[meteorite-list] Fusion crusts on stony meteorites

From: jbaxter112 at pol.net <jbaxter112_at_meteoritecentral.com>
Date: Fri, 23 Mar 2007 00:15:55 -0400 (EDT)
Message-ID: <39792.10.250.10.1.1174623355.squirrel_at_sq05.pol.net>

Hi Mike and Darren,

I probably would have had that response too without the benefit of turning
these over in my hands and looking at them in 3 dimensions. I'm 99% sure
that if you held these in your hands, and especially if you looked at them
under the microscope, you would conclude the black areas are crust. This
scan of reverse side of the 28 gram slide may be more convincing:

http://img.photobucket.com/albums/v614/CaneySprings/NWA2826LL528gmMarcinCimalareversecl.jpg

I also made an oblique photo of the other slice which shows the contiguity
of the area with the fragments(lower right hand corner of the top photo,
lower hand corner left of the lower photo) with the rest of the crust.

http://img.photobucket.com/albums/v614/CaneySprings/NWA282648gmobliqueview-1.jpg

http://img.photobucket.com/albums/v614/CaneySprings/NWA282648gmobliqueviewreverse-1.jpg

However, I'm sure I have about a thousandth the expertise of either of you
so I could well be off base.

Best wishes,
Jim

> I agree, I dont think that it is fusion crust, more
> likely a brecciated section on the edge of the
> meteorite.
> Michael Farmer
> --- Darren Garrison <cynapse at charter.net> wrote:
>
>> On Thu, 22 Mar 2007 21:58:51 -0400 (EDT), you wrote:
>>
>> >Hello Berndt et al.,
>> >
>> >I thought you and the list members might find
>> interesting a phenomenon
>> >that was shown to me by Marcin Cimala. In cutting
>> an LL5 he found areas
>> >where thick crust had built up and actually
>> incorporated within the crust
>> >small angular fragments of relatively unaltered
>> meteorite. Here are scans
>> >of a slice I obtained from Marcin:
>> >
>>
>>http://img.photobucket.com/albums/v614/CaneySprings/NWA2826LL528gmMarcinCimala.jpg
>> >
>>
>>http://img.photobucket.com/albums/v614/CaneySprings/NWA2826LL528gmMarcinCimalacloseup.jpg
>> >
>> >I assume that these fragments were dislodged late
>> in flight while the
>> >crust was still liquid but too late to be melted or
>> thermally altered.
>>
>> I would think that is just a darker clast in the
>> rock that happened to be only
>> on the outer edge of that slice.
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Received on Fri 23 Mar 2007 12:15:55 AM PDT