Correlated helium-3 and tungsten isotopes in iron meteorites: Quantitative cosmogenic corrections and planetesimal formation times

Markowski, A.; Leya, I.; Quitté, G.; Ammon, K.; Halliday, A. N.; Wieler, R.

doi:10.1016/j.epsl.2006.07.033

Cited by 77 publications

(97 citation statements)

References 32 publications

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“…As is evident from strong 182 W deficits in magmatic iron meteorites, core formation in their parent bodies was a very early process (Kleine et al 2005;Markowski et al 2006aMarkowski et al , 2006bScherstén et al 2006;Qin et al 2008a). Surprisingly, however, most iron meteorites exhibit 182 W/ 184 W lower than the solar system initial.…”

Section: Introductionmentioning

confidence: 99%

Nucleosynthetic Tungsten Isotope Anomalies in Acid Leachates of the Murchison Chondrite: Implications for Hafnium-Tungsten Chronometry

Burkhardt

Kleine

Dauphas

et al. 2012

ApJ

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Section: Introductionmentioning

confidence: 99%

Nucleosynthetic Tungsten Isotope Anomalies in Acid Leachates of the Murchison Chondrite: Implications for Hafnium-Tungsten Chronometry

Burkhardt

Kleine

Dauphas

et al. 2012

ApJ

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“…Another feature of the GCR effect is that cosmogenic " 182 W is approximately linearly correlated with cosmogenic " 184 W, although the sign and value of the slope are both uncertain due to model uncertainties. The negative " 182 W values measured in Tlacotepec, and other meteorites (Table 1) relative to the inferred initial composition of the solar nebula ($À3.5; Yin et al 2002;Kleine et al 2005) is primarily caused by GCR irradiation (Masarik 1997;Leya et al 2003;Markowski et al 2006b), given their relatively long exposure ages (e.g., Voshage & Feldmann 1979). However, this process cannot be responsible for the " 184 W deficiencies measured in IVBs.…”

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confidence: 90%

“…It has been shown both theoretically and experimentally that long-term exposure to GCR can cause negative shifts in internally normalized " 182 W values of iron meteorites (Masarik 1997;Leya et al 2003;Markowski et al 2006b). This is because GCRs can generate secondary neutrons causing W isotope shifts through neutron-capture reactions.…”

Section: Galactic Cosmic-ray Irradiation?mentioning

confidence: 99%

“…The Tlacotepec " 184 W datum by Nu-plasma is from Markowski et al (2006a). Because of GCR-related variations in " 182 W in this meteorite ( Markowski et al 2006b), no direct comparison of " 182 W can be made for Tlacotepec between Nu plasma and the other two instruments. [See the electronic edition of the Journal for a color version of this figure.] Fig.…”

Section: Nucleosynthetic Anomalies and Implications For 182 Hf-182 W mentioning

confidence: 99%

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Tungsten Nuclear Anomalies in Planetesimal Cores

Qin

Dauphas

Wadhwa

et al. 2008

ApJ

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Use of the extinct 182 Hf-182 W chronometer to constrain the timing of planetary accretion and differentiation rests on the assumption that the solar nebula had homogeneous tungsten isotopic composition. Here, we report deficiencies of $0.1 part in 10,000 in the abundance of 184 W in group IVB iron meteorites relative to the silicate Earth. These are most likely due to incomplete mixing at the planetesimal scale (2Y4 km radius bodies) of the products of slow (s-) and rapid (r-) neutron-capture nucleosynthesis in the solar nebula. The correction that must be applied to the 182 Hf-182 W model age of core formation in IVB irons due to the presence of these nuclear anomalies is $0.5 Myr.

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“…A major argument of Bottke et al (2006) for suggesting that the igneously differentiated asteroids formed at 1-2 AU is that parent bodies of iron meteorites accreted in the first 1.5 Myr (Kleine et al 2005;Markowski et al 2006aMarkowski et al , 2006b when 26 Al, which has a half-life of 0.73 Myr, was still capable of melting bodies larger than 20 km in radius (Hevey & Sanders 2006). Accretion rates would have been much faster at 1-2 AU than in the asteroid belt, due to the higher density of solids and the shorter orbital periods.…”

Section: Introductionmentioning

confidence: 99%

On the Effect of Giant Planets on the Scattering of Parent Bodies of Iron Meteorite From the Terrestrial Planet Region Into the Asteroid Belt: A Concept Study

Haghighipour

Scott

2012

ApJ

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In their model for the origin of the parent bodies of iron meteorites, Bottke et al. proposed differentiated planetesimals, formed in 1-2 AU during the first 1.5 Myr, as the parent bodies, and suggested that these objects and their fragments were scattered into the asteroid belt as a result of interactions with planetary embryos. Although viable, this model does not include the effect of a giant planet that might have existed or been growing in the outer regions. We present the results of a concept study where we have examined the effect of a planetary body in the orbit of Jupiter on the early scattering of planetesimals from the terrestrial region into the asteroid belt. We integrated the orbits of a large battery of planetesimals in a disk of planetary embryos and studied their evolutions for different values of the mass of the planet. Results indicate that when the mass of the planet is smaller than 10 M ⊕ , its effects on the interactions among planetesimals and planetary embryos are negligible. However, when the planet mass is between 10 and 50 M ⊕ , simulations point to a transitional regime with ∼50 M ⊕ being the value for which the perturbing effect of the planet can no longer be ignored. Simulations also show that further increase of the mass of the planet strongly reduces the efficiency of the scattering of planetesimals from the terrestrial planet region into the asteroid belt. We present the results of our simulations and discuss their possible implications for the time of giant planet formation.

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Correlated helium-3 and tungsten isotopes in iron meteorites: Quantitative cosmogenic corrections and planetesimal formation times

Cited by 77 publications

References 32 publications

Nucleosynthetic Tungsten Isotope Anomalies in Acid Leachates of the Murchison Chondrite: Implications for Hafnium-Tungsten Chronometry

Nucleosynthetic Tungsten Isotope Anomalies in Acid Leachates of the Murchison Chondrite: Implications for Hafnium-Tungsten Chronometry

Tungsten Nuclear Anomalies in Planetesimal Cores

On the Effect of Giant Planets on the Scattering of Parent Bodies of Iron Meteorite From the Terrestrial Planet Region Into the Asteroid Belt: A Concept Study

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