Petrological Studies on Yamato-74354, -74190, -74362, -74646 and -74115 Chondrites

• Main Author: Nagahara, Hiroko
• Language: English
• Published: 1979
• Subjects: Yamato; Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/record/1045/files/KJ00000011589.pdf

P(論文) Petrological description has been done on five different Yamato-74354 (L6), -74362 (L6), -74190 (L6), -74646 (LL6) and -74115 (H5) chondrites. Detailed microprobe analyses of the constituent minerals and chondrules indicate that these chondrites consist of homogeneous silicate minerals and remarkably heterogeneous Fe-Ni metals. They show various degrees of recrystallization but the equilibrium temperature of olivine, pyroxenes and chromite is about 900℃ and is quite similar among these five chondrites. The degree of recrystallization, therefore, would depend not only on the equilibrium temperature but also largely on the duration of recrystallization. It is also suggested that the bulk chemical composition of chondrules has been hardly affected by thermal metamorphism. departmental bulletin paper