Cosmogenic nuclides in stony meteorites revisited

Leya, I.; Masarik, J.

doi:10.1111/j.1945-5100.2009.tb00788.x

Cited by 187 publications

(555 citation statements)

References 74 publications

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“…1). Those of Hampel et al (1980) and Leya and Masarik (2009) tend to be higher than the measured 26 Al content (Fig. 1).…”

Section: P 26 Of Diogenites Ureilites and Angritesmentioning

confidence: 60%

“…However, the other elemental compositions do not. Although the Ca content also shows a positive linear relation to the 26 Al content, the 26 Al produced by Ca is only about one tenth of that of Si and Al (Leya and Masarik, 2009). The Ca content of stony meteorites ranges from 0.07 to 8% (Hutchison, 2004), and the 26 Al content produced by Ca is comparable to the errors of the 26 Al content measured by AMS (about 3% of 26 Al content).…”

Section: Relationship Between 26 Al Content and Major Element Contentmentioning

confidence: 91%

“…The production of 26 Al and other cosmogenic nuclides are mainly dependent on several factors: the target element compositions, the primary cosmic-ray flux, and the preatmospheric sizes and shape of the meteorites. To calculate the 26 Al production rate of a meteorite, numerical simulations using Monte Carlo particle production have been presented (e.g., Masarik and Reedy, 1994;Herpers et al, 1995;Leya et al, 2000;Leya and Masarik, 2009). However, these simulations use empirical production rates because the cross section of 26 Al production by high energy neutron reactions is not known.…”

Section: Cosmogenicmentioning

confidence: 99%

“…26 Al CONTENT Table 3 shows equations calculating P 26 in this study and in studies by Aylmer et al (1988), Hampel et al (1980), Cressy (1971), and Leya and Masarik (2009). The equation in Table 3 of Leya and Masarik (2009) was converted from their model calculation for a depth of about 60 g/cm 2 in a meteoroid with a radius of about 100 g/cm 2 composed of L chondrites.…”

Section: Estimation Ofmentioning

confidence: 99%

“…The equation in Table 3 of Leya and Masarik (2009) was converted from their model calculation for a depth of about 60 g/cm 2 in a meteoroid with a radius of about 100 g/cm 2 composed of L chondrites. Table 4 shows P 26 calculated using the five equations (Table 3) and the measured 26 Al content of the 37 meteorite samples.…”

Section: Estimation Ofmentioning

confidence: 99%

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Simple relationship between 26Al production rate and major elemental composition of meteorite samples

2013

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NOTE 83empirical equations, which calculated the 26 Al content in meteorites at the time of the meteorite's fall (P 26 ), based on the relationship between 26 Al content and the elemental composition of bulk or minerals in falls chondrites. However, the P 26 of howardites and eucrites calculated in equations by Cressy and Hampel, are overestimated. Aylmer et al. (1988) presented the empirical 26 Al production rate of eucrites. However, the P 26 of howardites and eucrites calculated by Aylmer's production rate tends to be higher than the actual 26 Al contents. In this study, we propose a new empirical equation for the 26 Al production rate based on the relationship between the bulk 26 Al content and the content of major elements in various classes of 37 falls stony meteorites (one howardite, 10 eucrites, 13 diogenites, 8 chondrites, 3 ureilites, and one angrite). 18 of the 37 meteorites were measured in this study and data of another 19 meteorites were obtained from literature. The relationship between 26 Al content and content of target element is obtained clearly by using various classes of meteorite with different elemental composition. Production rate of 26 Al in meteorites is strongly affected by the shielding effect. The shielding condition is not constant, because shielding effect depends on depth and shape of meteoroid. We expected the shielding effect to be averaged out by measuring 26 Al content from 37 meteorite samples.

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“…1). Those of Hampel et al (1980) and Leya and Masarik (2009) tend to be higher than the measured 26 Al content (Fig. 1).…”

Section: P 26 Of Diogenites Ureilites and Angritesmentioning

confidence: 60%

Section: Relationship Between 26 Al Content and Major Element Contentmentioning

confidence: 91%

Section: Cosmogenicmentioning

confidence: 99%

Section: Estimation Ofmentioning

confidence: 99%

Section: Estimation Ofmentioning

confidence: 99%

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Simple relationship between 26Al production rate and major elemental composition of meteorite samples

2013

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The Galactic Cosmic Ray Intensity over the Past 106–109 Years as Recorded by Cosmogenic Nuclides in Meteorites and Terrestrial Samples

Wieler¹,

Beer²,

Leya³

2011

Cosmic Rays in the Heliosphere

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Concentrations of stable and radioactive nuclides produced by cosmic ray particles in meteorites allow us to track the long term average of the primary flux of galactic cosmic rays (GCR). During the past ∼10 Ma, the average GCR flux remained constant over timescales of hundreds of thousands to millions of years, and, if corrected for known variations in solar modulation, also during the past several years to hundreds of years. Because the cosmic ray concentrations in meteorites represent integral signals, it is difficult to assess the limits of uncertainty of this statement, but they are larger than the often quoted analytical and model uncertainties of some 30%. Time series of concentrations of the radionuclide 10 Be in terrestrial samples strengthen the conclusions drawn from meteorite studies, indicating that the GCR intensity on a ∼0.5 million year scale has remained constant within some ±10% during the past ∼10 million years. The very long-lived radioactive nuclide 40 K allows to assess the GCR flux over about the past one billion years. The flux over the past few million years has been the same as the longer-term average in the past 0.5-1 billion years within a factor of ∼1.5. However, newer data do not confirm a long-held belief that the flux in the past few million years has been higher by some 30-50% than the very long term average. Neither does our analysis confirm a hypothesis that the iron meteorite data indicate a ∼150 million year periodicity in the cosmic ray flux, possibly related to variations in the long-term terrestrial climate.

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Isotope Variations in the Solar System: Supernova Fingerprints

Ott¹

2016

Handbook of Supernovae

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Cosmogenic nuclides in stony meteorites revisited

Cited by 187 publications

References 74 publications

Simple relationship between 26Al production rate and major elemental composition of meteorite samples

Simple relationship between 26Al production rate and major elemental composition of meteorite samples

The Galactic Cosmic Ray Intensity over the Past 106–109 Years as Recorded by Cosmogenic Nuclides in Meteorites and Terrestrial Samples

Isotope Variations in the Solar System: Supernova Fingerprints

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