[meteorite-list] Shirokovsky
From: bernd.pauli_at_paulinet.de <bernd.pauli_at_meteoritecentral.com>
Date: Mon Jul 18 15:02:30 2005 Message-ID: <DIIE.0000002F00003AC9_at_paulinet.de> Paul kindly wrote/forwarded this: "Based on the information given I would concur that this is a man-made material, probably derived from a furnace and quite possibly part of a furnace lining, i.e. a refractory brick that has been strongly altered by reaction with the molten con- tents of the furnace. This is supported by the very iron-rich composition of the olivine and the presence of magnesiowustite and magnesioferrite. This conclusion is also supported by the reported 'eutectic' nature of the metal-oxide intergrowth." Hello Paul and List, I thought I might throw in some explanatory remarks to make it easier for everybody to understand this metallurgist's comments with regard to the Shirokovsky material: refractory: - difficult to fuse, heat-resisting - capable of enduring high temperature Allende is known to contain refractory inclusions w?stite: - basically FeO (iron oxide) with a cubic structure ferrite: I think this is basically kamacite eutectic: McSWEEN H.Y. (1999) Meteorites and Their Parent Planets (Cambridge University Press, Glossary, p. 290): - the liquid that occurs at the lowest temperature in a chemical system. On p. 142, McSween writes this about acapulcoites: "At temperatures of 950-1,000?C, a specific combination (called a eutectic mixture) of iron-nickel metal and troilite melted." Best regards, Bernd Received on Mon 18 Jul 2005 03:02:27 PM PDT |
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