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

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Wed, 15 Oct 2008 15:56:35 -0500
Message-ID: <0a3b01c92f08$839a2150$144ee146_at_ATARIENGINE>

Hi, Paul, List,


    Are these "alleged tektites" that you refer to the
ones found in Glenmora, Rapides Parish, that were
reported on by King in 1970?
http://adsabs.harvard.edu/abs/1970Metic...5Q.205K
No abstract or paper available. I guess these tektites
are not popular.

    Former (?) List member Ed Albin:
http://www.lpi.usra.edu/meetings/LPSC99/pdf/1357.pdf
"King [1968] described a bediasite find within the
upper Eocene Wellborn Formation in Grimes County,
Texas. This deposit has been traced eastward and
correlates with the Yazoo Clay Formation in Louisiana,
Mississippi, Alabama, and the Dry Branch Formation
in Georgia. It is entirely possible that North American
tektites may eventually be recovered from upper Eocene
deposits between Georgia and Texas."

    But were King's tektites North American tektites in
composition? Wetback Bediasites, as it were?

    In 1986, leading geochemist Cristian Koeberl
said the King tektites from Louisiana were Australites:
http://arjournals.annualreviews.org/doi/abs/10.1146/annurev.ea.14.050186.001543?journalCode=earth
I can't get to that paper, naturally.

    I can get to this paper by Koeberl (and so can
everybody else on the List). It's his analysis of the
Cuban "tektite" which proved to be a member of
the North American strewnfield:
http://adsabs.harvard.edu/full/1988Metic..23..161K
but I can't pull a quote out as the paper's a page image,
not text. The gist of Koeberl's remark is that the
"Cuban" tektite is genuine, in distinction to King's tektites
which were "allergedly" found in Louisiana, were then
disovered to be Australites, and therefore could not have
come from Louisiana. He said that they were a fraud, in
other words. The tektites are tektites, but is the find
a find in Louisiana?

    What Koeberl was not aware of is that some years
later Alan Hildebrandt (another geochemical authority)
found some Australities in and around Tikal, the ancient
Mayan city in Guatemala adjacent to the Yucatan. On the
global scale, Louisiana and the Yucatan a mere tektite's
throw apart, and both roughly antipodal to the Australasian
strewnfield.

    If this is the case, then no amount of analysis of
the "alleged" tektites is meaningful -- they are tektites!
You would need instead need to investigate the
circumstances of the find, the character and motives
of the finder. This would seem to be a difficult goal
to pursue definitively after a 38 year lapse.

    But if they are (both) Australites and were discovered
in situ, that in itself is major news (or an inconvenience to
be ignored, of course), like the Ivory Coast tektite
(identified by analysis in 1982 by Shaw and Wasserberg)
found off the coast of Australia in the sea bed. (Currents?
Yeah, sure...)

    If Koerberl said the Louisiana tektites were real
(and Australites), then they were tektites. No question.
Better go find some more! Did anybody record the exact
location of the find?


Sterling K. Webb
----------------------------------------------------------------
----- Original Message -----
From: "Paul" <bristolia at yahoo.com>
To: <meteorite-list at meteoritecentral.com>
Sent: Wednesday, October 15, 2008 2:13 PM
Subject: [meteorite-list] Question About Potassium-Argon (K/Ar) dates
forNorth American and Australasian Tektites


Thank you-all for your replies to my question, including
a ?reference list for tektites?. They have been most helpful.

Sterling K. Webb wrote:

?The largest source for bulk composition data of a
large number of tektites is: J.A. O'Keefe, Editor,
Tektites, Univ. of Chicago Press, Chicago, Illinois
(1963), ...?

I lucked out on this one as the library, where I work
has this book in its collections. Needless to say, I have
checked it out and looking through all the data,
information, and ideas it contains.

Now I just need to figure if the alleged Louisiana
tektites are fact or fiction. At this time, I suspect
the latter until someone finds some more.

Best Regards,

Paul H.




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Received on Wed 15 Oct 2008 04:56:35 PM PDT