I have been looking at a number of pictures of fragments of Shirokovsky that were shown on various web pages and pictures of pallasites. After comparing them, there appears to be, in my opinion, a rather drastic difference in the texture of the olivine grains within each.. In the pallasites, indvidual grains are equant and either rounded or euhedral. Also, in the pallasites, a person can find examples of olivine grains that have coalesced together.
Examples of this texture can be seen at: http://www.meteoriteman.com/collection/thiel.htm http://www.meteoriteman.com/collection/dora.htm http://www.meteoriteman.com/collection/mtvernon.htm http://meteorites.asu.edu/pallasite.jpg In comparison, pictures of the pieces of Shirokovsky that I have found have a different texture. the olivine crystals are far more angular and variable in outline than found in the pallasites, for which I found pivtures. In fact, some of the olivine pieces in pictures of Shirokovsky are even flat rectagular blades quite unlike anything seen in true pallasites. In addition, I don't see any of the merged / coalesced olivines seen in other, Overall, the Shirokovsky has the apperance of a terrazzo floor made up of fragmented rocks. This is suggestive of fragmented chips of olivine that have been cemented together by the matrix. The difference in the texture of the olivine in the pallasites and the Shirokovsky pseudometeorite is quite striking. The texture, outline, distribution of the olivine grains distinguish Shirokovsky as being different from many pallisites. Also, the angular and highly variable shape of the olivine grains in the Shirokovsky suggest some sort natural or artificial olivine breccia. Although might be / are pallasites that are breccias, it seems like the texture of the Shirokovsky pseudometeorite should have raised a red flag as to its nature. Yours, Paul Baton Rouge, LA __________________________________ Do you Yahoo!? Yahoo! Calendar - Free online calendar with sync to Outlook(TM). http://calendar.yahoo.com ______________________________________________ Meteorite-list mailing list [EMAIL PROTECTED] http://www.pairlist.net/mailman/listinfo/meteorite-list
