[meteorite-list] TEKTITE STUFF

From: Sterling K. Webb <sterling_k_webb_at_meteoritecentral.com>
Date: Thu Oct 19 22:11:09 2006
Message-ID: <005301c6f3ec$fe0ca1f0$6e57e146_at_ATARIENGINE>

Hi,

    This is for the Tektite Subtribe on the List!

    One hears (reads) many references to the work
of Chapman at experimentally duplicating the forms
of australites in a high-heat hypersonic flow and
explaining their aerodynamics, but I never found
a copy of it until I found this one:
NASA Technical Report R-134:
AERODYNAMIC EVIDENCE PERTAINING TO THE ENTRY
OF TEKTITES INTO THE EARTH'S ATMOSPHERE
By DEAN R. CHAPMAN, HOWARD K. LARSON.
and LEWIS A. ANDERSON, 1962
http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19630008899_1963008899.pdf
    Particularly interesting is his discussion of the strange
flow lines seen on tektites and his comparison of them
to certain anomalous iron meteorites which show the same
features. They apparently only appear on objects that
enter the Earth's atmosphere just barely above escape
velocity (most meteorites are much faster). Makes the
markings and flow issues less mysterious. Downloadable.

    The Czech Geological Survey has a recent very thorough
survey of moldavite distribution and abundance that is
downloadable:
Trnka and Houzar: Moldavites, 2002, Czech Geological Survey (in English)
http://nts1.cgu.cz/portal/page/portal/bulletin/contents/2002/vol77no4/04trnkafinal.pdf

    The Smithsonian studies of tektites are very expensive
to acquire (if you can even find them). Here's one free:
Occurrence, Distribution, and Age of Australian Tektites
By R. 0. Chalmers, E. P. Henderson, and Brian Mason, 1977
http://www.sil.si.edu/smithsoniancontributions/EarthSciences/pdf/sces-0017.pdf

    This is just the abstract, but is the corrective to the
oft-repeated error that tektites contain nickel-iron spherules
of meteoritic origin (they don't). Oh, they contain NiFe
spherules alright, but the metal is terrestrial...
http://adsabs.harvard.edu/abs/1983E&PSL..65..225G

    George Baker's chief work (1962) on tektites was an
explanation of the evolution of tektite forms by the rotations
of molten materials in free fall, but it was a theoretical work.
Here is the first experimental demonstration of how the forms
evolve, done by spinning melt! Downloadable:
A Laboratory Model of Splash-Form Tektites,
by Elkins-Tanton, 2002
http://web.mit.edu/nnf/people/jbico/elkins03.pdf

    Somebody else besides me is sure to want to pour over these...


Sterling K. Webb
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Received on Thu 19 Oct 2006 10:11:01 PM PDT