Unusual meteorite donated to the Field Museum

Collections & Research Committee member Terry Boudreaux donated a very unusual meteorite specimen to The Field Museum’s Robert A. Pritzker Center for Meteoritics and Polar Studies.  The meteorite is named NWA 5492 after northwest Africa where it was found.  Its petrology and chemical composition are very different compared to other meteorites and it cannot be classified with the existing scheme.  It is therefore just described as an ungrouped chondrite.  Two recently published detailed descriptions of NWA 5492 leave the meteoritics community even more perplexed with regard of the formation mechanisms of this meteorite (Weisberg et al. 2011; Friend et al. 2011).  Robert A. Pritzker Assistant Curator for Meteoritics and Polar Studies Dr. Philipp R. Heck is excited to add this enigmatic specimen to the Field Museum’s collection, as “Oddballs like NWA 5492 force meteoriticists to reassess meteorite classification, and find new explanations for their formation.”  Pictured above is the slice of the ungrouped chondrite NWA 5492, the newest addition to the Museum’s world-class meteorite collection (FMNH specimen number ME 5794).  Note the unusually high metal content (bright and shiny material) for a chondritic meteorite.  The dark materials are mainly silicate chondrules and lithic fragments.  The vertical lines are saw marks.  The Geology Department thanks Terry Boudreaux for this generous donation.  Photo credits to James Holstein and Elizabeth Pelker.