A Brachina-like inclusion in the Yamato-75097 L6 chondrite: A preliminary examination

• Main Authors: Yanai, Keizo, Matsumoto, Yukio, Kojima, Hideyasu
• Language: English
• Published: 1983
• Subjects: Yamato; Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/record/1549/files/KJ00000012182.pdf

P(論文) A Brachina-like inclusion is identified in the Yamato-75097 L6 chondrite. The inclusion has a shiny black fusion crust and is relatively large (2.5×2.5×0.8cm) and about 15g in weight. The fusion crust is distinguished clearly from the dull black fusion crust of the host. Microscopically, the inclusion has a fine-grained granular texture and consists mainly of olivine with minor merrillite and plagioclase, and a little chromite. Plagioclase is isotropic and presumably maskelynite. Pyroxene, nickel-iron and troilite were not identified. The texture of the inclusion appears to be similar to that of the Brachina meteorite. Compositions of the constituent minerals are olivine average Fo_<76> (range Fo_<75.0-76.5>, %M. D.=1.1), maskelynite An_<15>Ab_<75>Or_<10> and merrillite (MgO_<=3.62> FeO_<=0.48> CaO_<=44.9> Na_2O_<=2.79> P_2O_<5=47.4>). Olivine is compositionally homogeneous and relatively Mg-rich compared with that of Brachina. The olivine composition is very similar to that of the host. departmental bulletin paper