Orisin of chondrites interms of metal-sulfide

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Chondrites are primitive meteorites, which preserve information about primordial solar nebula. We set a working hypothesis that metel-sulfide grains in, chondrites have been once formed as molten droplets like silicate chondrules during chondrule formaticm and deformedduring of after accumulation as a parent body. The purpose of this study is to verify the hypothesis rniainly by analyzing three-dimensional structure of a chondrite with high-resolution X-ray CT system.An industrial high-resolution X-ray CT scanner was equipped at Osaka Uniyersity in the present project. The evaluation X-ray CT Scanner was successfully made, Such as quantification of contrasts in CT images. Based on this result, three demensional description of the Kobe meteorite was made and possibility of three-demensional curation of meteorite samples was discussed. Furthermore, X-ray CT system with higher resolution using synchrotron radiation was developed at Spring-8.Samples of carbonaceous chondrite, Y77003 (CO3.5), were imaged with these CT apparatuses. Analysis of three-dimensional CT images showed that the hypothesis is correct. Detailed three-dimensional structures suggested that metal-sulfide grains were deformed during accumulation as a parent body. So far, research of chondrites has been made mainly on silicates. In the present study, the origin of metal-sulfide grains was systematically understood with formation of silicate chondrules as a comprehensive model for chondrites formation.