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Yamato 792947, 793408 and 82038: The most primitive H chondrites, with abundant refractory inclusions
Author(s) -
Kimura M.,
Hiyagon H.,
Palme H.,
Spettel B.,
Wolf D.,
Clayton R. N.,
Mayeda T. K.,
Sato T.,
Suzuki A.,
Kojima H.
Publication year - 2002
Publication title -
meteoritics and planetary science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.09
H-Index - 100
eISSN - 1945-5100
pISSN - 1086-9379
DOI - 10.1111/j.1945-5100.2002.tb01038.x
Subject(s) - chondrite , chondrule , meteorite , refractory (planetary science) , geology , geochemistry , astrobiology , isotopes of oxygen , formation and evolution of the solar system , chemical composition , mineralogy , chemistry , physics , organic chemistry
— In this paper we report petrological and chemical data of the unusual chondritic meteorites Yamato (Y)‐792947, Y‐93408 and Y‐82038. The three meteorites are very similar in texture and chemical composition, suggesting that they are pieces of a single fall. The whole‐rock oxygen isotopes and the chemical compositions are indicative of H chondrites. In addition, the mineralogy, and the abundances of chondrule types, opaque minerals and matrices suggest that these meteorites are H3 chondrites. They were hardly affected by thermal and shock metamorphism. The degree of weathering is very low. We conclude that these are the most primitive H chondrites, H3.2–3.4 (S1), known to date. On the other hand, these chondrites contain extraordinarily high amounts of refractory inclusions, intermediate between those of ordinary and carbonaceous chondrites. The distribution of the inclusions may have been highly heterogeneous in the primitive solar nebula. The mineralogy, chemistry and oxygen isotopic compositions of inclusions studied here are similar to those in CO and E chondrites.