Magnetic properties of a freshly fallen LL ordinary chondrite: the Bensour meteorite

摘要: Abstract A comprehensive rock magnetic, magnetic anisotropy and paleomagnetic study has been undertaken in the brecciated LL6 Bensour ordinary chondrite, a few months only after its fall on Earth. Microscopic observations electronic microprobe analyses indicate presence of Ni-rich taenite, tetrataenite rare Co-rich kamacite. Tetrataenite is main carrier remanence. Magnetization measurements were performed mutually oriented 125 mm 3 sub-samples. very strong coherent susceptibility remanence evidenced interpreted as due to large impact responsible for post-metamorphic compaction this material disruption parent body. We show that acquisition remanent magnetization postdates metamorphism body predates entering meteorite Earth’s atmosphere. Three components could be isolated. soft component closely related shock acquired during same Two harder random directions at mm scale. This randomness attributed either formation mechanism or brecciation. All are likely low (≈μT) null ambient field, demonstrated by comparison with demagnetization behavior isothermal magnetization. other meteorites, Kilabo St-Mesmin, have also studied Bensour.