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Re: iridium



Poor guy. That is about 10-100 tons of iridium.

On Sun, 10 May 1998, Earl Wood wrote:

> 
> 
> James R. Cunningham wrote:
> 
> > > At 08:28 PM 5/6/98 -0700, Earl Wood wrote:
> > > >     I would like to know if anyone has calculated the amount of Iridium
> > > >needed to
> > > >cover the entire earths surface , at the depth associated with the K C
> > > >boundary ? and if so does anyone have these figures , or a reference
> > > >that would be available to Joe citizen ?
> >
> > This is from memory, so is untrustworthy.  I believe I read some years
> > ago that assuming iridium concentrations typical of other meteors, it
> > would have taken an asteroid about 5-8 miles in diameter to contain the
> > iridium needed to match measured amounts at the K-T boundary.
> >                         Best wishes,
> >                                 Jim
> 
>      In my efforts to find the answer to this question , I looked at the
> Alvarez work on this question and their figures state.......common meteorites
> have iridium of about 500 parts per billion, they calculated that the world
> wide iridium anomaly at about ( 0.5 million tons)to introduce that much 
> iridium
> would require a meteorite 10 kilometers in diameter ,
> slightly larger than the nucleus of Halley's comet . This was taken from their
> paper in
> Science magazine.  Just a refresher in case you are interested. Thanks for 
> your
> post
> I really appreciate any help I can Get..
>      Earl Wood
>      candles@jps.net
> 
> 
>