¹Emmanuel Jacquet,²Yves Marrocchi
Meteoritics & Planetary Science (in Press) Link to Article [DOI: 10.1111/maps.12985]
¹Institut de Minéralogie, de Physique des Matériaux et de Cosmochimie, CNRS & Muséum National d’Histoire Naturelle, UMR 7590, Paris, France
²Centre de Recherches Pétrographiques et Géochimiques, CNRS, Université de Lorraine, UMR 7358, Vandoeuvre-lès-Nancy, France
Publishedby arrangement with John Wiley & Sons

We report combined oxygen isotope and mineral-scale trace element analyses of amoeboid olivine aggregates (AOA) and chondrules in ungrouped carbonaceous chondrite, Northwest Africa 5958. The trace element geochemistry of olivine in AOA, for the first time measured by LA-ICP-MS, is consistent with a condensation origin, although the shallow slope of its rare earth element (REE) pattern is yet to be physically explained. Ferromagnesian silicates in type I chondrules resemble those in other carbonaceous chondrites both geochemically and isotopically, and we find a correlation between 16O enrichment and many incompatible elements in olivine. The variation in incompatible element concentrations may relate to varying amounts of olivine crystallization during a subisothermal stage of chondrule-forming events, the duration of which may be anticorrelated with the local solid/gas ratio if this was the determinant of oxygen isotopic ratios as proposed recently. While aqueous alteration has depleted many chondrule mesostases in REE, some chondrules show recognizable subdued group II-like patterns supporting the idea that the immediate precursors of chondrules were nebular condensates.

¹Tomáš Magna, ²Karel Žák, ³Andreas Pack, ^4,5Frédéric Moynier, ⁴Bérengère Mougel, ³Stefan Peters, ²Roman Skála, ²Šárka Jonášová, ⁶Jiří Mizera, ⁶Zdeněk Řanda
Nature Communications 8, 261, Link to Article [doi:10.1038/s41467-017-00192-5]
¹Czech Geological Survey, Klárov 3, Prague 1, CZ-118 21, Czech Republic
²Institute of Geology of the Czech Academy of Sciences, v.v.i., Rozvojová 269, Prague 6, CZ-165 00, Czech Republic
³Geowissenschaftliches Zentrum, Abteilung Isotopengeologie, Universität Göttingen, Goldschmidtstraße 1, Göttingen, D-37077, Germany
⁴Institut de Physique du Globe de Paris, Université Paris Diderot, 1 rue Jussieu, Paris, F-75005, France
⁵Insitut Universitaire de France, Paris, F-75005, France
⁶Nuclear Physics Institute of the Czech Academy of Sciences, v.v.i., Husinec-Řež, CZ-250 68, Czech Republic

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