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MINERALOGY, PETROGRAPHY AND CHEMISTRY OF THE CHONDRITE, KAMIOMI, SASHIMA‐GUN, IBARAKI‐KEN, JAPAN
Author(s) -
Okada Akihiko,
Shima Masako,
Murayama Sadao
Publication year - 1979
Publication title -
meteoritics
Language(s) - English
Resource type - Journals
eISSN - 1945-5100
pISSN - 0026-1114
DOI - 10.1111/j.1945-5100.1979.tb00492.x
Subject(s) - olivine , chondrite , chondrule , troilite , petrography , geology , plagioclase , geochemistry , chromite , parent body , mineralogy , ordinary chondrite , meteorite , astrobiology , physics , paleontology , quartz
The Kamiomi, Sashima‐gun (Iwai‐shi), Ibaraki‐ken, Japan, chondrite (observed to fall in spring, during the period 1913–6), consists of olivine, orthopyroxene, nickel‐iron and troilite with minor amount of plagioclase, clinopyroxene, apatite and chromite. The average molar composition of olivine (Fa 19 ) and orthopyroxene (Fs 17 ) indicates that Kamiomi is a typical olivine bronzite chondrite. From the well‐recrystallized texture, the presence of poorly‐definable chondrules, homogeneous composition of olivine and absence of glass, this chondrite could be classified in petrologic type 5. The bulk chemical composition, especially, total Fe (27.33%) and metallic Fe (17.00%) as well as Fe total /SiO 2 (0.72), Fe metal /Fe total (0–633) and SiO 2 /MgO (1.59) support the above conclusion. Coexistence of heavily‐shocked olivine grains in the matrix composed of olivines and pyroxenes which suffered from light to moderate shock effect suggest that impacting phenomena, small‐scaled but locally strong, occurred on the Kamiomi parent body.