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

作者：Sakamoto Naoya^*; Itoh Shoichi; Yurimoto Hisayoshi

来源：Applied Surface Science, 2008, 255(4): 1458-1460.

DOI：10.1016/j.apsusc.2008.05.052

• Direct-imaging
• Stigmatic-SIMS
• Ion detector
• Oxygen isotope
• Meteorite
• Solar System

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 O-17 and O-18 of +18% relative to the Earth's 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 (sigma) by volume using elemental mapping with a 7 mu m(2) spatial resolution by FE-SEM-EDS on the meteorite thin section. The average size of identified materials is 5 mu m x 5 mu m x 5 mu m. Therefore, isotope imaging capability over 500 mu m x 500 mu m area with micron resolution and an isotopic ratio precision of 1% is required to investigate about the presence of such material.

• 出版日期2008-12-15