OXYGEN ISOTOPES IN CALCIUM-ALUMINUM-RICH INCLUSIONS FROM ENSTATITE CHONDRITES: NEW EVIDENCE FOR A SINGLE CAI SOURCE IN THE SOLAR NEBULA

Abstract

Calcium-aluminum-rich inclusions (CAIs) from enstatite chondrites have large 16O excesses, similar to CAIs in carbonaceous and ordinary chondrites, and are also similar in morphology, mineralogy and Al-Mg isotopic systematics. These similarities provide new evidence that most CAIs might have formed in a single, restricted nebular locale and were then distributed unevenly throughout the various chondrite accretion regions.