Oxygen isotopic zoning of reversely zoned melilite crystals in a fluffy type A Ca-Al-rich inclusions from the Vigarano meteorite

摘要: – The oxygen isotopic microdistributions within melilite measured using in situ secondary ion mass spectrometry correspond to the chemical zoning profiles single crystals of a fluffy type A Ca-Al-rich inclusions (CAIs) reduced CV3 Vigarano meteorite. show reverse an individual crystal from akermanite-rich core akermanite-poor rim. composition changes continuously with growth. structures suggest that grew hot nebular gas by condensation decreasing pressure. also 16O-poor 16O-rich These observations proceeded change consistent astrophysical setting around inner edge protoplanetary disk where both solar coronal and dense could coexist. Fluffy CAIs have been formed surrounding early sun.