Raman spectroscopy to determine CO2 solubility in mafic silicate melts at high pressure: Haplobasaltic, haploandesitic and approach of basaltic compositions

Autor: Nicolas Sator, Julien Amalberti, Philippe Sarda, Daniel R. Neuville, Charles Le Losq, Bertrand Guillot, Tahar Hammouda, Sylvie Le Floch, Eva Chamorro-Pérez
Přispěvatelé: Géosciences Paris Saclay (GEOPS), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP (UMR_7154)), Institut national des sciences de l'Univers (INSU - CNRS)-Université de La Réunion (UR)-Institut de Physique du Globe de Paris (IPG Paris)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Cité (UPCité), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement (LGL-TPE), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut national des sciences de l'Univers (INSU - CNRS)-Université Jean Monnet - Saint-Étienne (UJM)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Physique Théorique de la Matière Condensée (LPTMC), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Magmas et Volcans (LMV), Institut national des sciences de l'Univers (INSU - CNRS)-Institut de Recherche pour le Développement et la société-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Observatoire de Physique du Globe de Clermont-Ferrand (OPGC), Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne (UCA), (nano)Matériaux pour l'énergie (ENERGIE), Institut Lumière Matière [Villeurbanne] (ILM), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut de Physique du Globe de Paris (IPGP), Institut national des sciences de l'Univers (INSU - CNRS)-IPG PARIS-Université de La Réunion (UR)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), Laboratoire de Géologie de Lyon - Terre, Planètes, Environnement [Lyon] (LGL-TPE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon), Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon
Jazyk: angličtina
Rok vydání: 2021
Předmět:
Zdroj: Chemical Geology
Chemical Geology, 2021, 582, pp.120413. ⟨10.1016/j.chemgeo.2021.120413⟩
Chemical Geology, Elsevier, 2021, 582, pp.120413. ⟨10.1016/j.chemgeo.2021.120413⟩
ISSN: 0009-2541
DOI: 10.1016/j.chemgeo.2021.120413⟩
Popis: CO2 degassing of mafic silicate melts is an important part of the terrestrial carbon cycle, at mid-ocean ridges, oceanic hot spots, or in the middle of continents. Deeper CO2-bearing mafic magmas may also exist, such as those suspected in the D″ zone, and certainly existed in the magma ocean of the early Earth. Knowledge of the CO2 solubility in mafic melts at high pressure is therefore important but unknown at present. Results from molecular dynamics simulation (e.g., Guillot and Sator, 2011) predict that CO2 solubility in basalt may be much higher than previously thought at pressures and temperatures relevant to the upper mantle. But some recent models predict low solubility at high pressure (e.g., Eguchi and Dasgupta, 2018). The present study thus experimentally investigates the solubility of CO2 in basalt and andesite in the pressure range 1.5–8.5 GPa at 1820–2130 K in oxidizing conditions. Up to 4 GPa, the quenched samples are essentially vitreous and CO2-saturated. Their CO2 contents are measured using confocal micro-Raman spectroscopy, where we establish an internal calibration line relating CO2 content to the area of the Raman band assigned to the ν1 stretching vibration of carbonate groups. This calibration appears independent from the spectrometer, sample or experimentalist, thus enhancing confidence in this method. At 5 and 8.5 GPa, some of the quenched samples are found partially crystallized. Their CO2 abundance is estimated at micro-scale from Raman mapping, and at large scale from image analysis and presence/absence of vesicles. Over the 1.5–8.5 GPa pressure range, obtained CO2 concentrations vary between 1.8 and > 13.6 wt%. At 5 GPa and 1873 K, the CO2 content in basalt and andesite are similar. These findings experimentally confirm the ability of mafic melts to accommodate large amounts of CO2 at conditions prevailing in the deep Earth. A consequence is that magmas issued from partial melting of carbonate-bearing silicate rocks may ascend with significant quantities of CO2 of several wt% and more: when reaching shallower depths, they may degas large quantities of CO2. Present estimates of the global carbon flux to the atmosphere may thus be underestimated, and implications to early magma ocean degassing may be considered. Other consequences may concern the genesis of kimberlites and carbonatites. We finally speculate that, if silicate melts exist in the D″ zone, significant amounts of carbon may be stored there, and consequences may arise as to carbon sequestration in the core.
Databáze: OpenAIRE
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