[meteorite-list] CRE ages of Nakhlites and NWA 998

[Gerald Flaherty]

Thanks Bob and Walter. I knew it I was just testing[YEA RIGHT!]
Jerry Flaherty
----- Original Message ----- 
From: "Walter Branch" <waltbranch at bellsouth.net>
To: "Gerald Flaherty" <grf2 at verizon.net>; "Meteorite List" 
<meteorite-list at meteoritecentral.com>
Sent: Saturday, November 11, 2006 2:18 PM
Subject: Re: [meteorite-list] CRE ages of Nakhlites and NWA 998


> Hi Jerry,
>
> CRE = Cosmic Ray Exposure age.  An estimate of the time the rock has been 
> in space.
>
> -Walter
> ________________________
> ----- Original Message ----- 
> From: "Gerald Flaherty" <grf2 at verizon.net>
> To: "Walter Branch" <waltbranch at bellsouth.net>; "Meteorite List" 
> <meteorite-list at meteoritecentral.com>
> Sent: Saturday, November 11, 2006 2:03 PM
> Subject: Re: [meteorite-list] CRE ages of Nakhlites and NWA 998
>
>
>> Help! CRE age??
>> Jerry Flaherty
>> ----- Original Message ----- 
>> From: "Walter Branch" <waltbranch at bellsouth.net>
>> To: "Meteorite List" <meteorite-list at meteoritecentral.com>
>> Sent: Saturday, November 11, 2006 3:15 AM
>> Subject: [meteorite-list] CRE ages of Nakhlites and NWA 998
>>
>>
>>> Hello Everyone,
>>>
>>> I have been studying nakhlites in general and martian meteorite NWA 998 
>>> in particular.  This paper,
>>> http://www-curator.jsc.nasa.gov/antmet/mmc/XXV_NWA998.pdf
>>>
>>> quotes a CRE of 9.3 m.y. using 38Ar.  This paper
>>>
>>> http://www.lpi.usra.edu/meetings/lpsc2005/pdf/1137.pdf
>>>
>>> quotes a CRE age of 9.4 m.y, again using 38Ar.  However, the paper 
>>> further points out CRE ages using 3He and 21Ne are in better agreement 
>>> (12.2 and 11.7 m.y., respectively) and are in agreement with other 
>>> nakhlite CRE ages. The authors state, "All nakhlite CRE ages based on Ar 
>>> are significant (sic) younger than those based on He and Ne, an 
>>> unexplained characteristic also observed among some shergotite CRE 
>>> ages."
>>>
>>> Does anyone know why this is?
>>>
>>> -Walter Branch
>>>
>>> ________________________
>>>
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>>
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>
>