If specimens are part of an observed fall and are very fresh looking, one
supposes (without absolute certainty) that the different individuals are
paired. If stones are found lying on the ground in an area that has yielded
few other meteorites, then one can also assume that they are paired, but the
certainty is lower. The probability can increase, however, if they are of a
rare type. But if stones are found in a region where there are overlapping
strewnfields or if some concentration mechanism has brought different
meteorites together, then we are less certain that they are paired even if
they are of an unusual type. We may say that they are probably paired
(particularly if they have similar textures, bulk compositions, terrestrial
ages, cosmic-ray expsosure ages, etc.), but the prudent thing to do (since
we generally don't have all of these data) is to treat them as separate
meteorites with separate numbers and let the pairing be a scientifically
derived conclusion, not a curatorial assignment.
Alan Rubin
Institute of Geophysics and Planetary Physics
University of California
3845 Slichter Hall
603 Charles Young Dr. E
Los Angeles, CA 90095-1567
phone: 310-825-3202
e-mail: [email protected]
website: http://cosmochemists.igpp.ucla.edu/Rubin.html
----- Original Message -----
From: "Mendy Ouzillou" <[email protected]>
To: "'Robert Verish'" <[email protected]>; "'Jeff Grossman'"
<[email protected]>; <[email protected]>
Sent: Sunday, February 17, 2013 3:13 PM
Subject: Re: [meteorite-list] Met Bulletin Update - EL's and OC's
Bob,
Sorry it took me so long to respond - the email got buried under a Russian
meteorite.
Your explanation is logical, but the classifiers did not mention these two
stones as being paired. Seeing as these were very likely found close to each
other (but perhaps subjected to different weathering conditions) they should
at a minimum be stated as paired. I know it is impossible to prevent the
explosion of numbers assigned for the reasons you stated below - I get that,
but at what point does it become too burdensome (rhetorical question)? How
do scientists know what numbers are paired together if the two
classifications do not state it that way (not rhetorical)?
Best,
Mendy
-----Original Message-----
From: Robert Verish [mailto:[email protected]]
Sent: Sunday, February 17, 2013 1:02 AM
To: 'Jeff Grossman'; [email protected]; Mendy Ouzillou
Subject: Re: [meteorite-list] Met Bulletin Update - EL's and OC's
One benefit of having two numbers is that it allows the classifier to
clarify the differences between the two stones in order to show the range of
variation among these paired EL stones. The difference in this case being
one stone has "Alabandite present", and the second stone was "Extremely
weathered showing only rare metal. Rare alabandite".
This would actually aid a subsequent classifier of another EL6 stone to be
able to pair that third stone to the other two. Otherwise that subsequent
classifier (not being aware of this variation) may be misled into thinking
that the third stone is unpaired.
When I first read Mendy's question about "assignment of NWA numbers", I
thought he was making reference to assignment of provisional numbers. These
are usually assigned before the stones are classified and if the stones have
any appearance of outwardly looking different to each other, the prudent
requester is wise to get a number for each stone.
Once a requester gets two numbers "assigned", it's not likely that a
classifier will get rid of one number. Where is the motivation if the
classifier will get more type-specimen by having each stone numbered.
If the classifier submits a classification for each numbered stone, the
NomCom will accommodate that classifier by "approving" both numbers.
Anything less, and the NomCom would be considered "unaccommodating".
Now, in defense of the classifier for not getting rid of one of the numbers,
I would say that the test lies in answering this question:
"What is the added-value in discarding a number?"
(Which is basically what Jeff Grossman was saying when he asked, "Why is
this a problem?")
Or stated another way:
"Is there any added-value in approving two numbers that were assigned to two
stones that were subsequently paired?"
For one answer to that question as it relates to these two EL6 stones, go to
the beginning of this post.
Bob V.
--- On Sat, 2/16/13, Mendy Ouzillou <[email protected]> wrote:
From: Mendy Ouzillou <[email protected]>
Subject: Re: [meteorite-list] Met Bulletin Update - EL's and OC's
To: "'Jeff Grossman'" <[email protected]>,
[email protected]
Date: Saturday, February 16, 2013, 8:51 PM
Because as I read it
the data for both specimens are the same within the margin of error
and the two specimens should share one number.
M
-----Original Message-----
From: [email protected]
[mailto:[email protected]]
On Behalf Of Jeff Grossman
Sent: Saturday, February 16, 2013 7:24 PM
To: [email protected]
Subject: Re: [meteorite-list] Met Bulletin Update - EL's and OC's
Why is this a problem? -jeff
On 2/16/2013 9:46 PM, Mendy Ouzillou wrote:
> Why are two consecutive numbers assigned to the same
group of stones.
EL6, two stones and same classifiers. I don't get it ...
>
> Mendy Ouzillou
>
> On Feb 16, 2013, at 10:20 AM, "Galactic Stone &
Ironworks" <[email protected]> wrote:
>
> Hi Bulletin Watchers,
>
> There are a handful of new approvals - all are NWA meteorites.
>
> Link -
http://www.lpi.usra.edu/meteor/metbull.php?sea=&sfor=names&ants=&falls
=&valids=&stype=contains&lrec=50&map=ge&browse=&country=All&srt=name&c
ateg=All&mblist=All&rect=&phot=&snew=1&pnt=Normal%20table&dr=&page=0
>
> Best regards,
>
> MikeG
>
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