Orgueil Meteorite

Orgeuil Meteorite / Carbonaceous Chondrite / CI1 This extremely rare carbonaceous chondrite fell in Tarn-et-Garonne, France in 1864 few minutes after 8 PM. A luminous meteor and sonic booms were followed by the fall of twenty stones; the largest stone was the size of a man's head, but most were only fist-sized. The fall covered an area of over two miles. This is the most chemically primitive of the meteorite classes. Orgueil is a micro-regolith breccia consisting of fragments up to several 100 microns in size. The matrix is composed of a heterogeneous mixture of minerals produced through aqueous alteration. Chondrules are not present, but presolar grains of graphite, diamond and corundum occur. The total recovered weight of this low-density meteorite was ~13 kg. ORGUEIL METEORITE From >http://www4.nau.edu/meteorite/Meteorite/Book-GlossaryO.html A large carbonaceous chondrite that disintegrated and fell in fragments near the French town of Orgueil on May 14, 1864. About 20 pieces, totaling ~12 kg in mass, were subsequently recovered from an area of several square km, some head-sized but most were smaller than a fist. Specimens could be cut with a knife and, when sharpened, could be used like a pencil. Pristine pieces of Orgueil contain a relatively simple mixture of amino acids, consisting primarily of glycine and β-alanine. The carbon isotope composition of the amino acids indicate that they do not represent terrestrial contamination, but formed in space. Whereas CM carbonaceous chondrites contain a complex mix of amino acids made up of more than 70 different types of amino acids, Orgueil (and Ivuna) seem to be made up primarily of just two amino acids. The CM meteorites are widely believed to be pieces of an asteroid, but the amino acid signatures within Orgueil are consistent with formation from components such as hydrogen cyanide, which have been recently observed in the comets Hale-Bopp and Hyakutake. This suggests that the organic material in Orgueil and Ivuna is the product of reactions that once took place in the nucleus of a comet, which, if true, would make these meteorites the first to be identified as having come from a comet nucleus.