Experimental investigation of FeCO3 (siderite) stability in Earth's lower mantle using XANES spectroscopy

Valerio Cerantola*, Max Wilke, Innokenty Kantor, Leyla Ismailova, Ilya Kupenko, Catherine McCammon, Sakura Pascarelli, Leonid S. Dubrovinsky

*Corresponding author for this work

Research output: Contribution to journalJournal articleResearchpeer-review

Abstract

We studied FeCO3 using Fe K-edge X-ray absorption near-edge structure (XANES) spectroscopy at pressures up to 54 GPa and temperatures above 2000 K. First-principles calculations of Fe at the K-edge in FeCO3 were performed to support the interpretation of the XANES spectra. The variation of iron absorption edge features with pressure and temperature in FeCO3 matches well with recently reported observations on FeCO3 at extreme conditions, and provides new insight into the stability of Fe-carbonates in Earth's mantle. Here we show that at conditions of the mid-lower mantle, similar to 50 GPa and similar to ~2200 K, FeCO3 melts and partially decomposes to high-pressure Fe3O4. Carbon (diamond) and oxygen are also inferred products of the reaction. We constrained the thermodynamic phase boundary between crystalline FeCO3 and melt to be at 51(1) GPa and similar to ~1850 K. We observe that at 54(1) GPa, temperature-induced spin crossover of Fe2+ takes place from low to high spin such that at 1735(100) K, all iron in FeCO3 is in the high-spin state. A comparison between experiment and theory provides a more detailed understanding of FeCO3 decomposition observed in X-ray absorption spectra and helps to explain spectral changes due to pressure-induced spin crossover in FeCO3 at ambient temperature.
Original languageEnglish
JournalAmerican Mineralogist
Volume104
Issue number8
Pages (from-to)1083-1091
Number of pages9
ISSN0003-004X
DOIs
Publication statusPublished - 2019

Cite this

Cerantola, V., Wilke, M., Kantor, I., Ismailova, L., Kupenko, I., McCammon, C., ... Dubrovinsky, L. S. (2019). Experimental investigation of FeCO3 (siderite) stability in Earth's lower mantle using XANES spectroscopy. American Mineralogist, 104(8), 1083-1091. https://doi.org/10.2138/am-2019-6428
Cerantola, Valerio ; Wilke, Max ; Kantor, Innokenty ; Ismailova, Leyla ; Kupenko, Ilya ; McCammon, Catherine ; Pascarelli, Sakura ; Dubrovinsky, Leonid S. / Experimental investigation of FeCO3 (siderite) stability in Earth's lower mantle using XANES spectroscopy. In: American Mineralogist. 2019 ; Vol. 104, No. 8. pp. 1083-1091.
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title = "Experimental investigation of FeCO3 (siderite) stability in Earth's lower mantle using XANES spectroscopy",
abstract = "We studied FeCO3 using Fe K-edge X-ray absorption near-edge structure (XANES) spectroscopy at pressures up to 54 GPa and temperatures above 2000 K. First-principles calculations of Fe at the K-edge in FeCO3 were performed to support the interpretation of the XANES spectra. The variation of iron absorption edge features with pressure and temperature in FeCO3 matches well with recently reported observations on FeCO3 at extreme conditions, and provides new insight into the stability of Fe-carbonates in Earth's mantle. Here we show that at conditions of the mid-lower mantle, similar to 50 GPa and similar to ~2200 K, FeCO3 melts and partially decomposes to high-pressure Fe3O4. Carbon (diamond) and oxygen are also inferred products of the reaction. We constrained the thermodynamic phase boundary between crystalline FeCO3 and melt to be at 51(1) GPa and similar to ~1850 K. We observe that at 54(1) GPa, temperature-induced spin crossover of Fe2+ takes place from low to high spin such that at 1735(100) K, all iron in FeCO3 is in the high-spin state. A comparison between experiment and theory provides a more detailed understanding of FeCO3 decomposition observed in X-ray absorption spectra and helps to explain spectral changes due to pressure-induced spin crossover in FeCO3 at ambient temperature.",
author = "Valerio Cerantola and Max Wilke and Innokenty Kantor and Leyla Ismailova and Ilya Kupenko and Catherine McCammon and Sakura Pascarelli and Dubrovinsky, {Leonid S.}",
year = "2019",
doi = "10.2138/am-2019-6428",
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volume = "104",
pages = "1083--1091",
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Cerantola, V, Wilke, M, Kantor, I, Ismailova, L, Kupenko, I, McCammon, C, Pascarelli, S & Dubrovinsky, LS 2019, 'Experimental investigation of FeCO3 (siderite) stability in Earth's lower mantle using XANES spectroscopy', American Mineralogist, vol. 104, no. 8, pp. 1083-1091. https://doi.org/10.2138/am-2019-6428

Experimental investigation of FeCO3 (siderite) stability in Earth's lower mantle using XANES spectroscopy. / Cerantola, Valerio; Wilke, Max; Kantor, Innokenty; Ismailova, Leyla; Kupenko, Ilya; McCammon, Catherine; Pascarelli, Sakura; Dubrovinsky, Leonid S.

In: American Mineralogist, Vol. 104, No. 8, 2019, p. 1083-1091.

Research output: Contribution to journalJournal articleResearchpeer-review

TY - JOUR

T1 - Experimental investigation of FeCO3 (siderite) stability in Earth's lower mantle using XANES spectroscopy

AU - Cerantola, Valerio

AU - Wilke, Max

AU - Kantor, Innokenty

AU - Ismailova, Leyla

AU - Kupenko, Ilya

AU - McCammon, Catherine

AU - Pascarelli, Sakura

AU - Dubrovinsky, Leonid S.

PY - 2019

Y1 - 2019

N2 - We studied FeCO3 using Fe K-edge X-ray absorption near-edge structure (XANES) spectroscopy at pressures up to 54 GPa and temperatures above 2000 K. First-principles calculations of Fe at the K-edge in FeCO3 were performed to support the interpretation of the XANES spectra. The variation of iron absorption edge features with pressure and temperature in FeCO3 matches well with recently reported observations on FeCO3 at extreme conditions, and provides new insight into the stability of Fe-carbonates in Earth's mantle. Here we show that at conditions of the mid-lower mantle, similar to 50 GPa and similar to ~2200 K, FeCO3 melts and partially decomposes to high-pressure Fe3O4. Carbon (diamond) and oxygen are also inferred products of the reaction. We constrained the thermodynamic phase boundary between crystalline FeCO3 and melt to be at 51(1) GPa and similar to ~1850 K. We observe that at 54(1) GPa, temperature-induced spin crossover of Fe2+ takes place from low to high spin such that at 1735(100) K, all iron in FeCO3 is in the high-spin state. A comparison between experiment and theory provides a more detailed understanding of FeCO3 decomposition observed in X-ray absorption spectra and helps to explain spectral changes due to pressure-induced spin crossover in FeCO3 at ambient temperature.

AB - We studied FeCO3 using Fe K-edge X-ray absorption near-edge structure (XANES) spectroscopy at pressures up to 54 GPa and temperatures above 2000 K. First-principles calculations of Fe at the K-edge in FeCO3 were performed to support the interpretation of the XANES spectra. The variation of iron absorption edge features with pressure and temperature in FeCO3 matches well with recently reported observations on FeCO3 at extreme conditions, and provides new insight into the stability of Fe-carbonates in Earth's mantle. Here we show that at conditions of the mid-lower mantle, similar to 50 GPa and similar to ~2200 K, FeCO3 melts and partially decomposes to high-pressure Fe3O4. Carbon (diamond) and oxygen are also inferred products of the reaction. We constrained the thermodynamic phase boundary between crystalline FeCO3 and melt to be at 51(1) GPa and similar to ~1850 K. We observe that at 54(1) GPa, temperature-induced spin crossover of Fe2+ takes place from low to high spin such that at 1735(100) K, all iron in FeCO3 is in the high-spin state. A comparison between experiment and theory provides a more detailed understanding of FeCO3 decomposition observed in X-ray absorption spectra and helps to explain spectral changes due to pressure-induced spin crossover in FeCO3 at ambient temperature.

U2 - 10.2138/am-2019-6428

DO - 10.2138/am-2019-6428

M3 - Journal article

VL - 104

SP - 1083

EP - 1091

JO - American Mineralogist

JF - American Mineralogist

SN - 0003-004X

IS - 8

ER -