Publication Date:
2017-04-04
Description:
We report here on the first hydrogen determinations in the volcanic gas plume of
Mount Etna, in Italy, which we obtained during periodic field surveys on the volcano’s summit area with an upgraded MultiGAS. Using a specific (EZT3HYT) electrochemical sensor, we resolved H2 concentrations in the plume of 1–3 ppm above ambient (background) atmosphere and derived H2‐SO2 and H2‐H2O plume molar ratios of
0.002–0.044 (mean 0.013) and 0.0001–0.0042 (mean 0.0018), respectively. Taking the
above H2‐SO2 ratios in combination with a time‐averaged SO2 flux of 1600 Gg yr−1,
we evaluate that Etna contributes a time‐averaged H2 flux of ∼0.65 Gg yr−1,
suggesting that the volcanogenic contribution to the global atmospheric H2 budget (70,000–100,000 Gg yr−1) is marginal. We also use our observed H2‐H2O ratios to
propose that Etna’s passive plume composition is (at least partially) representative of a quenched (temperatures between 750°C and 950°C) equilibrium in the gas‐magma system, at redox conditions close to the nickel‐nickel oxide (NNO) mineral buffer. The positive dependence between H2‐SO2, H2‐H2O, and CO2‐SO2 ratios suggests that H2 is likely supplied (at least in part) by deeply rising CO2‐rich gas bubbles, fluxing through a CO2‐depleted shallow conduit magma.
Description:
Published
Description:
B10204
Description:
1.2. TTC - Sorveglianza geochimica delle aree vulcaniche attive
Description:
2.4. TTC - Laboratori di geochimica dei fluidi
Description:
JCR Journal
Description:
restricted
Keywords:
Hydrogen
;
Mount Etna
;
Open-vent volcano
;
plume
;
01. Atmosphere::01.01. Atmosphere::01.01.07. Volcanic effects
;
04. Solid Earth::04.02. Exploration geophysics::04.02.01. Geochemical exploration
;
04. Solid Earth::04.04. Geology::04.04.12. Fluid Geochemistry
;
04. Solid Earth::04.08. Volcanology::04.08.01. Gases
;
04. Solid Earth::04.08. Volcanology::04.08.06. Volcano monitoring
Repository Name:
Istituto Nazionale di Geofisica e Vulcanologia (INGV)
Type:
article
