Modeling the earth’s cosmic radiation

Argento, David C.; Reedy, R. C.; Stone, John O.

doi:10.1016/j.nimb.2012.05.022

Cited by 50 publications

(39 citation statements)

References 29 publications

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“…Analysis of two cosmogenic isotopes with different half-lives can provide information about complex exposure and burial histories (Granger and Muzikar, 2001;Nishiizumi et al, 1989Nishiizumi et al, , 1991. In the case of the two isotopes employed here, 26 Al is produced ~6.75 times as rapidly as 10 Be, although the uncertainty of the production ratio is not well constrained, and recent work has suggested that the ratio may actually be closer to ~6.9-7.0 (Argento et al, 2013). Once a sample is buried and nuclide production ceases, the 26 Al/ 10 Be ratio will drop from 6.75 because the half-life of 26 Al (0.71 m.y.)…”

Section: Theoretical Backgroundmentioning

confidence: 93%

Constraining landscape history and glacial erosivity using paired cosmogenic nuclides in Upernavik, northwest Greenland

Corbett

Bierman

Graly

et al. 2013

Geological Society of America Bulletin

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High-latitude landscape evolution processes have the potential to preserve old, relict surfaces through burial by cold-based, nonerosive glacial ice. To investigate landscape history and age in the high Arctic, we analyzed in situ cosmogenic 10 Be and 26 Al in 33 rocks from Upernavik, northwest Greenland. We sampled adjacent bedrock-boulder pairs along a 100 km transect at elevations up to 1000 m above sea level. Bedrock samples gave signifi cantly older apparent exposure ages than corresponding boulder samples, and minimum limiting ages increased with elevation. Two-isotope calculations ( 26 Al/ 10 Be) on 20 of the 33 samples yielded minimum limiting exposure durations up to 112 k.y., minimum limiting burial durations up to 900 k.y., and minimum limiting total histories up to 990 k.y. The prevalence of 10 Be and 26 Al inherited from previous periods of exposure, especially in bedrock samples at high elevation, indicates that these areas record long and complex surface exposure histories, including signifi cant periods of burial with little subglacial erosion. The long total histories suggest that these highelevation surfaces were largely preserved beneath cold-based, nonerosive ice or snowfi elds for at least the latter half of the Quaternary. Because of high concentrations of inherited nuclides, only the six youngest boulder samples appear to record the timing of ice retreat. These six samples suggest deglaciation of the Upernavik coast at 11.3 ± 0.5 ka (average ± 1 standard deviation). There is no difference in deglaciation age along the 100 km sample transect, indicating that the ice-marginal position retreated rapidly at rates of ~120 m yr −1 .

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Section: Theoretical Backgroundmentioning

confidence: 93%

Constraining landscape history and glacial erosivity using paired cosmogenic nuclides in Upernavik, northwest Greenland

Corbett

Bierman

Graly

et al. 2013

Geological Society of America Bulletin

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“…The first models were simplified quasi-analytical (e.g., Lingenfelter 1963;O'Brien and Burke 1973) or semiempirical models (e.g., Castagnoli and Lal 1980). With the fast advance of computing facilities it became possible to exploit the best numerical method suitable for such problems-Monte-Carlo (e.g., Beer 1999, 2009;Webber and Higbie 2003;Webber et al 2007;Usoskin and Kovaltsov 2008b;Kovaltsov and Usoskin 2010;Kovaltsov et al 2012;Argento et al 2013). The fact that models, based on different independent Monte-Carlo packages, namely, a general GEANT tool and a specific CORSIKA code, yield similar results provides additional verification of the approach.…”

Section: Cosmic-ray-induced Atmospheric Cascadementioning

confidence: 99%

A history of solar activity over millennia

Usoskin

2017

Living Rev Sol Phys

391

241

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Presented here is a review of present knowledge of the long-term behavior of solar activity on a multi-millennial timescale, as reconstructed using the indirect proxy method. The concept of solar activity is discussed along with an overview of the special indices used to quantify different aspects of variable solar activity, with special emphasis upon sunspot number. Over long timescales, quantitative information about past solar activity can only be obtained using a method based upon indirect proxies, such as the cosmogenic isotopes 14 C and 10 Be in natural stratified archives (e.g., tree rings or ice cores). We give an historical overview of the development of the proxy-based method for past solar-activity reconstruction over millennia, as well as a description of the modern state. Special attention is paid to the verification and cross-calibration of reconstructions. It is argued that this method of cosmogenic isotopes makes a solid basis for studies of solar variability in the past on a long timescale (centuries to millennia) during the Holocene. A separate section is devoted to reconstructions of strong solar energetic-particle (SEP) events in the past, that suggest that the present-day average SEP flux is broadly consistent with estimates on longer timescales, and that the occurrence of extra-strong events is unlikely. Finally, the main features of the long-term evolution of solar magnetic activity, including the

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“…Surprisingly, these scaling schemes have not succeeded in predicting the calibration sample concentrations significantly better than the original scaling scheme of Lal (1991) (Lifton et al, 2014;Phillips et al, 2015). It is therefore essential to continue building our understandings of the radiation cascade and resulting production of cosmogenic nuclides through the use of physics based models (Argento et al, 2013;Kovaltsov and Usoskin, 2010;Masarik and Beer, 2009). The purpose of this research is to develop an apriori, physics-based model that allows us to simulate all of the processes in cosmogenic nuclide production separately, as opposed to natural sample calibration, in which they are superimposed.…”

Section: Introductionmentioning

confidence: 99%

“…Several improvements and enhancements have been made to the model since the preliminary results were published (Argento et al, 2013). Most importantly, we optimized the high energy physics settings for MCNPX.…”

Section: Introductionmentioning

confidence: 99%