A novel radiocarbon dating technique applied to an ice core from the Alps indicating late Pleistocene ages

• Published in: Journal of Geophysical Research
• Main Authors: M. Jenk, Theo, Szidat, Sönke, Bolius, David, Sigl, Michael, Gäggeler, Heinz W., Wacker, Lukas, Ruff, Matthias, Barbante, Carlo, Boutron, Claude F., Schwikowski, Margit
• Other Authors: Paul Scherrer Institute (PSI), Department of Chemistry and Biochemistry, Universität Bern / University of Bern (UNIBE), Institute for Particle Physics, Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology Zürich (ETH Zürich), Institute for the Dynamics of Environmental Processes-CNR, University of Ca’ Foscari Venice, Italy, Environmental Sciences Department, Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Observatoire des Sciences de l'Univers de Grenoble (OSUG), Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Institut national des sciences de l'Univers (INSU - CNRS)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Université Savoie Mont Blanc (USMB Université de Savoie Université de Chambéry )-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Oeschger Centre for Climate Change Research (OCCR), NCCR Climate project of the Swiss National Science Foundation (projects VITA and VIVALDI), the EU FP6 project MILLENNIUM (017008), and the Istituto Nazionale per la Ricerca Scientifica e Tecnologica sulla Montagna (INRM).
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2009
• Subjects: ice cores; radiocarbon dating; carbonaceous particles; [SDU.STU.GL]Sciences of the Universe [physics]/Earth Sciences/Glaciology; ice core
• Online Access: https://insu.hal.science/insu-00420844; https://insu.hal.science/insu-00420844/document; https://insu.hal.science/insu-00420844/file/2009JD011860.pdf; https://doi.org/10.1029/2009JD011860

International audience Ice cores retrieved from high-altitude glaciers are important archives of past climatic and atmospheric conditions in midlatitude and tropical regions. Because of the specific flow behavior of ice, their age-depth relationship is nonlinear, preventing the application of common dating methods such as annual layer counting in the deepest and oldest part. Here we present a new approach and technique, allowing dating of any such ice core at arbitrary depth for the age range between ∼500 years B.P. and the late Pleistocene. This new, complementary dating tool has great potential for numerous ice core related paleoclimate studies since it allows improvement and extension of existing and future chronologies. Using small to ultrasmall sample size (100 μg > carbon content > 5 μg) accelerator mass spectrometry, we take advantage of the ice-included, water-insoluble organic carbon fraction of carbonaceous aerosols for radiocarbon (14C) dating. Analysis and dating of the bottom ice of the Colle Gnifetti glacier (Swiss-Italian Alps, 45°55′50″N, 7°52′33″E, 4455 m asl) has been successful in a first application, and the results revealed the core to cover most of the Holocene at the least with indication for late Pleistocene ice present at the very bottom.