1. Stability of iron-bearing carbonates in the deep Earth's interior
- Author
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Volodymyr Svitlyk, Jeroen Jacobs, Sylvain Petitgirard, Michael Hanfland, Clemens Prescher, Catherine McCammon, Mohamed Mezouar, Marco Merlini, Leonid Dubrovinsky, Maxim Bykov, Valerio Cerantola, Ilya Kupenko, Innokenty Kantor, Elena Bykova, A. I. Chumakov, Leyla Ismailova, Rudolf Rüffer, Vitali B. Prakapenka, Univ Bayreuth, Bayer Geoinst, D-95440 Bayreuth, Germany, European Synchrotron Radiation Facility (ESRF), DESY, Extreme Condit Beamline P02 2, Notkestr 85, D-22607 Hamburg, Germany, Univ Munster, Inst Mineral, Corrensstr 24, D-48149 Munster, Germany, Univ Milan, Dipartimento Sci Terra, Via Botticelli 23, I-20133 Milan, Italy, Skolkovo Innovat Ctr, Skolkovo Inst Sci & Technol, Ctr Hydrocarbon Recovery, Moscow 143026, Russia, Natl Univ Sci & Technol MSIS, Mat Modeling & Dev Lab, Moscow 119049, Russia, MAX IV Lab, Fotongatan 2, S-22594 Lund, Sweden, Univ Cologne, Inst Geol & Mineral, Greinstr 4-6, D-50939 Cologne, Germany, University of Chicago, Cerantola, V, Bykova, E, Kupenko, I, Merlini, M, Ismailova, L, Mccammon, C, Bykov, M, Chumakov, A, Petitgirard, S, Kantor, I, Svitlyk, V, Jacobs, J, Hanfland, M, Mezouar, M, Prescher, C, Ruffer, R, Prakapenka, V, and Dubrovinsky, L
- Subjects
Materials science ,010504 meteorology & atmospheric sciences ,XRD ,Science ,General Physics and Astronomy ,Mineralogy ,[SDU.STU]Sciences of the Universe [physics]/Earth Sciences ,reaction ,Crystal structure ,engineering.material ,010502 geochemistry & geophysics ,01 natural sciences ,General Biochemistry, Genetics and Molecular Biology ,Diamond anvil cell ,Mantle (geology) ,Article ,high temperature ,Mössbauer spectroscopy ,synchrotron ,14. Life underwater ,Geothermal gradient ,0105 earth and related environmental sciences ,Multidisciplinary ,Iron carbonate ,siderite ,Diamond ,General Chemistry ,laser heating ,phase diagram ,high pressure ,diamond anvil cell ,13. Climate action ,phase transition ,redox ,engineering ,ddc:500 ,tetracarbonate - Abstract
The presence of carbonates in inclusions in diamonds coming from depths exceeding 670 km are obvious evidence that carbonates exist in the Earth’s lower mantle. However, their range of stability, crystal structures and the thermodynamic conditions of the decarbonation processes remain poorly constrained. Here we investigate the behaviour of pure iron carbonate at pressures over 100 GPa and temperatures over 2,500 K using single-crystal X-ray diffraction and Mössbauer spectroscopy in laser-heated diamond anvil cells. On heating to temperatures of the Earth’s geotherm at pressures to ∼50 GPa FeCO3 partially dissociates to form various iron oxides. At higher pressures FeCO3 forms two new structures—tetrairon(III) orthocarbonate Fe43+C3O12, and diiron(II) diiron(III) tetracarbonate Fe22+Fe23+C4O13, both phases containing CO4 tetrahedra. Fe4C4O13 is stable at conditions along the entire geotherm to depths of at least 2,500 km, thus demonstrating that self-oxidation-reduction reactions can preserve carbonates in the Earth’s lower mantle., Carbonates are shown to exist in the lower mantle as seen in diamond inclusions, but thermodynamic constraints are poorly understood. Here, the authors synthesise two new iron carbonate compounds and find that self-oxidation-reduction reactions can preserve carbonates in the mantle.
- Published
- 2017
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