Microstructural Analysis of a Wark- Lovering Rim around an Allende Cai
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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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Introduction: Most components of CV chondrites show variable degrees of late-stage alteration resulting in the modification of preexisting mineral assemblages and/or in the formation of new minerals. The conditions and environment under which these processes occurred are highly debated, with arguments in favor of solar nebular as well as asteroidal settings [1]. In the particular case of calciu...
متن کاملComment on “Valence state of titanium in the Wark–Lovering rim of a Leoville CAI as a record of progressive oxidation in the early Solar Nebula― by K.A. Dyl, J.I. Simon and E.D. Young
Dyl et al. (2011) state that their results confirm the conclusion of J. Simon et al. (2005) that the pyroxene in Wark–Lovering rims (Wark and Lovering, 1977) found on Ca-, Al-rich refractory inclusions has lower Ti/Ti ratios than the primary pyroxene in the interiors of inclusions. While true, the claim is misleading because J. Simon et al. (2005) concluded that there was no Ti in the rims, whe...
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Introduction: The refractory Calcium-Aluminumrich Inclusions (CAIs) preserve petrographic and geochemical records of the earliest events that shaped our Solar System. Absolute high-resolution Pb-Pb dating of CAIs has revealed them to be the oldest solids in the Solar System [1-4]. Another useful high-resolution relative dating technique is the Al-Mg short-lived chronometer which has been used e...
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Combined petrologic, oxygen and magnesium isotopic and trace element analyses of a compound calcium–aluminum-rich inclusion (CAI) from the Efremovka reduced CV3 carbonaceous chondrite reveal that it consists of a Mg-rich, O-rich xenolithic CAI, previously altered in the nebula, that impacted an extensively molten, O-depleted, type A host CAI shortly before the end of the host's crystallization....
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