Extreme 16 O Enrichment in Calcium - Aluminium - Rich Inclusions from the Isheyevo ( Ch / Cb )
نویسندگان
چکیده
Introduction: Calcium-aluminum-rich inclusions (CAIs) from the metal-rich (CH/CB-like) carbonaceous chondrite Ish-eyevo are mineralogically pristine and show no evidence for postcrystallization alteration [1]. Many of them are composed of very refractory minerals, such as hibonite (CaAl 12 O 19), grossite (CaAl 4 O 7), aluminum-rich pyroxene, and perovskite (CaTiO 3). We will present oxygen isotopic compositions of these pristine CAIs, some of which may have recorded the isotopic composition of the Sun. Methods: Mineralogy of CAIs was determined using conventional techniques at MNHN. The oxygen isotopic compositions were measured in Hawai'i using the UH CAMECA 1280 ion probe and following techniques described in [2].
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