[meteorite-list] Irons DON'T form Fusion Crust's - yes they DO

From: Mr EMan <mstreman53_at_meteoritecentral.com>
Date: Sun, 7 Jan 2007 10:27:02 -0800 (PST)
Message-ID: <519290.82008.qm_at_web51010.mail.yahoo.com>

Hello Listoids, Svend
--- "Dr. Svend Buhl" <info at niger-meteorite-recon.de>
wrote:... I do not agree that the Glossary of
 Geology of the American Geological Institute is a
sound reference for nomenclature and terminology of
meteorites.

GIST: For those that don't want to read the details, I
am asserting that even thought there is something to a
complex ablation surface on iron meteorites, the
widely accepted and published definition of fusion
crust states that it is a glassy coating, which would
exclude the coatings on irons from being called fusion
crusts. I also call for a revision of the definition
to overcome that exclusion.

Thank you for joining the debate, Svend. Nice to know
someone has access to Buckwald's hand book. It is good
we can have academic debates and not attack the
messengers. I trust you will accept this as a
discussion of a deficiency in the literature and not a
disregard for yourself nor V.F. Buchwald. I believe
the use of the term "fusion crust" is weakly founded
in literature in general for the ablation surface is
far more complicated than the simplification of
a"glassy melt". This need not be an"angels on the
head of a pin" argument for I feel that a revised
definition dropping "glass/glassy" else making a
distinction for the rind on iron meteorites being
different is long overdue.

It is human nature to tend to believe the references
we have in our possession over those not in our
possession. Unfortunately, Buchwald's work at
$2000-$3000 isn't available to most institutions,
researchers, nor collectors. There is also no easily
found evidence that he attempted to change the
definition of fusion crust to include the rind that
forms on irons. Rather he adopted a concept already in
use. An opinion by a distinguished researcher in 1975
may open a door to a revision of the definition but
the accepted definition in literature simply does not
address the rind/coating/glaze occurring on iron
meteorites. We need a revised definition for fusion
crust however, I've no idea who would be the crusade
leader.

The reality remains that the vast
citations/definitions in world literature still
specifically state "glass" as a component of fusion
crust when composition is discussed. Without an
uniform operational definition that is accepted
throughout the research/education community any
discussion--even by Buchwald, has a fatal flaw
semantically speaking. As it is, I am not incorrect in
asserting as I did in previous posts, according to
widely published definition, there is no occurrence of
fusion crust on iron meteorites. There is something,
yes, but it isn't covered by the literature at large.

Exhibits cited from the web:

NASA
Fusion Crust: Dark glassy coating on the surface of a
meteorite..
<http://ares.jsc.nasa.gov/Education/Activities/ExpMetMys/Glossary.pdf>

Typical definition found at Institutions of higher
learning:
FUSION CRUST ? Melted glassy exterior of a meteorite
that forms when it passes through Earth?s
atmosphere... ...fuses to form a thin, glassy skin
which envelopes the whole meteorite.

<http://www4.nau.edu/meteorite/Meteorite/Book-GlossaryF.html>

Planetary Science Research Discoveries (PSRD)
Fusion crust: The glassy, melted rind on a meteorite
that forms when the rock passes through the Earth's
atmosphere.
<http://www.psrd.hawaii.edu/PSRDglossary.html>


Britannica: any meteorite consisting mainly of iron,
usually combined with small amounts of nickel. When
such meteorites, called irons, fall through the
atmosphere, a thin, black crust of iron oxide may form
that quickly weathers to rust.

Elton aka Eman
Received on Sun 07 Jan 2007 01:27:02 PM PST