Verification and interpretation of the I-Xe chronometer

Brazzle, R. H.; Pravdivtseva, O. V.; Meshik, A. P.; Hohenberg, C. M.

doi:10.1016/s0016-7037(98)00314-7

Cited by 116 publications

(105 citation statements)

References 24 publications

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“…All Rb-Sr ages would be older by 1.3% using ϭ 1.402 ϫ 10 Ϫ11 . c (a) This work; (b) Olsen et al, 1994l (c) Synder et al, 1998(d) Göpel et al, 1985; (e) Burnett and Wasserburg, 1967a; (f) Bogard et al, 1969; Birck and Allègre, 1998;(h) Neimeyer, 1980;(i0 Sanz et al, 1970; Bogard et al, 1968; Brazzle et al, 1999; Burnett and Wasserburg, 1967b; (m) Evensen et al, 1979; Casanova et al, 1995Casanova et al, . 2140 D. D. Bogard, D. H. Garrison, and T. J. McCoy with lower K/Ca degassing Ar at higher temperatures show slightly lower Ar-Ar ages.…”

Section: Milesmentioning

confidence: 90%

Chronology and petrology of silicates from IIE iron meteorites: evidence of a complex parent body evolution

Bogard

Garrison

McCoy

2000

Geochimica et Cosmochimica Acta

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Abstract-IIE iron meteorites contain silicate inclusions the characteristics of which suggest a parent body similar to that of H-chondrites. However, these silicates show a wide range of alteration, ranging from Netschaëvo and Techado, the inclusions of which are little altered, to highly differentiated silicates like those in Kodaikanal, Weekeroo Station, and Colomera, which have lost metal and sulfur and are enriched in feldspar. We find these inclusions to show varying degrees of shock alteration. We made 39 Ar-40 Ar age determinations of Watson, Techado, Miles, Colomera, and Sombrerete. Watson has an Ar-Ar age of 3.677 Ϯ 0.007 Gyr, similar to previously reported ages for Kodaikanal and Netschaëvo. We suggest that the various determined radiometric ages of these three meteorites were probably reset by a common impact event. The space exposure ages for these three meteorites are also similar to each other and are considerably younger than exposure ages of other IIEs.39 Ar ages inferred for the other four meteorites analyzed are considerably older than Watson and are: Techado ϭ 4.49 Ϯ 0.01 Gyr, Miles ϭ 4.405 Ϯ 0.012 Gyr, Colomera ϭ 4.470 Ϯ 0.010 Gyr, and Sombrerete ϭ 4.541 Ϯ 0.0012 Gyr. These ages are in fair agreement with previously reported Rb-Sr isochron ages for Colomera and Weekeroo Station. Although several mechanisms to form IIE meteorites have been suggested, it is not obvious that a single mechanism could produce a suite of meteorites with very different degrees of silicate differentiation and with isotopic ages that differ by Ͼ0.8 Gyr. We suggest that those IIEs with older isotopic ages are a product of partial melting and differentiation within the parent body, followed by mixing of silicate and metal while both were relatively hot. Netschaëvo and Watson may have formed by this same process or by impact mixing ϳ4.5 Gyr ago, but their isotopic ages may have been subsequently reset by shock heating. Kodaikanal apparently is required to have formed more recently, in which case impact melting and differentiation seems the only viable process. We see no compelling reasons to believe that IIE silicate and metal derived from different parent bodies or that the parent body of IIEs was the same as that of H-chondrites.

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Section: Milesmentioning

confidence: 90%

Chronology and petrology of silicates from IIE iron meteorites: evidence of a complex parent body evolution

Bogard

Garrison

McCoy

2000

Geochimica et Cosmochimica Acta

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“…In possible support of this suggestion is the observation that space (CRE) exposure ages of most acapulcoites and lodranites fall in a narrow range (Herzog, 2003), likely indicating their ejection from the parent object in only a few impact events. In the cooling model presented for Acapulco by Pellas et al (1997), initial cooling of the parent body was rapid down to temperatures of $700 K, to account for the older Pb-Pb and I-Xe ages of 4.557 Ga (Brazzle et al, 1999), but was much slower for temperatures of <700K, in order to explain the younger Ar-Ar ages and even younger Pu fission track ages. By this model the segregation of Fe,Ni-FeS from silicate described above would have occurred prior to closure of the Ar-Ar age.…”

Section: Ar-40 Ar Datingmentioning

confidence: 99%

Graves Nunataks 95209: A snapshot of metal segregation and core formation

McCoy

Carlson

Nittler

et al. 2006

Geochimica et Cosmochimica Acta

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“…The 60 Fe is a critical problem which we discuss extensively. Further experimental work and theoretical discussion on various short-lived radioactive isotopes may be found in Hudson et al (1989), MacPherson, Davis, & Zinner (1995), Russell et al (1996), Chen et al (1996), Murty et al (1997), Stewart, Papanastassiou, & Wasserburg (1996), Arnould et al (1997), Brazzle et al (1999) and Goswami & Vanhala (2000).…”

Section: Se Non è Vero è Bene Trovato Ancient Italian Motto 1 Introdumentioning

confidence: 99%

“…The first column lists the radioactive nuclide (R), the second the stable reference isotope (S), the third the meanlife of R and the fourth the ratio (N R /N S ) for the initial state of the solar system, as estimated from the measurements. The column labeled 'Place' refers to the class of objects in which evidence has been found for the presence of R. This means that when Lee et al (1976Lee et al ( , 1977; (3) Srinivasan, Ulyanov, & Goswami 1994; (4) Birck & Allègre (1985); Rotaru, Birck, & Allègre (1992); Lugmair & Shukolyukov (1998);Hutcheon et al (1998); (5) Shukolyukov & Lugmair (1993a, 1993b; Lugmair et al (1995); (6) Birck & Lugmair 1988; (7) Tachibana & Huss (2003a, 2003b, Mostefaoui et al (2003); (8) Kelly & Wasserburg (1978); (9) Reynolds (1960); Jeffery & Reynolds (1961); Brazzle et al (1999); (10) Lugmair & Marti (1977); Lugmair & Galer 1992;(11) Harper & Jacobsen (1994); Lee & Halliday (1995); Yin et al (2002); Kleine et al (2002); (12) Rowe & Kuroda (1965);Alexander et al (1971); (13) Murty, Goswami, & Shukolyukov (1997); (14 'Place' refers to very early condensates, like CAIs, then the measurement and the data for the initial state (column 4) coincide. When, instead, measurements refer to younger samples, such as, for example, 107 Pd, then the initial abundance should be higher than measured.…”

Section: Se Non è Vero è Bene Trovato Ancient Italian Motto 1 Introdumentioning

confidence: 99%

Short-Lived Nuclei in the Early Solar System: A Low Mass Stellar Source?

Busso

Gallino

Wasserburg³

2003

Publ. – Astron. Soc. Aust

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Abstract:We discuss possible stellar origins of short-lived radioactive nuclei with meanlifeτ ≤ 100 Myr, which were shown to be alive in the Early Solar System (ESS). We first review current ideas on the production of nuclides having 10 ≤τ ≤ 100 Myr, which presumably derive from the continuous interplay of galactic astration, nucleosynthesis from massive supernovae and free decay in the interstellar medium. The abundance of the shorter lived 53 Mn might be explained by this same scenario. Then we consider the nuclei 107 Pd, 26 Al, 41 Ca and 60 Fe, whose early solar system abundances are too high to have originated in this way. Present evidence favours a stellar origin, particularly for 107 Pd, 26 Al and 60 Fe, rather than an in situ production by energetic solar particles. The idea of an encounter (rather close in time and space) between the forming Sun and a dying star is therefore discussed: this star may or may not have also triggered the solar formation. Recent nucleosynthesis calculations for the yields of the relevant short-lived isotopes and of their stable reference nuclei are discussed. Massive stars evolving to type II supernovae (either leaving a neutron star or a black hole as a remnant) seem incapable of explaining the four most critical ESS radioactivities in their observed abundance ratios. An asymptotic giant branch (AGB) star seems to be a viable source, especially if of relatively low initial mass (M ≤ 3M ⊙ ) and with low neutron exposure: this model can provide a solution for 26 Al, 41 Ca and 107 Pd, with important contributions to 60 Fe, which are inside the present uncertainty range of the 60 Fe early solar system abundance. Such a model requires that 26 Al is produced substantially on the AGB by cool bottom processing. The remaining inventory of short-lived species in the solar nebula would then be attributed to the continuous galactic processing, with the exception of 10 Be, which must reflect production by later proton bombardment at a low level during early solar history.

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Verification and interpretation of the I-Xe chronometer

Cited by 116 publications

References 24 publications

Chronology and petrology of silicates from IIE iron meteorites: evidence of a complex parent body evolution

Chronology and petrology of silicates from IIE iron meteorites: evidence of a complex parent body evolution

Graves Nunataks 95209: A snapshot of metal segregation and core formation

Short-Lived Nuclei in the Early Solar System: A Low Mass Stellar Source?

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