Hello all,Hello Gene, and all the other 'non-self-destruct mode' List Members!While some of the dealers have gone off into self-destruct mode, I thought
some of us might like to continue with the subject at hand...meteorites.I've attached a scanned image of a small slice of Gao I found at a dealer's
table a while back and became intrigued by the two metal inclusions in it.
(Sorry about the scan quality, but I didn't have time to play with it.)The slice weighs about 43 grams and is 6 mm thick. The metal inclusions do not
show through to the other side and it was the only slice the dealer had
showing metal inclusions, so I don't know how thick they are. The elogate
inclusion is approximately 3 mm by 9 mm. Where it runs to the edge it is <2 mm
thick. the roundish inclusion is about 8 mm by 10 mm and has a 3 mm by 4 mm
troilite inclusion within it!Gao is reported as a H5 brecciated chondrite with a low shock stage of S1-2.
The inclusions probably have something to do with the brecciation, but the
rounded inclusion is contained within a rounded clast approximately defined by
the white circle. The elongate clast appears to be part of the primary matrix.
The slice has heavy metal flaking, not atypical for a H chondrite.If anyone has thoughts on the formation of these inclusions and how they came
to be in chondritic material, I would be interested.Gene
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[Image]
Prof.Dr. J.Otto, Min.Petr.Inst., Univ. Freiburg, Albertstr. 23b, D-79104 Freiburg, Germany: (1) Macroscopic description: A fresh fragment partly covered with fusion crust shows several chondrules and many metal-ore particles in the brownish-grey interior. The sample may be brecciated . (2) Thin section: The thin section shows a partly recrystallized chondritic texture. The chondrules are mostly intergrown with the crystalline environment, but a few are still sharply delineated. The sample contains olivine and orthopyroxene, much clinopyroxene but only little plagioclase. Shock effects are minor (S2). Only a small part of the metal is oxidized (W1). (3) Electron microprobe analysis: Olivine Fa 18.4 - 19.6, average Fa 19.1 (n=15), Ca-poor pyroxene Fs 16.8 - 17.3, average Fs 17.1 (n=8), Wo 0.6 - 0.8, average Wo 0.7 (n=8), plagioclase An 9.7 Ab 85.1 Or 5.2 (n=1).
Some years ago, while I was still cooperating with the SML, I translated this classification for Prof. Dr. J. Otto. I don't know if it answers Gene's problem but in case it doesn't, he might ask Prof. Otto directly or perhaps contact Rolf Bühler (SML).
Regards, Bernd Pauli