Hi list
I wondered if there is anyone on the list who has collected a lot of
australites and knows about the grooving on these tektites. What does it look
like? Is it generally on the anterior side? Is it associated with particular
shapes and not others?
I am really interested to understand how australite morphologies fit in with
the classic lenticular and breadcrust philippinites, which have grooving on
only one side. I was also fascinated by the recent emails on stretch tektites.
The more I look at philippinites, the more I think the U grooves are an
original feature as oppose to chemical weathering. The U grooves occur on only
one side and, when better developed, have a polygonal structure. I know this is
usually explained as being the anterior side with flakes coming off due to
thermal expansion/contraction, but I still wonder if that is the case. I wonder
if these cracks developed (?perhaps as the tektite cooled) but the interior
remained plastic. When this interior became solid, the solid would take up less
space than the liquid. So, when it cooled totally did it 'suck' in at the
grooves. I saw a similar thing when playing with solid and liquid wax. Are the
grooves on one side then lost due to ablation, thus making the smooth side the
anterior? Are these grooves in anyway similar to the starburst ray skin-splits
featured on 'The Tektite Source' webpage? I understand this idea creates more
problems, such as why do tektites from Vietnam area not
show polygonal cracks like philippinites. I'm sure there is still much to be
learnt, but if anyone knows answers I'm keen to learn.
Thanks, Aubrey
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