Towards orbital dating of the EPICA Dome C ice core using deltaO2/N2

Landais, A.; Dreyfus, G.; Capron, E. ORCID: https://orcid.org/0000-0003-0784-1884; Pol, K.; Loutre, M.F.; Raynaud, D.; Lipenkov, V.Y.; Arnaud, L.; Masson-Delmotte, V.; Paillard, D.; Jouzel, J.; Leuenberger, M.. 2012 Towards orbital dating of the EPICA Dome C ice core using deltaO2/N2. Climate of the Past, 8 (1). 191-203. 10.5194/cp-8-191-2012

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Abstract/Summary

Based on a composite of several measurement series performed on ice samples stored at −25 °C or −50 °C, we present and discuss the first δO2/N2 record of trapped air from the EPICA Dome C (EDC) ice core covering the period between 300 and 800 ka (thousands of years before present). The samples stored at −25 °C show clear gas loss affecting the precision and mean level of the δO2/N2 record. Two different gas loss corrections are proposed to account for this effect, without altering the spectral properties of the original datasets. Although processes at play remain to be fully understood, previous studies have proposed a link between surface insolation, ice grain properties at close-off, and δO2/N2 in air bubbles, from which orbitally tuned chronologies of the Vostok and Dome Fuji ice core records have been derived over the last four climatic cycles. Here, we show that limitations caused by data quality and resolution, data filtering, and uncertainties in the orbital tuning target limit the precision of this tuning method for EDC. Moreover, our extended record includes two periods of low eccentricity. During these intervals (around 400 ka and 750 ka), the matching between δO2/N2 and the different insolation curves is ambiguous because some local insolation maxima cannot be identified in the δO2/N2 record (and vice versa). Recognizing these limitations, we restrict the use of our δO2/N2 record to show that the EDC3 age scale is generally correct within its published uncertainty (6 kyr) over the 300–800 ka period.

Item Type:	Publication - Article
Digital Object Identifier (DOI):	10.5194/cp-8-191-2012
Programmes:	BAS Programmes > Polar Science for Planet Earth (2009 - ) > Chemistry and Past Climate
ISSN:	1814-9332
Additional Information. Not used in RCUK Gateway to Research.:	This work is distributed under the Creative Commons Attribution 3.0 License together with an author copyright. This license does not conflict with the regulations of the Crown Copyright.
Date made live:	08 Apr 2013 13:56 +0 (UTC)
URI:	https://nora.nerc.ac.uk/id/eprint/500923

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