Condensation of major elements during chondrule formation and its implication to the origin of chondrules

Nagahara, H.; Kita, N. T.; Ozawa, Kazuhito; Morishita, Y.

doi:10.1016/j.gca.2007.12.020

Cited by 51 publications

(45 citation statements)

References 58 publications

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“…Spinel, olivine and pyroxene represent the primary O-isotopic compositions of ARCs, and define a line (dashed) with a slope of ~ 0.7 ± 0.1. They are 16 O-poor relative to their counterparts reported by Russell et al (2000) but similar to those by Nagahara et al (2008). The gray ellipse covers the range of in situ O-isotopic compositions of ferromagnesian chondrules in UOCs (Kita et al, 2010).…”

Section: Volatility-controlled Gas-solid Reactionsupporting

confidence: 53%

“…To date, three main scenarios have been proposed for the origin of ARCs. These include: (1) melting of CAI and ferromagnesian chondrule mixtures (Krot et al, 2002;; (2) volatility-controlled gas-solid reaction (MacPherson and Huss, 2005); and (3) formation of the CAI-like melt by Mg, Si-rich gas condensation (Nagahara et al, 2008). With the mineralogical and O-isotopic data obtained in ARCs from ordinary chondrites, we will discuss each of these models as following.…”

Section: Discussionmentioning

confidence: 99%

“…The third hypothesis for the formation of ARCs invoked a local shock heating event which induced melting of Type C CAI and concomitant evaporation of dusts and ferromagnesian chondrules, and then produced Mg and Si-rich gas condensed onto the melt droplets upon cooling (Nagahara et al, 2008). This model, based on two glassy ARCs in Semarkona, accounts well for the continuity between Type C CAIs and ARCs, which is not explained well by the first two models, but also answers a perplexing question, that is why ARCs are on a mixing line between the ferromagnesian chondrules and Type C CAIs, not any melilite-rich (Types A and B) CAIs.…”

Section: The Cai-like Melt By Mg and Si-rich Gas Condensationmentioning

confidence: 99%

“…They concluded that ARCs were not simple mixtures of these two components. Recently, Nagahara et al (2008) measured oxygen isotopes of two glassy ARCs in Semarkona (LL3.0), the most primitive UOC. Their data plot on or above the terrestrial mass fractionation (TF) line.…”

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confidence: 99%

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In situ SIMS oxygen isotope analyses: Evidence for the formation of aluminum-rich chondrules from ordinary chondrites

Jiang

Hsu

Guan

et al. 2015

Sci. China Earth Sci.

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Aluminum-rich chondrules (ARCs), which share mineralogic and chemical properties with both Ca, Al-rich inclusions (CAIs) and ferromagnesian chondrules, play an important role in revealing their temporal and petrogenetic relationships. In this work, seven ARCs were found in three ordinary chondrites GRV 022410 (H4), GRV 052722 (H3.7) and Julesburg (L3.6). They contain bulk Al 2 O 3 ~ 17%−33% and exhibit igneous textures composed of olivine, high-and low-Ca pyroxene, plagioclase, spinel and glass. In situ SIMS analyses show that ARCs have oxygen isotopic compositions (δ 18 O=-6.1‰-7.1‰; δ 17 O= -4.5‰-5.1‰) close to ferromagnesian chondrules but far more depleted in 16 O than CAIs (δ 18 O=−40‰; δ 17 O=−40‰). Most ARCs plot close to the terrestrial mass fractionation (TF) line, and a few between the TF and carbonaceous chondrite anhydrous mixing (CCAM) lines. Plagioclase, nepheline and glass suffered O-isotopic exchanges during the metamorphism processes in the parent body. Spinel, olivine and pyroxene represent the primary O-isotopic compositions of ARCs, and define a fitted line with a slope of ~ 0.7±0.1. Compared with the results of previous studies, shallower slope as well as more depleted 16 O compositions further demonstrates that ARCs in ordinary chondrites are not a simple mixing product of ferromagnesian chondrules and CAIs. Instead, they probably experienced higher-degree oxygen isotope exchange with a 16 O-poor nebular gas reservoir during multiple melting episodes. O-isotope, SIMS, Al-rich chondrule, ordinary chondrite, Antarctic meteorite Citation:Jiang Y, Hsu WB, Guan YB, et al. 2015. In situ SIMS oxygen isotope analyses: Evidence for the formation of aluminum-rich chondrules from ordinary chondrites. Science China: Earth Sciences,

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Section: Volatility-controlled Gas-solid Reactionsupporting

confidence: 53%

Section: Discussionmentioning

confidence: 99%

Section: The Cai-like Melt By Mg and Si-rich Gas Condensationmentioning

confidence: 99%

mentioning

confidence: 99%

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In situ SIMS oxygen isotope analyses: Evidence for the formation of aluminum-rich chondrules from ordinary chondrites

Jiang

Hsu

Guan

et al. 2015

Sci. China Earth Sci.

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“…It is important to investigate the relationship between chemical and isotopic fractionations through evaporation and recondensation during CAI and chondrule formation to understand the physical and chemical conditions that resulted in the insignificant mass-dependent isotopic fractionation (Nagahara et al 2008). Ozawa and Nagahara (2001) explored a model for a silicate melt sphere that was heated instantaneously to an above solidus temperature and then cooled in a closed system.…”

Section: Introductionmentioning

confidence: 99%

The role of exchange reactions in oxygen isotope fractionation during CAI and chondrule formation

Nagahara¹,

Ozawa

2012

Meteorit & Planetary Scien

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Abstract-The role of oxygen isotope exchange during evaporation and condensation of silicate melt is quantitatively evaluated. Silicate dusts instantaneously heated above liquidus temperature are assumed to cool in gas and experience partial evaporation and subsequent recondensation. The results show that isotopic exchange effectively suppresses massdependent O-isotope fractionation even if the degree of evaporation is large, which is the fundamental difference from the case without isotopic exchange. The final composition of silicate melt strongly depends on the initial abundance of oxygen in the ambient gas relative to that in silicate dust, but not on the cooling rate of the system. The model was applied to O-isotope evolution of silicate melts in isotopically distinct gas of the protoplanetary disk. It was found that deviation from a straight mixing line toward the d18 O-rich side on the threeoxygen isotope diagram is inevitable when mass-dependent fractionation and isotopic exchange take place simultaneously; the degree of deviation depends on the abundance of oxygen in an ambient gas and isotopic exchange efficiency. The model is applied to explain O-isotopic compositions of igneous CAIs and chondrules.

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Chondrule Properties and Formation Conditions

Marrocchi,

Jones,

Russell

et al. 2024

Space Sci Rev

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Chondrules are iconic sub-millimeter spheroids representing the most abundant high-temperature dust formed during the evolution of the circumsolar disk. Chondrules have been the subject of a great deal of research, but no consensus has yet emerged as to their formation conditions. In particular, the question of whether chondrules are of nebular or planetary origin remains largely debated. Building upon decades of chondrule investigation and recent headways in combining petrographic observations and O−Ti−Cr isotopic compositions, we here propose a comprehensive vision of chondrule formation. This holistic approach points toward a nebular origin of both NC and CC chondrules, with repetitive high-temperature recycling processes controlling the petrographic and isotopic diversities shown by chondrules. Chondrule precursors correspond to mixing between (i) early-formed refractory inclusions ± NC-like dust and (ii) previous generation of chondrules ± CI-like material. Chondrule formation took place under open conditions with gas-melt interactions with multi-species gas (H2O, Mg, SiO) playing a key role for establishing their characteristics. Petrographic and isotopic systematics do not support disk-wide transport of chondrules but point toward local formation of chondrules within their respective accretion reservoirs. Altogether, this shows that several generations of genetically-related chondrules (i.e., deriving from each other) co-exist in chondrites. In addition to supporting the nebular brand of chondrule-forming scenarios, this argues for repetitive and extremely localized heating events for producing chondrules.

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Condensation of major elements during chondrule formation and its implication to the origin of chondrules

Cited by 51 publications

References 58 publications

In situ SIMS oxygen isotope analyses: Evidence for the formation of aluminum-rich chondrules from ordinary chondrites

In situ SIMS oxygen isotope analyses: Evidence for the formation of aluminum-rich chondrules from ordinary chondrites

The role of exchange reactions in oxygen isotope fractionation during CAI and chondrule formation

Chondrule Properties and Formation Conditions

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