A Spectrum of Oxygen Isotopic Zoning Profiles in CAIs Records Varying Exposure to Distinct Protoplane-
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Oxygen Isotope Measurements of a Rare Murchison Type a Cai and Its Rim
Introduction: Ca-, Al-rich inclusions (CAIs) from CV chondrites commonly show oxygen isotope heterogeneity among different mineral phases within individual inclusions reflecting the complex history of CAIs in both the solar nebula and/or parent bodies [1]. The degree of isotopic exchange is typically mineralspecific, yielding O-rich spinel, hibonite and pyroxene and O-depleted melilite and anor...
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Micrometer-scale analyses of a calcium-, aluminum-rich inclusion (CAI) and the characteristic mineral bands mantling the CAI reveal that the outer parts of this primitive object have a large range of oxygen isotope compositions. The variations are systematic; the relative abundance of (16)O first decreases toward the CAI margin, approaching a planetary-like isotopic composition, then shifts to ...
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Introduction: Wark-Lovering (WL) rims [1] surrounding many refractory inclusions represent marker events in the early evolution of the Solar System in which many inclusions were exposed to changes in pressure [2], temperature [3], and isotopic reservoirs [4-7]. The effects of these events can be complex, not only producing mineralogical variability of WL rims [2], but also leading to mineralogi...
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The magnesium isotopic composition of Calcium-, Aluminium-rich Inclusions (CAIs) and chondrules from the CBb chondrites HH237 and QUE94411 was measured using MC-ICPMS coupled with a laser ablation system. CAIs from CBb chondrites exhibit limited mass-dependent fractionation (δ Mg′ (DSM3) b1.3‰) and formed with undetectable Al (Al/Al b4.6×10). Petrographic observations suggest that CBb CAIs are ...
متن کاملExtreme 16 O Enrichment in Calcium - Aluminium - Rich Inclusions from the Isheyevo ( Ch / Cb )
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 iso...
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