Correlations between oxygen-isotopic composition and petrologic setting in a coarse-grained Ca, Al-rich inclusion

Chondrites and Their Components

“…CAIs from CV chondrites typically exhibit oxygen-isotope heterogeneity within an individual inclusion, with spinel, hibonite, and pyroxene enriched and anorthite and melilite depleted in 16 O. At the same time, several coarse-grained igneous CAIs containing 16 O-rich and 16 O-poor melilite, anorthite and Al-Ti-diopside, and Al-Ti-diopside with oxygen-isotope zoning have been described in several CV chondrites (e.g., Imai and Yurimoto, 2000;Itoh et al, 2004;Katayama et al, 2011;Kim et al, 1998;MacPherson et al, 2012;Park et al, 2011;Yoshitake et al, 2005;Yurimoto et al, 1998). Based on these observations and experimental data on oxygen-isotope self-diffusion in CAI minerals (Ryerson and McKeegan, 1994), Yurimoto et al (1998) concluded that coarse-grained CAIs in CV chondrites were initially 16 O-rich and subsequently experienced oxygen-isotope exchange with 16 O-poor nebular gas while partly molten during reheating.…”

An oxygen isotope study of Wark–Lovering rims on type A CAIs in primitive carbonaceous chondrites

“…Fagan et al, 2004;Aléon et al, 2007;Yoshitake et al, 2005;Itoh et al, 2004). The exception to this is spinel in CH or CB chondrite CAIs that is uniformly 16 O-depleted and may result from a late impact induced re-melting event .…”

Two oxygen isotopic components with extra-selenial origins observed among lunar metallic grains – In search for the solar wind component

“…16 O-rich) are portions of refractory inclusions from primitive chondrites (calcium-aluminumrich inclusions (CAIs)) and amoeboid olivine aggregates (AOAs), which have d 17 O % d 18 O % À50& (e.g., Yoshitake et al, 2005;Krot et al, 2006;Aléon et al, 2007), and a specific chondrule from the CH chondrite Acfer 214 with d 17 O % d 18 O % À75& (Kobayashi et al, 2003) (Fig. 12).…”

“…This is observed at different scales (see e.g., Clayton, 1993Clayton, , 2005: at the planetary scale (between terrestrial samples and Martian meteorites), among asteroidal bodies (in bulk between meteorites belonging to different groups) and among micrometer to millimeter size meteoritic components such as anhydrous minerals in chondrules and in calcium-aluminum-rich inclusions (CAIs) or hydrous minerals (e.g., Choi et al, 1998;Sakamoto et al, 2007; see review by Yurimoto et al, 2008). Generally, the smaller the scale, the larger the degree of isotopic variations (Ozima et al 2007a (Kobayashi et al, 2003), or À50& (e.g., Yoshitake et al, 2005;Krot et al, 2006;Aléon et al, 2007) among the anhydrous minerals, to d 17 O % d 18 O % +180& in an iron-oxide phase (Sakamoto et al, 2007), characterized as ''cosmic symplectite" (Seto et al, 2008). In carbonaceous chondrites anhydrous minerals with large 16 diagram along a line of slope close to 1 (exactly 0.94 ± 0.02 and intercept À4.2&, Clayton et al, 1977) named the CCAM line (for carbonaceous chondrite anhydrous minerals line).…”