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

From: Starsinthedirt at aol.com <Starsinthedirt_at_meteoritecentral.com>
Date: Thu, 27 May 2010 11:57:28 EDT
Message-ID: <addbe.61bc98f.392ff068_at_aol.com>

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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Received on Thu 27 May 2010 11:57:28 AM PDT