The WP1 goal is to constrain experimentally the behaviour of halogens in magma, from production to emission.
WP1 Tasks 1 and 2 will quantify experimentally the halogens (Br, I) behavior in magma during their production, storage and transfer toward the surface and implement the findings into a numerical model of magma degassing. This degassing model will be used in conjunction with analyses of eruption samples (melt inclusions) to, finally, constrain the chemical composition of volcanic gases as they reach the open vent and are emitted to the atmosphere. The results feed into WP2 Task 3 that quantifies emissions and their near-source processing by field-observations, and subsequently into Task 4 and 5 atmospheric modelling.
Task 1: Halogens transfer from mantle to crustal reservoir
Task 1 will explore the halogens behavior in magmas at mantle depth (1-4 GPa) in order to constrain the halogens (Br and I) inputs to the shallow reservoir. It builds directly on our group’s in-situ HT-HP (High-Temperature High-Pressure) experiments providing some of the very first data on Br and I (Bureau et al., 2010, 2016, Cochain et al, 2015).
Task 2: Halogen transfer from crustal reservoir to the surface
Reservoirs in the shallow crust (< ~400 MPa) are the most obvious source of diffuse or central degassing in active volcanoes. Task 2 (Subtask 2.1 and 2.2) will quantify bromine and iodine behaviour in the shallow reservoir, during magma crustal storage and its final transfer to the surface. In Task 2.3 the experimental data (Tasks 1 and 2) will be incorporated into degassing models to quantify volcanic halogen emissions.
Task 2.1 Experimental study of Br and I behaviour at crustal pressure
Task 2.2 Sampling experiments: on-line volcanic gas analyses
Task 2.3 Modelling of halogens behaviour during decompression
The WP1 research activities rely on state-of-the-art HTHP (high-temperature high-pressure) experimental facilities at IMPMC and ISTO that enable to study magma properties and the partitioning of volatiles (sulfur, halogens Cl, Br, I …) between fluid and melt through ‘volcano-in-a-lab’ experiments.
