First volatile inventory for Gorely volcano, Kamchatka

Abstract

We report here the very first assessment of volatile flux emissions from Gorely, an actively degassing volcano in Kamchatka. Using a variety of in situ and remote sensing techniques, we determined the bulk plume concentrations of major volatiles (H 2 O ∼93.5%, CO 2 , ∼2.6%, SO 2 ∼2.2%, HCl 1.1%, HF 0.3%, H 2 0.2%) and trace‐halogens (Br, I), therefore estimating a total gas release of ∼11,000 tons·day −1 during September 2011, at which time the target was non‐eruptively degassing at ∼900°C. Gorely is a typical arc emitter, contributing 0.3% and 1.6% of the total global fluxes from arc volcanism for CO 2 and HCl, respectively. We show that Gorely's volcanic gas (H 2 O/SO 2 ∼43, CO 2 /SO 2 ∼1.2, HCl/SO 2 ∼0.5) is a representative mean end‐member for arc magmatism in the north‐west Pacific region. On this basis we derive new constraints for the abundances and origins of volatiles in the subduction‐modified mantle source which feeds magmatism in Kamchatka.