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Gas Emissions From Volcanoes of the Kuril Island Arc (NW Pacific): Geochemistry and Fluxes

2018; Wiley; Volume: 19; Issue: 6 Linguagem: Inglês

10.1029/2018gc007477

1525-2027

Yuri Taran, Mikhail Zelenski, Ilya Chaplygin, Natalia Malik, Robin Campion, Salvatore Inguaggiato, B. G. Pokrovsky, Elena Kalacheva, Dmitry Melnikov, Ryunosuke Kazahaya, Tobias P. Fischer,

Atmospheric Ozone and Climate

Abstract The Kuril Island arc extending for about 1,200 km from Kamchatka Peninsula to Hokkaido Island is a typical active subduction zone with ∼40 historically active subaerial volcanoes, some of which are persistently degassing. Seven Kurilian volcanoes (Ebeko, Sinarka, Kuntomintar, Chirinkotan, Pallas, Berg, and Kudryavy) on six islands (Paramushir, Shiashkotan, Chirinkotan, Ketoy, Urup, and Iturup) emit into the atmosphere > 90% of the total fumarolic gas of the arc. During the field campaigns in 2015–2017 direct sampling of fumaroles, MultiGas measurements of the fumarolic plumes and DOAS remote determinations of the SO 2 flux were conducted on these volcanoes. Maximal temperatures of the fumaroles in 2015–2016 were 510°C (Ebeko), 440°C (Sinarka), 260°C (Kuntomintar), 720°C (Pallas), and 820°C (Kudryavy). The total SO 2 flux (in metric tons per day) from fumarolic fields of the studied volcanoes was measured as ∼1,800 ± 300 t/d, and the CO 2 flux is estimated as 1,250 ± 400 t/d. Geochemical characteristics of the sampled gases include δD and δ 18 O of fumarolic condensates, δ 13 C of CO 2 , δ 34 S of the total sulfur, ratios 3 He/ 4 He and 40 Ar/ 36 Ar, concentrations of the major gas species, and trace elements in the volcanic gas condensates. The mole ratios C/S are generally <1. All volcanoes of the arc, except the southernmost Mendeleev and Golovnin volcanoes on Kunashir Island, emit gases with 3 He/ 4 He values of >7R A (where R A is the atmospheric 3 He/ 4 He). The highest 3 He/ 4 He ratios of 8.3R A were measured in fumaroles of the Pallas volcano (Ketoy Island) in the middle of the arc.