Effects of hydrostaticity and Mn-substitution on dolomite stability at high pressure

Wang, Faxiang; Zhao, Chao; Xu, Liangxu; Liu, Jin

doi:10.2138/am-2022-8248

Cited by 6 publications

(4 citation statements)

References 52 publications

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“…Fe could prompt Fe-dolomite to decompose into magnesite (or siderite) and aragonite at high temperature and high pressure 67 . Phase transitions of dolomite can be regarded as a function of iron content at high temperature and high pressure [68][69][70] . Moreover, carbonatesilicate cations exchange may accelerate cations disorder in carbonates, affecting their phase stability as well 27,71,72 .…”

Section: Discussionmentioning

confidence: 99%

Recycled carbonates elevate the electrical conductivity of deeply subducting eclogite in the Earth’s interior

Jing

Dai

et al. 2023

Commun Earth Environ

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The elevated pressure and temperature conditions encountered by a subducted slab entering the deep Earth can substantially alter the chemical composition and physical properties of recycled carbonates. Carbonate-silicate reactions are believed to have a pivotal role in this process. Here we conduct high temperature and high pressure experiments on carbonated eclogite and measure the electrical conductivity in order to constrain the evolution of geophysical properties and chemical composition in the carbonate-bearing eclogitic slab. We find that the carbonate-silicate reaction elevates the conductivity of carbonated eclogite by cations (e.g., Ca, Mg, Fe) exchange between carbonates and silicate. We propose that carbonate-silicate cations exchange can alter the chemical composition of recycled carbonates, potentially impacting their stability and reducing the solidus temperature of carbonate-bearing systems. Combining thermodynamic calculations with the elevated conductivity in our experiments, we re-evaluate the contribution of recycled carbonates to the Earth mantle geophysical anomalies and obtain the potential carbonate capacity in the subducting slab.

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Section: Discussionmentioning

confidence: 99%

Recycled carbonates elevate the electrical conductivity of deeply subducting eclogite in the Earth’s interior

Jing

Dai

et al. 2023

Commun Earth Environ

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“…The band is shifted to 1099 cm −1 in dolomite and to 1093 cm −1 in magnesite. It is important to understand that the partial cation replacement leads to a loss of symmetry in the crystal lattice unit cell as observed in the case of dolomite and predicted by the theoretical approach [3,4,10,33]. For the external modes, the shift caused by the cation substitution is the same observed in the bending mode.…”

Section: Raman Shiftmentioning

confidence: 91%

“…Eight of these modes are Raman active: the asymmetrical stretching of the C-O bond (E g symmetry) appears around 1440 cm −1 ; the symmetrical stretching of the C-O bond (A g symmetry) appears around 1100 cm −1 , and for the COO bending mode, there are two bands with E g and A g symmetries, appearing around 720 and 880 cm −1 , respectively. All the other vibrational modes correspond to lattice movements [3,4,10,33].…”

Section: Vibrational Analysismentioning

confidence: 99%

Revisiting the Raman Spectra of Carbonate Minerals

Alves,

Edwards,

Korsakov

et al. 2023

Minerals

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This work presents a new discussion about the vibrational properties of the carbonate ion displayed in several different environments. The microparameters introduced by cation substitution and different crystal lattices in addition to the crystal aggregation are present in the discussion. The work comments on how the Raman modes are affected by these changes by using data obtained with four different laser excitation sources. Raman spectra excited at 1064 nm are reported at 1 cm−1 resolution. New observations and approaches based on the Raman modes highlight the differences observed in the relative intensity and width of the bands. The new data contribute to the understanding of these materials and their spectra, bringing new observations based on the Raman modes. This work presents a new approach highlighting the differences observed in the relative intensity and width of the Raman bands. The results indicate some evidence of the influence of the crystal habit and/or the growth of the mineral itself on the Raman spectrum. In addition, the data show the influence of cation substitution upon Raman bandwidth and the interference of the size of the spot of the laser in the measurement.

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“…Comparatively, dolomite has a rhombohedral structure (space group R3 − ) with MgO 6 and CaO 6 units alternating along the c-axis on the Earth's surface, and its phase transitions are more complicated than magnesite under deep-mantle conditions. To date, a series of dolomite's high-P phases have been reported, including dolomite-II, -III, -IIIc, -IV, and -V (Mao et al, 2011;Merlini et al, 2012Merlini et al, , 2017Efthimiopoulos et al, 2017Efthimiopoulos et al, , 2018Vennari and Williams, 2018;Binck et al, 2020b;Wang et al, 2022). Furthermore, magnesite, dolomite, and other carbonate minerals have frequently been discovered in superdeep diamond inclusions, evidencing that carbonate might exist in the mantle transition zone and the lower mantle (Kaminsky et al, 2009;Walter et al, 2011;Mazza et al, 2019).…”

Section: Introductionmentioning

confidence: 99%

Effects of Spin Transition and Cation Substitution on the Optical Properties and Iron Partitioning in Carbonate Minerals

Liu

et al. 2023

Acta Geologica Sinica (Eng)

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The high-pressure behavior of deep carbonate dictates the state and dynamics of oxidized carbon in the Earth's mantle, playing a vital role in the global carbon cycle and potentially influencing long-term climate change. Optical absorption and Raman spectroscopic measurements were carried out on two natural carbonate samples in diamond-anvil cells up to 60 GPa. Mg-substitution in high-spin siderite FeCO 3 increases the crystal field absorption band position by approximately 1000 cm −1 , but such an effect is marginal at >40 GPa when entering the low-spin state. The crystal field absorption band of dolomite cannot be recognized upon compression to 45.8 GPa at room temperature but, in contrast, the high-pressure polymorph of dolomite exhibits a strong absorption band at frequencies higher than (Mg,Fe)CO 3 in the lowspin state by 2000-2500 cm −1 . Additionally, these carbonate minerals show more complicated features for the absorption edge, decreasing with pressure and undergoing a dramatic change through the spin crossover. The optical and vibrational properties of carbonate minerals are highly correlated with iron content and spin transition, indicating that iron is preferentially partitioned into low-spin carbonates. These results shed new light on how carbonate minerals evolve in the mantle, which is crucial to decode the deep carbon cycle.

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Effects of hydrostaticity and Mn-substitution on dolomite stability at high pressure

Cited by 6 publications

References 52 publications

Recycled carbonates elevate the electrical conductivity of deeply subducting eclogite in the Earth’s interior

Recycled carbonates elevate the electrical conductivity of deeply subducting eclogite in the Earth’s interior

Revisiting the Raman Spectra of Carbonate Minerals

Effects of Spin Transition and Cation Substitution on the Optical Properties and Iron Partitioning in Carbonate Minerals

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