[meteorite-list] [AD]: NWA 8276 - the "NOT SO" ordinary chondrite L3.00/W1 (and the start of an interesting discussion?)

Mon Mar 10 20:23:01 EDT 2014

Carl,

Your comments and questions are always welcome and I am already looking into it ...

Can you comment on the shock question below?

Mendy Ouzillou

----- Original Message -----
> From: Carl Agee <agee at unm.edu>
> To: Mendy Ouzillou <ouzillou at yahoo.com>
> Cc: kashuba <mary.kashuba at verizon.net>; Met-List <meteorite-list at meteoritecentral.com>; Adam Bates <sales at bcmeteorites.com>
> Sent: Monday, March 10, 2014 5:18 PM
> Subject: Re: [meteorite-list] [AD]: NWA 8276 - the "NOT SO" ordinary chondrite L3.00/W1 (and the start of an interesting discussion?)
> 
> Probably none of my business, but I would have some thin sections
> made. We did that for NWA 7731 for research and they are spectacular.
> The porphyritic chondrules -- dazzling and crystal clear!
> 
> Carl Agee
> *************************************
> Carl B. Agee
> Director and Curator, Institute of Meteoritics
> Professor, Earth and Planetary Sciences
> MSC03 2050
> University of New Mexico
> Albuquerque NM 87131-1126
> 
> Tel: (505) 750-7172
> Fax: (505) 277-3577
> Email: agee at unm.edu
> http://meteorite.unm.edu/people/carl_agee/
> 
> 
> 
> On Mon, Mar 10, 2014 at 6:13 PM, Mendy Ouzillou <ouzillou at yahoo.com> 
> wrote:
>> 
>> 
>>  John,
>> 
>>  That is a great question and one that deserves an educated response. I will 
> do my best, but hopefully Carl can chime in.
>> 
>>  We went back and forth on listing the shock for this stone and ultimately 
> felt it would be confusing. Shock equals heat and this stone being a 3.00 has 
> had no thermal metamorphism. It is possible that its shock value is as high as 
> S2 but as I understand it there is no way to reliably measure shock in such a 
> low petrologic state as 3.00.
>> 
>>  Best!
>> 
>>  Mendy Ouzillou
>> 
>> 
>> 
>>> ________________________________
>>>  From: kashuba <mary.kashuba at verizon.net>
>>> To: 'Mendy Ouzillou' <ouzillou at yahoo.com>; 
> 'Met-List' <meteorite-list at meteoritecentral.com>; 'Adam 
> Bates' <sales at bcmeteorites.com>
>>> Sent: Monday, March 10, 2014 5:09 PM
>>> Subject: RE: [meteorite-list] [AD]: NWA 8276 - the "NOT SO" 
> ordinary chondrite    L3.00/W1 (and the start of an interesting discussion?)
>>> 
>>> 
>>> Mendy, Adam, List,
>>> 
>>> Congratulations on discovering this special rock.  I saw it in 
> Adam's room
>>> in Tucson and we talked about it.  A 3.00 calls to every collector.  But
>>> there was no shock rating so I was reluctant to buy.  There was another
>>> valuable stone at another dealer that I passed on for the same reason.
>>> 
>>> Maybe I'm stuck in tradition, but when I'm considering a shocked 
> stone, I
>>> like to know how shocked it is.  When I'm considering a pristine 
> chondrite,
>>> I want to know how pristine.  That includes the effects of thermal
>>> metamorphism, aqueous alteration, terrestrial weathering and shock.  
> None of
>>> these is necessarily a deal breaker, but each plays into my seat of the
>>> pants cost-benefit deliberation.
>>> 
>>> Semarkona is considered unshocked and unequilibrated.  It is spectacular 
> in
>>> thin section.  It's hard to know what NWA 8276 L3.00 W1 would look 
> like.
>>> 
>>> Sincerely,
>>> 
>>> John Kashuba
>>> Bend, Oregon
>>> 
>>> -----Original Message-----
>>> From: meteorite-list-bounces at meteoritecentral.com
>>> [mailto:meteorite-list-bounces at meteoritecentral.com] On Behalf Of Mendy
>>> Ouzillou
>>> Sent: Monday, March 10, 2014 12:35 PM
>>> To: Met-List; Adam Bates
>>> Subject: [meteorite-list] [AD]: NWA 8276 - the "NOT SO" 
> ordinary chondrite
>>> L3.00/W1 (and the start of an interesting discussion?)
>>> 
>>> 
>>> 
>>> Hello everyone, The NWA desert continues to thrill us this with unique 
> and
>>> amazing specimens. NWA 8276 is just such a meteorite. It is the second 
> L3.00
>>> and is "possibly" paired to NWA 7731. NWA 8276 features a 
> rich, black crust
>>> and a yellowish matrix densely packed with chondrules. Extensive 
> analysis by
>>> Dr. Carl Agee and Karen Ziegler support the 3.00 classification - a
>>> classification that indicates no heat or aqueous alteration of any kind 
> (at
>>> least as far as can be presently evaluated). In fact, this meteorite
>>> represents material from the earliest history of our solar system. Older
>>> than CAIs? Not sure, but maybe Dr. Agee can chime in.
>>> 
>>> The complete writeup may be found here:
>>> http://www.lpi.usra.edu/meteor/metbull.php?sea=3.00&sfor=types&ants=&falls=&
>>> valids=&stype=contains&lrec=50&map=ge&browse=&country=All&srt=name&categ=All
>>> &mblist=All&rect=&phot=&snew=0&pnt=Normal%20table&code=59487
>>> 
>>> 
>>> The
>>> explanation how this meteorite was identified makes for a short but very
>>> good read (from MetBull):
>>> "Adam Bates identified this meteorite from images he received as a 
> possible
>>> pairing to NWA 7731,even though they came from a different Moroccan
>>> meteorite dealer. Both pieces were then purchased within a few weeks of 
> each
>>> other in October 2013."
>>> 
>>> Adam Bates and I partnered on half the stone and anxiously awaited for 
> Dr.
>>> Agee's results. It was not a given that this was in fact paired with 
> NWA
>>> 7731, especially since the meteorite was bought from a completely 
> different
>>> dealer. There were visual differences in the stone that led Carl to
>>> initially believe that 8276 may be different from 7731. In the end, the
>>> classification came back as L3.00 but with enough differences to state 
> that
>>> NWA 8276 is "possibly" paired with NWA 7731. The terrestrial 
> weathering is
>>> also
>>> quite low and only an W1.
>>> 
>>> Many people state meteorites as being rare, but some are certainly rarer
>>> than others. The type 3.00 classification has only been given to 3
>>> meteorites: Semarkona (LL3.00), NWA 7731 (L3.00) and now NWA 8276 
> (L3.00).
>>> Here is an excerpt from Dr. Agee's FB discussion with David Weir on 
> the 3.00
>>> classification and the rarity of this material:
>>> "Grossman and Brearley (2005)define the subtypes less than 3.2 as 
> 3.15,
>>> 3.10, 3.05, and 3.00. [This scale is] primarily based on the mean value 
> and
>>> standard deviation of Cr2O3 in coarse ferroan chondrule olivines. 
> I'm not
>>> saying that the Grossman and Brearley scheme is the ultimate, but it is
>>> simply the standard currently. What will really improve the subtype 3
>>> nomenclature (and understanding of unequilibrated OCs) are more samples 
> like
>>> NWA 7731 and NWA 8276. Up to now we have so few in the 3.15-3.00 range 
> that
>>> the statistics of small numbers makes it hard to have meaningful
>>> subdivisions. I would gladly use an even finer scale (i.e. 3.01, 3.02, 
> 3.03,
>>> 3.04 etc.) if it were actually established. The Grossman and Brearley 
> (2005)
>>> scale is the only one that exists with any sort of sampling to anchor 
> it. We
>>> just have too few samples to establish a finer scale. And when one 
> starts
>>> talking about all the possible subtle differences around 3.00, I'm 
> not sure
>>> if a
>>> numerical, linear scale would even make sense. The nice thing about
>>> discovering more of these very low type 3s is that more  will hopefully 
> be
>>> available for research. Semarkona, because much of it  resides in India 
> and
>>> some at the Smithsonian (I believe), it is hard to get a hold of. For
>>> example we only have a couple thin sections of Semarkona at UNM -- not 
> even
>>> a tiny fragment!"
>>> 
>>> 
>>> The items for sale (and pricing) may be viewed at
>>> http://www.meteoritesusa.com/meteorites-for-sale-4/nwa-8276-l3-00-w1-a-remar
>>> kable-and-scientifically-important-meteorite/
>>> 
>>> 
>>> The photos have had no color manipulation and represent the true colors 
> of
>>> this meteorite as viewed under studio lighting (5500K). Anyone 
> interested in
>>> acquiring material may contact me by responding privately to this email 
> or
>>> to Adam Bates (sales at bcmeteorites.com). The transaction and any 
> associated
>>> details will be kept strictly confidential.
>>> 
>>> 
>>> Regards,
>>> 
>>> Mendy Ouzillou
>>> ______________________________________________
>>> 
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> 
>>> 
>>> 
>>> 
>>> 
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