[meteorite-list] Planetary Pairings...some facts, some guesses

From: Martin Altmann <altmann_at_meteoritecentral.com>
Date: Wed, 29 Sep 2010 14:32:40 +0200
Message-ID: <007301cb5fd2$68ef1160$3acd3420$_at_de>

Hi Zelimir,

no worries,
was a simple typo, digittwiddler.

I meant NWA 3136 not NWA 3163.

NWA 3163/4483/4881 are paired and beautiful.


> who gave it for
>classification to different institutes,

No, all three were classified by Irving, Kuehner et al.

To us it makes often most sense, if we by our own suspect a pairing,
to give it there, where the classification of the first stone was made.

Anyway the top classifiers of the world are in close contact which
each-other.
Lunars and Martians are so rare, but also so important, that possible
pairings will be always cleared.
But it wouldn't make much sense, to give such a stone to an university,
without any experiences with such materials or to a college - because at
best they would end anyway again in the labs, of those, who had already all
lunars in their hands - and that is good so.

The whole NWA 5400 debate would e.g. have been unnecessary, if the suspected
pairings would have been handed in there, where 5400 was classified.

Best!
Martin

-----Urspr?ngliche Nachricht-----
Von: Zelimir Gabelica [mailto:Zelimir.Gabelica at uha.fr]
Gesendet: Mittwoch, 29. September 2010 13:25
An: Martin Altmann; meteorite-list at meteoritecentral.com
Betreff: Planetary Pairings...some facts, some guesses

Hi Martin, list,

NWA 3163 IS paired with NWA 4483 and 4881 (Korotev & Met. Bull.).
All the other unpaired from your compilations are correct.

This being and, on another note, because NWA 4483
was quasi certified having been found in Algeria
(Ralew and also Met. Bull. database), I guess it
is also so with its two pairings?
In Met. Bull. database, both NWA 3163 and NWA
4881 are reported coming from "Algeria or Mauritania".
Wouldn't it then be right to claim that all three come from Algeria ?

Would this conclusion hold based on an as simple statement ?
Not sure....

Let's now consider more in depth the above (rather simple) pairing issue.
Here are the purchase circumstances for the three
paired meteorites (MetBull database):

NWA 3163: Purchased by Hup? in Ouarzazate, in 2005
NWA 4483: Purchased by Ralew in Erfoud, in 2006
NWA 4881: Purchased by Ralew in Ouarzazate, in 2007

This suggests that a Lunar found "somewhere
between Mauritania and Algeria" or "somewhere in
between ?" (these 2 countries do share a common
border), pre 2005, was brought to Ourzazate where
sold to two different dealers (probably by two
different vendors) in an interval of two years,
while the same meteorite was also sold (probably
by a third person) to Ralew in Erfoud in 2006.
Excellent example of a meteorite walking from one
vendor to another, from one place to another,
with time, to finally reach different dealers.

Whatever it be, it is amazing that science is
today able to (start to) reconstitute (partly)
this meteorite and define its identity and status
from an independent sophisticated analysis of the
3 NWA samples that wandered independently in
space and time, ending up independently in the
basket of different dealers who gave it for
classification to different institutes, who
eventually came into conclusion that it is the
(probably) the very same meteorite.

This is a real performance and confirms that Greg
Hup? is right when he decides to have every
fragment of an important meteorite probed for its O isotopic abundance.
But...what a waste of time and money!
Wouldn't it be far more simple that once a
meteorite is found, all the fragments are
assembled by the finder and sold (or distributed
among other vendors) under the same provisional
code until it is eventually classified ?
We all know (from our early debating this topic)
that this is totally illusory because money and
personal interests would predominate over scientific interests.

And, by the way, the "almost happy end" regarding
this Lunar pairing issue was likely because it is
a Lunar that is often readily classified by
institutes.....but this possibly suggests that
most of the NWA ordinary chondrites (or even
achondrites) will never get the chance to have
their pairing status defined, simply because it
is less interesting to study them.

This perhaps explains the large number of NWA's
found and their relatively low tkw's....

Large speculative debate....

Take care,

Zelimir


At 01:07 29/09/2010, you wrote:
>Though I wrote it privately... ;-)
>
>But especially the lunars and Martians, which are always checked, if they
>are paired,
>there one can see well, that there is no rule, that no stone comes alone
>from NWA.
>
>Some have immediate pairings, from some every few years another sample
>surfaces,
>others there suddenly after a long break of many years more comes to light.
>
>
>So far unpaired NWA-Martians are:
>
>NWA 817
>NWA 856
>NWA 998
>NWA 1195
>NWA 1669
>NWA 1950
>NWA 2046
>NWA 2626
>NWA 2646
>NWA 2737
>NWA 2800
>NWA 3137
>NWA 4222
>NWA 4468
>NWA 4480
>NWA 4797
>NWA 5029
>NWA 5289
>NWA 5718
>NWA 5789
>NWA 5990
>NWA 6162
>
>So from the 28 different NWA-Martian, there are only 6 which build up a
>pairing group.
>22 are unpaired.
>
>Moon:
>
>Unpaired:
>
>NWA 482
>NWA 2200
>NWA 2998
>NWA 3163
>NWA 4734
>NWA 4819
>NWA 4884
>NWA 4898
>NWA 4932
>NWA 5000
>NWA 5153
>NWA 5207
>NWA 5744
>
>(The NWA 773 - Anoual I lumped together)
>
>
>So there 13 out of 19 unpaired.
>
>
>Well, and as far as the general rareness of NWAs compared to historical
>finds/falls is concerned.
>To me it seems, that the NWAs in general - also if you take paired numbers
>together - have on average a much smaller tkw than non-desert-finds. Well
>one would need some ling winter-evenings to verify that.
>
>Though sometimes - tiny fragments, without any crust, non-magnetic
>achrondites - e.g. some of the Martians from the NWA 2975 - or if you
>remember the tiny peas of the NWA 1068 group, looking like sandstone.
>For me it's a sheer riddle, how you can find such pieces at all!
>Crawling on my knees through the field, I wouldn't find them.
>
>Or cause we just had it NWA 4485, NWA 4472 - all around a fat weathering
>crust, white like chalk.
>Who the heck would ever pick up such a stone from the field and suspect it
>to be a meteorite?
>
>It is truly amazing, what the hunters do down there.
>
>Best!
>Martin

Prof. Zelimir Gabelica
Universit? de Haute Alsace
ENSCMu, Lab. GSEC,
3, Rue A. Werner,
F-68093 Mulhouse Cedex, France
Tel: +33 (0)3 89 33 68 94
Fax: +33 (0)3 89 33 68 15
Received on Wed 29 Sep 2010 08:32:40 AM PDT