Ion microprobe Al–Mg dating of single plagioclase grains in an Efremovka chondrule

Sano, Yuji; Takada, Mio; Takahata, Naoto; Fujiya, Wataru; Sugiura, N.

doi:10.2343/geochemj.2.0294

Cited by 7 publications

(1 citation statement)

References 29 publications

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“…Kimura and Ikeda, 1995;1997;Ichimura et al, 2017), and could explain disturbed Al-Mg isotope systematics among type ≥3.1 chondrite chondrules with this feature (e.g. Sano et al, 2014;Nagashima et al, 2017). Finally, we note that the extent of thermal metamorphism is often variable throughout a chondrite sample, meaning some FeO-poor chondrules with unaltered plagioclase may exist in type ≥3.1 chondrites.…”

Section: Chondrule Intermineral O-isotope Comparisons Suggest Plagioclasementioning

confidence: 65%

Extended chondrule formation intervals in distinct physicochemical environments: Evidence from Al-Mg isotope systematics of CR chondrite chondrules with unaltered plagioclase

Tenner

Nakashima

Ushikubo

et al. 2019

Geochimica et Cosmochimica Acta

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Al-Mg isotope systematics of twelve FeO-poor (type I) chondrules from CR chondrites Queen Alexandra Range 99177 and Meteorite Hills 00426 were investigated by secondary ion mass spectrometry (SIMS). Five chondrules with Mg#'s of 99.0 to 99.2 and Δ 17 O of −4.2‰ to −5.3‰ have resolvable excess 26 Mg. Their inferred ( 26 Al/ 27 Al) 0 values range from (3.5 ± 1.3) × 10 -6 to (6.0 ± 3.9) × 10 -6 . This corresponds to formation times of 2.2 (-0.5/+1.1) Myr to 2.8 (-0.3/+0.5) Myr after CAIs, using a canonical ( 26 Al/ 27 Al) 0 of 5.23 × 10 ˗5 , and assuming homogeneously distributed 26 Al that yielded a uniform initial 26 Al/ 27 Al in the Solar System. Seven chondrules lack resolvable excess 26 Mg. They have lower Mg#'s (94.2 to 98.7) and generally higher Δ 17 O (−0.9‰ to −4.9‰) than chondrules with resolvable excess 26 Mg. Their inferred ( 26 Al/ 27 Al) 0 upper limits range from 1.3 × 10 -6 to 3.2 × 10 -6 , corresponding to formation >2.9 to >3.7 Myr after CAIs. Al-Mg isochrons depend critically on chondrule plagioclase, and several characteristics indicate the chondrule plagioclase is unaltered: (1) SIMS 27 Al/ 24 Mg depth profile patterns match those from anorthite standards, and SEM/EDS of chondrule SIMS pits show no foreign inclusions; (2) transmission electron microscopy (TEM) reveals no nanometer-scale microinclusions and no alteration due to thermal metamorphism; (3) oxygen isotopes of chondrule

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Section: Chondrule Intermineral O-isotope Comparisons Suggest Plagioclasementioning

confidence: 65%

Extended chondrule formation intervals in distinct physicochemical environments: Evidence from Al-Mg isotope systematics of CR chondrite chondrules with unaltered plagioclase

Tenner

Nakashima

Ushikubo

et al. 2019

Geochimica et Cosmochimica Acta

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26 Al– 26 Mg systematics in chondrules from Kaba and Yamato 980145 CV3 carbonaceous chondrites

Nagashima

Krot

Komatsu

2017

Geochimica et Cosmochimica Acta

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A temporal shift of chondrule generation from the inner to outer Solar System inferred from oxygen isotopes and Al-Mg chronology of chondrules from primitive CM and CO chondrites

Fukuda

Tenner

Kimura

et al. 2022

Geochimica et Cosmochimica Acta

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Ion microprobe Al–Mg dating of single plagioclase grains in an Efremovka chondrule

Cited by 7 publications

References 29 publications

Extended chondrule formation intervals in distinct physicochemical environments: Evidence from Al-Mg isotope systematics of CR chondrite chondrules with unaltered plagioclase

Extended chondrule formation intervals in distinct physicochemical environments: Evidence from Al-Mg isotope systematics of CR chondrite chondrules with unaltered plagioclase

26 Al– 26 Mg systematics in chondrules from Kaba and Yamato 980145 CV3 carbonaceous chondrites

A temporal shift of chondrule generation from the inner to outer Solar System inferred from oxygen isotopes and Al-Mg chronology of chondrules from primitive CM and CO chondrites

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