Magnetic properties of the LL5 ordinary chondrite Chelyabinsk (fall of February 15, 2013)

TitleMagnetic properties of the LL5 ordinary chondrite Chelyabinsk (fall of February 15, 2013)
Publication TypeJournal Article
Year of Publication2014
AuthorsBezaeva NS, Badyukov DD, Nazarov MA, Rochette P, Feinberg JM, Markov GP, Borschneck D, Demory F, Gattacceca J, Borisovskiy SE
JournalMeteoritics & Planetary Science

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 1073K 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 paleointensity protocol suggests 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). 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 ~75K remanence is dominated by chromite. The metal contents of the light and dark lithologies are 3.7 wt% and 4.1 wt%, respectively, and are based on values of saturation magnetization.