Abstract : The dehydration and decarbonation in the subducting slab are intricately related and the knowledge of the physical properties of the resulting C–H–O fluid is crucial to interpret the petrological, geochemical, and geophysical processes associated with subduction zones. In this study, we
investigate the C–H–O fluid released during the progressive devolatilization of carbonate-bearing serpentine-polymorph chrysotile, with in situ electrical conductivity measurements at high pressures and temperatures. The C–H–O fluid produced by carbonated chrysotile exhibits high electrical conductivity compared to carbon-free aqueous fluids and can be an excellent indicator of the migration of carbon in subduction zones. The crystallization of diamond and graphite indicates that the oxidized C–H–O fluids are responsible for the recycling of carbon in the wedge mantle. The carbonate and chrysotile bearing assemblages stabilize dolomite during the devolatilization process. This unique dolomite forming mechanism in chrysotile in subduction slabs may facilitate the transport of carbon into the deep mantle.
https://hal.uca.fr/hal-03139930 Contributor : Sylvaine JouhannelConnect in order to contact the contributor Submitted on : Friday, February 12, 2021 - 1:43:18 PM Last modification on : Sunday, June 26, 2022 - 3:04:46 AM Long-term archiving on: : Friday, May 14, 2021 - 9:32:19 AM
Geeth Manthilake, Mainak Mookherjee, N. Miyajima. Insights on the deep carbon cycle from the electrical conductivity of carbon‑bearing aqueous fluids. Scientific Reports, Nature Publishing Group, 2021, 11, pp.2745. ⟨10.1038/s41598-021-82174-8⟩. ⟨hal-03139930⟩