Embedded iron particles surrounded by carbonized rings in the outer layer of a mammoth tusk from Alaska. Inset photo shows how an object ripped through the tusk. Image courtesy Richard Firestone.
Embedded iron particles surrounded by carbonized rings in the outer layer of a mammoth tusk from Alaska. Inset photo shows how an object ripped through the tusk. Image courtesy Richard Firestone.
Fred, I had the same thing in mind as I reviewed the article.
https://www.mail-archive.com/meteorite-
Abstract:
“We have discovered what appear to be micrometeorites imbedded in seven Alaskan Mammoth tusks and a Siberian bison skull.The micrometeorites apparently shattered on impact leaving 2-5 mm hemispherical debris patterns
surrounded by carbonized rings. Multiple impacts are observed on only one side of the tusks and skull consistent with the micrometeorites having come from a single direction.The impact sites are strongly magnetic indicating significant iron content.”
(Snip)
“The bison skull shows evidence of new bone growth over
the micrometeorite impact sites indicating the animal survived the bombardment and is dated at ~26 ka which is younger than the tusks. This age is consistent with exposure of the bison to an enriched source of radiocarbon following the impact.”
“It appears likely that the impacts, cosmogenic isotope increases,magnetic excursion, and population declines are related events(Occam’s razor), although their precise nature remains to be determined.”
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d I. Barnes, et al,
Current Biology 17, 1-4 (2007).