Lead-210 and radon-222 anomalies in Mont Blanc snow, French Alps

Pourchet, M.; Richon, Patrick; Sabroux, J. C.

doi:10.1016/s0265-931x(99)00084-3

Cited by 9 publications

(4 citation statements)

References 13 publications

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“…The atmosphere in the Mercantour Massif is probably enriched with 222 Rn released from uranium ores outcropping in the area, and transformed to 210 Pb in this compartment. Pourchet et al (2000) also measured high 210 Pb activities in ice of the Mont-Blanc; they assumed that 222 Ra emanates from the underlying rocks and transforms into 210 Pb before release to the atmosphere; they calculated an ascending flux of 0.084 Bq cm ÿ2 y ÿ1 . Nevertheless this explanation cannot account for the high values in the Bore´on area, which is not covered by permanent snow, but only occasionally by 1e2 m snow in winter and early spring.…”

Section: Pb In a Flat Soil And Comparison With Soil Amentioning

confidence: 99%

Evaluation of 137Cs fallout from the Chernobyl accident in a forest soil and its impact on Alpine Lake sediments, Mercantour Massif, S.E. France

Rezzoug

Michel

Fernex

et al. 2006

Journal of Environmental Radioactivity

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Section: Pb In a Flat Soil And Comparison With Soil Amentioning

confidence: 99%

Evaluation of 137Cs fallout from the Chernobyl accident in a forest soil and its impact on Alpine Lake sediments, Mercantour Massif, S.E. France

Rezzoug

Michel

Fernex

et al. 2006

Journal of Environmental Radioactivity

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“…With a half-life of 3.8 d, its tropospheric background concentration is low and temporal variations caused by changes in atmospheric transport are more clearly detectable than for other tracers with longer atmospheric lifetimes. Furthermore, seasonal snow cover attenuates emissions (Yamazawa et al, 2005) and we assume that emissions are negligible in the area with permanent snow cover surrounding Jungfraujoch, even though there are reports of sites above the snow line where the snow cover does allow radon to escape from the bedrock below (Pourchet et al, 2000).…”

Section: Introductionmentioning

confidence: 99%

Surface-to-mountaintop transport characterised by radon observations at the Jungfraujoch

et al. 2014

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Abstract. Atmospheric composition measurements at Jungfraujoch are affected intermittently by boundary-layer air which is brought to the station by processes including thermally driven (anabatic) mountain winds. Using observations of radon-222, and a new objective analysis method, we quantify the land-surface influence at Jungfraujoch hour by hour and detect the presence of anabatic winds on a daily basis. During 2010-2011, anabatic winds occurred on 40 % of days, but only from April to September. Anabatic wind days were associated with warmer air temperatures over a large fraction of Europe and with a shift in air-mass properties, even when comparing days with a similar mean radon concentration. Excluding days with anabatic winds, however, did not lead to a better definition of the unperturbed aerosol background than a definition based on radon alone. This implies that a radon threshold reliably excludes local influences from both anabatic and non-anabatic vertical-transport processes.

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“…As outlined before, the 210 Pb perturbations found at the drill site were attributed to the granite bedrock at CDD in combination with the presence of crevasses in the vicinity of the drill site. Pourchet et al (2000)…”

Section: The 210 Pb Depth Profiles 230mentioning

confidence: 99%

“…The presence of one or more crevasses in the upstream vicinity of the drill site was also suspected to cause strongly elevated concentrations of 210 Pb observed 55 in the C10 core (Vincent et al, 1997). This was concluded, since the bedrock at the CDD consists of granite that emits 222 Rn (half-life of 3.8 days), which is able to diffuse in snow and firn, but much less in ice (see also Pourchet et al, 2000), and subsequently decays to produce 210 Pb (half-life of 22.3 years).…”

Section: Introduction 35mentioning

confidence: 98%

Impact of subsurface crevassing on the depth-age relationship of high-alpine ice cores extracted at Col du Dôme between 1994 and 2012

Preunkert

Bohleber

Legrand

et al. 2023

Preprint

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Abstract. Three seasonally-resolved ice-core records covering the 20th century were extracted in 1994, 2004 and 2012 at a nearly identical location at the Col du Dôme (4250 m above sea level, m asl, Mont Blanc, French Alps) drill site. Here we complete and combine chemical records of major ions and radiometric measurements of 3H and 210Pb obtained on these three cores together with a 3D ice flow model of the Col du Dôme glacier, to investigate in detail the origin of the discontinuities observed in the depth-age relation of the ice cores drilled in 2004 and 2012. Taking advantage of the granitic bedrock at Col du Dôme, which makes the 210Pb ice-core records sensitive to the presence of upstream crevasses, and the fact that the depth-age disturbances are observed at depths for which absolute time markers were available, we draw an overall picture of a dynamic crevasse formation which can explain the non-disturbed depth-age relation of the ice core drilled in 1994 as well as the perturbations observed in those drilled in 2004 and 2012. Since crevasses are common at high alpine glacier sites, our study points out the mandatory need of rigorous investigations of the depth-age scale before using high alpine sites to interpret atmospheric changes.

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Lead-210 and radon-222 anomalies in Mont Blanc snow, French Alps

Cited by 9 publications

References 13 publications

Evaluation of 137Cs fallout from the Chernobyl accident in a forest soil and its impact on Alpine Lake sediments, Mercantour Massif, S.E. France

Evaluation of 137Cs fallout from the Chernobyl accident in a forest soil and its impact on Alpine Lake sediments, Mercantour Massif, S.E. France

Surface-to-mountaintop transport characterised by radon observations at the Jungfraujoch

Impact of subsurface crevassing on the depth-age relationship of high-alpine ice cores extracted at Col du Dôme between 1994 and 2012

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