Publications des scientifiques de l'IRD

Schipper C. I., Moussallam Y., Curtis A., Peters N., Barnie T., Bani Philipson, Jost H. J., Hamilton D., Aiuppa A., Tamburello G., Giudice G. (2017). Isotopically (delta C-13 and delta O-18) heavy volcanic plumes from Central Andean volcanoes : a field study. Bulletin of Volcanology, 79 (8), p. art. 65 [15 p.]. ISSN 0258-8900.

Titre du document
Isotopically (delta C-13 and delta O-18) heavy volcanic plumes from Central Andean volcanoes : a field study
Année de publication
2017
Type de document
Article référencé dans le Web of Science WOS:000407718700007
Auteurs
Schipper C. I., Moussallam Y., Curtis A., Peters N., Barnie T., Bani Philipson, Jost H. J., Hamilton D., Aiuppa A., Tamburello G., Giudice G.
Source
Bulletin of Volcanology, 2017, 79 (8), p. art. 65 [15 p.] ISSN 0258-8900
Stable isotopes of carbon and oxygen in volcanic gases are key tracers of volatile transfer between Earth's interior and atmosphere. Although important, these data are available for few volcanoes because they have traditionally been difficult to obtain and are usually measured on gas samples collected from fumaroles. We present new field measurements of bulk plume composition and stable isotopes (delta(CCO2)-C-13 and delta(OH2O+)-O-18 CO2) carried out at three northern Chilean volcanoes using MultiGAS and isotope ratio infrared spectroscopy. Carbon and oxygen in magmatic gas plumes of Lastarria and Isluga volcanoes have delta C-13 in CO2 of + 0.76% to + 0.77% (VPDB), similar to slab carbonate; and delta O-18 in the H2O + CO2 system ranging from + 12.2% to + 20.7% (VSMOW), suggesting significant contributions from altered slab pore water and carbonate. The hydrothermal plume at Tacora has lower delta(CCO2)-C-13 of -3.2% and delta(OH2O)-O-18+ CO2 of + 7.0%, reflecting various scrubbing, kinetic fractionation, and contamination processes. We show the isotopic characterization of volcanic gases in the field to be a practical complement to traditional sampling methods, with the potential to remove sampling bias that is a risk when only a few samples from accessible fumaroles are used to characterize a given volcano's volatile output. Our results indicate that there is a previously unrecognized, relatively heavy isotopic signature to bulk volcanic gas plumes in the Central Andes, which can be attributed to a strong influence from components of the subducting slab, but may also reflect some local crustal contamination. The techniques we describe open new avenues for quantifying the roles that subduction zones and arc volcanoes play in the global carbon cycle.
Plan de classement
Hydrologie [062] ; Géologie et formations superficielles [064] ; Géophysique interne [066]
Description Géographique
CHILI ; ANDES
Localisation
Fonds IRD [F B010070921]
Identifiant IRD
fdi:010070921
Contact