[meteorite-list] Weird inclusion in NWA 2086 CV3

From: Jeff Kuyken <info_at_meteoritecentral.com>
Date: Wed, 11 Aug 2010 19:46:30 +1000
Message-ID: <E874C16707884F798A92CDD530FA255C_at_JeffPC>

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" <meteoritemike at gmail.com>
To: "Jason Utas" <meteoritekid at gmail.com>
Cc: "Jeff Grossman" <jgrossman at usgs.gov>; "Meteorite-list"
<meteorite-list at 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 <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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>>>>>>
>>>>>>
>>>>>
>>>>> --
>>>>> ______________________________________________
>>>>> Visit the Archives at
>>>>> http://www.meteoritecentral.com/mailing-list-archives.html
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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
> ------------------------------------------------------------
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Received on Wed 11 Aug 2010 05:46:30 AM PDT