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

From: Malvin Bishop Jr <magbish3_at_meteoritecentral.com>
Date: Tue, 21 May 2013 17:51:11 -0400
Message-ID: <519BEC4F.3030409_at_lowcountry.com>

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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>>>
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Received on Tue 21 May 2013 05:51:11 PM PDT