This is not about enthusiasm or generations of scientists. This is
about specimen availability and curation. With extremely rare classes,
like lunar meteorites, scientists do try to obtain every specimen they
possibly can, and there has been a lot of work done on NWA meteorites.
However, with virtually all other types of meteorites, this is not the
case. For these, Antarctic meteorites receive much more attention
because the samples are well-curated and easily available.
As far as your and Ted's assertion that there is "bias..." You imply
that workers are choosing one specimen over another simply because of
where it comes from. I don't know of any scientist who would do that.
People tend to work on the material to which they have access, and avoid
making extra effort to purchase or search for other material unless that
have to. The simple fact is that access to NWA samples is relatively
poor. Many museums don't have large collections of NWAs (e.g., in the
United States, the SI, AMNH, FMNH), the reasons for which are irrelevant
to this discussion. Types specimens tend to be small even in
institutions that have them. I am not alone, I am sure, in reporting
that I have had serious difficulty getting research material for many
hot-desert meteorites (including those from Oman and NWA), but nearly
all my requests for Antarctic meteorites have been fulfilled. These are
the reasons that NWAs are relatively understudied and, I would argue,
less valuable to science in general.
jeff
On 2010-01-19 12:00 PM, Adam Hupe wrote:
Thank you, Ted for pointing out that a meteorite doesn't care where it lands. I
noticed that this bias concerning Antarctic versus NWA finds is disappearing
with the current generation of scientists. Years ago at the LPSC in Houston,
about one and ten papers concerning planetary meteorites mentioned NWA. The
last time I went to this conference, over half the papers that dealt with
planetary meteorites included NWA specimens. When talking to the up and coming
planetary scientists, I observed that they were equally enthusiastic about
specimens and have not developed any bias whatsoever.
I have seen both Antarctic and NWA specimens and I am equally impressed with
both. I saw a freezer and a nitrogen filled case full of Antarctic specimens at
the Antarctic Laboratory when I visited it a couple of years ago. I failed to
see a difference other than the the Antarctic pieces were treated much better
in the handling and preservation department. I observed heavy weathering on
most of the pieces but they were preserved in the same manner as the few fresh
pieces I saw. They just weathered differently then the NWA material with a lot
of evaporates and salt clinging to them. NWA material, on the other hand,
develops caliche deposits and really weathered examples tend to crack or
fragment. In my opinion, both locations are equally capable of producing fresh
and desirable specimens.
Best Regards,
Adam
----- Original Message ----
From: Ted Bunch<tbe...@cableone.net>
To: Jeff Grossman<jgross...@usgs.gov>;
Meteorite-list<meteorite-list@meteoritecentral.com>
Sent: Tue, January 19, 2010 7:54:23 AM
Subject: Re: [meteorite-list] Pairing discussion/questions
Jeff - your statement from below " Also, don't overlook the fact that
Antarctic meteorite have proven to be vastly more valuable scientifically
than NWA meteorites" is misleading and somewhat biased. Meteorites of the
various classes are nearly equally represented in the Antarctic and Desert
collections. Some classes are better represented from the desert
collections, for examples, brachinites, angrites, Martians and the Antarctic
collections have more acapulcoites, aubrites, and some carbonaceous. But,
the number of samples doesn't really matter.
The number of scientific publications "> 10X" means little in terms of
scientific significance. The use of Antarctic specimens is largely biased if
you consider the following:
1) NSF funded Antarctic samples are more easily obtained for research
compared with trying to obtain samples from collectors, dealers and
repository collections and they are usually prepared for instant study (thin
sections, cleaned, diced, boxed, etc.).
2) NSF has put pressure on various institutions to either publish more on
the 1000s of Antarctic meteorites, obtained with NSF funding, or lose
support for future Expeditions.
3) There is considerable bias among some researchers to not use Desert
samples for political reasons and the lack of exact find locations (Nomads
do not use GPS instruments, not that this means much). Some museums are
extremely biased against "dirty desert meteorites" and will not let them in
the door, thus depriving researchers for easy access to samples for study -
a very prominent Federally funded museum comes to mind.
4) The Japanese publish almost exclusively on their Antarctic meteorites,
not Desert specimens.
5) More and more research papers deal with both Desert and Antarctic
samples and that tact is becoming more prevalent with time as bias
diminishes and the reality of "desert significance" enters the mind set. I
don't know how you factor that into the "numbers game".
6) A shot at "more valuable scientifically" - if not for the valuable lunar
samples collected from the deserts, we would know much less about the Moon -
see the Korotev web site on Lunars. And, and we know a Hell of a lot more
about Mars from Desert Martians - See Irving web site on Martians.
Bottom line - geography has little to do with a meteorite's significance.
As a colleague of mine said "A meteorite doesn't care where it lands".
Regards, Ted
On 1/19/10 5:46 AM, "Jeff Grossman"<jgross...@usgs.gov> wrote:
Make your homework. How many different meteorites do we have from
Antarctica after a third of a century hunting and spending billions of
USD? 7000.
This statement, appearing in some of the recent emails, is wrong. There
are over 16,000 classified meteorites from the ANSMET expeditions, plus
a few thousand unclassified. Counting the Japanese, Chinese,European,
Korean, and minor collections, There ~27,000 classified Antarctic
meteorites, and probably close to 20,000 not yet classified (mostly in
the Japanese and Chinese collections). And where in the world did this
figure of billions of dollars being spent by the US to collect its
20,000 meteorites come from?
Also, don't overlook the fact that Antarctic meteorite have proven to be
vastly more valuable scientifically than NWA meteorites. They probably
occur as subjects of scientific publications at>10x the frequency as
NWA meteorites (I posted statistics on this some years ago, but can't
locate it at the moment). This is because the main masses are well curated.
Jeff
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Dr. Jeffrey N. Grossman phone: (703) 648-6184
US Geological Survey fax: (703) 648-6383
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Reston, VA 20192, USA
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