Identification of the parent bodies of micrometeorites with high-precision oxygen isotope ratios

• Published in: Earth and Planetary Science Letters
• Main Authors: Suavet, Clément, Alexandre, Anne, Franchi, Ian, A, Gattacceca, Jérôme, Sonzogni, Corinne, Greenwood, Richard, Folco, Luigi, Rochette, Pierre
• Other Authors: Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement (CEREGE), Institut de Recherche pour le Développement (IRD)-Institut National de la Recherche Agronomique (INRA)-Aix Marseille Université (AMU)-Collège de France (CdF (institution))-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), The Open University Milton Keynes (OU), University of Portsmouth, Museo Nazionale dell'Antartide, Università degli Studi di Siena = University of Siena (UNISI)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2010
• Subjects: ordinary chondrites; laser fluorination; micrometeorites; carbonaceous chondrites; parent bodies; cosmic spherules; [SDE]Environmental Sciences; [SDU.STU.GC]Sciences of the Universe [physics]/Earth Sciences/Geochemistry; Antarc*; Antarctica
• Online Access: https://hal.science/hal-01909569; https://hal.science/hal-01909569/document; https://hal.science/hal-01909569/file/Suavet%20et%20al.,%202010.pdf; https://doi.org/10.1016/j.epsl.2010.02.046

International audience Oxygen isotopic compositions allow identification of potential parent bodies of extraterrestrial materials. We measured oxygen isotope ratios of 33 large (diameter > 500 μm) silicate melted micrometeorites (cosmic spherules) from Antarctica, using IR-laser fluorination coupled with mass spectrometry. It is the first time that this high-precision method is used on individual micrometeorites. The selected micrometeorites are representative of the influx of extraterrestrial materials to the Earth. Our results show that most micrometeorites are related to carbonaceous chondrites, which is consistent with previous studies. However, 20–50% of them seem to be related to CO/CV carbonaceous chondrites, whereas CM/CR carbonaceous chondrites were thought to be the main source for micrometeorites. Furthermore, ∼ 30% of measured samples have oxygen isotope ratios lying above the terrestrial fractionation line, which relates them to ordinary chondrites or other, as yet, unsampled parent bodies.