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Magnetic analysis of K/T boundary layer clay from Stevns Klint, Denmark
Author(s) -
Morden S. J.
Publication year - 1993
Publication title -
meteoritics
Language(s) - English
Resource type - Journals
eISSN - 1945-5100
pISSN - 0026-1114
DOI - 10.1111/j.1945-5100.1993.tb00284.x
Subject(s) - magnetite , ferrimagnetism , pyrrhotite , geology , mineralogy , remanence , materials science , geochemistry , analytical chemistry (journal) , chemistry , magnetization , environmental chemistry , pyrite , paleontology , magnetic field , physics , quantum mechanics
— Following the distribution at The 53rd Annual Meeting of the Meteoritical Society of 40 kg of Cretaceous‐Tertiary boundary layer clay (Fish Clay) recovered from Stevns Klint, Denmark, a magnetic analysis of both the coarse and fine fractions was carried out. The magnetic mineralogy was found to be complex, consisting of single‐domain magnetite and fine‐grained sulphides of Fe. The Fe sulphide was present as ferrimagnetic pyrrhotite (Fe 7 S 8 ) and other sulphides that decayed on heating to produce magnetite. A magnetic fraction of the material was separated by using a strong hand magnet. The separate from the coarse fraction was found to contain low‐Ni, Fe (T C =750–770 °C) in trace quantities. Since contamination seems unlikely, it must be concluded that the Fe has an extraterrestrial origin. Whilst partially‐degraded cosmic spherules may add to the signal, their input is believed to be insignificant. The other obvious source is debris from the vapourization of a K/T impactor.