Ice cores from Arctic sub-polar glaciers: chronology and post-depositional processes deduced from radioactivity measurements.
JEAN FRANCIS PINGLOT(1), REIN A. VAIKMAE(2), KOKICHI KAMIYAMA(3), MAKOTO IGARASHI(3), DIEDRICH FRITZSCHE(4), FRANK WILHELMS(5), Roy KOERNER(6), LORI HENDERSON(7), ELISABETH ISAKSSON(8), JAN GUNNAR WINTHER(8), RODERIK S.W. VAN DE WAL(9), MARC FOURNIER(10), PATRICK BOUISSET(10), HARRO A.J. MEIJER(11)
Journal of glaciology, Vol. 49, N° 164, 2003
The response of Arctic ice masses to climate change is studied using ice cores containing information on past climatic and environmental features. Interpretation of his information requires accurate chronological data. Absolute dating of ice cores from sub-polar Arctic glaciers is possible using well-known radioactive layers deposited by atmospheric nuclear tests (maximum fallout in 1963) and the Chernobyl accident (1986). Analysis of several isotopes (3H, 137Cs) shows that 3H provides the most accurate dating of the 1963 maximum, as indicated also in comparison with results from total-beta measurements (90Sr and 137Cs). Mean annual net mass balances are derived from the dated ice cores from 1963 up to the date of the drillings. The 137 Cs and 3H deposited by nuclear tests, after decay correction, are used to define a melt index for all I3 ice cores studied. The relative strength of melting and percolation post-depositional processes is studied on the basis of these 137Cs and 3H deposits.
|(1) Laboratoire de Glaciology et Géophysique de l’Environnement, CNRS, BP 196, 38402 SAINT MARTIN D’HERES Cedex France|
(2) Institute of Geology, Tallinn Technical University, 7 Estonia Avenue, EE-10143 Tallinn, Estonia
(3) Meteorological and Glaciological Section, National Institute of Polar Research, 1-9-10 Kaga 1-chome, Itabashi-ku, Tokyo 173-8515, Japan
(4) Alfred-Wegener Institute for Polar and Marine Research, P.O. Box 600149, D-14473 Potsdam, Germany
(5) Alfred-Wegener Institute for Polar and Marine Research, PO. Box 120161, D-27515 Bremerhaven, Germany
(6) Glacio1ogy Section, Terrain Sciences Division, Geological Survey of Canada, 601 Booth Street, Ottawa, Ontario KIWI OE8, Canada
(7) Department of Earth Sciences, University of Ottawa, 140 Louis Pasteur, Ottawa, Ontario KJN 6N5 Canada
(8) Norwegian Polar Institute, Polar Environmental Centre, N-9296 Tromso,Noway
(9) Institute for Marine and Atmospheric Research, Utrech University, Princetonplein 5, 3584 CC Utrech, TheNetherlands
(10) Institute de Protection et de Sûreté Nucléaire, DPRE/SERNAT/LMRE, Bât. 501, Bois des Rames, 91400 Orsay Cedex, France
(11) Centre for Isotope Research, University of Groningen, Nijenborgh 4, 9747 AG Groningen, The Netherlands