[meteorite-list] Troilite inclusions

From: bernd.pauli_at_paulinet.de <bernd.pauli_at_meteoritecentral.com>
Date: Mon Jan 3 17:42:48 2005
Message-ID: <DIIE.0000002E00003025_at_paulinet.de>

Norm wrote:

> Norton doesn't answer the Troilite question anywhere that
> I can see. He simply provides descriptive comments.

Hello Norm, John, Steve, and List,

Unfortunately O.R. Norton is not the only one. Even the famous
Vagn Buchwald only comes up with a descriptive comment:

"Troilite usually occurs as shapeless nodules, bars and dumbbells.
The smaller ones may be bar-, diamond-, or plate-shaped."

And:

"At austentitic temperatures troilite, chromite and taenite were
the only phases present in many iron meteorites. Therefore, when
the taenite cooled and started to decompose, the first kamacite
and schreibersite to precipitate formed heterogeneously upon the
available troilite and chromite * n u c l e i *. That is why so
many troilite and chromite inclusions are wrapped in successive
sheets of various minerals. Beautiful examples are to be found in,
e.g., Canyon Diablo, Coahuila, Sikhote-Alin, Cape York, Chupaderos
and Wiley."

BUCHWALD V.F. (1975) Handbook of Iron Meteorites, Volume 1, p. 107.

I also tried to find something in Cohen's trilogy. Same result: descriptive
comments - on page 192, vol.1, you can read in 19th century German (!):

"Schwefeleisen tritt vorherrschend in knollenf?rmigen Massen von sehr
wechselnder Gr??e auf; besonders charakteristisch sind rundliche bis
eif?rmige, auch wohl linsenf?rmige Partien. Sie erreichen nicht gerade
selten Wallnussgr?sse und sind aus Seel?sgen bis zu 9 cm, aus Magura
sogar bis zu 13 cm gross beschrieben worden; aus Cosby's Creek isolirte
Smith ein 200 g schweres St?ck. In manchen Meteoreisen trifft man sie
ziemlich h?ufig von fast idealer Kugelform."

Sulfurous iron is mainly found as globular lumps differing considerably in size
with roundish or egg-shaped but also lenticular parts being especially prominent.
Sometimes they even reach walnut-size and have been described in Seel?sgen
(diameter up to 9 cm), in Magura (even up to 13 cm); Smith separated/isolated
a piece weighing 200 grams from Cosby's Creek. In some meteoric irons you
even find them quite frequently displaying an almost ideal/perfect globular
shape.

COHEN E. (1894) Meteoritenkunde, Heft 1: Untersuchungsmethoden und
Charakteristik der Gemengtheile (Schweizerbart'sche Verlagshandlung,
Stuttgart).


Best wishes,

Bernd
Received on Mon 03 Jan 2005 05:42:45 PM PST