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

From: Sean T. Murray <stm_at_meteoritecentral.com>
Date: Tue, 21 May 2013 11:24:31 -0400
Message-ID: <D0A5E5384EC94FF883131134BEF0F1E6_at_PlatinumII>

I've noticed the same thing... I think this is a laterally exposed shock
vein... sometimes they are crusted over, other times they are pretty fresh,
so you can see the size of the exposed plane...

http://www.fallingrocks.com/Collections/Chelyabinsk.htm (4th picture down,
top left of photo...)

It's hard to take a picture of because it is so reflective, but it it quite
a beautiful feature of this fall.

Sean.

-----Original Message-----
From: Sergey Vasiliev
Sent: Tuesday, May 21, 2013 11:16 AM
To: Michael Mulgrew
Cc: meteorite list
Subject: Re: [meteorite-list] Chelyabinsk - slickensides or shock planes?

Hi All,
Look at the two pictures of the same stone.

This is a fresh broken side with black shock veins on a very light matrix:
- http://sv-meteorites.com/gallery/chelybinsk/02.jpg

And this side is secondary crust over the shock vein:
- http://sv-meteorites.com/gallery/chelybinsk/01.jpg

You can find a lot of interesting things in Chelyabinsk ;-)

All the best,
Sergey

On Tue, May 21, 2013 at 4:59 PM, Michael Mulgrew <mikestang at gmail.com>
wrote:
> Bob,
>
> My piece is just over 5g, but it was broken off a slightly larger
> piece, probably less than 50g before it broke.
>
> Michael in so. Cal.
>
> On Tue, May 21, 2013 at 7:48 AM, Bob King <nightsky55 at gmail.com> wrote:
>> Michael and all,
>> I forgot to add that even small 2-3g Chelyabinsks show this same
>> slick, grey material coating their broken faces. Can slickensides form
>> on rocks this small?
>> Bob
>>
>> On Tue, May 21, 2013 at 9:43 AM, Michael Mulgrew <mikestang at gmail.com>
>> wrote:
>>> Bob, Jim, List,
>>>
>>> I have a small piece that displays the slickenside in 3 distinct
>>> locations; it's definitely not secondary fusion crust. Looking
>>> forward to hearing more on the subject.
>>>
>>> Michael in so. Cal.
>>>
>>> On Tue, May 21, 2013 at 7:29 AM, Jim Wooddell <jimwooddell at gmail.com>
>>> 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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>>>>
>>>>
>>>>
>>>> --
>>>> Jim Wooddell
>>>> jimwooddell at gmail.com
>>>> 928-247-2675
>>>> ______________________________________________
>>>>
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Received on Tue 21 May 2013 11:24:31 AM PDT