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TEKTITE QUESTION

R.F. Fudali et al. (1993) The stratigraphic age of  Australites
revisited (Meteoritics 28-1, 1993, pp. 114-119)

SUMMARY AND CONCLUSIONS (p. 118, excerpts):

Contrary to previous assertions, the stratigraphic evidence in the Port
Campbell area for a 5000-15,000 year B.P. age of australites is
nonexistent. The great majority of these tektites show clear and
unequivocal EVIDENCE OF BEING TRANSPORTED into YOUNGER HORIZONS.
Further, the oldest, and previously unrecognized, stratigraphic unit
containing tektites at Port Campbell, while poorly constrained in time,
is certainly not incompatible with a mid-Pleistocene event.

Based on cosmic ray exposure histories of alluvial diamonds, the MINIMUM
AGE of tektite-bearing gravel terraces just south of Lake Argyle,
Western Australia, is 250,000 years B.P. This is the first direct
evidence bearing on the residence time of the Australasian tektites at
the Earth's surface, and it is TOTALLY INCOMPATIBLE with the proposed
5000-15,000 year stratigraphic age. THE PROPOSED 5000-15,000 YEAR AGE IS
CLEARLY INCORRECT and a critical re-examination of the evidence, said to
be supportive of this age, should show such evidence to be either
equivocal or nonexistent as it is at Port Campbell.

 A selected suite of tektites collected from the Nullarbor Plain
currently awaits 26Al determinations at the University of Pennsylvania
AMS facility. For various reasons, these tektites are believed to have
spent their time since fall on or very near the surface and so should
yield a direct and more accurate exposure (terrestrial fall) age for the
australites. I fully expect this will be supportive of the radiometric
ages.


Regards, Bernd