[meteorite-list] Micrograph gallery post Lunar crust and Lodranite

Thu May 27 11:57:28 EDT 2010

I know I look insane answering my self but while  sending NWA 2371 images 
to Carl (and more specifically, selecting which ones to  send) I made the 
observation that the dentrites are within an only slightly  altered existing 
matrix structure.  This means the material was not  completely melted/accreted 
but was heated to the point of melt with out total  alteration of the 
matrix.

So, as Carl suggested, some part of the  interior (although only less than 
a 1/4 mm) was getting quite hot.

Tom  Phillips

In a message dated 5/27/2010 9:27:21 A.M. Mountain Daylight  Time, 
Starsinthedirt at aol.com writes:
Thanks Carl,  I think you are right  but I  have grown shy of making large 
sweeping claims.  When ever  I do, I just  learn what I don't know.

I would say that in some  instances, melted  material from entry remains on 
the meteorite.   But as it has been long  accepted that the trailing edge 
of 
an oriented  stone can accrete some material,  this may not be a 
significant  
observation.  If I found this in all fresh  crust, then I would be  onto 
some 
thing.

A couple years ago I wrote a  Micro Vision  article for Meteorite Times 
Magazine called Crystals in the   Crust"  It was centered on NWA 2371 H4.  
I 
chose this  meteorite  because of the very cool inclusion on the edge of my 

sample.  Sort of  crystals in the crystals!  The image  clarity was not as 
good 
back then and  the focus seemed to be on the  inclusion structure and not 
the  
dentrites.

Perhaps I should  make an update to the NWA 2371 Gallery  post.  For now, 
any one  who wants to see a few of those "New" images, just  email me.  I 
will  
embed (Reduced!) several images and try to send one full  size as an  
attachment.  Due to file size only one full size file can be  sent  at a 
time and 
even at that, some of the ISP's will not allow a file  that  big.

Thanks for the interest.

Tom Phillips    

In  a message dated 5/27/2010 8:32:44 A.M. Mountain Daylight Time,  
cdtucson at cox.net  writes:
Tom,
On a serious note with regard to  the dendrites found in Lunar  fusion 
crusts.
This is not only  amazing to look at but, you may have stumbled  upon 
something of  significant importance here.
It has always been a chore to  determine  whether what appears to be fusion 
crust is actual fusion crust or   perhaps something else.
The choices include Fusion crust, desert varnish  and  weathering rind to 
name a few. 
In iron meteorites this  dendritic texture  is  proof of melting. Many 
irons 
display this  texture throughout the entire  meteorite again as proof that 
it was  once molten. 
Your discovery of this  texture found only on the exterior  of this lunar 
meteorite seems to be  sufficient proof that only the  exterior of this 
Lunar 
meteorite actually  melted?  As you point  out that this texture is only 
seen 
in the crustal  area of the  meteorite.
Although this may be an anomaly and may not occur in  all  fusion crust. 
One 
thing may be certain. If it does occur there maybe  melting  going on. This 
would be far different than what occurs in the  forming of a  desert 
varnish 
or a weathering rind.
So, in summary.  It seems to me this  could be a significant aid to our 
Scientific  community in initial determination  and analysis of what is 
going on  
with respect to fusion crusts. And ultimately  add to the proof that  the 
rock was once in space. What else would cause only the  exterior  portion 
of a 
rock to melt? Fusion crust is key in recognizing   meteorites and this new 
discovery may have just made recognition a whole  lot  easier. 
Perhaps all crusts could be checked at this great  magnification to  see if 
they too have this texture.
Even if this  texture is not always present  in crusts at least when it is, 

there would be no doubt about how it formed  and what it is.
This  could save valuable microprobe time as it does not cost  much money 
to  
look at the crust at a high magnification. If it has this texture  the  
Scientist knows he needs to continue to study. 
Back in the day. I  do  know that David Kring would always require that 
polished thin  sections would  always include the fusion crust area for 
observation.  So, is this a well kept  secret and scientists already look 
for this?  
It would be great to see how  often this texture actually does occur in  
crusts of stony meteorites. I know I  have thin sections with crust  but, 
no 
high power microscope. Tom, perhaps you  could lead the charge  on this. 
Maybe 
start a service to check crusts prior to  sending them  off to Scientists. 
This could weed out at least some of the  junk?  
Great job Tom.
Carl

--
Carl or Debbie   Esparza
Meteoritemax

---- Starsinthedirt at aol.com wrote:  
>  Hi List,  Paul (Meteorite Times) has worked  his magic  and set up two  
new 
> articles on my meteorite micrograph   gallery.
> 
>  The first is NWA 6075 Lodranite found   at
> 
>   http://www.meteorite.com/meteorite-gallery/articles/nwa-6075/
>  
>  
> The  second is a set of very high magnification  images of a Lunar  crust 
on 
> NWA  2977.  There really  are crystals in this  crust!   It can be found  
at   
> 
>   http://www.meteorite.com/meteorite-gallery/articles/nwa-2977/
>  
>  I  previously posted some of these shots on Face Book and  some of you 
may  
> have seen  them but many more have been  posted in my  gallery.
> 
> Please take a look and   comments are  appreciated!
> 
> Tom Phillips  
>  
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