Ir in bones

[Bill Adlam <bill.adlam@st-peters.oxford.ac.uk>]

On Mon, 29 May 1995 STEVEN9120@aol.com wrote:

> The scenario of the meteor impact theory poses one question.  Although
> meteors carry iridium would that not be detected in fossilized bone?  As well
> as radiation since the impact would have been more devastating than any
> nuclear blast recorded in history?...

Iridium would be detectable in fossil bone if:
1) The animal concerned absorbs iridium from its environment,
2) any iridium is deposited in its bones,
3) it is exposed for long enough to deposit iridium and
4) it gets fossilised.

I don't think 1 is true for a typical vertebrate, 2 might be, 3 depends on
how fast an impact would act.  However, as previous posters have mentioned,
the fourth criterion is very unusual, and there might only be one or two 
dinosaur fossils in museums worldwide which actually died in the K-T event.

An impact would not generate radioactivity, although it would release
radioactive heavy nuclei in the bolide and perhaps in rocks.  However, it's
easier and more informative to look for heavy metals in general than measure 
radioactivity.
                                                                        Bill