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

• Published in: Geophysical Research Letters
• Main Authors: Hasselle, Nathalie, Rouwet, Dmitri, Aiuppa, Alessandro, Jacome Paz, M. P., Pfeffer, Melissa, Taran, Y., Campion, R., Bitetto, M., Giudice, Gaetano, Bergsson, B.
• Other Authors: #PLACEHOLDER_PARENT_METADATA_VALUE#, Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione Bologna, Bologna, Italia, Istituto Nazionale di Geofisica e Vulcanologia (INGV), Sezione Palermo, Palermo, Italia
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2018
• Subjects: Askja; Crater Lake; Iceland
• Online Access: http://hdl.handle.net/2122/12300; https://doi.org/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 0.02–0.06 t/day. Curiously, SO2 is also detected at trace levels in the gases released from both lakes (0.003–0.3 ppmv).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. Published 7504-7513 4V. Processi pre-eruttivi JCR Journal