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Presence of an iron‐rich nanophase material in the upper layer of the Cretaceous‐Tertiary boundary clay
Author(s) -
WDOWIAK Thomas J.,
ARMENDAREZ Lawrence P.,
AGRESTI David G.,
WADE Manson L.,
WDOWIAK Suzanne Y.,
CLAEYS Philippe,
IZETT Glenn
Publication year - 2001
Publication title -
meteoritics and planetary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 100
eISSN - 1945-5100
pISSN - 1086-9379
DOI - 10.1111/j.1945-5100.2001.tb01814.x
Subject(s) - geology , cretaceous , atmosphere (unit) , sedimentary rock , iridium , geochemistry , mineralogy , paleontology , chemistry , biochemistry , physics , thermodynamics , catalysis
— We report new geochemical evidence from ten Cretaceous‐Tertiary (K‐T) boundary sites in North America and Europe, indicating the presence of a material remnant of a large asteroid or comet that struck the Earth at 65.0 Ma. Mössbauer spectroscopic data reveals that a ubiquitous iron‐rich nanophase material exists at the uppermost part of the K‐T boundary layer in the Western Hemisphere and in Europe in marine and continental fine‐grained sedimentary rock. The high surface‐to‐volume ratio of nanophase material suggests that it may be the carrier of the iridium abundance enhancement that marks the K‐T boundary. Even more provocative is the possibility that the discovered nanophase material is, for the most part, composed of the vaporized impactor after the impact‐generated high‐temperature vapor plume rose and cooled above the atmosphere.