 |
| Titel |
Towards orbital dating of the EPICA Dome C ice core using δO2/N2 |
| VerfasserIn |
A. Landais, G. Dreyfus, E. Capron, K. Pol, M. F. Loutre, D. Raynaud, V. Y. Lipenkov, L. Arnaud, V. Masson-Delmotte, D. Paillard, J. Jouzel, M. Leuenberger |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1814-9324
|
| Digitales Dokument |
URL |
| Erschienen |
In: Climate of the Past ; 8, no. 1 ; Nr. 8, no. 1 (2012-01-31), S.191-203 |
| Datensatznummer |
250005368
|
| Publikation (Nr.) |
 copernicus.org/cp-8-191-2012.pdf |
|
|
|
|
|
| Zusammenfassung |
| 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. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|