[meteorite-list] Weird inclusion in NWA 2086 CV3

From: Jason Utas <meteoritekid_at_meteoritecentral.com>
Date: Tue, 10 Aug 2010 13:54:40 -0700
Message-ID: <AANLkTimOpeeb6vyF9P4EXdke7ZbC5oJq-jFJFtseTb33_at_mail.gmail.com>

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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Received on Tue 10 Aug 2010 04:54:40 PM PDT