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

From: Graham Ensor <graham.ensor_at_meteoritecentral.com>
Date: Tue, 21 May 2013 20:23:06 +0100
Message-ID: <CAJkn+kYc0ZtoovzonYXVvCC=_tpvJGZGgjdXPQTBKmUiU+-aHg_at_mail.gmail.com>

hi Bob....to my knowledge the slickensides most likely form in the
original asteroidal body in space (large collision or impact) and then
are left in the small stones after the atmospheric breakup.

Graham

On Tue, May 21, 2013 at 3:48 PM, 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 03:23:06 PM PDT