The chemical composition of the Earth: Enstatite chondrite models

Javoy, M.; Kaminski, É.; Guyot, F.; Andrault, Denis; Sanloup, C.; Moreira, Manuel; Labrosse, S.; Jambon, Albert; Agrinier, Pierre; Davaille, Anne; Jaupart, Claude

doi:10.1016/j.epsl.2010.02.033

Cited by 397 publications

(294 citation statements)

References 71 publications

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“…If so, an isotopically identical Earth and Theia may not conflict with an isotopically distinct Mars in this case. This could also potentially allow for an isotopically uniform inner solar nebula (Javoy et al 2010;Dauphas et al 2014), with Mars being polluted by more distant planetesimals. However, this scenario is untested and should be the subject of future studies.…”

Section: Random Distributionmentioning

confidence: 99%

The feeding zones of terrestrial planets and insights into Moon formation

Kaib

Cowan

2015

Icarus

105

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The final stage of terrestrial planet formation consists of several hundred approximately lunar mass bodies accreting into a few terrestrial planets. This final stage is stochastic, making it hard to predict which parts of the original planetesimal disk contributed to each of our terrestrial planets. Here we present an extensive suite of terrestrial planet formation simulations that allows quantitative analysis of this process. Although there is a general correlation between a planet's location and the initial semi-major axes of its constituent planetesimals, we concur with previous studies that Venus, Earth, and Mars analogs have overlapping, stochastic feeding zones. We quantify the feeding zone width, ∆a, as the mass-weighted standard deviation of the initial semi-major axes of the planetary embryos and planetesimals that make up the final planet. The size of a planet's feeding zone in our simulations does not correlate with its final mass or semi-major axis, suggesting there is no systematic trend between a planet's mass and its volatile inventory. Instead, we find that the feeding zone of any planet more massive than 0.1M ⊕ is roughly proportional to the radial extent of the initial disk from which it formed: ∆a ≈ 0.25(a max − a min ), where a min and a max are the inner and outer edge of the initial planetesimal disk. These wide stochastic feeding zones have significant consequences for the origin of the Moon, since the canonical scenario predicts the Moon should be primarily composed of material from Earth's last major impactor (Theia), yet its isotopic composition is indistinguishable from Earth. In particular, we find that the feeding zones of Theia analogs are significantly more stochastic than the planetary analogs. Depending on our assumed initial distribution of oxygen isotopes within the planetesimal disk, we find a ∼5% or less probability that the Earth and Theia will form with an isotopic difference equal to or smaller than the Earth and Moon's. In fact we predict that every planetary mass body should be expected to have a unique isotopic signature. In addition, we find paucities of massive Theia analogs and high velocity moon-forming collisions, two recently proposed explanations for the Moon's isotopic composition. Our work suggests that there is still no scenario for the Moon's origin that explains its isotopic composition with a high probability event.

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Section: Random Distributionmentioning

confidence: 99%

The feeding zones of terrestrial planets and insights into Moon formation

Kaib

Cowan

2015

Icarus

105

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“…We made the assumption that Mercury formed by accretion of metal-rich chondritic building blocks (enstatite chondrites and/or bencubbinite chondrites; Malavergne et al, 2010Malavergne et al, , 2014Zolotov et al, 2013). We used average sulfide modes (10.0 ± 2.50 wt.%; Jarosewich, 1990;Javoy et al, 2010) and compositions (∼ FeS with 37.0 ± 1.5 wt.% S; Javoy et al, 2010) in EH and CB meteorites and calculated that Mercury may contain 2.7-4.6 wt.% S with the highest probability lying in the range of 3.8 ± 0.5 wt.% S. The exact nature of Mercurian building blocks is however unimportant for the following discussion because all chondritic materials have high S content (∼2-5 wt.% S; Fig. 1).…”

Section: Sulfur Content Of the Mantle And The Corementioning

confidence: 99%

Sulfur solubility in reduced mafic silicate melts: Implications for the speciation and distribution of sulfur on Mercury

Namur

Charlier

Holtz

et al. 2016

Earth and Planetary Science Letters

113

160

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Chemical data from the MESSENGER spacecraft revealed that surface rocks on Mercury are unusually enriched in sulfur compared to samples from other terrestrial planets. In order to understand the speciation and distribution of sulfur on Mercury, we performed high temperature (1200-1750 • C), lowto high-pressure (1 bar to 4 GPa) experiments on compositions representative of Mercurian lavas and on the silicate composition of an enstatite chondrite. We equilibrated silicate melts with sulfide and metallic melts under highly reducing conditions (IW-1.5 to IW-9.4; IW = iron-wüstite oxygen fugacity buffer). Under these oxygen fugacity conditions, sulfur dissolves in the silicate melt as S 2− and forms complexes with Fe 2+ , Mg 2+ and Ca 2+ . The sulfur concentration in silicate melts at sulfide saturation (SCSS) increases with increasing reducing conditions (from <1 wt.% S at IW-2 to >10 wt.% S at IW-8) and with increasing temperature. Metallic melts have a low sulfur content which decreases from 3 wt.% at IW-2 to 0 wt.% at IW-9. We developed an empirical parameterization to predict SCSS in Mercurian magmas as a function of oxygen fugacity ( f O 2 ), temperature, pressure and silicate melt composition. SCSS being not strictly a redox reaction, our expression is fully valid for magmatic systems containing a metal phase. Using physical constraints of the Mercurian mantle and magmas as well as our experimental results, we suggest that basalts on Mercury were free of sulfide globules when they erupted. The high sulfur contents revealed by MESSENGER result from the high sulfur solubility in silicate melt at reducing conditions. We make the realistic assumption that the oxygen fugacity of mantle rocks was set during equilibration of the magma ocean with the core and/or that the mantle contains a minor metal phase and combine our parameterization of SCSS with chemical data from MESSENGER to constrain the oxygen fugacity of Mercury's interior to IW-5.4 ± 0.4. We also calculate that the mantle of Mercury contains 7-11 wt.% S and that the metallic core of the planet has little sulfur (<1.5 wt.% S). The external part of the Mercurian core is likely to be made up of a thin (<90 km) FeS layer.

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“…A significant contributor to this heat flux comes from the heat producing elements, K, Th and U, with its flux proportion dependent upon their absolute abundance inside the Earth. The many models that describe the composition of the Earth come from cosmochemical, geochemical and geophysical observations and predict a range of abundances and distributions of these elements [228][229][230][231].…”

Section: Introductionmentioning

confidence: 99%

The next-generation liquid-scintillator neutrino observatory LENA

Wurm

Beacom

Bezrukov

et al. 2012

Astroparticle Physics

212

200

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2As part of the European LAGUNA design study on a next-generation neutrino detector, we propose the liquid-scintillator detector LENA (Low Energy Neutrino Astronomy) as a multipurpose neutrino observatory. The outstanding successes of the Borexino and KamLAND experiments demonstrate the large potential of liquid-scintillator detectors in low-energy neutrino physics. Low energy threshold, good energy resolution and efficient background discrimination are inherent to the liquidscintillator technique. A target mass of 50 kt will offer a substantial increase in detection sensitivity.At low energies, the variety of detection channels available in liquid scintillator will allow for an energy-and flavor-resolved analysis of the neutrino burst emitted by a galactic Supernova. Due to target mass and background conditions, LENA will also be sensitive to the faint signal of the Diffuse Supernova Neutrino Background. Solar metallicity, time-variation in the solar neutrino flux and deviations from MSW-LMA survival probabilities can be investigated based on unprecedented statistics. Low background conditions allow to search for dark matter by observing rare annihilation neutrinos. The large number of events expected for geoneutrinos will give valuable information on the abundances of Uranium and Thorium and their relative ratio in the Earth's crust and mantle. Reactor neutrinos enable a high-precision measurement of solar mixing parameters. A strong radioactive or pion decay-at-rest neutrino source can be placed close to the detector to investigate neutrino oscillations for short distances and sub-MeV to MeV energies.At high energies, LENA will provide a new lifetime limit for the SUSY-favored proton decay mode into kaon and antineutrino, surpassing current experimental limits by about one order of magnitude. Recent studies have demonstrated that a reconstruction of momentum and energy of GeV particles is well feasible in liquid scintillator. Monte Carlo studies on the reconstruction of the complex event topologies found for neutrino interactions at multi-GeV energies have shown promising results. If this is confirmed, LENA might serve as far detector in a long-baseline neutrino oscillation experiment currently investigated in LAGUNA-LBNO.3

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The chemical composition of the Earth: Enstatite chondrite models

Cited by 397 publications

References 71 publications

The feeding zones of terrestrial planets and insights into Moon formation

The feeding zones of terrestrial planets and insights into Moon formation

Sulfur solubility in reduced mafic silicate melts: Implications for the speciation and distribution of sulfur on Mercury

The next-generation liquid-scintillator neutrino observatory LENA

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