[meteorite-list] Weird inclusion in NWA 2086 CV3

From: Galactic Stone & Ironworks <meteoritemike_at_meteoritecentral.com>
Date: Wed, 11 Aug 2010 00:02:44 -0400
Message-ID: <AANLkTimH=Y3TCts5nE-0an+RB8Nok6Fmo1kGGh1144Fa_at_mail.gmail.com>

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 <meteoritemike at 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 <meteoritekid at 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 <jgrossman at 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.pauli at paulinet.de
>>>> <bernd.pauli at 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
>>>>>
>>>>>
>>>>>
>>>>> ______________________________________________
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>>>>>
>>>>>
>>>>
>>>> --
>>>> ______________________________________________
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>>>>
>>>
>>>
>>> --
>>> Dr. Jeffrey N. Grossman phone: (703) 648-6184
>>> US Geological Survey fax: (703) 648-6383
>>> 954 National Center
>>> Reston, VA 20192, USA
>>>
>>>
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>

-- 
------------------------------------------------------------
Mike Gilmer - Galactic Stone & Ironworks Meteorites
http://www.galactic-stone.com
http://www.facebook.com/galacticstone
------------------------------------------------------------

Received on Wed 11 Aug 2010 12:02:44 AM PDT