[meteorite-list] Northwest Africa Falls - Question

From: Dave Gheesling <dave_at_meteoritecentral.com>
Date: Sun, 18 Jan 2009 22:17:22 -0500
Message-ID: <9A77D732D1FE4B73B01138807BE1AE46_at_meteorroom>

Jim & All,
I'd have to agree, Jim, for quite a good many Bensour AND Oum Dreyga
individuals. The pieces I've seen with some oxidation seemed to have hit
the market at substantially later dates, which would be consistent with
having been recovered at some later point...perhaps.
Dave
www.fallingrocks.com

-----Original Message-----
From: meteorite-list-bounces at meteoritecentral.com
[mailto:meteorite-list-bounces at meteoritecentral.com] On Behalf Of
jbaxter112 at pol.net
Sent: Sunday, January 18, 2009 9:33 PM
To: jgrossman at usgs.gov
Cc: meteorite-list at meteoritecentral.com
Subject: Re: [meteorite-list] Northwest Africa Falls - Question

Hi Jeff,

I believe your data about the story but I am surprised. I have to say that
the pieces of Bensour I received are so pristine and rust free, both crust
and interior, that of all the 'falls' listed I would have guessed that
Bensour would have been the LEAST likely to have sat around any length of
time after it fell. Just an observation.

Cheers,
Jim Baxter

> Please don't misunderstand me... I just said there was reason to be
> suspicious from a statistical point of view, and of course there is an
> obvious financial motive. But I was not saying that I thought any of
> the fall stories were false, since I never even tried to assess them.
>
> So let's see if there is consensus to be found here on these recent
> falls. I did a simple reading of the fall accounts and used google
> scholar to search for cosmogenic nuclide or other supporting data.
> Here are my zeroth order ratings of each fall story:
>
> Chergach - highly likely
> Bassikounou - highly likely
> Benguerir - probable
> Beni M'hira - probable
> Bensour - questionable
> Oum Dreyga - questionable
> The new one - nothing to evaluate
> Maigatari-Danduma - ignore since it isn't really in the NWA region
>
> Bensour is such a weak story that I'm leaning towards changing it from
> a fall to a find in my database, which is basically what the MetBull
> article also said. I'm not even sure how it got listed as a fall. Do
> any of you take issue with this?
>
> The Oum Dreyga story also has strange elements. The witnesses saw it
> "falling on ... [the] mountains," which probably means that if there
> was a real fall, it was very distant. The fact that many of the
> stones were weathered also raises my doubts. So I rate this as weak.
> Anybody want to take the stand on Oum Dreyga's behalf? Or argue
> against any of the ones I called probable or highly likely?
>
> If two are really finds and one is eliminated because it is really not
> in this region, then we are left with 4 in the 2000s decade, plus the
> new one which remains to be seen. Four is certainly a more palatable
> number than eight from a blind statistical point of view, neglecting
> other sociological factors.
>
> Jeff
>
> Dr. Svend Buhl wrote:
>> Interesting debate. Reminds me on the good old days of the Acedemie
>> Francaise, the days before Biot and Chladni, where scientists doubted
>> the accounts of local eyewitnesses on rocks falling from the skies
>> for sociological reasons.
>>
>> As far as I am concerned, I still trust the people who measured e.g.
>> the cosmogenic radionuclides of the meteorites produced by these
>> recent falls. I absolutely doubt that the Swiss or French labs who
>> worked on these stones made up their results just to make them fit
>> the newspaper reports and eyewitness accounts.
>>
>> Svend Buhl
>>
>>
>> ----- Original Message ----- From: "Jeff Grossman"
>> <jgrossman at usgs.gov> To: "Meteorite-list"
>> <meteorite-list at meteoritecentral.com>
>> Sent: Saturday, January 17, 2009 11:27 PM
>> Subject: Re: [meteorite-list] Northwest Africa Falls - Question
>>
>>
>>> Martin and list,
>>>
>>> Actually, there is something suspicious. Northwest Africa (the
>>> countries you listed plus Western Sahara and Tunisia) has seen
>>> between 0 and 3 falls per decade from the 1900s through the 1980s.
>>> The 1990s saw 6, and the 2000s have now got 8. There is no parallel
>>> increase in the rest of Africa, which in fact has been steadily
>>> declining in fall rates since the 1940s. Europe has also been
>>> declining since the 1930s (in fall rates), as has North America. I
>>> think northwest Africa is the only place in the world that is seeing
>>> any kind of increase in rate, and it has been dramatic, tripling in
>>> the last decade.
>>>
>>> The are various sociological reasons why this increase might have
>>> happened, which we can argue about. But there certainly IS
>>> something to raise ones eyebrows.
>>>
>>> Jeff
>>>
>>> Martin Altmann wrote:
>>>> Hi Ryan,
>>>> it's because of the iron mountain in Atlas, which still has to be
>>>> found and which attracts with his magnetic field all iron-bearing
>>>> lumps from space.
>>>>
>>>> No. Take a World map, hold little Europe (forget a little bit about
>>>> Scandinavia), hold it against that NWA region, Algeria, Mali,
>>>> Niger, Morocco, Mauretania....
>>>>
>>>> And let's count the falls:
>>>>
>>>> Let's start with Zag 1998.
>>>>
>>>> NWA-Regions:
>>>>
>>>> Zag 1998
>>>> El Idrissa 1998
>>>> Djoumine 1999
>>>> Beni M'hira 2001
>>>> Bensour 2002
>>>> Oum Dreyga 2003
>>>> Maigatari-Danduma 2004
>>>> Benguerir 2004
>>>> Bassikounou 2006
>>>> Chergach 2007
>>>> And now the new possible fall.
>>>>
>>>> Europe:
>>>>
>>>> Ourique 1998
>>>> Leighlinbridge 1999
>>>> Moravka 2000
>>>> San Michele 2002
>>>> Neuschwanstein 2002
>>>> Alby sur Cheran 2002
>>>> Villalbeto 2004
>>>> Moss 2006
>>>> Puerto Lapice 2007
>>>> Romanian Fall 2008
>>>>
>>>> 11 : 11.
>>>>
>>>> So nothing suspicious.
>>>>
>>>> USA had 7
>>>> India 10
>>>>
>>>> Best!
>>>> Martin
>>>>
>>>>
>>>>
>>>>
>>>> Ok Folks,
>>>>
>>>> I am curious to know why there are so many witnessed (recovered)
>>>> meteorite falls in Northwest Africa as opposed to anywhere else in
>>>> the world.
>>>> Is there
>>>> a good logical and/or scientifc explanation for this?.. or just a
>>>> coincidence? I understand that some "falls" simply turn out to be a
>>>> case of Nomadic lies in an attempt to liquidate (recycle) old
>>>> material, but what about the others? Perhpas it has something to do
>>>> with it's geographical location in relation to..?
>>>> And yes, I do understand these people spend countless hours
>>>> outdoors, in the desert, ect. but..
>>>>
>>>> What are your thoughts?
>>>>
>>>> Ryan
>>>>
>>>>
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>>>>
>>>
>>>
>>> --
>>> Dr. Jeffrey N. Grossman phone: (703) 648-6184
>>> US Geological Survey fax: (703) 648-6383
>>> 954 National Center
>>> Reston, VA 20192, USA
>>>
>>>
>>> ______________________________________________
>>> http://www.meteoritecentral.com
>>> Meteorite-list mailing list
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>>> http://six.pairlist.net/mailman/listinfo/meteorite-list
>>
>> ______________________________________________
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>
>
> --
> Dr. Jeffrey N. Grossman phone: (703) 648-6184
> US Geological Survey fax: (703) 648-6383
> 954 National Center
> Reston, VA 20192, USA
>
>
> ______________________________________________
> http://www.meteoritecentral.com
> Meteorite-list mailing list
> Meteorite-list at meteoritecentral.com
> http://six.pairlist.net/mailman/listinfo/meteorite-list



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Received on Sun 18 Jan 2009 10:17:22 PM PST