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Itqiy: A study of noble gases and oxygen isotopes including its terrestrial age and a comparison with Zakłodzie
Author(s) -
Patzer Andrea,
Hill Dolores H.,
Boynton William V.,
Franke Luitgard,
Schultz Ludolf,
Jull A. J. Timothy,
McHargue Lanny R.,
Franchi Ian A.
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.tb00858.x
Subject(s) - enstatite , chondrite , noble gas , meteorite , geology , isotopes of oxygen , chromia , geochemistry , astrobiology , isotopes of argon , achondrite , mineralogy , isotope , materials science , physics , oxide , atomic physics , nuclear physics , metallurgy
— We report noble gas, oxygen isotope, 14 C and 10 Be data of Itqiy as well as noble gas, 14 C and 10 Be results for Zakłodzie. Both samples have been recently classified as anomalous enstatite meteorites and have been compared in terms of their mineralogy and chemical composition. The composition of enstatite and kamacite and the occurrence of specific sulfide phases in Itqiy indicate it formed under similar reducing conditions to those postulated for enstatite chondrites. The new results now seem to point at a direct spatial link. The noble gas record of Itqiy exhibits the presence of a trapped subsolar component, which is diagnostic for petrologic types 4–6 among enstatite chondrites. The concentration of radiogenic 4 He is very low in Itqiy and indicates a recent thermal event. Its 21 Ne cosmic‐ray exposure age is 30.1 ± 3.0 Ma and matches the most common age range of enstatite chondrites (mostly EL6 chondrites) but not that of Zakłodzie. Itqiy's isotopic composition of oxygen is in good agreement with that observed in Zakłodzie as well as those found in enstatite meteorites suggesting an origin from a common oxygen pool. The noble gas results, on the other hand, give reason to believe that the origin and evolution of Itqiy and Zakłodzie are not directly connected. Itqiy's terrestrial age of 5800 ± 500 years sheds crucial light on the uncertain circumstances of its recovery and proves that Itqiy is not a modern fall, whereas the 14 C results from Zakłodzie suggest it hit Earth only recently.