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

From: Carl Agee <agee_at_meteoritecentral.com>
Date: Mon, 10 Mar 2014 18:18:27 -0600
Message-ID: <CADYrzhpJ30ZYVL2ZQ2G0K9DsZg_wRtc+4Oxrug=x9fZYntNAtA_at_mail.gmail.com>

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
>>______________________________________________
>>
>>Visit the Archives at http://www.meteorite-list-archives.com
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>>
>>
>>
>>
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Received on Mon 10 Mar 2014 08:18:27 PM PDT