That's a Dark Inclusion (DI) as per my email yesterday about them. There are
a number of different types of them which have commonly and traditionally
been mistaken for other carbonaceous-type clasts.
Cheers,
Jeff
----- Original Message -----
From: "Galactic Stone & Ironworks" <meteoritem...@gmail.com>
To: "Jason Utas" <meteorite...@gmail.com>
Cc: "Jeff Grossman" <jgross...@usgs.gov>; "Meteorite-list"
<meteorite-list@meteoritecentral.com>
Sent: Wednesday, August 11, 2010 2:02 PM
Subject: Re: [meteorite-list] Weird inclusion in NWA 2086 CV3
Wow, see this photo -
http://www.meteorite-house.com/MHContentFiles/MHmetPix/PicStoneCHotherNWA208612.html
Andreas' specimen does have a clast like mine! Notice the close-up of
the clast in his piece. It is very similar to the light-colored
regions in my stone. There is even chondrule deformation.
:)
On 8/10/10, Galactic Stone & Ironworks <meteoritem...@gmail.com> wrote:
Hi Jason and List,
Jason makes a great point about this being an "inclusion within an
inclusion". These specimens were taken from a small, jagged, fragment
that was obviously a remnant of a larger mass. Before that mass
fragmented (either in flight, on impact, or through weathering), it
was presumably a whole stone with a more representative lithology of
this meteorite. This light-colored region with squashed chondrules
and it's brown "inclusion" was previously embedded in the larger
stone. It would have been great to see a slice of the whole stone
that this fragment came from.
As for being NWA 2086 or not, I would question it also if presented
with my initial post and photos. But, I did cut a larger batch of
this material and all of it (except for this fragment) looked exactly
like typical NWA 2086 - darker matrix, more spherical chondrules, more
colorful chondrules, CAI's, etc. Also, I asked my source about the
chain of provenance regarding this batch and I was told that it came
directly from a very respected source. I don't want to name drop, but
contact me off-list if curious. The provenance is very solid. So I
am very confident that this material is indeed NWA 2086.
The question in my mind now is about the brown inclusion - is it a
product of weathering/oxidation, or was it originally present in the
meteorite? If the latter, then what is it? This question will be
answered soon, because one List member has offered to thin-section
this material for me and another list-member with thin-section
experience purchased the largest piece. So, two different veteran
list members are going to make qualitative examinations and analysis
of these specimens in the future. And I hope they will share the
results with us.
Also, for those who might inquire, this "brown inclusion / light
lithology" material is sold out. I kept one slice and sold the
remaining pieces. All I have remaining are small crumbs and a few
sub-gram pieces that show some chondrules. The slice I kept will
likely become another thin-section, pending further discussion.
I did some looking on the web, and I found a single photo of NWA 2086
that has a clast that somewhat resembles the lighter lithology in my
specimens. In this linked photo, look in the lower left-hand portion
of the specimen, near the 7-oclock position. You will see a clast on
the edge that is a different lithology than the rest of the specimen.
The clast is similar in color to my specimens, but it lacks the
squashed ellipsoidal chondrules.
http://www.meteorite-house.com/MHContentFiles/MHmetPix/PicStoneCHotherNWA208611.html
I examined my slice under the microscope at 60x tonight, and the
matrix in the light-colored area looks "stippled". It appears to be
composed of tiny black dots set into a whitish background matrix.
Whatever it is, it is very fine-grained compared to the darker
lithology that is seen on the same specimen. I am glad there is the
boundary line and region of common NWA 2086 lithology in these pieces,
because it provides a good contrast for comparing the two lithologies.
Best regards,
MikeG
------------------------------------------------------------
Mike Gilmer - Galactic Stone & Ironworks Meteorites
http://www.galactic-stone.com
http://www.facebook.com/galacticstone
------------------------------------------------------------
On 8/10/10, Jason Utas <meteorite...@gmail.com> wrote:
Hello Jeff, All,
The only reason that I assumed that this slice *might* be a piece of
NWA 2089 is because of that "dark corner" - it's the only part of this
stone that looks *like* NWA 2086.
The light lithology that you say looks like NWA 2086 looks very unlike
other samples of 2086:
http://www.aerolite.org/prizes/nwa-2086.htm
http://www.meteoriteguy.com/catalog/nwa2086.htm
http://www.meteorite-times.com/Back_Links/2008/march/Accretion_Desk.htm
So what we're looking at here, if it's a piece of NWA 2086, is a slice
comprised almost entirely of a light clast that is in no way typical
of most NWA 2086 specimens.
That strange brown thing that everyone's arguing about has chondrules
in it. If it has discolored differently than the rest of the
meteorite due to weathering or some other process, it would still
point towards that area being composed of a different material (why
would it weather differently if it were made of the same stuff?).
Given that it seems to have a lesser concentration of chondrules
within it (as opposed to the rest of the lighter clast), I would
assume that it is indeed foreign meteoric material.
But CV3's have strange C-type inclusions in 'em all the time. What's
the biggie?
...It's an inclusion within an inclusion? That's cool...
Regards,
Jason
On Tue, Aug 10, 2010 at 1:07 PM, Jeff Grossman <jgross...@usgs.gov>
wrote:
My money's on terrestrial weathering as the cause of the brown area,
although there is a clear lithologic boundary on the right side of
photo:
http://i268.photobucket.com/albums/jj24/Meteoritethrower/2086-slice-weird-1.jpg.
Jeff
On 2010-08-10 2:22 PM, Galactic Stone & Ironworks wrote:
Hi Bernd and List,
That's funny you mention that because Bob King also raised the
possibility of phyllosilicates. I took some more photos of the
specimen that show a better representation of what the specimen looks
like. You can also see a distinct boundary line between the typical
NWA 2086 lithology (darker matrix) and the strange "lighter colored"
lithology that the majority of this stone has. One area near the end
shows the type of matrix we expect from NWA 2086.
The brown inclusion does not show any features under it or through it,
except in one small spot where two chondrules appear to be immersed in
it, while the rest of the inclusion flows around the chondrules like a
river flows around islands.
http://i268.photobucket.com/albums/jj24/Meteoritethrower/endcut-519-a.jpg
http://i268.photobucket.com/albums/jj24/Meteoritethrower/endcut-326-1.jpg
http://i268.photobucket.com/albums/jj24/Meteoritethrower/2086-slice-weird-1.jpg
Best regards,
MikeG
------------------------------------------------------------
Mike Gilmer - Galactic Stone& Ironworks Meteorites
http://www.galactic-stone.com
http://www.facebook.com/galacticstone
------------------------------------------------------------
On 10 Aug 2010 15:21:51 UT, bernd.pa...@paulinet.de
<bernd.pa...@paulinet.de> wrote:
http://i268.photobucket.com/albums/jj24/Meteoritethrower/2086-inclusion.jpg
Hello All,
Michael G. wrote:
"So I am thinking that there must have been a surface fracture that
extended
down into
the interior of the stone. Weathering products intruded through this
crack
and the brown
'inclusion' is probably just a clay-like replacement mineral."
"clay-like" => phyllosilicates are clay minerals!
.. and *if* it is preterrestrial, this might be an extended
area of phyllosilicates, saponite, smectite or something!
Cheers,
Bernd
______________________________________________
Visit the Archives at
http://www.meteoritecentral.com/mailing-list-archives.html
Meteorite-list mailing list
Meteorite-list@meteoritecentral.com
http://six.pairlist.net/mailman/listinfo/meteorite-list
--
______________________________________________
Visit the Archives at
http://www.meteoritecentral.com/mailing-list-archives.html
Meteorite-list mailing list
Meteorite-list@meteoritecentral.com
http://six.pairlist.net/mailman/listinfo/meteorite-list
--
Dr. Jeffrey N. Grossman phone: (703) 648-6184
US Geological Survey fax: (703) 648-6383
954 National Center
Reston, VA 20192, USA
______________________________________________
Visit the Archives at
http://www.meteoritecentral.com/mailing-list-archives.html
Meteorite-list mailing list
Meteorite-list@meteoritecentral.com
http://six.pairlist.net/mailman/listinfo/meteorite-list
______________________________________________
Visit the Archives at
http://www.meteoritecentral.com/mailing-list-archives.html
Meteorite-list mailing list
Meteorite-list@meteoritecentral.com
http://six.pairlist.net/mailman/listinfo/meteorite-list
--
------------------------------------------------------------
Mike Gilmer - Galactic Stone & Ironworks Meteorites
http://www.galactic-stone.com
http://www.facebook.com/galacticstone
------------------------------------------------------------
______________________________________________
Visit the Archives at
http://www.meteoritecentral.com/mailing-list-archives.html
Meteorite-list mailing list
Meteorite-list@meteoritecentral.com
http://six.pairlist.net/mailman/listinfo/meteorite-list
______________________________________________
Visit the Archives at http://www.meteoritecentral.com/mailing-list-archives.html
Meteorite-list mailing list
Meteorite-list@meteoritecentral.com
http://six.pairlist.net/mailman/listinfo/meteorite-list
