[meteorite-list] Question About Potassium-Argon (K/Ar) dates for North American and Australasian Tektites

[Norm Lehrman]

Michael & list,
  
Greetings from Tanzania! Sorry to be so out of touch, but electricity and internet service are both pretty insecure here.

Michael,  K-Ar and Ar40/Ar39 techniques are not limited to volcanic rocks.  Anything containing potassium (certainly including tektites) can work.  There are always interpretative issues, but that's another subject.

I spend a fair bit of my field time here working with geochronology where 2.8 billion years is "young" and an error bracket of +/- 40 million years is almost too sloppy to be of use!  I'm learning some new stuff.

No meteorites so far, and virtually no decent search environments.  I found a killer little iron in the middle of a jungle trail a while back, but a quick zap with a Niton portable XRF unit showed no Ni.  Just a nice chip off of an iron plow or sledge hammer---.  

The Niton ray gun is driving me crazy.  At virtually no cost, I can pull the trigger and analyze for the entire periodic table heaver than Na in less than 1 minute.  This machine should be able to let us non-destructively differentiate iron meteorites, and maybe tektites.  Why am I going crazy?  ALL my collection is in storage in the USA and I can't test the technology! The unit costs around $35,000 US.  Here, now, I have unlimited access to one, and soon, several.  

Imagine being able to instantly (in relative terms), go though a collection of irons and verify their identity.  I've got some in my collection that are potentially with the wrong tag, and I bet every museum in the world fits into that fellowship.  What if we can easily zap tektites to confirm/differentiate Ivorites, Bediasites, and Australasians?  Authenticate moldavites and reject etched glass?  I THINK this tool is in our hands now.

I'm coming to the US at Christmas time.  Who can offer me a nice wide variety of approx. 1 cm sq slices of irons at a decent price?  I could even return them afterwards (subject to the risk of confiscation in customs somewhere---).  If this works as I think it could, I'd consider buying a Niton on my return to the USA, and offering verification services.

If anyone is able to provide me with a dozen or so little iron chips (for a price of course), please let me know.  This could be very cool.

Regards to all, 

Norm
http://tektitesource.com



, 10/14/08, Michael L Blood <mlblood at cox.net> wrote:


> From: Michael L Blood <mlblood at cox.net>

> Subject: Re: [meteorite-list] Question About Potassium-Argon (K/Ar) dates for North American and Australasian Tektites

> To: bristolia at yahoo.com, "Meteorite List" <meteorite-list at meteoritecentral.com>

> Date: Tuesday, October 14, 2008, 10:56 AM

> Hi Paul & all,

>         K-A dating is only applicable to volcanic material,

> therefore,

> It would not be applicable to tektites.

>         Best wishes, Michael

> 

> on 10/14/08 9:14 AM, Paul at bristolia at yahoo.com wrote:

> 

> > Dear Friends,

> > 

> > Can anyone recommend a publication that provides a

> > comprehensive listing of Potassium-Argon (K/Ar) dates

> > that have been published for the North American and

> > Australasian tektites?

> > 

> > Also, what the authorative reference(s) work for

> > the bulk composition of tektites from each of these

> > strewn fields?

> > 

> > Any citations, which you can recommend would be

> > greatly appreciated.

> > 

> > Best Regards,

> > 

> > Paul H.

> > 

> > 

> >       

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