[meteorite-list] Chelyabinsk - IMB or SMB? The nomenclature of Melts.

From: Jim Wooddell <jimwooddell_at_meteoritecentral.com>
Date: Thu, 25 Apr 2013 17:29:23 -0700
Message-ID: <CAH_zgwHDGmGd2TcBgBB_KgSwOEGVrTkiwmO973UTdueQdpQd=w_at_mail.gmail.com>

 Hi All!
Just a point of information. I just read Dr. Rubin's paper, Multiple
melting in a four-layered barred-olivine chondrule with
compositionally heterogeneous glass from LL3.0 Semarkona
Whew! That's a title for a paper!
While we are on the subject of melts, I thought I'd point out this
paper. Enjoyed reading it the first time....actually understood some
of it and will read it once again after thinking about it for a while.
 You folks might enjoy reading it when you get a chance!
Thanks Alan!!



Jim Wooddell


On Wed, Apr 24, 2013 at 8:24 PM, Jim Wooddell <jimwooddell at gmail.com> wrote:
> Hi Jeff!
>
> To me, Impact Melt should mean total melt to liquid...no fragments of any
> kind. In the case of the classified S4, partial melting occurred,
> confirmed by fragments. Still, various flavors understandable especially at
> boundaries.
> Yep, I think nodules is the keyword that is questionable. Graphite "nodules"
> are found in Canyon Diablo, for example. Once they find large enough pieces
> of this meteorite, they might confirm nodules but they would not be abnormal
> or a special anomaly if they are impact melt.
>
> Jim
>
>
>
> On Wed, Apr 24, 2013 at 7:53 PM, Jeff Kuyken <info at meteorites.com.au> wrote:
>>
>> Definitely IMB although you will find variations within different stones.
>> Some will be shocked to the point of melt and others will not quite get
>> there. Personally I think IMB and SMB are the exact same terms as both are
>> "melt breccias" and shock is derived from impact.
>>
>> The official classification of Chely states: "A significant portion (1/3)
>> of
>> the stones consist of a dark, fine-grained impact melt containing mineral
>> and chondrule fragments."
>>
>> http://www.lpi.usra.edu/meteor/metbull.php?code=57165
>>
>> I personally don't think "nodules" is really the correct terminology
>> either.
>> They are just individuals / fragments of the same material shocked to a
>> higher degree in the parent body. For example... compare it to Gao. We
>> don't
>> call the IMB pieces, nodules. They are IMB individuals. The term "nodules"
>> would seem to me to be better reserved for things like "iron nodules" in a
>> stony Mesosiderite or a "Troilite nodule" in an iron meteorite.
>>
>> Good question Mike.
>>
>> Cheers,
>>
>> Jeff
>>
>> -----Original Message-----
>> From: meteorite-list-bounces at meteoritecentral.com
>> [mailto:meteorite-list-bounces at meteoritecentral.com] On Behalf Of Galactic
>> Stone & Ironworks
>> Sent: Thursday, 25 April 2013 10:42 AM
>> To: Meteorite List
>> Subject: [meteorite-list] Chelyabinsk - IMB or SMB? The nomenclature of
>> Melts.
>>
>> Hi List,
>>
>> We keep hearing about the "IMB nodules" that have been recovered -
>> these have an all-black lithology with no chondrules, shock veins, or
>> grey matrix material.
>>
>> However, these nodules were not created on impact. Had there been
>> such an impact, we would have a visible crater and the nodules would
>> be located in a radius directly adjacent to the crater amidst the
>> ejecta. Instead, these nodules were apparently created during the
>> fragmentation events that took place while the body was still in
>> atmospheric flight.
>>
>> If this is true, shouldn't these nodules be called "shock melt" and
>> not "impact melt" ?
>>
>> Is there any distinction in the official nomenclature between an
>> impact melt and a shock melt?
>>
>> Is it correct to continue using IMB in reference to these Chelyabinsk
>> specimens?
>>
>> Best regards,
>>
>> MikeG
>>
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>
>
>
> --
> Jim Wooddell
> jimwooddell at gmail.com
> 928-247-2675

-- 
Jim Wooddell
jimwooddell at gmail.com
928-247-2675

Received on Thu 25 Apr 2013 08:29:23 PM PDT