Corundum, rutile, periclase, and CaO in Ca,Al-Rich inclusions from carbonaceous chondrites

Science

Volumn 272, Issue 5266, 1996, Pages 1316-1318

  Greshake, A ^a   Bischoff, A ^a   Putnis, A ^a   Palme, H ^b  

^a UNIVERSITY OF MÜNSTER   (Germany)

^b UNIVERSITY OF COLOGNE   (Germany)

Author keywords

[No Author keywords available]

Indexed keywords

CALCIUM OXIDE; CARBONACEOUS CHONDRITE; CORUNDUM; INCLUSION; PERICLASE; RUTILE;

EID: 0029752437     PISSN: 00368075     EISSN: None     Source Type: Journal    
DOI: 10.1126/science.272.5266.1316     Document Type: Article

References (21)

1. G. J. MacPherson et al., in Meteorites and the Early Solar System, J. F. Kerridge and M. S. Matthews, Eds. (Univ. of Arizona Press, Tucson, 1988), pp. 746-807.
2. L. Grossman, Geochim. Cosmochim. Acta 36, 597 (1972).
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8. M. Bar-Matthews, I. D. Hutcheon, G. J. MacPherson, L. Grossman, Geochim. Cosmochim. Acta 46, 31 (1982); G. J. MacPherson, L. Grossman, A. Hashimoto, M. Bar-Matthews, T. Tanaka, Proc. Lunar Planet. Sci. Conf. 15, C229 (1984).
9. A. Bischoff, H. Palme, B. Spettel, Lunar Planet. Sci. XVIII, 81 (1987).
10. The TEM studies were performed with a 200-kV Philips CM 20 scanning TEM (Institut für Planetologie, Universität Münster, Germany), equipped with a TRACOR EDAX x-ray detector sensitive to elements with atomic numbers >5, and a JEOL JEM 100 operating at 100 kV (Department of Earth Sciences, University of Cambridge). A thin-film procedure was used in measuring the compositions [G. Cliff and G. W. Lorimer, J. Microsc. 103, 203 (1975)]. Experimental EDS corrections (K factors) were derived from analyses of thin-film standards.
11. 0-33) with minor and highly variable proportions of spinel, hibonite, perovskite, and fassaite (1). There is evidence that type A inclusions formed by vaporsolid condensation and were never molten [see, for example, G. J. MacPherson and L Grossman, Geochim. Cosmochim Acta 48, 29 (1984); S. B. Simon et al., Lunar Planet. Sci. XXIV, 115 (1993)].
12. 0-33) with minor and highly variable proportions of spinel, hibonite, perovskite, and fassaite (1). There is evidence that type A inclusions formed by vaporsolid condensation and were never molten [see, for example, G. J. MacPherson and L Grossman, Geochim. Cosmochim Acta 48, 29 (1984); S. B. Simon et al., Lunar Planet. Sci. XXIV, 115 (1993)].
13. J. Newton et al., Meteoritics 30, 47 (1995).
14. Acfer 082, Acfer 086, and Allende belong to the CV meteorite dass [D. W. Sears and R. T. Dodd, in (1), pp. 3-31]. Acfer 094 is a unique primitive carbonaceous chondrite whose mineralogy and oxygen isotopes do not match those of any previously known meteorite class [A. Bischoff and T. Geiger, Lunar Planet. Sci. XXV, 1309 (1994); (11)]. The CAI in Acfer 082 is 5.2 mm by 2 mm in apparent size; in Acfer 086, 7 mm by 3.5 mm; and in Allende, 8 mm by 3 mm.
15. Acfer 082, Acfer 086, and Allende belong to the CV meteorite dass [D. W. Sears and R. T. Dodd, in (1), pp. 3-31]. Acfer 094 is a unique primitive carbonaceous chondrite whose mineralogy and oxygen isotopes do not match those of any previously known meteorite class [A. Bischoff and T. Geiger, Lunar Planet. Sci. XXV, 1309 (1994); (11)]. The CAI in Acfer 082 is 5.2 mm by 2 mm in apparent size; in Acfer 086, 7 mm by 3.5 mm; and in Allende, 8 mm by 3 mm.
16. Samples were ion thinned with a GATAN 600 DIF ion mill at 4.5 kV and 12°.
17. 2; in Acfer 086, 2.5 to 4.0 weight %; in Allende, up to 18 weight % (8); and in Acfer 094, 2.0 to 4.5 weight %.
18. H. Palme and B. Fegley Jr., Earth Planet. Sci. Lett. 101, 180 (1990).
19. R. A. Rolie, B. S. Hemingway, J. R. Fisher, U.S. Geol. Surv. Bull. 1452 (1979).
20. H. Palme and H. Beer, in Landolt-Bömstein, vol. 3, subvol. A of Group VI Astronomy and Astrophysics, H. M. Voigt, Ed. (Springer-Verlag, New York, 1993), pp. 196-221.
21. We thank F. Bartschat for photographic work and two anonymous reviewers for their helpful comments. This study was supported by the Deutsche Forschungsgemeinschaft and is part of the thesis of A.G. (Institut für Planetologie, Universität Münster, Germany).