[meteorite-list] Types of twinning in chondrites?

[Jim Wooddell]

Thanks Melinda, Alan and Bernd and all!

My next question would have been; Would it be safe to say if I see 
polysynthetic twinning, odds are it's low-Ca cpx, but Melinda
pretty much answered this.
I have certainly seen this but the jury is out if I've seen other types 
of twinning while playing around on the scope.

Jim


On 2/22/2014 9:25 AM, Alan Rubin wrote:
> The most common type of twinning in chondrules in unmetamorphosed 
> chondrites is found in low-Ca clinopyroxenes.  It is polysynthetic 
> twinning -- it looks like the pyroxene grains have narrow stripes.  
> These disappear when temperatures go above 630 C or so and won't be 
> found in orthopyroxene.
> Alan
>
>
> Alan Rubin
> Institute of Geophysics and Planetary Physics
> University of California
> 3845 Slichter Hall
> 603 Charles Young Dr. E
> Los Angeles, CA  90095-1567
> phone: 310-825-3202
> e-mail: aerubin at ucla.edu
> website: http://cosmochemists.igpp.ucla.edu/Rubin.html
>
>
> ----- Original Message ----- From: "Jim Wooddell" 
> <jim.wooddell at suddenlink.net>
> To: <meteorite-list at meteoritecentral.com>
> Sent: Saturday, February 22, 2014 5:52 AM
> Subject: [meteorite-list] Types of twinning in chondrites?
>
>
>> Hi all,
>>
>> I was wondering, for those that are experienced with petrology, what 
>> types of crystal twinning to do see the most in OC's?
>>
>> Thanks!
>>
>> Jim
>>
>> -- 
>> Jim Wooddell
>> jim.wooddell at suddenlink.net
>> http://pages.suddenlink.net/chondrule/
>>
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-- 
Jim Wooddell
jim.wooddell at suddenlink.net
http://pages.suddenlink.net/chondrule/