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Elevated gas flux and trace metal degassing from the 2014–2015 fissure eruption at the Bárðarbunga volcanic system, Iceland
Author(s) -
Gauthier PierreJean,
Sigmarsson Olgeir,
Gouhier Mathieu,
Haddadi Baptiste,
Moune Séverine
Publication year - 2016
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1002/2015jb012111
Subject(s) - geology , volcano , lava , melt inclusions , trace element , magma , plume , volcanic gases , geochemistry , flux (metallurgy) , trace metal , mineralogy , metal , chemistry , physics , organic chemistry , thermodynamics
The 2014 Bárðarbunga rifting event in Iceland resulted in a 6‐month long eruption at Holuhraun. This eruption was characterized by high lava discharge rate and significant gas emission. The SO 2 flux for the first 3 months was measured with satellite sensors and the petrologic method. High‐resolution time series of the satellite data give 1200 kg/s that concurs with 1050 kg/s obtained from melt inclusion minus degassed lava sulfur contents scaled to the mass of magma produced. A high‐purity gas sample, with elevated S/Cl due to limited chlorine degassing, reveals a similar degassing pattern of trace metals as observed at Kīlauea (Hawai'i) and Erta Ale (Ethiopia). This suggests a common degassing mechanism at mantle plume‐related volcanoes. The trace metal fluxes, calculated from trace element to sulfur ratios in the gas sample and scaled to the sulfur dioxide flux, are 1–2 orders of magnitude stronger at Holuhraun than Kīlauea and Erta Ale. In contrast, volcanoes at convergent margins (Etna and Stromboli, Italy) have 1–2 orders of magnitude higher trace element fluxes, most likely caused by abundant chlorine degassing. This emphasizes the importance of metal degassing as chlorine species. Short‐lived disequilibria between radon daughters, 210 Pb‐ 210 Bi‐ 210 Po measured in the gas, suggest degassing of a continuously replenished magma batch beneath the eruption site. Earlier and deep degassing phase of carbon dioxide and polonium is inferred from low ( 210 Po/ 210 Pb) in the gas, consistent with magma transfer rate of 0.75 m/s.