Magnetic properties of the LL5 ordinary chondrite Chelyabinsk (fall of February 15, 2013) |
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| Authors: | Natalia S. Bezaeva Dmitry D. Badyukov Mikhail A. Nazarov Pierre Rochette Joshua M. Feinberg Gennadiy P. Markov Daniel Borschneck François Demory Jérôme Gattacceca Sergey E. Borisovskiy Anna Ya Skripnik |
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| Affiliation: | 1. Earth Physics Department, Faculty of Physics, M.V. Lomonosov Moscow State University, , 119991 Moscow, Russia;2. Ural Federal University, , 620002 Ekaterinburg, Russia;3. Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, , 119991 Moscow, Russia;4. CEREGE CNRS/Aix‐Marseille Université, , Cedex 4, France;5. Institute for Rock Magnetism, University of Minnesota, , Minneapolis, Minnesota, 55455 USA;6. Department of Earth Sciences, University of Minnesota, , Minneapolis, Minnesota, 55455 USA;7. Schmidt Institute of Physics of the Earth, Russian Academy of Sciences, , 123995 Moscow, Russia;8. Department of Earth, Atmospheric, and Planetary Sciences, Massachusetts Institute of Technology, , Cambridge, Massachusetts, 02139 USA;9. Institute of Geology of Ore Deposits, Petrography, Mineralogy and Geochemistry, Russian Academy of Sciences, , 119017 Moscow, Russia |
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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. |
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