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Isotopic studies of Mg, Fe, Mo, Ru and W in Fremdlinge from Allende refractory inclusions

Hutcheon, Ian D. and Armstrong, John T. and Wasserburg, G. J. (1987) Isotopic studies of Mg, Fe, Mo, Ru and W in Fremdlinge from Allende refractory inclusions. Geochimica et Cosmochimica Acta, 51 (12). pp. 3175-3192. ISSN 0016-7037. doi:10.1016/0016-7037(87)90126-8.

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The isotopic abundances of Mg, Fe, Mo, Ru and W in Fremdlinge and a refractory metal nugget in coarse-grained, Ca-Al-rich inclusions from the Allende meteorite have been determined using the PANURGE ion microprobe. These data represent the first measurement of the isotopic composition of Fremdlinge. No evidence for large, non-mass-dependent deviations (≳1%) from normal solar isotopic abundances was found for any of the elements measured. The only hint, of a nonlinear isotopic anomaly is for Mo in Fremdling 1 of Allende inclusion 5171; the measured ^(100)Mo/^(98)Mo ratio lies slightly more than two standard deviations above the value measured in standards. Isotopic variations due to mass-dependent fractionation are suggested for Mo in two Fremdlinge, Zelda of Egg 6 and Fremdling 1 of 5171, and for Ru in a refractory metal nugget in the FUN inclusion Cl. Mo is enriched in the lighter isotopes by ~ 4‰/amu and ~ 9‰/amu, respectively, while Ru is enriched in the heavier isotopes by ~ 4‰/amu. Despite their unusual mineralogy and extreme enrichment in refractory siderophile elements, Fremdlinge do not contain an enhanced component from a single nucleosynthetic source, but appear to contain the normal solar system mixture of є-, s-, and r-process material. While the possibility that some Fremdlinge may have formed under presolar conditions cannot be excluded, we believe that the chemical, petrologic and isotopic data are most plausibly interpreted in terms of the origin of Fremdlinge within the solar nebula.

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Wasserburg, G. J.0000-0002-7957-8029
Additional Information:© 1987 Pergamon Journals Ltd. Received December 19, 1986; accepted in revised form September 4, 1987. We thank D. A. Papanastassiou for helpful comments and J. Teshima for acute observations of interesting Fremdlinge. We acknowledge B. Mason and the U.S. National Museum of Natural History for lending some of the thin sections studied in the work, L. Hedges for sample preparation, and C. Price for manuscript preparation. The manuscript benefited from constructive, and insightful reviews by A. Kornacki and, especially, E. Zinner. This work was supported by NASA Grant NAG 9-43. Division Contribution No. 4364 (539). Editorial handling: J. D. Macdougall
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Caltech Division of Geological and Planetary Sciences4364
Lunatic Asylum Lab539
Issue or Number:12
Record Number:CaltechAUTHORS:20131029-153637025
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Official Citation:Ian D. Hutcheon, John T. Armstrong, G.J. Wasserburg, Isotopic studies of Mg, Fe, Mo, Ru and W in Fremdlinge from Allende refractory inclusions, Geochimica et Cosmochimica Acta, Volume 51, Issue 12, December 1987, Pages 3175-3192, ISSN 0016-7037, (
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:42122
Deposited By: Ruth Sustaita
Deposited On:30 Oct 2013 16:45
Last Modified:10 Nov 2021 16:17

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