[meteorite-list] Mineral migration pattern in NWA 2977 lunar fleck of iron

[STARSANDSCOPES at aol.com]

Hi list,

This is not just a plug to look  at my micrographs of NWA 2977 Lunar.  

I have noted a pattern (in  some small iron flecks) that looks like a small 
version of Widmanstatten Pattern  or at least some kind of mineral migration 
pattern.  This is not in all  meteorite iron.  I note it rather infrequently.   
I am speaking  about iron in stone meteorites, not iron meteorites!

These patterns are  quite small as the magnification is often approaching 
2000X.  Revealing  this pattern requires a high polish (I use a 1/4 micron 
diamond slurry) and  reflected cross polarized light.

Recently, in a NWA 2977 lunar gabbro  thin section I spotted an iron fleck 
with this pattern.  This was a first  for me in a Lunar.  Not the first iron 
fleck in a Lunar, but the first with  a pattern.  

What is the consensus?  Is it a caused by a  process similar to what creates 
Widmanstatten?   I have had it  dismissed as a shock structure but I don't buy 
into that idea.  It is my  idea that heating of the iron removes evidence of 
the pattern just as occurs  with Widmanstatten and that is why it is rather 
rare.

This September  Meteorite Times has images of this NWA 2977 iron.   
http://www.meteorite-times.com/meteorite_frame.htm  In the menu to the left  click on 
Micro Visions.   Please let me know what you  think.

Thanks,  Tom Phillips  




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