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

From: Malvin Bishop Jr <magbish3_at_meteoritecentral.com>
Date: Tue, 21 May 2013 18:17:55 -0400
Message-ID: <519BF293.4080206_at_lowcountry.com>

Thank you, Anne, I was pretty sure I was correct in my opinion on this,
but verification by other esteemed list members NEVER hurts!

Copying my photo?... no harm, no foul. Taking liberties sometimes is a
good thing. :-)

Thanks again -
Mal


On 5/21/2013 6:10 PM, Anne Black wrote:
> Yes, Mal,
> I believe that what you are looking at on this picture is a fracture
> along a shock vein, it is patchy, it is not as shiny and it is not
> fibrous looking like a slickenside.
> I took the liberty of copying your picture and putting side by side with
> mine, I hope you don't mind.
> Look at the difference.
>
>
> Anne M. Black
> www.IMPACTIKA.com
> IMPACTIKA at aol.com
>
>
> -----Original Message-----
> From: Malvin Bishop Jr <magbish3 at lowcountry.com>
> To: meteorite-list <meteorite-list at meteoritecentral.com>
> Sent: Tue, May 21, 2013 3:51 pm
> Subject: Re: [meteorite-list] Chelyabinsk - slickensides or shock planes?
>
>
> This is what I was referring to in my previous email regarding one of my
> Chelyabinsk specimens showing 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
> very evident. Am I thinking correctly on this Mike, Sean, or whomever
> wishes to respond?
>
> http://s1300.photobucket.com/user/N68830/media/Chelyabinsk_fragment_zps1a7dfce6.jpg.html
>
>
> Mal
>
>
> On 5/21/2013 11:48 AM, Bob King wrote:
>> Hi Sean,
>> That photo shows it exactly!
>> Thanks,
>> Bob
>>
>> On Tue, May 21, 2013 at 10:24 AM, Sean T. Murray <stm at bellsouth.net>
> wrote:
>>> 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 06:17:55 PM PDT