[meteorite-list] KATOL (L6) is official

From: Jeff Grossman <jngrossman_at_meteoritecentral.com>
Date: Tue, 31 Dec 2013 20:04:09 -0500
Message-ID: <52C36989.9080908_at_gmail.com>

Can't resist doing some arm-chair science... usually a bad move, but oh
well... I'll probably end up retracting much of this speculation...

There IS something strange about this meteorite to me. I don't know how
good the XRF analysis is, but it is not what I would expect from an L
chondrite. These analyses show a 30-40% enrichment in Ca and Al
relative to Si over what an L chondrite should be, and siderophiles are
~20% too high as well. If these are accurate, then there has been
fractionation, suggestive of enrichment in low-melting components (which
is odd). Sodium does not fit this story, but it's a harder element to
analyze by xrf. I also agree that coarse poikilitic grains are hard to
explain by solid-state metamorpism, but they could also be derived from
relict chondrules. If this rock was melted to a large extent, I'd
expect it to be depleted in metal and sulfide. So I'm betting that the
whole system has experienced low-degree partial melting, and some of
these melts have infiltrated this particular chunk of
high-metamorphic-grade L chondrite.

I agree with Carl that this has hallmarks of what many people call a
type 7 chondrite. But the whole issue of how to draw lines (or if there
ARE lines) between primitive achondrites, type 7 chondrites, and
products of shock heating/melting is very fuzzy and tends to be highly
interpretive. In a sense, this is the same discussion that surrounds
Portales Valley, an ordinary chondrite that has also "been around the
block."

Here is an article on Katol that Laurence Garvie pointed me to:
http://www.geosocindia.org/abstracts/2013/feb/p151-157.pdf

Jeff

On 12/31/2013 6:33 PM, Jason Utas wrote:
> Hello Carl, All,
> The low standard deviation on Fa and Fs denotes a high degree of
> equilibration, not just "5 or 6." "Five or above" would be more
> accurate. The nearly absent chondrules and high Wo are at [or beyond]
> type 6. If you're a researcher who believes in type 7 chondrites,
> since not all do.
>
> Based upon similar observations, one would simply call Al Haggounia
> 001 an aubrite, or an EL3 if one were lucky enough to find an
> unequilibrated chondrule. The textural observations would be
> irrelevant. If we looked at other meteorites in a similar fashion,
> subgroups and textural designations would disappear.
>
> Since nomenclature blows back and forth, this is something of a
> semantic argument; as I understand it, the "poikilitic shergottite"
> you recently analyzed would have been a "lherzolite" only a few years
> ago, and no amount of discussion then or now would have changed that.
> And there is of course variation in analyses. NWA 5205 is paired with
> NWA 5421 and our NWA 6501. Which was supposedly paired with NWA 6283.
> Very distinctive material, with classifications ranging from LL3.2 to
> LL3.7 to H3.6.
>
> But you did note that the shergottite was poikilitic. So is Katol.
> This stone has been metamorphosed in a unique way for a chondrite, and
> its classification required a much greater degree of attention because
> of that. But the result does not reflect that. Just like Al
> Haggounia 001, the "aubrite." It's odd, and I do think that
> 'pigeonholing' is the right term to use here.
>
> Regards,
> Jason
>
> www.fallsandfinds.com
>
>
> On Tue, Dec 31, 2013 at 2:45 PM, Carl Agee <agee at unm.edu> wrote:
>> Mike, Andy, Jim,
>>
>> I don't have bias one way or another in the case of Katol, but looking
>> at the data in the write-up this is a clear-cut L6 chondrite -- no
>> ambiguity. There are chondrules albeit highly equilbrated, the
>> olivines are L6, the pyroxenes are L6, the oxygen isotopes are
>> L-chondrite. If there were no chondrules, high Wo and OC-type olivine
>> and pyroxene, then one could make the case for type 7. I'm just going
>> by the numbers given in the write-up, I haven't looked at this beyond
>> a quick glance in hand specimen, not an achondrite -- period.
>>
>> Carl
>> *************************************
>> 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 Tue, Dec 31, 2013 at 3:19 PM, Michael Farmer <mike at meteoriteguy.com> wrote:
>>> I was also under the impression that this was transitional likely between L
>>> chondrites and primitive achondrites.
>>> Michael Farmer
>>>
>>> Sent from my iPhone
>>>
>>> On Dec 31, 2013, at 3:15 PM, Andy Tomkins <rockdocta at gmail.com> wrote:
>>>
>>> With great respect and just to be a little bit controversial... With a high
>>> wollastonite content in the opx like that, sparse remnant chondrules and
>>> many of the other features, perhaps this might be a L7? An example of why
>>> there needs to be a clearer definition of what defines Type 6 from Type 7?
>>>
>>> Andy Tomkins
>>>
>>> On Wednesday, 1 January 2014, Andy Tomkins wrote:
>>>>
>>>>
>>>> On Wednesday, 1 January 2014, Carl Agee wrote:
>>>>
>>>> Hi Mike,
>>>>
>>>> No doubt an interesting meteorite! I guess I should qualify it by
>>>> saying the oxygen and the olivine and pyroxene geochem data are garden
>>>> variety EOC. I guess looks can be deceiving -- yet another testimony
>>>> to lab data being the "blind taste test".
>>>>
>>>> Carl
>>>> *************************************
>>>> 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 Tue, Dec 31, 2013 at 10:23 AM, Michael Farmer <mike at meteoriteguy.com>
>>>> wrote:
>>>>> Carl, the huge metal nodules, the large green crystals throughout the
>>>>> matrix, very odd meteorites, everyone who looked at it thought it was an
>>>>> achondrite, including many scientists.....
>>>>> I've never seen an L6 with white matrix and some pieces nearly green
>>>>> with crystals.
>>>>> Not your garden variety L6 for sure.
>>>>> Michael Farmer
>>>>>
>>>>> Sent from my iPad
>>>>>
>>>>> On Dec 31, 2013, at 10:14 AM, Carl Agee <agee at unm.edu> wrote:
>>>>>
>>>>>> Super write-up by Laurence Garvie, but strange that there was so much
>>>>>> mystery surrounding what turns out to be garden variety "L6", albeit a
>>>>>> nice fresh fall. I wonder why people thought it was "achondrite-ung"?
>>>>>> Oxygen and geochem are unequivocal EOC, no mystery at all.
>>>>>>
>>>>>> 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 Tue, Dec 31, 2013 at 9:06 AM, Jim Wooddell
>>>>>> <jim.wooddell at suddenlink.net> wrote:
>>>>>>> Nice GeoChem data. Interesting to see the XFR data included.
>>>>>>>
>>>>>>>
>>>>>>> Happy New Year!
>>>>>>>
>>>>>>> Jim Wooddell
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>>
>>>>>>> On 12/31/2013 8:14 AM, karmaka wrote:
>>>>>>>> Dear list members,
>>>>>>>> Katol is officially listed as an L6 in the Bulletin now!
>>>>>>>>
>>>>>>>>
>>>>>>>>
>>>>>>>> http://www.lpi.usra.edu/meteor/metbull.php?sea=Katol&sfor=names&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=58500
>>>>>>>> Happy new year 2014 to all of you!
>>>>>>>> Martin
>>>>>>>> ______________________________________________
>>>>>>>>
>>>>>>>> Visit the Archives at http://www.meteorite-list-archives.com
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>>>>>>>>
>>>>>>>>
>>>>>>>> -----
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>>>>>>>
>>>>>>>
>>>>>>> --
>>>>>>> Jim Wooddell
>>>>>>> jim.wooddell at suddenlink.net
>>>>>>> http://pages.suddenlink.net/chondrule/
>>>>>>>
>>>>>>>
>>>>>>> ______________________________________________
>>>>>>>
>>>>>>> Vis
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Received on Tue 31 Dec 2013 08:04:09 PM PST