[meteorite-list] Troilite inclusions

From: MexicoDoug_at_aol.com <MexicoDoug_at_meteoritecentral.com>
Date: Wed Jan 5 12:29:34 2005
Message-ID: <142.3c7c871d.2f0d7dee_at_aol.com>

En un mensaje con fecha 01/05/2005 12:13:08 AM Mexico Standard Time,
MexicoDoug escribe:

"It is much more believable to me that we start out with the elements
[reactants to form FeS] and then they react at the high temperatures in the foundry
planetesimal core. Thus the troilite very plausibly would be produced right
then and there in a 1:1 Fe-S ratio without looking for a more complicated
explanation."
 
This statement I made got me to thinking further. While I strongly support
it in response to Zelimir's scenario on "oxidation" and equilibration, and
the scenario of in situ troilite production in the planetesimals, it may be
partially moot since more relevant in the context of the question on how the
troilite formed in the first place, I think there actually is a very good
argument to say that the Troilite formed BEFORE the differentiated parent body
(e.g., planetesimal). This is easy to even support experimentally, although
indirectly!!
 
What the esteemed colleagues say or have said/measured on this issue? Merit
or part of the story at least?
 
This said, experimentally we simply need to consider the troilite content of
the chondrites relative to iron and nickel, considering them as precursors to
 the planetesimals - the most primative bla bla materials of the solar
disk.... Yup, just take a simple ratio or two. If the ratio is fairly similar
(and how interesting to see if it is more consistent with a particular
chondrite group along with the Fe/Ni ratios for added potential agreement!!), that
suggests to me that the miscibility-phase separation model reigns supreme as
the hypothesis for the spherical troilite inclusions. (And I am fairy sold
that at the high pressure the miscible phase is easy to get in protoplanet P-T
situations getting back to the phase diagrams.)
 
Makes one want to go back to graduate school:) or at least show up at the
Met Soc and Planetary science meetings and get a real technical education:).
 
Saludos, Doug
Received on Wed 05 Jan 2005 12:29:18 PM PST