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PETROLOGY OF NINE ORDINARY CHONDRITE FALLS FROM CHINA

1987; Wiley; Volume: 22; Issue: 1 Linguagem: Inglês

10.1111/j.1945-5100.1987.tb00886.x

2374-9512

Daode Wang, Alan E. Rubin,

Geological and Geochemical Analysis

Nine twentieth‐century ordinary chondrite falls from China are described and classified. They include: Nantong (H6), Zaoyang (H5), Zhaodong (L4), Qidong (L‐LL5), Raoyang (L6), Sheyang (L6), Guangnan (L6), Suizhou (L6) and Nan Yang Pao (L6). Kamacite in Qidong is rare and contains much more Co (15 mg/g) than is characteristic of L‐group chondrites; Qidong may be a member of a chondrite group intermediate in its properties between L and LL. Zhaodong, Qidong, Raoyang, Sheyang and Suizhou have several olivine and/or low‐Ca pyroxene grains with aberrant Fel(Fe + Mg) ratios; it is probable that these five chondrites are fragmental breccias. The lack of correlation between shock facies and occurrence of aberrant silicate grains suggests that breccia lithification caused only minimal shock effects in many meteorites. Alternatively, postshock annealing may have resulted in the recrystallization of shock‐indicating phases, leading to assignment of a shock facies that is lower than that present immediately after the shock event.