Opaque Minerals in the Yamato-74191 Chondrules

• Main Authors: Kimura, Makoto, Yagi, Kenzo, Onuma, Kosuke
• Language: English
• Published: 1980
• Subjects: Yamato; Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/record/1091/files/KJ00000011617.pdf; https://nipr.repo.nii.ac.jp/records/1091

P(論文) Opaque minerals occur often as phenocrysts in porphyritic chondrules. Troilite is common in comparison with metallic iron in chondrules, and is often distributed separately from metallic iron in a chondrule. Since some opaque minerals are included in silicate minerals, opaque minerals had crystallized in a chondrule before the crystallization of silicate minerals. Rare chromites are always in contact with troilites. These chromites, including some other meteoritic chromites, have cation deficiency in the B site. This cation deficiency may be interpreted by a substitution of 3Fe^<2+>=2Cr^<8+>+Vacancy. Chromites and olivines in chondrule crystallized in disequilibrium to each other. departmental bulletin paper