Influence of volatiles (H$_{2}$O and CO$_{2}$) on shoshonite phase equilibria
Experiments were performed at 500 MPa, 1080 °C and water activities (aH$_{2}$O) from 0.0 to 1.0, in fluid-present and fluid-absent conditions, with the aim of constraining the effect of volatiles on phase equilibrium assemblages of a shoshonite from Vulcanello (Aeolian Islands, Italy). Experiments w...
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Académie des sciences
2023
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ftdoajarticles:oai:doaj.org/article:ba266c3eeea84a18bb235d2397b18b49 2023-11-12T04:20:02+01:00 Influence of volatiles (H$_{2}$O and CO$_{2}$) on shoshonite phase equilibria Vetere, Francesco Namur, Olivier Holtz, Francois Almeev, Renat Donato, Paola Frondini, Francesco Cassetta, Michele Pisello, Alessandro Perugini, Diego 2023-07-01T00:00:00Z https://doi.org/10.5802/crgeos.226 https://doaj.org/article/ba266c3eeea84a18bb235d2397b18b49 EN FR eng fre Académie des sciences https://comptes-rendus.academie-sciences.fr/geoscience/articles/10.5802/crgeos.226/ https://doaj.org/toc/1778-7025 doi:10.5802/crgeos.226 1778-7025 https://doaj.org/article/ba266c3eeea84a18bb235d2397b18b49 Comptes Rendus. Géoscience, Vol , Iss , Pp 1-18 (2023) Vulcanello Shoshonite Phase equilibria Mineral assemblage H$_{2}$O–CO$_{2}$ Geophysics. Cosmic physics QC801-809 Chemistry QD1-999 Geology QE1-996.5 article 2023 ftdoajarticles https://doi.org/10.5802/crgeos.226 2023-10-29T00:40:06Z Experiments were performed at 500 MPa, 1080 °C and water activities (aH$_{2}$O) from 0.0 to 1.0, in fluid-present and fluid-absent conditions, with the aim of constraining the effect of volatiles on phase equilibrium assemblages of a shoshonite from Vulcanello (Aeolian Islands, Italy). Experiments were run both under reducing and oxidizing conditions and results show that proportions, shapes and size of crystals vary as a function of the volatile composition (XH$_{2}$O and XCO$_{2}$) and volatile content. Clinopyroxene (Cpx) is the main crystallising phase and is compositionally analogous to Cpx crystals found in the natural rock. Plagioclase (Pl) is stable only for water activity lower than 0.1, whereas Fe–Ti oxides are present in all experimental runs, except for those where log fO$_{2}$ was lower than ${-}$9, (${\Delta }$NNO ${-}$0.11) irrespective of the presence of CO$_{2}$. The addition of CO$_{2}$ (2.8 wt%) in nominally dry experimental charges substantially reduces the crystallinity by ca. 1/3 compared to volatile free experiments. This result has important consequences upon the physical properties of the magma because it influences its viscosity and, as a consequence, velocity during its travel to the Earth surface.Assuming that the widths of Vulcanello conduits vary from 0.5 to 1.5 m, estimates of the ascent velocity vary in the range 1.5 ${\times }$ 10$^{-4}$–3.5 ${\times }$ 10$^{-2}$ m${\cdot }$s$^{-1}$ for CO$_{2}$ free systems and from 5.7 ${\times }$ 10$^{-4}$–1.3 ${\times }$ 10$^{-1}$ m${\cdot }$s$^{-1}$ for CO$_{2}$ bearing systems.Since shoshonitic magmas are common not only in the Italian volcanic provinces (Aeolian Arc, Campi Flegrei, Ischia Island, Pontine Islands, Monti Cimini, Monte Amiata, Capraia Island, Radicofani, Roccamonfina) but also in different volcanoes worldwide (Yellowstone, Mariana Arc, Kurile Arc, Tonga Arc, Andean Arc, Kamchatka Arc), we suggest that the new data will be useful to better understand shoshonitic magma behaviour under relevant geological scenarios. As such, we ... Article in Journal/Newspaper Kamchatka Directory of Open Access Journals: DOAJ Articles Monti ENVELOPE(162.495,162.495,-74.983,-74.983) Tonga ENVELOPE(7.990,7.990,63.065,63.065) Comptes Rendus. Géoscience 356 S1 1 18 |
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Vulcanello Shoshonite Phase equilibria Mineral assemblage H$_{2}$O–CO$_{2}$ Geophysics. Cosmic physics QC801-809 Chemistry QD1-999 Geology QE1-996.5 |
spellingShingle |
Vulcanello Shoshonite Phase equilibria Mineral assemblage H$_{2}$O–CO$_{2}$ Geophysics. Cosmic physics QC801-809 Chemistry QD1-999 Geology QE1-996.5 Vetere, Francesco Namur, Olivier Holtz, Francois Almeev, Renat Donato, Paola Frondini, Francesco Cassetta, Michele Pisello, Alessandro Perugini, Diego Influence of volatiles (H$_{2}$O and CO$_{2}$) on shoshonite phase equilibria |
topic_facet |
Vulcanello Shoshonite Phase equilibria Mineral assemblage H$_{2}$O–CO$_{2}$ Geophysics. Cosmic physics QC801-809 Chemistry QD1-999 Geology QE1-996.5 |
description |
Experiments were performed at 500 MPa, 1080 °C and water activities (aH$_{2}$O) from 0.0 to 1.0, in fluid-present and fluid-absent conditions, with the aim of constraining the effect of volatiles on phase equilibrium assemblages of a shoshonite from Vulcanello (Aeolian Islands, Italy). Experiments were run both under reducing and oxidizing conditions and results show that proportions, shapes and size of crystals vary as a function of the volatile composition (XH$_{2}$O and XCO$_{2}$) and volatile content. Clinopyroxene (Cpx) is the main crystallising phase and is compositionally analogous to Cpx crystals found in the natural rock. Plagioclase (Pl) is stable only for water activity lower than 0.1, whereas Fe–Ti oxides are present in all experimental runs, except for those where log fO$_{2}$ was lower than ${-}$9, (${\Delta }$NNO ${-}$0.11) irrespective of the presence of CO$_{2}$. The addition of CO$_{2}$ (2.8 wt%) in nominally dry experimental charges substantially reduces the crystallinity by ca. 1/3 compared to volatile free experiments. This result has important consequences upon the physical properties of the magma because it influences its viscosity and, as a consequence, velocity during its travel to the Earth surface.Assuming that the widths of Vulcanello conduits vary from 0.5 to 1.5 m, estimates of the ascent velocity vary in the range 1.5 ${\times }$ 10$^{-4}$–3.5 ${\times }$ 10$^{-2}$ m${\cdot }$s$^{-1}$ for CO$_{2}$ free systems and from 5.7 ${\times }$ 10$^{-4}$–1.3 ${\times }$ 10$^{-1}$ m${\cdot }$s$^{-1}$ for CO$_{2}$ bearing systems.Since shoshonitic magmas are common not only in the Italian volcanic provinces (Aeolian Arc, Campi Flegrei, Ischia Island, Pontine Islands, Monti Cimini, Monte Amiata, Capraia Island, Radicofani, Roccamonfina) but also in different volcanoes worldwide (Yellowstone, Mariana Arc, Kurile Arc, Tonga Arc, Andean Arc, Kamchatka Arc), we suggest that the new data will be useful to better understand shoshonitic magma behaviour under relevant geological scenarios. As such, we ... |
format |
Article in Journal/Newspaper |
author |
Vetere, Francesco Namur, Olivier Holtz, Francois Almeev, Renat Donato, Paola Frondini, Francesco Cassetta, Michele Pisello, Alessandro Perugini, Diego |
author_facet |
Vetere, Francesco Namur, Olivier Holtz, Francois Almeev, Renat Donato, Paola Frondini, Francesco Cassetta, Michele Pisello, Alessandro Perugini, Diego |
author_sort |
Vetere, Francesco |
title |
Influence of volatiles (H$_{2}$O and CO$_{2}$) on shoshonite phase equilibria |
title_short |
Influence of volatiles (H$_{2}$O and CO$_{2}$) on shoshonite phase equilibria |
title_full |
Influence of volatiles (H$_{2}$O and CO$_{2}$) on shoshonite phase equilibria |
title_fullStr |
Influence of volatiles (H$_{2}$O and CO$_{2}$) on shoshonite phase equilibria |
title_full_unstemmed |
Influence of volatiles (H$_{2}$O and CO$_{2}$) on shoshonite phase equilibria |
title_sort |
influence of volatiles (h$_{2}$o and co$_{2}$) on shoshonite phase equilibria |
publisher |
Académie des sciences |
publishDate |
2023 |
url |
https://doi.org/10.5802/crgeos.226 https://doaj.org/article/ba266c3eeea84a18bb235d2397b18b49 |
long_lat |
ENVELOPE(162.495,162.495,-74.983,-74.983) ENVELOPE(7.990,7.990,63.065,63.065) |
geographic |
Monti Tonga |
geographic_facet |
Monti Tonga |
genre |
Kamchatka |
genre_facet |
Kamchatka |
op_source |
Comptes Rendus. Géoscience, Vol , Iss , Pp 1-18 (2023) |
op_relation |
https://comptes-rendus.academie-sciences.fr/geoscience/articles/10.5802/crgeos.226/ https://doaj.org/toc/1778-7025 doi:10.5802/crgeos.226 1778-7025 https://doaj.org/article/ba266c3eeea84a18bb235d2397b18b49 |
op_doi |
https://doi.org/10.5802/crgeos.226 |
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Comptes Rendus. Géoscience |
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356 |
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18 |
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