Carbon Dioxide Carbonates in the Earth’s Mantle: Implications to the Deep Carbon Cycle

Yoo, Choong‐Shik; Sengupta, Amartya; Kim, Minseob

doi:10.1002/anie.201104689

Cited by 29 publications

(44 citation statements)

References 26 publications

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“…We discovered the phase transformations from CaCl 2 -type SiO 2 + MgCO 3 phase II to bridgmanite + diamond + O 2 and from seifertite + MgCO 3 phase II to bridgmanite/post-perovskite + diamond + O 2 for the first time in this experiment. The decomposition boundary of CO 2 has a steep gradient in the present phase diagram of MgCO 3 -SiO 2 system which is not consistent with the results of any previous studies on CO 2 , such as decomposition28 or phase transition of CO 2 30.…”

Section: Resultscontrasting

confidence: 99%

“…3). In this case, CO 2 might be a significant carbon carrier in the subducted slabs although its stability has been still controversial under high pressure and high temperature conditions2830. If early slab temperatures had been higher than the modern mantle adiabat33, the formation of CO 2 fluid28 or melting in the MgCO 3 -SiO 2 system26 would be expected down to the mantle transition zone.…”

Section: Discussionmentioning

confidence: 99%

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Diamond formation in the deep lower mantle: a high-pressure reaction of MgCO3 and SiO2

Maeda

Ohtani

Kamada

et al. 2017

Sci Rep

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Diamond is an evidence for carbon existing in the deep Earth. Some diamonds are considered to have originated at various depth ranges from the mantle transition zone to the lower mantle. These diamonds are expected to carry significant information about the deep Earth. Here, we determined the phase relations in the MgCO3-SiO2 system up to 152 GPa and 3,100 K using a double sided laser-heated diamond anvil cell combined with in situ synchrotron X-ray diffraction. MgCO3 transforms from magnesite to the high-pressure polymorph of MgCO3, phase II, above 80 GPa. A reaction between MgCO3 phase II and SiO2 (CaCl2-type SiO2 or seifertite) to form diamond and MgSiO3 (bridgmanite or post-perovsktite) was identified in the deep lower mantle conditions. These observations suggested that the reaction of the MgCO3 phase II with SiO2 causes formation of super-deep diamond in cold slabs descending into the deep lower mantle.

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Section: Resultscontrasting

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Diamond formation in the deep lower mantle: a high-pressure reaction of MgCO3 and SiO2

Maeda

Ohtani

Kamada

et al. 2017

Sci Rep

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“…Arrows signify the thermal pathways measured each phase boundaries, reported in Refs. [2] in red solid lines, [19] in green dotted lines, [13,25] in blue solid lines, and [18] in black dotted lines. The c notes the path-dependent nature of c-CO 2 , produced by laser-heating of quenched phase VI [15].…”

Section: Discussionmentioning

confidence: 99%

“…The large disparity in chemical bonding between the extended and molecular phases and relatively slow kinetics associated with the extended-to-molecular transitions, on the other hand, allow these extended solids to exist over a large pressure domain (down to a few GPa). At higher pressure-temperature conditions, these extended solids amorphize, ionize and decompose [18,19].…”

Section: Introductionmentioning

confidence: 99%

Transformation and structure of silicatelike CO2-V

et al. 2013

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We report the evidence of two different polymorphs for polymeric CO 2 -V in tridymite-like (V TD in P2 1 2 1 2 1 ) and β-cristobalite-like (V CR in I-42d) structures. The V TD phase is produced by laser-heating phase III (Cmca) above 40 GPa, whereas the V CR phase by laser-heating highly compressed phase II (P4 2 /mnm -iso-space group to stishovite) and IV (P4 1 2 1 2 -iso-space group to α-cristobalite) above 35 GPa. The density of the V CR (3.988 g/cm 3 ) is ~12 % larger than that of the V TD (3.559 g/cm 3 ) at 50 GPa, while the density difference reduces to ~4% at ambient pressure. This results in a substantially smaller bulk modulus (B o = 127 GPa, B'=5.6) for the V CR phase than that of the V TD (B o = 270 GPa, B'=1.9). The smaller density of the V TD is due to the open structure of corner shared CO4 tetrahedra and a great level of distortion in C-O-C angles resulting in a highly buckled layer structure; yet, the structural relationship gives rise to the specific transition to occur depending on the initial phase, either displacively from phase IV to phase V CR or diffusively from phase III to phase V TD . The results also provide new constraints for the phase/chemical transformation diagram of carbon dioxide.

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“…The high-P -T regime of CO 2 is also disputed as far as several experiments and theoretical works often led to conflicting results 21,22,[42][43][44][45][46][47][48] . A liquid-liquid-solid triple point was recently proposed to exist inside the Earth's geotherm region as well 21,22 .…”

Section: Introductionmentioning

confidence: 99%

Structural evolution in high-pressure amorphousCO2fromab initiomolecular dynamics

Plašienka

Martoňák

2014

Phys. Rev. B

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By employing ab initio molecular dynamics simulations at constant pressure we investigated behavior of amorphous carbon dioxide between 0-100 GPa and 200-500 K. We focused on evolution of the high-pressure polymeric amorphous form known as a-carbonia on its way down to zero pressure, where it eventually converts into a molecular state. During the simulations we observed a spectrum of amorphous forms between two limiting polymeric forms with different proportion of three and four-coordinated carbon atoms. Besides that we also found a new mixed molecular-polymeric form that shows pronounced metastability at certain conditions. The observed behavior suggests CO2 as possible candidate for polyamorphism. We discuss structural and physical properties of the observed amorphous forms as well as their relations to crystalline phases.

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Carbon Dioxide Carbonates in the Earth’s Mantle: Implications to the Deep Carbon Cycle

Cited by 29 publications

References 26 publications

Diamond formation in the deep lower mantle: a high-pressure reaction of MgCO3 and SiO2

Diamond formation in the deep lower mantle: a high-pressure reaction of MgCO3 and SiO2

Transformation and structure of silicatelike CO2-V

Structural evolution in high-pressure amorphousCO2fromab initiomolecular dynamics

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