An extension of the TALDICE ice core age scale reaching back to MIS 10.1

Ilaria Crotti,Amaelle Landais,Barbara Stenni,Lucie Bazin,Frédéric Parrenin,Massimo Frezzotti,Florian Ritterbusch,Zheng-Tian Lu,Wei Jiang,Guo-Min Yang,Elise Fourré,Anais Orsi,Roxanne Jacob,Bénédicte Minster,Frédéric Prié,Giuliano Dreossi,Carlo Barbante

doi:10.1016/j.quascirev.2021.107078

Abstract

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. The Antarctic Ice Core Common Chronology (AICC2012) extended the age scale of the core until ∼150 ka (1438 m depth) (Bazin et al., 2013), while no age scale was available below 1438 m depth.In this work we present the new TALDICE-deep1 chronology using the new measurements of δ18Oatm, δD and 81Kr as well as the inverse model IceChrono1.The TALDICE-deep1 chronology stops at 1548 m, as the portion below this depth is probably affected by mixing processes. The new age scale extends the climate record for the Ross Sea Sector of the East Antarctic Ice Sheet back to MIS 10.1–343 ka (1548 m depth) and identifies both MIS 7 and 9 warm stages, which show specificities in the δD signal. However, it is not possible to recover the isotopic record beyond stage 10.1 as the signal shows a quasi-flat shape. Thereby, the new chronology TADICE-deep1 doubles the extension of the previous age scale as it covers the three past glacial/interglacial cycles.

Highlights

Because of ice thinning from the top to the bottom of the icesheet, the deepest sections of ice cores store most of the paleoclimatic information
To build the Talos Dome Ice core Project (TALDICE)-deep1 age scale we employ the inverse model IceChrono1 (Parrenin et al, 2015), which provides the best compromise between a background chronology and observations
The combination of our different observations for the portion of the TALDICE ice core below 1438 m depth with the previous data sets published by Buiron et al (2011) and Bazin et al (2013) extends the core chronology beyond the limits set by the AICC2012 age scale

Summary

Introduction

Because of ice thinning from the top to the bottom of the icesheet, the deepest sections of ice cores store most of the paleoclimatic information. In the following two sub-sections we describe how we define the background scenario associated with the deep portion of the TALDICE ice core, integrating previous estimation of glaciological parameters from Buiron et al (2011) (Section 4.1) with our new d15N data set (Section 4.2). In order to build the TALDICE-deep age scale we use the accumulation rate and thinning function estimated by Buiron et al (2011) for the TALDICE-1 age scale until 1597 m depth, while we estimate a new LID profile from novel d15N measurements Our choice is driven by the fact that no new data set of field measurements is available for the TALDICE ice core for the accumulation rate and the thinning function, estimated with the 1-D ice flow model (Parrenin et al, 2007)

Objectives

Results

Conclusion