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Systematics of Ti isotopes in carbonaceous chondrite whole‐rock samples
Author(s) -
Niemeyer S.
Publication year - 1985
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/gl012i010p00733
Subject(s) - meteorite , chondrite , carbonaceous chondrite , murchison meteorite , allende meteorite , parent body , geology , geochemistry , isotope , refractory (planetary science) , mineralogy , analytical chemistry (journal) , astrobiology , chemistry , physics , environmental chemistry , quantum mechanics
Titanium isotopic compositions in whole‐rock samples are reported for meteorites from all four carbonaceous chondrite classes. Characteristic isotopic patterns are derived for each class, since meteorites in a given class usually, though not always, give the same pattern. No anomalies are resolved at the 47/46 and 48/46 ratios, but small 50 excesses are prevalent [ε(50/46) mean values are CI=+1.0±0.8; CM=+2.4±0.6; CO=+3.0±0.5; CV=+3.3±0.5]. Among the three classes where Ti anomalies are clearly present, the mean values for the 50 excesses are the same within the uncertainties. In contrast, the CI class gives just a hint of a 50 excess. Available data, including analyses of Murchison (CM) density separates, suggest that anomalous Ti is not confined to phases in refractory inclusions. Kakangari, a petrologically and chemically peculiar meteorite, shows a clear deficit of 50, thereby supporting a previous suggestion that it is a unique carbonaceous chondrite.