Discovery of 17,18O-rich material from meteorite by direct-imaging method using stigmatic-SIMS and 2D ion detector

We report a discovery of a chemically and isotopically unique material distributed ubiquitously in fine-grained matrix of a primitive carbonaceous chondrite Acfer 094. The observations were made in situ using a novel high precision imaging technique adopted direct-imaging method. The material is extremely enriched in heavy oxygen isotopes of 17O and 18O of +18% relative to the Earthʹs ocean while previously reported variation of oxygen isotopes is as large as a range from −8% to 0%. Based on the unique chemical composition of the material, the abundance of the material in the meteorite matrix is calculated to be 94 ± 20 ppm (σ) by volume using elemental mapping with a 7 μm2 spatial resolution by FE-SEM-EDS on the meteorite thin section. The average size of identified materials is 5 μm × 5 μm × 5 μm. Therefore, isotope imaging capability over 500 μm × 500 μm area with micron resolution and an isotopic ratio precision of 1% is required to investigate about the presence of such material.