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Bomb-test Cl-36 measurements in Vostok snow (Antarctica) and the use of Cl-36 as a dating tool for deep ice cores

Delmas, RJ; Beer, J; Synal, HA; Muscheler, Raimund LU ; Petit, JR and Pourchet, M (2004) In Tellus. Series B: Chemical and Physical Meteorology 56(5). p.492-498
Abstract
A large pulse of atmospheric Cl-36 generated by a limited number of nuclear tests peaked in the late 1950s to early 1960s. The corresponding enhanced Cl-36 deposition is seen in various glaciological archives in the Northern Hemisphere. The profile of the bomb spike recorded in firn layers at Vostok Station, central East Antarctica. has been measured by employing accelerator mass spectrometry (AMS). The records obtained front two well-dated data sets collected in snow pits in 1997 and 1998 show a broad Cl-36 peak, beginning as early as the 1940s and reaching its maximum in the 1960s. The signal is followed by a long-lasting tail up to the surface. This pattern is totally unexpected. We show that the results, unlike the Greenland data, can... (More)
A large pulse of atmospheric Cl-36 generated by a limited number of nuclear tests peaked in the late 1950s to early 1960s. The corresponding enhanced Cl-36 deposition is seen in various glaciological archives in the Northern Hemisphere. The profile of the bomb spike recorded in firn layers at Vostok Station, central East Antarctica. has been measured by employing accelerator mass spectrometry (AMS). The records obtained front two well-dated data sets collected in snow pits in 1997 and 1998 show a broad Cl-36 peak, beginning as early as the 1940s and reaching its maximum in the 1960s. The signal is followed by a long-lasting tail up to the surface. This pattern is totally unexpected. We show that the results, unlike the Greenland data, can be explained by a mobility of HCl in the Antarctic firn. This experiment demonstrates the instability of gaseous Cl- deposits. a phenomenon which has important implications for the use of natural cosmogenic Cl-36 radionuclides as a reliable dating tool for deep ice cores from low-accumulation areas. However, during glacial times, under favourable atmospheric chemistry conditions this dating method may still be applicable. Snow metamorphism and ventilation are assumed to be the two main physical processes responsible for the observed patterns. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Tellus. Series B: Chemical and Physical Meteorology
volume
56
issue
5
pages
492 - 498
publisher
Taylor & Francis
external identifiers
  • wos:000225463000009
  • scopus:9444267622
ISSN
0280-6509
DOI
10.1111/j.1600-0889.2004.00109.x
language
English
LU publication?
yes
id
08efddca-a2b0-4319-92c2-5f7fac19d854 (old id 259445)
date added to LUP
2007-10-23 10:37:41
date last changed
2017-12-10 04:33:32
@article{08efddca-a2b0-4319-92c2-5f7fac19d854,
  abstract     = {A large pulse of atmospheric Cl-36 generated by a limited number of nuclear tests peaked in the late 1950s to early 1960s. The corresponding enhanced Cl-36 deposition is seen in various glaciological archives in the Northern Hemisphere. The profile of the bomb spike recorded in firn layers at Vostok Station, central East Antarctica. has been measured by employing accelerator mass spectrometry (AMS). The records obtained front two well-dated data sets collected in snow pits in 1997 and 1998 show a broad Cl-36 peak, beginning as early as the 1940s and reaching its maximum in the 1960s. The signal is followed by a long-lasting tail up to the surface. This pattern is totally unexpected. We show that the results, unlike the Greenland data, can be explained by a mobility of HCl in the Antarctic firn. This experiment demonstrates the instability of gaseous Cl- deposits. a phenomenon which has important implications for the use of natural cosmogenic Cl-36 radionuclides as a reliable dating tool for deep ice cores from low-accumulation areas. However, during glacial times, under favourable atmospheric chemistry conditions this dating method may still be applicable. Snow metamorphism and ventilation are assumed to be the two main physical processes responsible for the observed patterns.},
  author       = {Delmas, RJ and Beer, J and Synal, HA and Muscheler, Raimund and Petit, JR and Pourchet, M},
  issn         = {0280-6509},
  language     = {eng},
  number       = {5},
  pages        = {492--498},
  publisher    = {Taylor & Francis},
  series       = {Tellus. Series B: Chemical and Physical Meteorology},
  title        = {Bomb-test Cl-36 measurements in Vostok snow (Antarctica) and the use of Cl-36 as a dating tool for deep ice cores},
  url          = {http://dx.doi.org/10.1111/j.1600-0889.2004.00109.x},
  volume       = {56},
  year         = {2004},
}