[meteorite-list] Two Questions

[Walter Branch]

Hello Mark, Sterling, Eric, Bob and List,

Thanks very much for the infor regarding Martian atmospheric gasses and CRE
determination.  I do appreciate the input.  Thanks also for the reference so
I can follow-up on these interesting (to me) topics.

-Walter Branch
-----------------------------------------------------
----- Original Message ----- 
From: <mafer at imagineopals.com>
To: "Walter Branch" <branchw at bellsouth.net>
Sent: Tuesday, May 24, 2005 7:36 AM
Subject: Re: [meteorite-list] Two Questions


> Hello Walter
>
> What I learned in school about vulanism is that the atmosphere on earth
was
> created by volcanic action, (primarily the water content with carbon
> dioxide, and of course, the acids). Entrapped gases that researchers refer
> to may be like these basic gases along with some exotics. Or, that the
> entrapped gases reflect the atmosphere that they see today plus those
gases
> that outgas (and lost due to too little gravity) once exposed.
>
>
> As far as I know from cosmic ray penetration, I would have to assume that
> there is some measure of extrapolation involved to arrive at the original
> size of the rock prior to atmospheric entry. This is much the same as
> trying to age glassy rocks based on the rind caused by weathering. The
> determinations have to be based on local conditions, there is always some
> measure of error because of loss of rock mass, and conditions change over
> time.
>
> And because the time spent exposed to cosmic rays are based on penetration
> depths, and all we have are models for the mathmatics to determine
ablation
> (no one has a true measure of the size of any given meteorite prior to
> entry), any age determined has to be a best guess.
>
>
> Mark Ferguson
>
> On May 24, 1:45 pm "Walter Branch" <branchw at bellsouth.net> wrote:
> > 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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> >
>
>
>
>