Sulfur Degassing From Steam-Heated Crater Lakes: El Chichón (Chiapas, Mexico) and Víti (Iceland)

• Published in: Geophysical Research Letters
• Main Authors: Hasselle, N., Rouwet, D., Aiuppa, A., Jácome-Paz, M. P., Pfeffer, M., Taran, Y., Campion, R., Bitetto, M., Giudice, G., Bergsson, B.
• Other Authors: Hasselle, N.*, Jácome-Paz, M.P.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Blackwell Publishing Ltd 2018
• Subjects: El Chichón; Multi-GAS; sulfur degassing; volcanic lake; Víti; Geophysic; Earth and Planetary Sciences (all); Askja; Crater Lake; Iceland
• Online Access: http://hdl.handle.net/10447/347054; https://doi.org/10.1029/2018GL079012; https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018GL079012

The composition of the gases released by El Chichón (Chiapas, Mexico) and Víti (Askja volcano, Iceland) volcanic lakes is examined by Multi-GAS for the first time. Our results demonstrate that H2S and SO2 are degassed by these pH 2–3 lakes. We find higher CO2/H2S and H2/H2S ratios in the lakes' emissions (31–5,685 and 0.6–35, respectively) than in the fumarolic gases feeding the lakes (13–33 and 0.08–0.5, respectively), evidencing that only a fraction (0.2–5.4% at El Chichón) of the H2S(g) contributed by the subaquatic fumaroles ultimately reaches the atmosphere. At El Chichón, we estimate a H2S output from the crater lake of 0.02–0.06t/day. Curiously, SO2 is also detected at trace levels in the gases released from both lakes (0.003–0.3ppmv). We propose that H2S supplied into the lakes initiates a series of complex oxidation reactions, having sulfite as an intermediate product, and ultimately leading to SO2 production and degassing.