[meteorite-list] Chelyabinsk - slickensides or shock planes?

From: Malvin Bishop Jr <magbish3_at_meteoritecentral.com>
Date: Tue, 21 May 2013 10:41:46 -0400
Message-ID: <519B87AA.9000005_at_lowcountry.com>

Hi Bob, Jim, and list -

One of my Chelyabinsk specimens shows a feature where it appears
to be fractured along a weakened shock vein/point where melt had
filled the vein before the actual splitting apart. The melt is still
very evident covering a large portion of the fresh exposed matrix after
the specimen split in two.

In short, I tend to agree with Blaine.


Regards,
Mal




On 5/21/2013 10:29 AM, Jim Wooddell wrote:
> Hi Bob and all!
> I might be wrong in assuming, but your slickensides sounds like you
> are attempting to describe secondary fusion???
>
> We have lots of evidence in various meteorites where they broke apart
> for whatever reason at the weak boundaries. For example, Franconia
> area meteorites (some) break apart from both sides of a metal vein
> leaving three pieces...two chondrite fragments and an H-Metal
> "cornflake".
> It's sort of like looking at a bad weld through xray.
> How can you tell? Look at more and look closer. A 3D CT sort of scan
> that has become popular with Sutter's Mill or Dr. Agee's research on
> "Black Beauty" may reveal what you speak of. Just my thoughts.
>
> Kind Regards,
>
> Jim
>
>
> On Tue, May 21, 2013 at 7:06 AM, Bob King <nightsky55 at gmail.com> wrote:
>> Hi everyone,
>> Many pieces of broken Chelyabinsk specimens display what appears like
>> fusion crust over slickensides, but is that what it really is? I've
>> talked with Blaine Reed and he thinks we're seeing blackish shock
>> veins (planes really) where the meteorite split along a line of
>> weakness. He even mentioned a piece he's seen where a large shock vein
>> in the matrix leads directly to the broken, dark face. Assuming
>> Chelyabinsk shows both slickensides and shock vein planes, how do you
>> tell them apart?
>> Thanks for your thoughts.
>> Bob
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Received on Tue 21 May 2013 10:41:46 AM PDT