Analytical results for the material of the Chelyabinsk meteorite

Geochemistry International (Impact Factor: 0.53). 07/2013; 51(7). DOI: 10.1134/S0016702913070100

ABSTRACT This paper presents the results of the mineralogical, petrographic, elemental, and isotopic analysis of the Chelyabinsk meteorite and their geochemical interpretation. It was shown that the meteorite can be assigned to LL5-group ordinary chondrites and underwent moderate shock metamorphism (stage S4). The Chelyabinsk meteorite contains a significant fraction (approximately one-third by volume) of shock-melted material similar in composition to the main volume of the meteorite. The results of isotopic analysis suggest that the history of meteorite formation included an impact event approximately 290 Ma ago.

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Available from: M. A. Nazarov, Aug 13, 2015
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    • "It is natural to assume that a larger parent body could have been disrupted at Sun-grazing conditions. The recovered fragments of the Chelyabinsk meteorite contain significant portions of shock blackened material and melt veins (Galimov et al., 2013; Kohout et al., 2014; Ozawa et al., 2014) that could be produced in the Sun atmosphere (a temperature of the shock-melt vein matrix formation is estimated over 1700-2000º C in (Ozawa et al., 2014)). "
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    ABSTRACT: The orbit of the Chelyabinsk object is calculated, applying the least-squares method directly to astrometric positions. The dynamical evolution of this object in the past is studied by integrating equations of motion for particles with orbits from the confidence region. It is found that the majority of the Chelyabinsk clones reach the near-Sun state. Sixty-seven percent of these objects have collisions with the Sun for 15 Myr in our numerical simulations. The distribution of minimum solar distances shows that the most probable time for the encounters of the Chelyabinsk object with the Sun lies in the interval from −0.8 Myr to −2 Myr. This is consistent with the estimate of a cosmic ray exposure age of 1.2 Myr (Popova et al. 2013). A parent body of the Chelyabinsk object should experience strong tidal and thermal effects at this time. The possible association of the Chelyabinsk object with 86039 (1999 NC43) and 2008 DJ is discussed.
    11/2014; 49(12). DOI:10.1111/maps.12382
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    • "Compositions of olivine and pyroxene from sample 10–90 (Table 4) are very similar to those of LL chondrites and are located in low-Fe region of the Fs-Fa diagram occupied by LL chondrites (Brearly and Jones 1998). These data agree well with previously published data on the olivine and pyroxene compositions of the Chelyabinsk LL5 chondrite (Galimov et al. 2013). Chromite compositions (Table 4) also agree well with expected compositions for LL chromites (Brearly and Jones 1998; Wlotzka 2005). "
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    ABSTRACT: Here we characterize the magnetic properties of the Chelyabinsk chondrite (LL5, S4, W0) and constrain the composition, concentration, grain size distribution, and mineral fabric of the meteorite's magnetic mineral assemblage. Data were collected from 10 to 1073 K and include measurements of low‐field magnetic susceptibility (χ0), the anisotropy of χ0, hysteresis loops, first‐order reversal curves, Mössbauer spectroscopy, and X‐ray microtomography. The REM and REM′ paleointensity protocols suggest that the only magnetizations recorded by the chondrite are components of the Earth's magnetic field acquired during entry into our planet's atmosphere. The Chelyabinsk chondrite consists of light and dark lithologies. Fragments of the light lithology show logχ0 = 4.57 ± 0.09 (s.d.) (n = 135), while the dark lithology shows 4.65 ± 0.09 (n = 39) (where χ0 is in 10−9 m3 kg−1). Thus, Chelyabinsk is three times more magnetic than the average LL5 fall, but is similar to a subgroup of metal‐rich LL5 chondrites (Paragould, Aldsworth, Bawku, Richmond) and L/LL5 chondrites (Glanerbrug, Knyahinya). The meteorite's room‐temperature magnetization is dominated by multidomain FeNi alloys taenite and kamacite (no tetrataenite is present). However, below approximately 75 K remanence is dominated by chromite. The metal contents of the light and dark lithologies are 3.7 and 4.1 wt%, respectively, and are based on values of saturation magnetization.
    Meteoritics & planetary science 06/2014; 49(6). DOI:10.1111/maps.12307 · 2.83 Impact Factor
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    ABSTRACT: The mineralogy and physical properties of Chelyabinsk meteorites (fall, February 15, 2013) are presented. Three types of meteorite material are present, described as the light-colored, dark-colored, and impact-melt lithologies. All are of LL5 composition with the impact-melt lithology being close to whole-rock melt and the dark-colored lithology being shock-darkened due to partial melting of iron metal and sulfides. This enables us to study the effect of increasing shock on material with identical composition and origin. Based on the magnetic susceptibility, the Chelyabinsk meteorites are richer in metallic iron as compared to other LL chondrites. The measured bulk and grain densities and the porosity closely resemble other LL chondrites. Shock darkening does not have a significant effect on the material physical properties, but causes a decrease of reflectance and decrease in silicate absorption bands in the reflectance spectra. This is similar to the space weathering effects observed on asteroids. However, compared to space weathered materials, there is a negligible to minor slope change observed in impact-melt and shock-darkened meteorite spectra. Thus, it is possible that some dark asteroids with invisible silicate absorption bands may be composed of relatively fresh shock-darkened chondritic material.
    Icarus 01/2014; 228:78-85. DOI:10.1016/j.icarus.2013.09.027 · 2.84 Impact Factor
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