>Not quite Andrew. They have found shocked quartz, zircon, tektites etc
>at other event boundary deposition layers. Not quite as much Iridium,
>but this is not the
>only mineral/element for evidence of impact. I have just not read/heard much
>on further debate.

In all of the recent works I have read on extinction events, those
other than the K-T have been noted as LACKING tektites, iridium
enrichment etc.

Also, shocked quartz can be produced by volcanic activity; it was
once regarded as being impact-only.
--
Andrew Grebneff
165 Evans St, Dunedin, New Zealand
64 (3) 473-8863
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Fossil preparator
Seashell, Macintosh & VW/Toyota van nut
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