Cosmic ray exposure ages of chondrites, pre-irradiation and constancy of cosmic ray flux in the past

Nishiizumi, K.; Regnier, S.; Marti, K.

doi:10.1016/0012-821x(80)90126-0

Cited by 170 publications

(147 citation statements)

References 53 publications

Supporting

Mentioning

127

Contrasting

Order By: Relevance

“…In contrast, P21 based on 26 Al was almost 70% higher than the average P21 determined by the other three radionuclides. Müller et al (1981) Nishiizumi et al (1980) and hence a similar discrepancy. Both groups of authors considered various explanations for this discrepancy, including half-life errors (considered rather unlikely), minor concentrations of 21 Ne from a previous irradiation stage in some of the studied meteorites or a biased data selection, possibly leading, e.g., to imprecisely known saturation concentrations of certain nuclides or incorrect shielding corrections.…”

Section: The Gcr Flux During the Past 10 Million Years As Recorded Inmentioning

confidence: 79%

“…the past 1-1.5 Ma. Other stable nuclides which have a suitable radioactive precursor are 3 He( 3 H) and 22 Ne ( 22 Na), although in these cases the branching ratios between direct and indirect production are less well known (Begemann et al 1957;Nishiizumi et al 1980). Furthermore, radioactive 81 Kr (T 1/2 = 0.229 Ma) can also be used to determine shieldingcorrected production rates of stable cosmogenic Kr isotopes in stony meteorites (Marti 1967;Herzog 2003), although 81 Kr is not a precursor of a stable Kr isotope.…”

Section: Nuclide Production Rates In Meteoritesmentioning

confidence: 99%

“…Several early studies reported differences in noble gas production rates based on different radionuclides (e.g., Herzog and Anders 1971;Cressy and Bogard 1976 Nishiizumi et al (1980). In a similar study, Müller et al (1981) Ne, minor corrections were also applied in these and similar studies for the different major element compositions of different classes of chondritic meteorites, because the production rate of a nuclide is different for different target elements.…”

Section: The Gcr Flux During the Past 10 Million Years As Recorded Inmentioning

confidence: 99%

See 2 more Smart Citations

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

View full text Add to dashboard Cite

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.

show abstract

Section: The Gcr Flux During the Past 10 Million Years As Recorded Inmentioning

confidence: 79%

Section: Nuclide Production Rates In Meteoritesmentioning

confidence: 99%

Section: The Gcr Flux During the Past 10 Million Years As Recorded Inmentioning

confidence: 99%

See 1 more Smart Citation

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

View full text Add to dashboard Cite

show abstract

“…-8- Figure Caption: The cosmic ray exposure ages of chondritic meteorites, based on the work of Crabb and Schultz (1981), but using the calibrations of Nishiizumi et al (1980) for the time scale. Since the meteorites are all recent falls, the age indicates the time that the meteorite was created.…”

Section: Discussionmentioning

confidence: 99%

“…but the discrepancy is within known systematic uncertainties. Cosmic ray exposure ages calibrated by several methods (Moniot, 1983;Muller et al, 1981;Nishiizumi et al, 1980) give values that differ by about 10%. The discrepancy in the 26Al age suggests that there may still be unknown systematic errors in this age determination.…”

mentioning

confidence: 99%