Cosmogenic and trapped noble gases in individual chondrules: Clues to chondrule formation

Das, J. P.; Murty, S. V. S.

doi:10.1111/j.1945-5100.2009.tb01208.x

Cited by 14 publications

(42 citation statements)

References 59 publications

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“…As a simple, one-stage irradiation cannot explain such wide variation, these observations helped fuel a long-running debate over the nature and location of the irradiation(s) that produced the excesses (see discussion of Kapoeta in the succeeding text). The development of laser heating systems with low blanks has made it possible to analyze samples containing fewer than 10 6 atoms of noble gas isotopes, which in turn has reinvigorated the hunt for early irradiation effects (Das and Murty, 2009;Das et al, 2010Das et al, , 2011Roth et al, 2011). Roth et al measured apparent 21 Ne CRE ages (along with 3 He CRE ages) for chondrules from Allende and Murchison, respectively.…”

Section: Cre Ages and Long-lived Chronometersmentioning

confidence: 98%

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Cosmic-Ray Exposure Ages of Meteorites

Herzog

Caffee

2014

Treatise on Geochemistry

153

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Section: Cre Ages and Long-lived Chronometersmentioning

confidence: 98%

“…3. Can we determine separately the CRE histories of chondrules and other small components of meteorites (e.g., Das and Murty, 2009;Das et al, 2010Polnau et al, 2001)? 4.…”

Section: )mentioning

confidence: 99%

Cosmic-Ray Exposure Ages of Meteorites

Herzog

Caffee

2014

Treatise on Geochemistry

153

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“…Eugster et al. () and Das and Murty () also suggested the presence of small amounts of trapped Ne and Ar (of the order of 10 −6 –10 −9 cm 3 STP g −1 ) in chondrules of ordinary and carbonaceous chondrites. In their study, Q and presolar noble gases are the two major trapped components.…”

Section: Introductionmentioning

confidence: 94%

Noble gases in individual chondrules of the Allende CV3 chondrite

Miura

Nagao

Kimura

2014

Meteorit & Planetary Scien

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Abstract-We analyzed noble gases in nine individual chondrules, an assemblage of small chondrules, and four whole-rock samples of the Allende CV3 chondrite. Major elements were also determined for five chondrules. The cosmic ray exposure ages are calculated from cosmogenic 3 He to be 5.17 AE 0.38 and 5.15 AE 0.25 Myr for the averages of the chondrules and whole rocks, respectively, showing no significant pre-exposure evidence for the studied chondrules. Large amounts of 36 Ar, 80,82

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“…, ; Eugster et al. ; Das and Murty ; Matsuda et al. ) showed only small—if any—cosmogenic noble gas excesses in bulk or individual chondrules relative to matrix materials.…”

Section: Introductionmentioning

confidence: 98%

“…Studies of precompaction exposure effects in other chondrites (Polnau et al 1999(Polnau et al , 2001Eugster et al 2007;Das and Murty 2009;Matsuda et al 2010) showed only small-if any-cosmogenic noble gas excesses in bulk or individual chondrules relative to matrix materials. Some chondrules were found to have slightly higher exposure ages than the respective matrix samples.…”

Section: Introductionmentioning

confidence: 99%

Cosmic‐ray exposure ages of chondrules

Roth

Metzler

Baumgartner

et al. 2016

Meteorit & Planetary Scien

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Abstract-If chondrules were exposed to cosmic rays prior to meteorite compaction, they should retain an excess of cosmogenic noble gases. Beyersdorf-Kuis et al. (2015) showed that such excesses can be detected provided that the chemical composition of each individual chondrule is precisely known. However, their study was limited to a few samples as they had to be irradiated in a nuclear reactor for instrumental neutron activation analysis. We developed a novel analytical protocol that combines the measurements of He and Ne isotopic concentrations with a fast method to correct for differences in chemical composition using micro X-ray computed tomography. Our main idea is to combine noble gas, nuclear track, and petrography data for numerous chondrules to understand the precompaction exposure history of the chondrite parent bodies. Here, we report our results for a total of 77 chondrules and four matrix samples from NWA 8276 (L3.00), NWA 8007 (L3.2), and Bjurb€ ole (L/LL4). All chondrules from the same meteorite have within uncertainty identical 21 Ne exposure ages, and all chondrules from Bjurb€ ole have within uncertainty identical 3 He exposure ages. However, most chondrules from NWA 8276 and a few from NWA 8007 show small but resolvable differences in 3 He exposure age that we attribute to matrix contamination and/or gas loss. The finding that none of the chondrules has noble gas excesses is consistent with the uniform track density found for each meteorite. We conclude that the studied chondrules did not experience a precompaction exposure longer than a few Ma assuming present-day flux of galactic cosmic rays. A majority of chondrules from L and LL chondrites thus rapidly accreted and/or was efficiently shielded from cosmic rays in the solar nebula.

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Cosmogenic and trapped noble gases in individual chondrules: Clues to chondrule formation

Abstract: available online at http://meteoritics.org Cosmogenic and trapped noble gases in individual chondrules:Clues to chondrule formation

Cited by 14 publications

References 59 publications

Cosmic-Ray Exposure Ages of Meteorites

Cosmic-Ray Exposure Ages of Meteorites

Noble gases in individual chondrules of the Allende CV3 chondrite

Cosmic‐ray exposure ages of chondrules

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