[meteorite-list] Platinum is from outer space

[Michael Fowler]

Yes, and by extension, nearly all the other siderophile elements in  
the earth crust also came from meteorites.  This includes gold,  
nickel, cobalt, etc.

Mike Fowler
Chicago


> Hi David,
>
> Thanks for sharing this. It's very cool to think that the platinum
> around us is meteoritic. :)
>
> Best regards,
>
> MikeG
>
>
> On 7/31/09, David R. Vann <drvann at sas.upenn.edu> wrote:
>
> > Of general interest, perhaps - I was researching Komatiites, and  
> ran across
>
> > this-
>
> > Apparently all crustal platinum is from meteoritic deposits. So,  
> your
>
> > platinum
>
> > wedding band is made of meteorites...
>
> >
>
> > Contact me off-list if you are interested in a copy of this article.
>
> >
>
> > Nature Vol 460|30 July 2009
>
> > Progressive mixing of meteoritic veneer into the early
>
> > Earth’s deep mantle
>
> >
>
> >
>
> > Wolfgang D. Maier1, Stephen J. Barnes, Ian H. Campbell, Marco L.  
> Fiorentini,
>
> > Petri Peltonen,
>
> > Sarah-Jane Barnes & R. Hugh Smithies
>
> >
>
> > synopsis from R&D daily
>
> >
>
> > A research program aimed at using platinum as an exploration guide  
> for
>
> > nickel
>
> > has for the first time been able to put a time scale on the planet's
>
> > large-scale convection processes.
>
> >
>
> > The research is reported in a Nature paper titled "Progressive  
> mixing of
>
> > meteoritic veneer into the early Earth's deep mantle".
>
> >
>
> > Report author CSIRO Minerals Down Under Flagship researcher Dr  
> Stephen
>
> > Barnes
>
> > said the study group collected a large body of data on the  
> platinum content
>
> > of
>
> > lava flows called komatiites, which host some of the world's major  
> nickel
>
> > deposits.
>
> >
>
> > "We found that the oldest komatiites have the lowest platinum  
> content," Dr
>
> > Barnes said. "The platinum content gradually increases from about  
> 3.5
>
> > billion
>
> > years to 2.9 billion years ago. "This tells us that the deep  
> source where
>
> > the
>
> > komatiite came from, down near the boundary between the Earth's  
> core and
>
> > mantle, was gradually gaining platinum over time".
>
> >
>
> > The paper's authors now think they know why.
>
> >
>
> > "When the Earth's core formed, it took all the available platinum  
> with it,
>
> > leaving the mantle and crust with none," Dr Barnes said.
>
> >
>
> > "Following that, a steady rain of meteorites created the so-called  
> Late
>
> > Veneer—a