Noble gases in ureilites: cosmogenic, radiogenic, and trapped components

Vinai, K.; Murty, S. V. S.; Ott, U.

doi:10.1016/s0016-7037(03)00379-x

Cited by 49 publications

(117 citation statements)

References 53 publications

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“…Estimation of 36 Ar excess from the decay of short-lived 36 Cl hence highly depends on accurate determination and subtraction of these components. A recent study of isotopic compositions of noble gases in meteorites showed a large variation of 38 Ar͞ 36 Ar ratios caused by experimental artifact, requiring reassessment for the entire reported 36 Ar excess (21). Thus, it is likely that the previous report of 36 Cl decay products was inaccurate.…”

Section: Resultsmentioning

confidence: 99%

Short-lived chlorine-36 in a Ca- and Al-rich inclusion from the Ningqiang carbonaceous chondrite

Lin

Guan

Leshin

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

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Excesses of sulfur-36 in sodalite, a chlorine-rich mineral, in a calcium-and aluminum-rich inclusion from the Ningqiang carbonaceous chondrite linearly correlate with chorine͞sulfur ratios, providing direct evidence for the presence of short-lived chlorine-36 (with a half-life of 0.3 million years) in the early solar system. The best inferred ( 36 Cl͞ 35 Cl)o ratios of the sodalite are Ϸ5 ؋ 10 ؊6 . Different from other short-lived radionuclides, chlorine-36 was introduced into the inclusion by solid-gas reaction during secondary alteration. The alteration reaction probably took place at least 1.5 million years after the first formation of the inclusion, based on the correlated study of the 26 Al-26 Mg systems of the relict primary minerals and the alteration assemblages, from which we inferred an initial ratio of ( meteorite ͉ solar nebula ͉ sulfur isotopes ͉ magnesium isotopes ͉ chronometer S hort-lived, now extinct, radionuclides have been detected in primitive meteorites (1). They have been intensively studied and are still subjects of ongoing great interest for broad scientific audiences, because short-lived radionuclides may serve as the only available fine-scale chronometers to trace processes in the early solar system (1, 2), and their relative abundance can constrain the local galactic environment of solar system formation (3-6). However, the origin of short-lived radionuclides is a long-standing issue. One scenario holds that the short-lived radionuclides originated in stellar sources like supernovae (3, 7) or asymptotic giant branch stars (5, 6) in close proximity to the forming solar system. According to such a stellar origin, shortlived radionuclides were injected homogeneously in the solar nebula, hence they may be used as chronometers. This idea is supported by the measurement of U-Pb absolute ages of Caand Al-rich inclusions (CAIs) and chondrules with a Ϸ1-million year (My) resolution (8), which yields a time interval between formation of CAIs and chondrules similar to that inferred by many 26 Mg measurements, although a recent study reported that chondrule formation began contemporaneously with the formation of CAIs (9). On the other hand, the same short-lived radionuclides may be produced locally by intense irradiation of nebular materials by the proto-sun (10-12). The predictions of local irradiation models (4, 13) are compatible with the observed abundance of some nuclides (e.g., 10 Be, 26 Al, 41 Ca, and 53 Mn). According to local irradiation models, the systematically different initial ( 26 Al͞ 27 Al) o ratios between CAIs and chondrules are related to their different distances from the proto-sun, bearing no temporal significance.Chlorine-36 has a half-life of 0.3 My and decays to either 36 Ar (98.1%, ␤ Ϫ ) or 36 S (1.9%, and ␤ ϩ ) (14), hence it can be detected by measuring the excess of 36 Ar or 36 S. A previous study reported the excess of 36 Ar in matrix of the Efremovka carbonaceous chondrite (15), which was attributed to the decay of short-lived 36 Cl. In this study, we provide direc...

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Section: Resultsmentioning

confidence: 99%

Short-lived chlorine-36 in a Ca- and Al-rich inclusion from the Ningqiang carbonaceous chondrite

Lin

Guan

Leshin

et al. 2005

Proc. Natl. Acad. Sci. U.S.A.

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“…Goodrich et al (2004) provided a comprehensive review of polymict ureilites, including all of the samples examined in this study. EET 83309, EET 87720 and Nilpena contain solar-wind implanted gases, indicating derivation from regolith (Rai et al, 2003). Kallemeyn (1989, 1992) reported the bulk compositions of EET 83309 and EET 87720.…”

Section: Petrography Of Selected Polymict Ureilitesmentioning

confidence: 99%

“…1, lower panel. The different cosmicray exposure (CRE) ages of EET 83309 and EET 87520 (Rai et al, 2003) demonstrate that they are not paired.…”

Section: Petrography Of Selected Polymict Ureilitesmentioning

confidence: 99%

Evidence from polymict ureilite meteorites for a disrupted and re-accreted single ureilite parent asteroid gardened by several distinct impactors

Downes

Mittlefehldt

Kita

et al. 2008

Geochimica et Cosmochimica Acta

215

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“…Goodrich et al (2004) suggest that the ureilites, of which more than 300 are known today, were excavated by a single collision and then reassembled as part of a single parent body. Figure 12 shows the distribution of approximate 21 Ne ages of 28 ureilites calculated from a 21 Ne production rate of $0.412 Â 10 -8 cm 3 STP g -1 Ma -1 and the data compiled by Schultz and Franke (2002) and by Rai et al (2003). Four of the samples have unusually short ages -less than 2 Ma.…”

Section: Angritesmentioning

confidence: 99%