[meteorite-list] Rocks From Space Picture of the Day - October 15, 2006

[Matt Morgan]

Ed:
This excerpt was taken from 
http://www.lpi.usra.edu/meetings/lpsc97/pdf/1342.PDF, "Esquel: 
Implications for Pallasite Formation Processes Based on the Petrography 
of a Large Slab"
by Ulff-Moller, F. 
<http://adsabs.harvard.edu/cgi-bin/author_form?author=Ulff-Moller,+F&fullauthor=Ulff-Moller,%20F.&charset=UTF-8&db_key=AST>; 
Tran, J. 
<http://adsabs.harvard.edu/cgi-bin/author_form?author=Tran,+J&fullauthor=Tran,%20J.&charset=UTF-8&db_key=AST>; 
Choi, B.-G. 
<http://adsabs.harvard.edu/cgi-bin/author_form?author=Choi,+B&fullauthor=Choi,%20B.-G.&charset=UTF-8&db_key=AST>; 
Haag, R. 
<http://adsabs.harvard.edu/cgi-bin/author_form?author=Haag,+R&fullauthor=Haag,%20R.&charset=UTF-8&db_key=AST>; 
Rubin, A. E. 
<http://adsabs.harvard.edu/cgi-bin/author_form?author=Rubin,+A&fullauthor=Rubin,%20A.%20E.&charset=UTF-8&db_key=AST>; 
Wasson, J. T., 1997 
<http://adsabs.harvard.edu/cgi-bin/author_form?author=Wasson,+J&fullauthor=Wasson,%20J.%20T.&charset=UTF-8&db_key=AST>

It summarizes how the Esquel parent body may have formed, resulting in a 
beautiful meteorite when slabbed. Granted, this is not Krasnojarsk, but 
it probably formed in a similar way.

"The largest slab available is that of Esquel
(belonging to Haag); the slab is ~90´36 cm
(surface area ~2900 cm2). Olivine is
volumetrically the most abundant phase;
angular grains range from submillimeter size
to 2.5 cm. Approximately 25 vol.% of the
olivine occurs in compact subrounded to
subangular masses ranging from 3´7 cm to
10´17 cm. The large olivine masses are
transected by thin veins of metallic Fe-Ni;
these veins presumably formed by the high pressure
injection of low-viscosity metal,
probably during an impact event. The large
olivine masses are probably fragments of
much larger (>>1 m) blocks from the mantle.
It seems likely that most of the small olivine
fragments were also produced during the
original crushing event, but we cannot rule
out a role by subsequent events. There are
relatively few olivine grains having sizes <1
mm and these tend to occur together in
patches; these may record late events
because the fine particles produced during
the initial crushing event may have been
consumed during (very limited)
recrystallization. There is no clear-cut
evidence of flow of the metallic liquid based
on the orientations of the individual olivine
grains."


E.P. Grondine wrote:
> Hi all - 
>
> Sorry for a second post on this meteorite, but...  
>
> This is a wonderful slicing job by someone.
>
> The contrasts in its components make this meteorite
> remarkable.  How did it form?  There must have been
> great temperature contrasts, and the materials are so
> well separated. It would be nice to have microscopic
> images of the boundaries.
>
> great meteorite, but unfortunately I'd rather have a
> new used car...
>
> good hunting,
> Ed
> Man and Impact in the Americas
>
> --- SPACEROCKSINC at aol.com wrote:
>
>   
>> http://www.spacerocksinc.com/October_15.html
>>
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-- 
===============
Matt Morgan
Mile High Meteorites
P.O. Box 151293
Lakewood, CO 80215 USA
http://www.mhmeteorites.com
ebay id: mhmeteorites