[meteorite-list] Some help with [Brenham] inclusions
From: bernd.pauli at paulinet.de <bernd.pauli_at_meteoritecentral.com>
Date: 21 Aug 2007 21:27:20 UT Message-ID: <DIIE.0000009E00001D96_at_paulinet.de> Mike wrote: "a description of which inclusions and colors go with which elements." Hello Mike and List, Here is my take: The round or slightly oval inclusions are troilite (FeS), an iron sulfide - in meteorites the Fe:S ratio is almost ideally 1:1, one iron atom versus one sulphur atom. The elongated, "skeletal", inclusion with that golden tint should be schreibersite crystals - chemical formula (Fe, Ni)3P. The silvery "lining" surrounding the troilite inclusions and also around these elongated schreibersite crystal aggregates is swathing kamacite. That's what meteoriticists call that thin rim that often surrounds troilite, schreibersite and silicate inclusions. This kamacite (nickel-iron with less than 7.5% nickel) is the first to form from taenite (nickel-iron with more than 25% nickel) during the primary cooling phase. Reference: BUCHWALD V.F. (1975) Handbook of Iron Meteorites, Volume 1, pp. 88-89. Best regards, Bernd P.S.: I've really enjoyed your and Ruben's Glorieta Expedition adventures in METEORITE; May 2007, Vol. 13, No. 2, pp. 15-18. Absolutely worth reading ! Received on Tue 21 Aug 2007 05:27:20 PM PDT |
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