FW: [meteorite-list] dronino (in)stability: a solution ?

From: Steve Schoner <steve_schoner_at_meteoritecentral.com>
Date: Thu Apr 22 10:29:58 2004
Message-ID: <20030919162256.61715.qmail_at_web12701.mail.yahoo.com>

--- mark ford <markf_at_ssl.gb.com> wrote:
>
>
> Marcie,
>
> Absolutley, one should never coat, treat, or do
> anything to an
> unclassified specimen, as it is important to
> preserve the isotopic
> structure. I really meant this method is for use
> with the old favourites
> and well understood classified irons like Nantan
> where they will often
> disappear in a pile of rust within a few years,
> especially if you live
> near the sea!
>
> Best Wishes all,
>
> PS : hope the Hurricane is not causing you all too
> much trouble, looked
> pretty fierce on TV!
>
> Mark Ford
>
>

Mark and all,

I doubt that the NaOH soaking solution would
dramatically affect the isotopic composition of any
unclassified meteorite.

There might however be some changes in the chemistry
of certain silicates if the concentration of NaOH
high, but even this can be factored in.

But usually, due to the fact that terrestrial chlorine
has entered the specimen, terrestrialization caused by
that has already occurred. Terrestrialization will
have already leached isotopes out of the specimen and
the chemistry will have changed since the meteorite
fell. The NaOH process only leaches out terrestrial
chlorine from the iron and nickel (FeCl3;NiCl2) and
turns it into a more stable form of NaCl which is
further leached out from the specimen in subsequent
rinsing with distilled water.

I have challenged those that think otherwise to
provide proof of such alteration as a result of such
treatment. I have yet to receive a reply.

Other than the leaching out of terrestrial chlorine,
and the conversion of Fe and Ni to oxides, with a very
minor trace of NaCl, I doubt that any significant
alteration other than that caused by normal weathering
processes will have occured in NaCl treated specimens.
 And at best the NaOH treatment only penetrates a few
millimeters into the specimen, or along deep cracks,
leaving alone those areas that are not accessible to
oxygen, and water.

But this treatment should not be done on fresh
specimens, iron or stones such as the Monihans which
has unusual concentrations of water in extra
terrestrial salt grains. In such a case, the salt
would have been altered. Fresh specimens if properly
cared for would not have to be treated anyway.

Steve Schoner
http://www.geocities.com/american_meteorite_survey

 
> -----Original Message-----
> From: Marcia Swanson [mailto:MJSOfArc_at_webtv.net]
> Sent: 18 September 2003 14:13
> To: mark ford; meteorite-list_at_meteoritecentral.com
> Subject: Re: FW: [meteorite-list] dronino
> (in)stability: a solution ?
>
> Dear Mark,
> No questioning of ethics Mark, just concern about
> the fact that there is
> a product out here in the States that is used for
> rust treatment on
> automobiles, ect., very similiar to the one you
> described ,that does
> turn the rust to a polymer finish, and like I
> mentioned to you in my
> letter, it chemically changes the molecular
> arrangement of a compound ,
> having same percentage composition as original, but
> greater molecular
> weight and different properties.
> Thank-you for replying , and yes, letting an iron
> rust away to nothing "
> No hopers", I think you called them, for them ,
> after its been
> classified, it is a desirable treatment considering
> the option.
> I guess I was more concerned with a piece that
> hasn't been classified
> yet, that someone like me ( greener than green)
> might find in an
> extremely rusty state, but like you expained, it is
> to be used at the
> owners risk, and if a person is not sure of what
> type of iron it is,
> better not to try and treat it till it is
> classified. That was my
> concern. Thanks for the input Mark. Best Regards,
> Marcie
>
>
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Received on Fri 19 Sep 2003 12:22:56 PM PDT