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The CaCO3–Fe interaction : Kinetic approach for carbonate subduction to the deep Earth's mantle. / Martirosyan, N. S.; Yoshino, T.; Shatskiy, A. et al.
In: Physics of the Earth and Planetary Interiors, Vol. 259, 01.10.2016, p. 1-9.Research output: Contribution to journal › Article › peer-review
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TY - JOUR
T1 - The CaCO3–Fe interaction
T2 - Kinetic approach for carbonate subduction to the deep Earth's mantle
AU - Martirosyan, N. S.
AU - Yoshino, T.
AU - Shatskiy, A.
AU - Chanyshev, A. D.
AU - Litasov, K. D.
PY - 2016/10/1
Y1 - 2016/10/1
N2 - The CaCO3–Fe0 system, as a model for redox reactions between carbonates and reduced lithologies at the slab-mantle interface during subduction or at core-mantle boundary, was investigated systematically at temperatures from 650 to 1400 °C and pressures from 4 to 16 GPa using multianvil apparatus. CaCO3 reduction via reaction: 3 CaCO3 (aragonite) + 13 Fe0 (metal) = Fe7C3 (carbide) + 3 CaFe2O3 (Ca-wüstite) was observed. The thickness of the reaction-product layer (Δx) increases linearly with the square root of time in the time-series experiments (t), indicating diffusion-controlled process. The reaction rate constant (k = Δx2/2t) is log-linear relative to 1/T. Its temperature dependences was determined to be k [m2/s] = 2.1 × 10−7exp(−162[kJ/mol]/RT) at 4–6 GPa and k [m2/s] = 2.6 × 10−11exp(−65[kJ/mol]/RT) at 16 GPa. The sluggish kinetics of established CaCO3–Fe0 interaction suggests that significant amount of carbonates could survive during subduction from metal saturation boundary near 250 km depth down to the transition zone and presumably to the lower mantle if melting of carbonates is not involved.
AB - The CaCO3–Fe0 system, as a model for redox reactions between carbonates and reduced lithologies at the slab-mantle interface during subduction or at core-mantle boundary, was investigated systematically at temperatures from 650 to 1400 °C and pressures from 4 to 16 GPa using multianvil apparatus. CaCO3 reduction via reaction: 3 CaCO3 (aragonite) + 13 Fe0 (metal) = Fe7C3 (carbide) + 3 CaFe2O3 (Ca-wüstite) was observed. The thickness of the reaction-product layer (Δx) increases linearly with the square root of time in the time-series experiments (t), indicating diffusion-controlled process. The reaction rate constant (k = Δx2/2t) is log-linear relative to 1/T. Its temperature dependences was determined to be k [m2/s] = 2.1 × 10−7exp(−162[kJ/mol]/RT) at 4–6 GPa and k [m2/s] = 2.6 × 10−11exp(−65[kJ/mol]/RT) at 16 GPa. The sluggish kinetics of established CaCO3–Fe0 interaction suggests that significant amount of carbonates could survive during subduction from metal saturation boundary near 250 km depth down to the transition zone and presumably to the lower mantle if melting of carbonates is not involved.
KW - Ca-carbonate
KW - Ca-wüstite
KW - Iron carbide
KW - Kinetics
KW - Redox reaction
KW - Subducted slab
UR - http://www.scopus.com/inward/record.url?scp=84984652094&partnerID=8YFLogxK
U2 - 10.1016/j.pepi.2016.08.008
DO - 10.1016/j.pepi.2016.08.008
M3 - Article
AN - SCOPUS:84984652094
VL - 259
SP - 1
EP - 9
JO - Physics of the Earth and Planetary Interiors
JF - Physics of the Earth and Planetary Interiors
SN - 0031-9201
ER -
ID: 25789602