[meteorite-list] Northwest Africa Falls - Question

[Jeff Kuyken]

I would tend to agree with the opinions so far but whether you can use 
freshness as a justifiable reason to call it a find... well... that 
difficult job is yours Jeff! ;-)

I also thought most of these falls had pretty reliable fall evidence as some 
have mentioned. Also... wasn't Oum Dreyga witnessed and collected by the 
Western Saharan Military?

I purchased a small "Amgala" (Oum Dreyga) individual from Mike Farmer's very 
first 1kg batch out of Morocco. It is without equal in all the other falls I 
have. Bensour is a close second but the Oum Dreyga has thick, rich fusion 
crust like soot that you would expect to rub off on your hands.

Cheers,

Jeff


----- Original Message ----- 
From: "Michael Farmer" <meteoriteguy at yahoo.com>
To: "Meteorite-list" <meteorite-list at meteoritecentral.com>; "Jeff Grossman" 
<jgrossman at usgs.gov>
Sent: Monday, January 19, 2009 5:01 PM
Subject: Re: [meteorite-list] Northwest Africa Falls - Question



> Jeff

> I completely disagree with calling Bensour a find.  The 

> information/story/newspaper articles are more data than we have for many 

> finds. Take Bilanga, there is nothing in the news, no reports other than 

> missionary people taking out stones. Of course it is a fall, the people 

> all saw it, and fresh stones were everywhere. Why is Bensour any 

> different? I still have hundreds of Bensour stones, I have the main mass, 

> 10 kilograms, the soft velvety fusion crust on many stones still have the 

> iridescent sheen only seen in falls with no rain ever touching them. The 

> sand blowing there would have damaged the crust in days, the sub 200 mg 

> stones would never be found on an old fall. I have vials of them, most 

> oriented. I think Bensour was pretty well documented.

> Would be glad to send you some pieces to check, but you will find not the 

> slightest hint of weathering on any piece.

> Michael Farmer

>

>

> --- On Sun, 1/18/09, Jeff Grossman <jgrossman at usgs.gov> wrote:

>

>> From: Jeff Grossman <jgrossman at usgs.gov>

>> Subject: Re: [meteorite-list] Northwest Africa Falls - Question

>> To: "Meteorite-list" <meteorite-list at meteoritecentral.com>

>> Date: Sunday, January 18, 2009, 8:22 AM

>> 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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>> >>>

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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

>> >>

>> >>

>> >> ______________________________________________

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>> > ______________________________________________

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>> > Meteorite-list at meteoritecentral.com

>> >

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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

>>

>>

>> ______________________________________________

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>> Meteorite-list mailing list

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