[meteorite-list] TSCHERMAK G. (1885) - Part 3

From: bernd.pauli_at_paulinet.de <bernd.pauli_at_meteoritecentral.com>
Date: Thu Apr 22 10:32:49 2004
Message-ID: <DIIE.0000004000001BC8_at_paulinet.de>

Marcie kindly wrote:

> Just a quick thank-you for sending the 2 part translated information
> on meteorite identification to the list. Very helpful to me, and others
> I'm sure, as a person, trying to learn all I can about meteorites and
> starting from the beginning in education. Best Regards, Marcie

Hello Marcie, Mark, and List,

My pleasure but please bear in mind that this publication is more than
100 years old - in other words, some of the information may be outdated.
But apart from this tiny grain of salt, Tschermak makes very interesting
reading, and the 100 black and white pics of thin sections with detailed
descriptions presents a tremendous amount of information on the mineralogy
and petrography of meteorites.

Best wishes,

Bernd



TSCHERMAK G. (1885) Die mikroskopische Beschaffenheit der Meteoriten
(Stuttgart E. Schweizerbart'sche Verlagshandlung, E. Koch, 23 pp.).

English Translation: The Microscopic Properties of Meteorites, Vol. 4,
No. 6 (Smithsonian Contributions to Astrophysics, Washington, D.C., 1964).

Translation by J.A. Wood and E.M. Wood

General Characteristics of Meteorites

Stony meteorites very frequently have the character of a volcanic tuff,
consisting of small fragments, chips, and rock powder. The fragments
are sometimes alike (Shalka), sometimes conspicuously heterogeneous
in composition (Luotolax). Occasionally the solid groundmass is quite
different from the grains embedded in it, giving the meteorite a porphyritic
appearance (Goalpara).

Some of the stony meteorites have a crystalline-granular texture (Chassigny,
Shergotty, Ibbenb=FChren), but all gradations exist between these and tufflike
meteorites, so that the same stone (e.g., Stannern) may be described as
crystalline by one observer and clastic by another. Dense, semivitreous
masses (Tadjera), similar to the dark groundmasses of several breccias
noted above, are rare.

Most stones have a chondritic texture, conspicuous or indistinct. Spheres and
rounded bodies consisting of one or several single crystals or often of several
different minerals may form almost the whole of the stone (Borkut); or they may
lie, intact or fractured, in a friable or solid tuffaceous groundmass (Ausson).
These spherical structures are usually smaller than peas; I consider them to
be solidified drops. The groundmass is occasionally black (Renazzo, Grosnaja).
Several stones consist almost entirely of a black mass, colored by carbon
(Cold Bokkeveld).
Received on Sat 13 Mar 2004 06:18:52 AM PST