How would Iridium have caused the extinction of dinosaurs? Is it harmful??

Question

How would Iridium have caused the extinction of dinosaurs? Is it harmful??

Answer 1

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It is just a theory.  From a meteor?  But what other animals were wiped out?

-- The fact is that we do not see results of meteor or other impacts on the earth below the top layers.  It didn't happen "millions of years ago" for some reason - maybe because those layers were NEVER exposed for long periods of time (in reality far less than 100 years) that measured in the millions of years.  They just do not occur, the great question is why? I submit that these layers were not exposed, others can come up with "logical" reasons that fit their worldview or not?

Answer 2

It is not iridium that caused the extinction.

According to the supermeteor impact theory (the real name is "Cretaceous–Tertiary extinction event"),  the impact caused some much damages that it wiped out dinosaurs, and the meteor left iridium as a trace.

All the details here:

http://en.wikipedia.org/wiki/Cretaceous%...

This is a fascinating subject.