[meteorite-list] Georgia Tektites

From: bernd.pauli_at_paulinet.de <bernd.pauli_at_meteoritecentral.com>
Date: Thu Apr 22 10:25:44 2004
Message-ID: <DIIE.0000005C00000AAE_at_paulinet.de>

Mike wrote:

> a gorgeous perfect 8.5 gram tektite from ... a field in Johnson County,
> Georgia. I need information about them, why are they so rare?

Hello Mike, Norm and List,

Here is some information I culled from the article by Albin.

Best regards,

Bernd

1) Georgiaites and bediasites are macrotektites from east-central Georgia
    and eastern Texas, respectively; they constitute two compositionally distinct
    populations of North American tektites.

2) North American tektites have similar ages and apparently formed as
    a result of one or more impacts at ~35 Ma, that is, in the late Eocene.

3) Albin and Wampler (1996) reported a mean K-Ar age of 35.2 =B1 0.2 Ma.

4) Their isotopic composition indicates the possible involvement
    of crystalline rocks in the origin of georgiaites.

5) The georgiaites comprise some of the most Si-rich
    (79-83 wt% SiO2) glasses of the North American strewn field.

6) Glass compositions are similar to but not
    identical with average upper continental crust.

7) Si-rich material, probably a quartz-rich sand was
     predominant in the formation of georgiaites.

8) They may be linked to Eocene sediments
    at the Chesapeake Bay impact structure.

and, an interesting aside:

The tektites Albin investigated and described in the above paper
were picked up by farmers and other residents who found them
lying on the surface after a heavy rain.

Reference:

ALBIN E.F. et al. (2000) Major and trace element compositions of georgiaites:
Clues to the source of North American tektites (MAPS 35-4, 2000, pp. 795-806).

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Received on Sun 25 May 2003 06:52:55 AM PDT