Orgueil meteorite

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The Orgueil meteorite, a carbonaceous chondrite, fell on May 14, 1864 near Orgueil in southern France. About 20 stones fell over an area of several square miles. Orgueil is one of eight known meteorites belonging to the CI chondrite group (see meteorites classification), this being the largest (14 kg). This group is remarkable for having a composition that is essentially identical to that of the sun, excluding gaseous elements like hydrogen and helium.

For research purposes, the Orgueil meteorite was split up into several pieces which can now be seen in museums in Europe and the USA. The Museum d'Histoire Naturelle of Montauban in Tarn-et-garonne, France, has a large piece of the meteorite weighing eleven kilograms.

Because of its extraordinarily primitive composition and relatively large mass, Orgueil is one of the most-studied meteorites. One notable discovery in Orgueil was a high concentration of isotopically anomalous xenon called "xenon-HL". The carrier of this gas is extremely fine-grained diamond dust that is older than the solar system itself, known as presolar grains.

In 1962, Nagy et al. announced the discovery of 'organised elements' embedded in the Orgueil meteorite that were purportedly biological structures of extraterrestrial origin. These elements were subsequently shown to be either pollen (including that of ragwort) and fungal spores (Fitch & Anders, 1963) that had contaminated the sample, or crystals of the mineral olivine.

In 1965, a fragment of the Orgueil meteorite that had been kept in a sealed glass jar in Montauban since its discovery, was found to have a seed capsule embedded in it, whilst the original glassy layer on the outside remained apparently undisturbed. Despite great initial excitement, it was shown to be that of a European rush that had been glued into the fragment and camouflaged using coal dust. The outer 'fusion layer' was in fact glue. Whilst the perpetrator is unknown, it is thought that the hoax was aimed at influencing 19th century debate on spontaneous generation by demonstrating the transformation of inorganic to biological matter.

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  • Nagy B, Claus G, Hennessy DJ (1962) Organic Particles Embedded in Minerals in Orgueil and Ivuna Carbonaceous Chondrites. Nature 193 (4821) p.1129
  • Fitch FW, Anders E (1963) Organized Element - Possible Identification in Orgueil Meteorite. Science 140 (357) p.1097
  • Gilmour I, Wright I, Wright J 'Origins of Earth and Life', The Open University, 1997, ISBN 0-7492-8182-0