Redox behavior of degassing magmas: critical review and comparison of glass-based oxybarometers with application to Etna volcano

Moretti, Roberto

doi:10.5802/crgeos.135

Cited by 4 publications

(2 citation statements)

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“…At Kilauea, this decrease was related to sulphur degassing without the involvement of H 2 O and CO 2 (Moussallam et al, 2017). At Etna, the fO 2 decrease was instead related to compositional evolution, primarily dehydration, and decreasing pressure (Moretti, 2022). A similar effect is modelled by Moretti and Ottonello (2022) for the experimental ferri-basalts synthesized and investigated by Botcharnikov et al (2005), where water represents the main compositional variable.…”

Section: Fo 2 Behaviourmentioning

confidence: 76%

“…However, the interpretation of different fO 2 behaviours depends largely on adopted models, particularly the oxybarometers that are used to obtain and extrapolate fO 2 as a function of pressure, temperature and melt composition (i.e., melt-driven interactions related to its structure or polymerization state) from measured redox pairs of iron and/or sulfur (Moretti and Stefansson, 2020;Moretti, 2021;Moretti, 2022). Despite magmatic differentiation and dehydration increasing the nominal abundance of oxygen in Frontiers in Earth Science frontiersin.org magmas approaching the surface, the decrease of oxygen fugacity reflects the increase of melt polymerization and then the decrease of so called "free-oxygen" (i.e., O 2-) (Moretti, 2022), whose activity is proportional to oxygen fugacity (Moretti, 2005;Cicconi et al, 2020a;Moretti, 2021;Moretti and Ottonello, 2022).…”

Section: Fo 2 Behaviourmentioning

confidence: 99%

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Volatile emissions from past eruptions at La Soufrière de Guadeloupe (Lesser Antilles): insights into degassing processes and atmospheric impacts

et al. 2023

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Volatiles exert a critical control on volcanic eruption style and in turn impact the near source environment and global climate. La Soufrière de Guadeloupe in the Lesser Antilles has been experiencing volcanic unrest since 1992, increasing to a peak in 2018. The lack of data available on volatiles from past eruptions, and the well-developed hydrothermal system makes understanding deep-released volatile behaviour challenging. In this study, we analyse new melt inclusions and shed light on the volatile lifecycle and impacts at La Soufrière de Guadeloupe. We focus on four eruptions: 1657 CE (Vulcanian), 1010 CE (Plinian), 341 CE (Strombolian) and 5680 BCE (Plinian), and compare to the well-studied 1530 CE (Sub-Plinian) eruption. The maximum volatile content of these eruption melt inclusions are: 4.42 wt% H2O, 1700 CO2 ppm, 780 ppm S, 0.36 wt% Cl and 680 ppm F. We observe a decrease in S content over time indicating the whole system is evolving by early separation of FeS, resulting in a lower S content in younger magma. Using the CHOSETTO v1 model, we modelled degassing paths related to decompression at low pressures, suggesting the majority of S degassing has occurred during magma ascent. We also calculate the SO2 emissions using the petrologic method, and while the 1657 CE, 1530 CE and 341 CE eruptions have negligible emissions (0.0001–0.001 Mt of SO2), the 1010 CE and 5680 BCE eruptions (0.2 Mt and 0.3 Mt of SO2, respectively) are greater. Using the SO2 emissions and plume height, we calculated the climate forcing associated with each event. The 1010 CE and 5680 BCE Plinian eruptions produced a peak global mean stratospheric aerosol optical depth (SAOD) of 0.0055 and 0.0062, respectively. This suggests, that even the largest eruptions of La Soufrière de Guadeloupe did not exert a significant climate forcing individually, but are important contributors to the volcanic stratospheric sulfate aerosol background resulting from relatively moderate but frequent explosive eruptions. Overall, this study provides new insights into degassing processes and climate forcing not only at La Soufrière de Guadeloupe, but also for other basaltic-andesitic, magmatic-hydrothermal systems. These new constraints are vital particularly if the volcano is currently in a state of unrest and will contribute to improving monitoring crisis management and long-term planning.

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Section: Fo 2 Behaviourmentioning

confidence: 76%

Section: Fo 2 Behaviourmentioning

confidence: 99%

Volatile emissions from past eruptions at La Soufrière de Guadeloupe (Lesser Antilles): insights into degassing processes and atmospheric impacts

et al. 2023

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Diverse magma storage and major and volatile magma composition: What are the implications on the eruptive style across a volcanic arc? An example of the Lesser Antilles Arc

Metcalfe

Moune

Komorowski

et al. 2023

Earth-Science Reviews

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Glass, an ubiquitous material

Neuville

2022

Comptes Rendus. Géoscience

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Glasses play a fundamental role in our daily lives at the economic, cultural, societal, energy and geological levels. Geological glasses testify to igneous activity of the Earth and represent an important material for tools and ornamental objects from the Paleolithic to the present day. Glasses are also used to manufacture technical materials, such as containers (dishes, glasses, jars, bottles . . . ), screens (television, computer, smartphone . . . ), fibers with multiple applications (reinforcement, information, transport, energy, health . . . ), to ensure the storage of domestic or nuclear waste and, more recently, biomaterials (dental or bone implants . . . ). Thus, silica-based glasses are at the heart of the history of the Earth and humanity. The variation in composition of natural and industrial glasses is vast but its structure is generally based on a tetrahedral frame of SiO 4 units, the backbone of more than 90% of the glasses that surround us in our daily lives. Around this silica frame, other chemical elements are well constrained to form to form a single unit structure for use as network modifying elements, charge compensator, dyes, volatiles, and other substances. This article is a short introduction on glass.Résumé. Les verres jouent un rôle fondamental dans notre vie quotidienne aux niveaux économique, culturel, sociétal, énergétique et géologique. Les verres géologiques témoignent de l'activité ignée de la Terre et représentent une source importante d'outils et d'objets décoratifs du paléolithique à nos jours. Les verres sont également utilisés pour fabriquer des matériaux techniques, tels que des récipients (plats, verres, bocaux, bouteille . . .), des écrans (télévision, ordinateur, smartphone . . .), des fibres aux applications multiples (renforcement, transport d'information, énergie, santé . . .), pour assurer le stockage des déchets domestiques ou nucléaires et, plus récemment, des biomatériaux (implants dentaires ou osseux . . .). Les verres à base de silice sont donc au cur de l'histoire de la Terre et de l'humanité. La variation de la composition des verres naturels et industriels est vaste mais sa structure est généralement basée sur une trame tétraédrique d'unités SiO 4 , épine dorsale de plus de 90% des verres qui nous entourent au quotidien. Autour de cette trame de silice, les autres éléments chimiques se répartissent en éléments modificateurs de réseau, compensateur de charge, colorants, volatiles, et l'ensemble constitue un seul matériau ou substance. Cet article est une brève introduction au verre.

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Redox behavior of degassing magmas: critical review and comparison of glass-based oxybarometers with application to Etna volcano

Cited by 4 publications

References 123 publications

Volatile emissions from past eruptions at La Soufrière de Guadeloupe (Lesser Antilles): insights into degassing processes and atmospheric impacts

Volatile emissions from past eruptions at La Soufrière de Guadeloupe (Lesser Antilles): insights into degassing processes and atmospheric impacts

Diverse magma storage and major and volatile magma composition: What are the implications on the eruptive style across a volcanic arc? An example of the Lesser Antilles Arc

Glass, an ubiquitous material

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