calculated in the run performed using natural starting material with pre-existing nuclei are higher than those calculated in the runs performed using the vitrified starting material, while the nucleation rates show the opposite behavior with lower values for the run containing pre-existing nuclei.
Results and implications are presented in Bonechi 2020, Minerals
Partitioning of major, minor and trace elements between minerals and melts
2021. High pressure trace element partitioning between clinopyroxene and alkali basaltic melts
We present a new set of partition coefficient data derived from synthetic clinopyroxenes in equilibrium and in disequilibrium with a K-basaltic composition from the Campi Flegrei Volcanic District (CFVD) as a function of temperature and time. We overcame: i) the scarcity of quantitative experimental data on the role of the crystallization kinetics on clinopyroxene-melt trace elements partitioning behaviour at high-pressure conditions relevant for deep magmatic reservoirs; ii) the absence of clinopyroxene-melt partition coefficient experimental data for primitive compositions in the CFVD area. Finally, we explored the mineral assemblage involved in the magmatic differentiation at the deepest ponding level, applying the experimental results of this study.
Results and implications are presented in Bonechi et al. 2021, Geochimica et Cosmochimica Acta
2023 Experimental investigation of trace element partitioning between amphibole and alkali basaltic melt: towards a more general partitioning model with implications for amphibole fractionation at deep crustal levels
Time-series experiments were carried out to determine the element partition coefficients between amphibole and K-basalt melt. The influence of melt and amphibole composition, temperature, and pressure on the partition coefficients between amphiboles and glasses has also been investigated by comparing our data with a literature dataset spanning a wide range of pressures (0.6-2.5 GPa), temperatures (780-1100 °C), and compositions (from basanite to rhyolite). Finally, we modelled a deep fractional crystallization process using the amphibole-melt partition coefficients determined in this study, observing that significant amounts of amphibole crystallization (>30 wt%) well reproduce the composition of an andesitic melt similar to that of the calcalkaline volcanic products found in Parete and Castelvolturno bore-holes (NW of Campi Flegrei, Italy).
Results and implications are presented in Bonechi et al. 2023 American Mineralogist
Ultrapotassic magmas of Colli Albani Volcanic District
2022. Micro-Raman water calibration in ultrapotassic silicate glasses: Application to phono-tephrites and K-foidites of Colli Albani Volcanic District (Central Italy)
We calibrated a Raman model (m = 1.74) to derive water contents dissolved in phono-tephritic glasses. we estimated water content also for some natural K-foiditic glasses from the same volcanic district. Since m coefficient is strongly dependent on chemical composition, we extrapolated a m coefficient for the natural K-foiditic samples by means of an equation obtained in this study as function of the polymerization degree (NBO/T).
Results and implications are presented in Bonechi et al. 2022, Chemical Geology
2021. Uncommon K-foiditic magmas: the case study of Tufo del Palatino (Colli Albani Volcanic District, Italy)
We present new data on the hydromagmatic scoria clasts of the Tufo del Palatino eruptive unit (Colli Albani, Central Italy). This eruptive unit is richest in glasses which allow a privileged geochemical and spectroscopic characterization of the K-foiditic melts from which the leucititic rocks crystallize. We use this case study to discuss the processes at the origin of the K-foiditic magmas with the aim to answer at the main query emerging from the global rarity of these magmas: why K-foidites?
Results and implications are presented in Gaeta et al. 2021, Lithos
Rheological properties of primitive alkaline magmas
2022. Experimental measurements of the viscosity and melt structure of alkali basalts at high pressure and temperature
In this experimental study, we investigated the effect of pressure (0.7–7.0 GPa) and temperature (1335–2000 °C) on the viscosity and the atomic melt structure of a synthetic anhydrous primitive alkaline basalt, an analogue of the pre-eruptive magma that likely feeds the Campi Flegrei Volcanic District at present day. The Obtained viscosities (0.5–3.0 Pa s), mobility (0.1–0.4 g cm3 Pa−1 s−1) and ascent velocity (1.5–6.0 m yr−1) are presented to support geochemical and geophysical observations of Campi Flegrei as a critical volcanic district currently undergoing gradual magma recharge at depth.
Results and implications are presented in Bonechi et al. 2022, Scientific Reports
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