No iridium anomaly after the 1908 Tunguska impact: Evidence from a Greenland ice core

Abstract— We have determined the abundances of Ir and other elements by neutron activation analysis on annual dust samples from an ice core from Site B in the Crête region in central Greenland covering the years 1905–1914. Iridium was detected in all samples, but we found no excess Ir above the back...

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Bibliographic Details
Published in:Meteoritics
Main Authors: Rasmussen, Kaare L., Clausen, Henrk B., Kallemeyn, Gregory W.
Format: Article in Journal/Newspaper
Language:English
Published: Wiley 1995
Subjects:
General Earth and Planetary Sciences
General Environmental Science
Greenland
Tunguska
Greenland ice core
ice core
Online Access:http://dx.doi.org/10.1111/j.1945-5100.1995.tb01160.x
https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1945-5100.1995.tb01160.x
https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1945-5100.1995.tb01160.x
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Summary:Abstract— We have determined the abundances of Ir and other elements by neutron activation analysis on annual dust samples from an ice core from Site B in the Crête region in central Greenland covering the years 1905–1914. Iridium was detected in all samples, but we found no excess Ir above the background in the years following the Tunguska event. The lack of an Ir anomaly in the years after the Tunguska impact combined with the knowledge of the energy released during the impact and our present knowledge about stratospheric transport implies either a very low Ir content of the impactor or an exceptionally high geocentric velocity for the impactor.

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