[meteorite-list] Microtektites from Antarctica

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Tue, 7 Apr 2009 01:05:13 -0500
Message-ID: <D691F68CAF3A4F9FB3636D911DCE94FC_at_ATARIENGINE2>

Hi,

The article states: "...the Ivory Coast strewn
field (1.10 + or- 0.05 Ma). However the latter
has no extension south of the equator so these
microtektites must form an extension of the
Australasian field."

The Botsumtwi crater (which is in Ghana not
the Ivory Coast) is virtually ON the equator,
and there are Ivorites recovered from the seabed
in all directions for hundreds of miles, some of
which are "south" of the equator. However, that
is not the distance record for an Ivorite!

One of the "Australites," recovered from the NE
coast of Australia, and provided to the crucial and
oft-cited 1982 Shaw and Wasserburg study of
Sm-Nd systematics, turned out to be an Ivory
Coast tektite and not an australite (despite being
found in Australia)!

That find location is virtually "antipodal" to the
Ivory Coast (antipodal meaning 180 degrees
around the globe). Almost antipodal to the source
strewn field are the badly eroded Tikal tektites
identified as Australites by Alan Hildebrand.

Since the K-Ar dates are too vague to distinguish
between the two, it would be useful to apply a
fuller range of isotopic analysis (like the Shaw -
Wasserburg study) to them.

Widely discontinuous patches of a strewn field are
more common than a continuous strewn field. North
American tektites, presumably from the Chesapeake
crater, are found in "patches" in Georgia, Texas,
an isolated one in Massachusetts, some in Cuba,
and a few from the northern South American coast!

Tektites get around...


Sterling K. Webb
--------------------------------------------------------------------------
----- Original Message -----
From: "Paul" <bristolia at yahoo.com>
To: <meteorite-list at meteoritecentral.com>
Sent: Friday, April 03, 2009 4:45 PM
Subject: [meteorite-list] Microtektites from Antarctica


>
> McCall, J., 2008, Microtektites from Antarctica
> Geoscientist 18.8 September 2008
>
> http://www.geolsoc.org.uk/gsl/geoscientist/geonews/page4229.html
>
> Yours,
>
> Paul H.
>
>
>
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Received on Tue 07 Apr 2009 02:05:13 AM PDT