[meteorite-list] R Chondrites and Magnetism

[Tom Knudson]

"extensive aqueous alteration on the R parent body"

Water in space? That sounds like a whole new subject! : ) 

Thanks, Tom
peregrineflier <><

----- Original Message ----- 
From: <bernd.pauli at paulinet.de>
To: <Meteorite-list at meteoritecentral.com>
Sent: Tuesday, May 31, 2005 11:48 AM
Subject: [meteorite-list] R Chondrites and Magnetism


> Tom concluded:
> 
> > So, most R's have enough metal to be
> > attracted to a powerful enough magnet
> 
> Careful, please. I'd like to add the little word "just",
> leave out the word "most" and replace it by "some":
> 
> > Some R's have  j u s t  enough metal to be
> > attracted to a powerful enough magnet ...
> 
> This sounds better because almost all the iron is oxidized and
> also FeNi (nickel-iron) is extremely rare (only some tens of parts
> per million!)
> 
> In his Cambridge Encyclopedia, O.R. Norton writes on p. 116:
> 
> "There is almost no free iron metal (a few grains here and there) ..."
> 
> > ... if I can find out why R's have so little metal.
> 
> Oxidation (water was the oxidizing agent):
> 
> Step 1: extensive aqueous alteration on the R parent body
> Step 2: dehydration (removal of water) + thermal metamorphism
> 
> 
> Best wishes,
> 
> Bernd
> 
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