Neutron capture records of mesosiderites and an iron meteorite

Hidaka, Hiroshi; Yoneda, Shigekazu

doi:10.1016/j.gca.2011.07.012

Cited by 5 publications

(11 citation statements)

References 49 publications

(78 reference statements)

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“…This is mostly due to the low iron concentration in aubrites, which increases the resonance escape probability, i.e., reduces the epithermal neutron capture on, e.g., iron, and therefore increases the chance that the neutrons reach thermal energies. The other exceptions are the mesosiderites and the IAB iron meteorite Udei station (Hidaka and Yoneda ) that plot, as expected, in between the lines for ordinary chondrites and iron meteorites.…”

Section: Comparison With Previous Modeling and Datasupporting

confidence: 68%

“…, ; Sands et al. ; Hidaka and Yoneda , ). The agreement is in all cases good, giving further confidence in the model predictions.…”

Section: Discussionmentioning

confidence: 99%

“…, ), carbonaceous chondrites (Hidaka et al. ), and mesosiderites (Hidaka and Yoneda ). Also shown are the correlation lines modeled for carbonaceous chondrites, ordinary chondrites, and iron meteorites.…”

Section: Comparison With Previous Modeling and Datamentioning

confidence: 99%

“…; Hidaka et al. , ), mesosiderites and an iron meteorite (Hidaka and Yoneda ), and even to search for effects caused by an early active sun (Hidaka and Yoneda ).…”

Section: Introductionmentioning

confidence: 99%

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Thermal neutron capture effects in radioactive and stable nuclide systems

Leya

Masarik

2013

Meteorit & Planetary Scien

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Abstract-Neutron capture effects in meteorites and lunar surface samples have been successfully used in the past to study exposure histories and shielding conditions. In recent years, however, it turned out that neutron capture effects produce a nuisance for some of the short-lived radionuclide systems. The most prominent example is the 182 Hf-182 W system in iron meteorites, for which neutron capture effects lower the 182 W/ 184 W ratio, thereby producing too old apparent ages. Here, we present a thorough study of neutron capture effects in iron meteorites, ordinary chondrites, and carbonaceous chondrites, whereas the focus is on iron meteorites. We study in detail the effects responsible for neutron production, neutron transport, and neutron slowing down and find that neutron capture in all studied meteorite types is not, as usually expected, exclusively via thermal neutrons. In contrast, most of the neutron capture in iron meteorites is in the epithermal energy range and there is a significant contribution from epithermal neutron capture even in stony meteorites. Using sophisticated particle spectra and evaluated cross section data files for neutron capture reactions we calculate the neutron capture effects for Sm, Gd, Cd, Pd, Pt, and Os isotopes, which all can serve as neutron-dose proxies, either in stony or in iron meteorites. In addition, we model neutron capture effects in W and Ag isotopes. For W isotopes, the GCR-induced shifts perfectly correlate with Os and Pt isotope shifts, which therefore can be used as neutron-dose proxies and permit a reliable correction. We also found that GCR-induced effects for the 107 Pd-107 Ag system can be significant and need to be corrected, a result that is in contrast to earlier studies.

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Section: Comparison With Previous Modeling and Datasupporting

confidence: 68%

“…, ; Sands et al. ; Hidaka and Yoneda , ). The agreement is in all cases good, giving further confidence in the model predictions.…”

Section: Discussionmentioning

confidence: 99%

Section: Comparison With Previous Modeling and Datamentioning

confidence: 99%

“…; Hidaka et al. , ), mesosiderites and an iron meteorite (Hidaka and Yoneda ), and even to search for effects caused by an early active sun (Hidaka and Yoneda ).…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Thermal neutron capture effects in radioactive and stable nuclide systems

Leya

Masarik

2013

Meteorit & Planetary Scien

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“…Further studies of the meteorites and crater would be undertaken (e.g. McCall 1977;Consolmagno & Britt 1995;Smith & Hodge 1996;Hidaka & Yoneda 2011;Shoemaker et al 1990Shoemaker et al , 2005. But a year after Nininger & Huss' paper was published, an extraordinary coincidence occurred that linked everyone involved.…”

Section: The Nininger Expeditionsmentioning

confidence: 99%

The discovery and history of the Dalgaranga meteorite crater, Western Australia

Hamacher

O’Neill

2013

Australian Journal of Earth Sciences

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The Dalgaranga meteorite crater, 100 km northeast of Yalgoo, Western Australia, was one of the first impact structures identified in Australia, the smallest isolated crater found in Australia, and the only confirmed crater in the world associated with a mesosiderite projectile. 17 years passed before the Dalgaranga meteorites were described in the scientific literature and nearly 40 years passed before a survey of the structure was published. The reasons for the time-gap were never explained and a number of factual errors about the discovery and early history remain uncorrected in the scientific literature. Using historical and archival documents, and discussions with people involved in Dalgaranga research, the reasons for this time gap are explained by a series of minor misidentifications and coincidences. The age of the crater has yet to be determined, but using published data, we estimate the projectile mass to be 500-1000 kg.

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Barium isotope abundances in meteorites and their implications for early Solar System evolution

Bermingham

Mezger

Scherer

et al. 2016

Geochimica et Cosmochimica Acta

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Several nucleosynthetic processes contributed material to the Solar System; however, the relative contributions of each process, the timing of their input into the solar nebula, and how well these components were homogenized in the solar nebula remain only partially constrained. The Ba isotope system is particularly useful in addressing these issues because Ba contains isotopes are synthesized through three nucleosynthetic processes (s-, r-, p-process). In this study, high precision Ba isotope analyses of 22 different whole rock chondrites and achondrites (carbonaceous chondrites, ordinary chondrites, enstatite chondrites, Martian meteorites, and eucrites) were performed to constrain the distribution of Ba isotopes on the regional scale in the Solar System. A melting method using aerodynamic levitation and CO 2-laser heating was used to oxidize SiC, a primary carrier of Ba among presolar grains in carbonaceous chondrites. Destruction of these grains during the fusion process enabled the complete digestion of these samples. The Ba isotope data presented here are thus the first for which complete dissolution of the bulk meteorite samples was certain. Enstatite chondrites, ordinary chondrites, and all achondrites measured here possess Ba isotope compositions that are not resolved from the terrestrial Ba isotope composition. Barium isotope anomalies are evident in most of the carbonaceous chondrites analyzed, but the 135 Ba anomalies are generally smaller than previously reported for similarly sized splits of CM2 meteorites. Variation in the size of the 135 Ba anomaly is also apparent in fused samples from the same parent body (e.g., CM2 meteorites) and in different pieces from the same meteorite (e.g., Orgueil, CI). Here, we investigate the potential causes of variability in 135 Ba, including the contribution of radiogenic 135 Ba from the decay of 135 Cs and incomplete homogenization of the presolar components on the <0.8 g sample scale.

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Neutron capture records of mesosiderites and an iron meteorite

Cited by 5 publications

References 49 publications

Thermal neutron capture effects in radioactive and stable nuclide systems

Thermal neutron capture effects in radioactive and stable nuclide systems

The discovery and history of the Dalgaranga meteorite crater, Western Australia

Barium isotope abundances in meteorites and their implications for early Solar System evolution

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