A biological explaination of Iridium in the KT boundary

[WRFord@DOCKMASTER.NCSC.MIL]

A friend of mine suspects that the Iridium concentration at the KT boundary
may have a biological origin. A previous poster's comment that the actual
deposition times seem spread over a 100,000 years seems to support this.

His theory is that one or more species of bacteria developed a survival
mechanism in response to what ever was going on (the KT boundary probably
means SOMETHING different happened in that era) that resulted in them
concentrating Iridium.

His modern day example is the use of bacteria up in Vancoveur Canada to mind
gold. The bateria's actions concentrate the gold 100 times+ over tis
concentration in the ore.

He hasn't seen very much discussion in the literature.

I await responses with interest.

This is a very interesting list to be on.

Cheers all.