Glaciochemical dating of an ice core from upper Grenzgletscher (4200 m a.s.l.)

• Published in: Journal of Glaciology
• Main Authors: Eichler, Anja, Schwikowski, Margit, Gäggeler, Heinz W., Furrer, Verena, Synal, Hans-Arno, Beer, Jürg, Saurer, Matthias, Funk, Martin
• Format: Article in Journal/Newspaper
• Language: English
• Published: International Glaciological Society 2000
• Subjects: Monte Rosa; ice core; Journal of Glaciology
• Online Access: https://doi.org/10.3189/172756500781833098

One crucial condition for the interpretation of ice-core records is the establishment of an accurate time-scale. This task is especially difficult for glacier sites in a complex topography such as the Alps, due to the often irregular deposition of fresh precipitation. In this work, dating techniques were applied to an Alpine ice core from upper Grenzgletscher; Monte Rosa massif (4200 m a.s.l.), representing about two-thirds of the total glacier thickness. They are leased on (i) the radioactive decay of the isotope 210 Pb, (ii) seasonally varying signals such as the concentrations of NH 4 + and the isotopic ratio δ 18 O, and (iii) stratigraphic markers from Saharan dust falls, atmospheric nuclear weapon tests and the reactor accident in Chernobyl. From the combined application of these dating methods, a time period of 1937–94 covered by the ice core was derived. Dating uncertainty is <1 year for the period 1970–94 and ±2 years for the period 1937–69. The observed thinning of the annual layers as a function of depth could be well described by a simple kinematic glacier flow model.