کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
8911002 | 1637936 | 2018 | 44 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
A multielement isotopic study of refractory FUN and F CAIs: Mass-dependent and mass-independent isotope effects
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
علوم زمین و سیارات
ژئوشیمی و پترولوژی
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چکیده انگلیسی
The initial 26Al/27Al ratios inferred from model isochrons span a range from <1 Ã 10â6 to canonical (â¼5 Ã 10â5). The CAIs show a mutual exclusivity relationship between inferred incorporation of live 26Al and the presence of resolvable anomalies in 48Ca and 50Ti. Furthermore, a relationship exists between 26Al incorporation and Î17O in the hibonite-rich CAIs (i.e., 26Al-free CAIs have resolved variations in Î17O, while CAIs with resolved 26Mg excesses have Î17O values close to â23â°). Only the grossite-rich CAI has a relatively enhanced Î17O value (â¼â17â°) in spite of a near-canonical 26Al/27Al. We interpret these data as indicating that fractionated hibonite-rich CAIs formed over an extended time period and sampled multiple stages in the isotopic evolution of the solar nebula, including: (1) an 26Al-poor nebula with large positive and negative anomalies in 48Ca and 50Ti and variable Î17O; (2) a stage of 26Al-admixture, during which anomalies in 48Ca and 50Ti had been largely diluted and a Î17O value of â¼â23â° had been achieved in the CAI formation region; and (3) a nebula with an approximately canonical level of 26Al and a Î17O value of â¼â23â° in the CAI formation region.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Geochimica et Cosmochimica Acta - Volume 221, 15 January 2018, Pages 296-317
Journal: Geochimica et Cosmochimica Acta - Volume 221, 15 January 2018, Pages 296-317
نویسندگان
Levke Kööp, Daisuke Nakashima, Philipp R. Heck, Noriko T. Kita, Travis J. Tenner, Alexander N. Krot, Kazuhide Nagashima, Changkun Park, Andrew M. Davis,