Yamato-694 Meteorite: Chemical Composition of Silicate Minerals and Petrographic Nature

• Main Authors: Akihiko Okada, Makoto Shima
• Format: Report
• Language: English
• Published: The Institute of Physical and Chemical Research 1979
• Subjects: Yamato; Antarc*; Antarctica; Memoirs of National Institute of Polar Research; Polar Research
• Online Access: https://nipr.repo.nii.ac.jp/?action=repository_uri&item_id=962; http://id.nii.ac.jp/1291/00000962/; https://nipr.repo.nii.ac.jp/?action=repository_action_common_download&item_id=962&item_no=1&attribute_id=18&file_no=1

Yamato-694 meteorite collected near the Yamato Mountains in Antarctica in 1969 is an ordinary chondrite belonging to a high-iron group. Major chemical composition of its silicate minerals was determined by electron probe microanalysis. Molar composition of olivine, orthopyroxene and plagioclase is (Fo)_<81>, (En)_<82> and (An)_<10>, respectively. In comparison with the analytical data of silicate minerals in ordinary chondrites, the chemical composition of olivine, orthopyroxene and plagioclase in Yamato-694 meteorite agrees with that of silicate grains in equilibrated high-iron chondrites. The result corresponds to the microscopic feature of this meteorite specimen showing an advanced recrystallization texture.