The Effect of Water on Ionic Conductivity in Olivine

Fei, Hongzhan; Druzhbin, Dmitry; Katsura, Tomoo

doi:10.1029/2019jb019313

Cited by 26 publications

(28 citation statements)

References 42 publications

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“…The conductivity ( ) is expressed in S/m, temperature ( ) is in absolute temperature, is the pre-exponential factor in S/m, and is the gas constant in J K −1 mol −1 . We obtain the activation enthalpy and the pre-exponential factor following the combined electrical conductivity 43 , 44 . The notations , indicates distinct conduction mechanisms operating at different temperature intervals 45 (Table 1 ).…”

Section: Resultsmentioning

confidence: 99%

Insights on the deep carbon cycle from the electrical conductivity of carbon-bearing aqueous fluids

Manthilake

Mookherjee

Miyajima

2021

Sci Rep

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The dehydration and decarbonation in the subducting slab are intricately related and the knowledge of the physical properties of the resulting C–H–O fluid is crucial to interpret the petrological, geochemical, and geophysical processes associated with subduction zones. In this study, we investigate the C–H–O fluid released during the progressive devolatilization of carbonate-bearing serpentine-polymorph chrysotile, with in situ electrical conductivity measurements at high pressures and temperatures. The C–H–O fluid produced by carbonated chrysotile exhibits high electrical conductivity compared to carbon-free aqueous fluids and can be an excellent indicator of the migration of carbon in subduction zones. The crystallization of diamond and graphite indicates that the oxidized C–H–O fluids are responsible for the recycling of carbon in the wedge mantle. The carbonate and chrysotile bearing assemblages stabilize dolomite during the devolatilization process. This unique dolomite forming mechanism in chrysotile in subduction slabs may facilitate the transport of carbon into the deep mantle.

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Section: Resultsmentioning

confidence: 99%

Insights on the deep carbon cycle from the electrical conductivity of carbon-bearing aqueous fluids

Manthilake

Mookherjee

Miyajima

2021

Sci Rep

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“…The activation enthalpy (ΔH) of each conduction mechanism can be calculated by fitting the data to equation, σ = σ 0 exp (−ΔH| RT) , where σ is the electrical conductivity (S/m), T is the absolute temperature (K), σ 0 is the preexponential factor (S/m), and R is the gas constant (J/K mol). Here we analyzed the activation enthalpy, first by manually fitting different temperature segments to the fitting equation and, second, by fitting the equation to the entire temperature range (Fei et al, 2020). The estimated activation enthalpies for different conduction mechanisms obtained using two fitting methods are listed in Table 1. The electron probe microanalyzer, scanning electron microscope (SEM), and Raman grid-analyses indicate that liebermannite is the principal phase present in samples synthesized at 12, 15, and 24 GPa (Figure 4).…”

Section: Journal Of Geophysical Research: Solid Earthmentioning

confidence: 99%

The Electrical Conductivity of Liebermannite: Implications for Water Transport Into the Earth's Lower Mantle

et al. 2020

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Liebermannite (KAlSi3O8) is a principal mineral phase expected to be thermodynamically stable in deeply subducted continental and oceanic crusts. The crystal structure of liebermannite exhibits tunnels that are formed between the assemblies of double chains of edge‐sharing (Si, Al) O6 octahedral units, which act as a repository for large incompatible alkali ions. In this study, we investigate the electrical conductivity of liebermannite at 12, 15, and 24 GPa and temperature of 1500 K to track subduction pathways of continental sediments into the Earth's lower mantle. Further, we looked at whether liebermannite could sequester incompatible H2O at deep mantle conditions. We observe that the superionic conductivity of liebermannite due to the thermally activated hopping of K+ ions results in high electrical conductivity of more than 1 S/m. Infrared spectral features of hydrous liebermannite indicate the presence of both molecular H2O and hydroxyl (OH−) groups in its crystal structure. The observed high electrical conductivity in the mantle transition zone beneath Northeastern China and the lower mantle beneath the Philippine Sea can be attributed to the subduction pathways of continental sediments deep into the Earth's mantle. While major mineral phases in pyrolitic compositions are almost devoid of H2O under lower mantle conditions, our study demonstrates that liebermannite could be an important host of H2O in these conditions. We propose that the relatively high H2O contents of ocean island basalts derived from deep mantle plumes are primarily related to deeply subducted continental sediments, in which liebermannite is the principal H2O carrier.

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“…In the first case, the mechanism is better known as "small polaron" conduction, where the hopping of electron with low mobility causes the local distortion of the lattice, and the corresponding E a varies in the range 0.7 eV-1.5 eV [35,[64][65][66]. Lower values of E a such as~0.8 eV for olivine and 0.6 eV for wadsleyite are consistent with proton conduction due to the high mobility of hydrogen species [35,67].…”

Section: Discussionmentioning

confidence: 96%

Complex Electrical Conductivity of Biotite and Muscovite Micas at Elevated Temperatures: A Comparative Study

2020

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The unique physicochemical, electrical, mechanical, and thermal properties of micas make them suitable for a wide range of industrial applications, and thus, the interest for these kind of hydrous aluminosilicate minerals is still persistent, not only from a practical but also from a scientific point of view. In the present work, complex impedance spectroscopy measurements were carried out in muscovite and biotite micas, perpendicular to their cleavage planes, over a broad range of frequencies (10−2 Hz to 106 Hz) and temperatures (473–1173 K) that have not been measured so far. Different formalisms of data representation were used, namely, Cole-Cole plots of complex impedance, complex electrical conductivity and electric modulus to analyze the electrical behavior of micas and the electrical signatures of the dehydration/dehydroxylation processes. Our results suggest that ac-conductivity is affected by the structural hydroxyls and the different concentrations of transition metals (Fe, Ti and Mg) in biotite and muscovite micas. The estimated activation energies, i.e., 0.33–0.83 eV for biotite and 0.69–1.92 eV for muscovite, were attributed to proton and small polaron conduction, due to the bound water and different oxidation states of Fe.

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The Effect of Water on Ionic Conductivity in Olivine

Cited by 26 publications

References 42 publications

Insights on the deep carbon cycle from the electrical conductivity of carbon-bearing aqueous fluids

Insights on the deep carbon cycle from the electrical conductivity of carbon-bearing aqueous fluids

The Electrical Conductivity of Liebermannite: Implications for Water Transport Into the Earth's Lower Mantle

Complex Electrical Conductivity of Biotite and Muscovite Micas at Elevated Temperatures: A Comparative Study

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