[meteorite-list] Two Questions

From: Gerald Flaherty <grf2_at_meteoritecentral.com>
Date: Tue May 24 20:17:43 2005
Message-ID: <00d701c560bf$2673f200$2f01a8c0_at_Dell>

Yet?!?
----- Original Message -----
From: <star-bits_at_comcast.net>
To: "Gerald Flaherty" <grf2_at_verizon.net>;
<meteorite-list_at_meteoritecentral.com>
Sent: Tuesday, May 24, 2005 6:54 PM
Subject: Re: [meteorite-list] Two Questions


> No, there is no evidence of plate techtonics on Mars and therefor no
> subduction.
>
> --
> Eric Olson
> ELKK Meteorites
> http://www.star-bits.com
>
>
>> Hi Walter, Eric and List,
>> Would Martian Tectonic forces ie. subduction, be a possible mechanism to
>> trap and transport atmospheric gases into the bowels of the planet, later
>> to
>> be be contained in a magma chamber?
>> Just an odd thought. Jerry
>> ----- Original Message -----
>> From: <star-bits_at_comcast.net>
>> To: <meteorite-list_at_meteoritecentral.com>
>> Sent: Tuesday, May 24, 2005 1:26 PM
>> Subject: Re: [meteorite-list] Two Questions
>>
>>
>> > Walter Branch wrote:
>> >
>> > <I been researching but I can't find the answers to two questions.
>> >
>> > First, what is the mechanism by which atmospheric gasses
>> > are trapped in the formation of basalts? I have been doing some
>> > lit reviews on martian meteorites and I find it interesting that some
>> > were formed in magma chambers deep undergound. indeed, some are
>> > thought to have formed several kilometers down. How does the
>> > Martian atmosphere get trapped in cooling rock so far underground.>
>> >
>> > Hello Walter
>> >
>> > The mechanism for trapping gasses in Martian basalts is not entirely
>> > clear. One method that has been proven is implanting during shock
>> > events,
>> > such as being blasted off Mars. However there are some problems with
>> > this
>> > as well such as sometimes the gasses are fractionated (Kr/Xe ratio
>> > changes
>> > for instance). So although impact is likely part of the answer it
>> > isn't a
>> > clear winner. Another suggestion is fluid (water) transplant, however
>> > the
>> > gasses mostly reside in the water unaltered portions so this is likely
>> > not
>> > the answer. Trapping of mantle gasses during cooling has been
>> > suggested,
>> > but mantle reservoirs of gasses should have different ratios than
>> > atmospheric. So the exact mechanism is undetermined.
>> >
>> > <Second, when determining Cosmic Ray Exposure ages, can atmospheric
>> > fragmentation and ablation of a meteoroid affect the results from such
>> > testing and if so, how are fragmentation and ablation taken into
>> > consideration when determiniing CREs?>
>> >
>> > Yes fragmentation and ablation can affect the results and must be taken
>> > into account. Cosmic rays generally penetrate 3-10 meters into
>> > asteroidal
>> > bodies. Parts buried more than 10 meters or so receive almost no
>> > cosmic
>> > ray exposure so their CRE age is zero. If depth isn't taken into
>> > account
>> > a surface sample would show a older CRE than one at 5 meters. One
>> > method
>> > of determining depth is with Neon isotopes which have been shown to
>> > have a
>> > constant relationship with burial depth and cosmic ray exposure. So
>> > the
>> > neon can be used to determine depth and the other elemental isotopes
>> > can
>> > then be adusted for depth to give the CRE age.
>> >
>> >
>> > --
>> > Eric Olson
>> > ELKK Meteorites
>> > http://www.star-bits.com
>> >
>> >
>> >> Second try at posting this email:
>> >>
>> >> Hello Everyone,
>> >>
>> >> I been researching but I can't find the answers to two questions.
>> >>
>> >> First, what is the mechanism by which atmospheric gasses
>> >> are trapped in the formation of basalts? I have been doing some
>> >> lit reviews on martian meteorites and I find it interesting that some
>> >> were formed in magma chambers deep undergound. indeed, some are
>> >> thought to have formed several kilometers down. How does the
>> >> Martian atmosphere get trapped in cooling rock so far underground.
>> >>
>> >> Second, when determining Cosmic Ray Exposure ages, can atmospheric
>> >> fragmentation and ablation of a meteoroid affect the results from such
>> >> testing and if so, how are fragmentation and ablation taken into
>> >> consideration when determiniing CREs?
>> >>
>> >> Thanks to anyone who can help me understand these processes.
>> >>
>> >> -Walter Branch
>> >>
>> >>
>> >> ______________________________________________
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Received on Tue 24 May 2005 08:17:34 PM PDT