Carbon in olivine: Results from nuclear reaction analysis

Mathez, E. A.; Blacic, J. D.; Beery, J. G.; Hollander, Mark; Maggiore, C. J.

doi:10.1029/jb092ib05p03500

Cited by 26 publications

(8 citation statements)

References 22 publications

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“…Even when a carbon solubility in olivine is of the order of a few hundred ppm by weight, it would be sufficient to incorporate all carbon in the upper mantle into olivine. Numerous attempts have been therefore made to determine the carbon solubility in olivine since the early 1980s (Freund et al, 1980;Tsong et al, 1985;Mathez et al, 1987;Tingle et al, 1988;Keppler et al, 2003). Shcheka et al (2006) described that the carbon solubility in olivine increases exponentially by two orders of magnitude as a function of pressure.…”

Section: Introductionmentioning

confidence: 99%

Carbon substitution for oxygen in α–cristobalite

Mitani

Kyono

2017

Journal of Mineralogical and Petrological Sciences

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We investigated the carbon solubility into silica under high temperature condition. Mixtures of amorphous silica and graphite powder sealed in silica glass tubes were heated at 1300°C. The a lattice parameter and unit cell volume of α-cristobalite obtained are slightly increased compared with that heated without graphite. The c lattice parameter, on the other hand, almost unchanged. There is no clear dependency of the lattice parameter variations on carbon content mixed as the starting material. After re-heating the samples under atmospheric oxygen, the a lattice parameter and unit cell volume were reduced from the previous values. These changes indicate the possibility that carbon certainly incorporated into the α-cristobalite was oxidized with the atmospheric oxygen. The ab-initio calculation of disiloxane molecule showed that with carbon substitution for the bridging oxygen the Si-C bond distance increases whereas the Si-C-Si bond angle decreases compared with the Si-O bond distance and Si-O-Si bond angle. Consequently, the distance between Si atoms increases with the carbon substitution for the bridging oxygen. Since the expansion of Si-Si distance contributes twice as much to the a and b-axes than the c-axis in the unit cell of α-cristobalite, the ab-initio simulation result supports the observation that a lattice parameter increases with the carbon substitution relative to the c lattice parameter. The study strongly suggests that under reduced and high temperature conditions carbon is substituted not for silicon but for oxygen in α-cristobalite structure.

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Section: Introductionmentioning

confidence: 99%

Carbon substitution for oxygen in α–cristobalite

Mitani

Kyono

2017

Journal of Mineralogical and Petrological Sciences

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“…SOLID SOLUTIONS WITH CO 2 Any oxide and silicate crystallizing in the presence of CO 2 must also take up a small amount of CO 2 into solid solution. Some in the geoscience community reject outright the notion that carbon enters into the structure of oxides or silicates (Keppler et al 2003;Mathez et al 1987;Tingle et al 1991;Tsong et al 1985). This view is inconsistent with thermodynamics and solid-state principles.…”

Section: A2 Solid Solutions With H 2 Omentioning

confidence: 99%

Solid Solution Model for Interstellar Dust Grains and Their Organics

Freund

2006

ApJ

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We present a dust grain model based on the fundamental principle of solid solutions. The model is applicable to the mineral (silicate) component of the dust in the interstellar medium (ISM ). We show that nanometer-sized mineral grains, which condense in the gas-rich outflow of late-stage stars or expanding gas shells of supernova explosions, do not consist of just high melting point oxides or silicates. Instead they form solid solutions with gas-phase components H 2 O, CO, and CO 2 that are omnipresent in environments where the grains condense. Through a series of thermodynamically well-understood solid-state processes, these solid solutions become ''parents'' of organic matter that precipitates inside the grains. Thus, the mineral dust grains and their organics become part of the same thermodynamically defined solid phase and, hence, physically inseparable. This model can account for many astronomical observations, which no prior model can adequately address, specifically: (1) Organics in the diffuse ISM are identified by a 3.4 m IR band, characteristic of aliphatic hydrocarbons composed of ÀCH 2 À and of ÀCH 3 groups. (2) The methylene-to-methyl ratio is nearly constant, implying a CH 2 :CH 3 ratio of $5:2. (3) The intensity ratio between the 9.7 and the 3.4 m band is nearly constant, implying a silicate-to-organics ratio of $10:1. (4) In dense clouds the complex 3.4 m band is replaced by a weak, featureless 3.47 m band. (5) Whereas silicate grains identified by their 9.7 m band tend to align in magnetic fields, grains with a strong 3.4 m organic signature do not tend to align.

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“…Note added in proof. Ed Mathez (Department of Mineral Sciences, American Museum of Natural History, New York) and colleagues at Los Alamos National Laboratory recently analyzed specimen VIII67 using the •2C(d,p)13C nuclear reaction technique (see Mathez et al [1987]). The surface shown in Fig.…”

Section: Marty and Jambon [1987] Modelling C/3he In The Earthmentioning

confidence: 99%

“…graphitic and carbonaceous material, such as that described byMathez and Delaney [1981] andMathez [1987]. Some of the C in these crystals cannot beextracted until the sample has melted [Roedrier, 1965; S. Nadeau, personal communication, 1987).…”

mentioning

confidence: 99%

Experiments and observations bearing on the solubility and diffusivity of carbon in olivine

Tingle¹,

Green²,

Finnerty³

1988

J. Geophys. Res.

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The solubility and diffusivity of C in olivine at 0.1, 2.0, and 3.0 GPa have been constrained by annealing single crystals of San Carlos olivine in 14C‐labelled CO2, CO2‐H2O, and graphite at 1200°–1450°C. In nearly all annealed specimens, carbonaceous material was observed at the diffusion interface that consisted of either (1) graphite used as a C source, (2) elemental C (probably graphite) formed by reduction of the C‐O‐H fluid phase present, or (3) carbon‐rich surface films interpreted as silicate dissolved in the fluid phase at high pressure, quenched onto the crystal surface. The significant range of 14C‐beta particles in olivine (and photographic emulsion) coupled with the presence of carbonaceous material at the diffusion interface gives rise to apparent concentration profiles. After removal of the carbonaceous material we retained no unambiguous evidence for C diffusion into olivine. The sensitivity and spatial resolution of the beta track method constrain either the solubility to be less than 30 ppmw (parts per million by weight) C or the diffusivity to be less than 10−12 cm2/s. Observations and geochemical data on natural rocks bearing on the nature and distribution of C in the Earth's upper mantle are discussed in light of these constraints.

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Carbon in olivine: Results from nuclear reaction analysis

Cited by 26 publications

References 22 publications

Carbon substitution for oxygen in α–cristobalite

Carbon substitution for oxygen in α–cristobalite

Solid Solution Model for Interstellar Dust Grains and Their Organics

Experiments and observations bearing on the solubility and diffusivity of carbon in olivine

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