Orgueil meteorite

Hydroxypyrimidines have been detected in the Murchison, Murray, and Orgueil carbonaceous chondrites in abundances similar to those of amino acids [7]. Earlier analyses of the Orgueil meteorite By thin layer chromatography of organic extracts indicated the presence of melamine, ammeline, adenine, and guanine [8]. Although these could not be confirmed by Folsome, et al., [7] using GC/MS, recent studies by Schwartz [11] and by Hayatsu, et al., [12] have shown that these constituents of the nucleic acids may indeed exist in the carbonaceous chondrites. 

Figure 8. Figure (a) after Clayton et al. (1976, 1977). The scales are as in Figure 1. The O isotopic compositions of the different meteorite classes are represented ordinary chondrites (H, L, LL), enstatite chondrites (EFl, EL), differentiated meteorites (eucrites, lAB irons, SNCs) and some components of the carbonaceous chondrites. As the different areas do not overlap, a classification of the meteorites can be drawn based on O isotopes. Cr (b) and Mo (c) isotope compositions obtained by stepwise dissolution of the Cl carbonaceous chondrite Orgueil (Rotaru et al. 1992 Dauphas et al. 2002), are plotted as deviations relative to the terrestrial composition in 8 units. Isotopes are labeled according to their primary nucleosynthetic sources. ExpSi is for explosive Si burning and n-eq is for neutron-rich nuclear statistical equilibrium. The open squares represent a HNOj 4 N leachate at room temperature. The filled square correspond to the dissolution of the main silicate phase in a HCl-EIF mix. The M pattern for Mo in the silicates is similar to the s-process component found in micron-size SiC presolar grains as shown in Figure 7.

Eberhardt P, Jungck MHA, Meier FO, Niederer FR (1981) Aneon-E rich phase in Orgueil results obtained on density separates. Geochim Cosmochim Acta 45 1515-1528 El Goresy A, Zinner E, Marti K (1995) Survival of isotopically heterogeneous graphite in a differentiated meteorite. Nature 373 496-499... 

Jungck MHA, Eberhardt P (1979) Neon-E in Orgueil density separates. Meteoritics 14 439-440 Jungck MHA, Shimamura T, Lugmair GW (1984) Ca isotope variations in Allende. Geochim Cosmochim Acta 48 2651-2658... 

Podosek FA, Ott U, Brannon JC, Neal CR, Bematowicz TJ, Swan P, Mahan SE (1997) Thoroughly anomalous chromium in Orgueil. Meteorit Planet Sci 32 617-627... 

The Allende, Murchison, Murray and Orgueil meteorites are particularly highly prized for research into stellar grains, since several kilograms of this material have been identified in each of them. This is sufficient to be able to take samples of the order of 1 g without damaging the source. Such samples can then be subjected to compositional analysis. But how can we extract these stellar jewels, measuring at most 1 /rm in diameter, from the matrix in which they are embedded The best way of finding a needle in a haystack is to bum the hay. Cosmochemists employ basically the same method when they use chemical processes to isolate star dust trapped in meteoritic stone. They may then analyse... 

Examples of presolar silicon carbide from the Orgueil meteorite (a, b, c) and hibonite from the Semarkona meteorite (d). These are relatively large for presolar grains. Note the geometric outlines of crystal faces in images (a) and (d). Image (d) is reproduced by permission of the AAS. 

Carbon isotopic compositions of silicon carbide grains from the Murchison meteorite compared with the carbon isotopic compositions of carbon stars (low- to intermediate-mass AGB stars). The composition of carbon in the solar system is indicated by the vertical line. Note the similarity in the distributions of compositions in the two plots. These data indicate that the silicon carbide in the Orgueil meteorite came from a population of carbon stars very similar to that in the galaxy today. 

The characteristics of the presolar diamonds also change with the metamorphic grade of the host meteorite. F igure 5.15 shows the typical bimodal release of heavy noble gases (here illustrated by xenon) in Orgueil, an unheated chondrite. This pattern is compared to the xenon-release patterns of two ordinary chondrites that have experienced different degrees of mild metamorphism. The amount of low-temperature gas, labeled P3 for historical reasons, is a sensitive function of temperature. Its abundance correlates well with other indicators of... 

Huss, G. R. and Smith, J. A. (2007) Titanium isotopes in isotopically characterized silicon carbide grains from the Orgueil Cl chondrite. Meteoritics and Planetary Science, 42, 1055-1075. 

Podosek, F. A., Brannon, J. C., Neal, C. R. etal. (1997) Thoroughly anomalous chromium in Orgueil. Meteoritics and Planetary Science, 32, 617—627. 

Especially large amounts of the uncontaminated CM chondrites Murchison and Tagish Lake have been available since their falls in 1969 and 2000, respectively, and most modem research on extraterrestrial organic matter has focused on these meteorites. Considerable research has also been done on organic matter in the Orgueil Cl chondrite, but this meteorite has been contaminated during its nearly 150 years on Earth. 

BASS (M.N.), 1971. Montmorillonite and serpentine in Orgueil meteorite. Geochim. Acta., 5, 138-39. 

Kerogen, and in the Orgueil Meteorite A Preliminary Report, Proc. Natl. Acad. Sci. (1966) 56, 1383. 

Th fall of the Orgueil meteorite in 1864 enabled various scientists to confirm the previous observations once again. Cloez noted in 1864 the remarkable similarity between the elementary composition of the terrestrial humic substances and that of the carbonaceous matter in the Orgueil meteorite . 

Working on a sample of the Orgueil chondrite, in 1868 Berthelot detected the presence of hydrocarbons after the hydrogenation of a meteorite sample. This... 

The indigenous nature of the alkanes in at least the Murray, Murchison, and Orgueil meteorites (Studier et al., 1968, 1972) is supported by 4 lines of evidence,... 

---