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27 juillet 2021
A new age scale for the deep portion of TALDICE ice core, East Antarctica
A new age scale for the deep portion of TALDICE ice core, East Antarctica

Fig. 1. Top (a): High resolution δD record of TALDICE ice core on the TALDICE-deep age scale (red curve) for the last 343 ka. Bottom (b): New δ18Oatm profile (blue curve with stars) on the TALDICE-deep chronology and the June 21st insolation signal at 65°N

TALDICE (TALos Dome Ice CorE) is a 1620 m deep ice core drilled at Talos Dome, an ice dome located at the edge of the East Antarctic Plateau in the Ross Sea Sector o. The Antarctic Ice Core Common Chronology (AICC2012) extends the  age scale of the core until ~150 ka (1438 m depth) (Bazin et al., 2013), while no age scale is available for the lowermost portion of the core.

In this work we present the new TALDICE-deep chronology for the deepest part of the core, between 1438 and 1578 m depth, combining new measurements of δ18Oatm, δDice and 81Kr in the air bubbles as well as the inverse model IceChrono1. The chronology stops at 1578 m, as the bottom part is probably affected by mixing processes acting in the deepest ice layers. The new age scale allows to extend the climate record for the Ross Sea Sector of the East Antarctic Ice Sheet back to termination of MIS 10.1 ~343 ka (~1550 m depth) and to identify both MIS 7.5 and 9.3 events. However, it was not possible to recover the isotopic record beyond stage 10 as the signal assumes a quasi-flat shape. Thereby, the new chronology TADICE-deep allow to double the extension of the previous tile scale and elevate the core to the rank of old plateau cores like Vostok, Epica Dome C and Dome Fuji, as it covers the three past glacial/interglacial cycles.


Auteurs: I.  Crotti, A. Landais, B. Stenni, L. Bazin, F. Parrenin, M. Frezzotti, F. Ritterbusch, Z.-T. Lu, W. Jiang, G.-M. Yang, E. Fourré, A. Orsi, R. Jacob, B. Minster, F. Prié, G. Dreossi, C. Barbante

Reference :  Quaternary Science Reviews 266 (2021) 107078

#274 - Màj : 07/10/2021
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