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Australasian tektite age paradox - Part 1 of 2

TAYLOR S.R. (1999) The Australasian tektite age paradox (MAPS 34-3,
1999, From the Editors, page 311):

Students of tektites possess the interesting property of dividing
themselves into two irreconcilable camps. Even the embers of the long
dead lunar vs. terrestrial origin debate are still occasionally
rekindled into flame. Another division of longstanding has concerned the
age of fall of the tektites of the Australasian strewnfield that covers
about ten percent of the surface of the Earth. Early workers, including
such astute observers as Charles Fenner, George Baker, and Edmund Gill,
who picked up pristine tektites on the arid and ancient surface of
Australia, became convinced that this shower of glass had arrived very
recently. Ages around 10 000-20 000 years were usually quoted. As some
early radiometric age determinations of tektites gave spuriously old
ages, these data fuelled the notion that the age of the fall was
disconnected to the time of formation of tektites. It was then a short
intellectual leap to bring them from outside the Earth.
More precise dating eventually yielded ages ca. 770 000 years for the
time of formation of the glass. As the flanges on the famous
button-shaped australites gave effectively the same result, this also
marked the time of entry through the atmosphere of these aerodynamically
shaped forms. Thus the time of formation and fall was close. Then
microtektites were discovered in drill cores from deep-sea sediments,
close to, but not identical with the Brunhes-Matuyama Boundary. This
evidence from two separate disciplines convinced most workers that the
Australasian tektite event had occurred about three quarters of a
million years ago. The stratigraphic evidence was relegated by most
workers to an uncertain status on account of the difficulties of dating
Pleistocene land surfaces in Australia.


Best wishes,

Bernd

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