STUDY OF EXTRA-SOLAR MATERIALS ON THE VIEW OF OXYGEN ISOTOPES

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Extra-solar materials in Ca, Al-rich inclusions (CAIs) from Allende meteorite have been investigated in this projects. The project may be summarized as follows:(1)Concentration mapping of CAI minerals has been generated by electron micro probe analyzer. The results show crystallization sequences of the minerals.(2)A novel negative-metal ion source (BLAKE-V) for secondary ion mass spectrometry (SIMS) was developed for precise oxygen isotope analyses of CAI minerals.(3)A precise oxygen isotope analysis in CAI minerals was developed using the Au^- primary beam from the BLAKE-V ion source.(4)Oxygen isotope distribution was homogeneous in intra-mineral in CAI, whereas was quite heterogeneous among minerals. Such relationship cannot be interpreted by chemical equilibrium among minerals.(5)The origin of CAI may be interpreted as follows: (a)Spinel grains in CAIs ware crystallized in super novae remnant. (b)pyroxene grains were generated in the mixing gas between the solar nebula and the remnant at the most outer rim of the solar nebulae. (c)In the solar nebulae super cooling liquid was precipitated, and melilite and anorthite grains were crystallized in the liquid.