Synchronisation of the EDML and EDC ice cores for the last 52 kyr by volcanic signature matching

• Main Authors: Severi, M., Becagli, S., Castellano, E., Morganti, A., Traversi, R., Udisti, R., Ruth, U., Fischer, H., Huybrechts, P., Wolff, E., Parrenin, F., Kaufmann, P., Lambert, F., Steffensen, J. P.
• Other Authors: Department of Chemistry, Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung (AWI), Departement Geografie, British Antarctic Survey (BAS), Natural Environment Research Council (NERC), Laboratoire de glaciologie et géophysique de l'environnement (LGGE), Centre National de la Recherche Scientifique (CNRS)-Institut national des sciences de l'Univers (INSU - CNRS)-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 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), Climate and Environmental Physics Bern (CEP), Physikalisches Institut Bern, Universität Bern Bern -Universität Bern Bern, Niels Bohr Institute Copenhagen (NBI), Faculty of Science Copenhagen, University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2007
• Subjects: [SDU.ENVI]Sciences of the Universe [physics]/Continental interfaces; environment; [SDU.STU]Sciences of the Universe [physics]/Earth Sciences; Dome The; Dronning Maud Land; EPICA; ice core
• Online Access: https://hal.archives-ouvertes.fr/hal-00330727; https://hal.archives-ouvertes.fr/hal-00330727/document; https://hal.archives-ouvertes.fr/hal-00330727/file/cpd-3-409-2007.pdf

International audience A common time scale for the EPICA ice cores from Dome C (EDC) and Dronning Maud Land (EDML) was established. Since EDML core was not drilled on a dome, the development of the EDML1 time scale for the EPICA ice core drilled in Dronning Maud Land was carried on by creating a detailed stratigraphic link between this core and the one drilled at Dome C, dated by a simpler 1D ice-flow model. The synchronisation between the two ice cores was built via the identification of several common volcanic signatures. This paper describes the rigorous method, using the signature of volcanic sulfate, which was employed for the last 52 kyr of the record. By evaluating the ratio R of the apparent duration of temporal intervals between couples of isochrones, the depth comparison between the two cores was turned into an estimate of anomalies between the modelled EDC and EDML glaciological age models during the studied period. On average R ranges between 0.8 and 1.2 corresponding to an uncertainty within 20% in the estimate of the time duration in at least one of the two ice cores. Significant deviations of R up to 1.4–1.5 are observed between 18 and 28 kyr BP. At this step our approach is not able to unequivocally find out which of the models is affected by the errors, but assuming the thinning function at both sites and accumulation history at Dome C, which was drilled on a dome, as being correct, this anomaly can be ascribed to a complex spatial accumulation variability (which may be different at present day and in the past) and to upstream ice flow in the area of the EDML core.