Electrical conductivity of the serpentinised mantle and fluid flow in subduction zones

International audienceIn the mantle wedge of subduction zones, electromagnetic profiles reveal high electrical-conductivity bodies. In hot areas (>700 degrees C), water released by dehydration of the slab induces melting of the mantle under volcanic arcs that can explain the observed high conductivities. In the cold (= 1 m) fluids during progressive serpentinisation of the mantle wedge. These fluids can mix with arc magmas at depths and account for high chlorine/water ratios in arc lava