The AICC2023 chronological framework and associated timescale for the EPICA Dome C ice core

• Main Authors: Bouchet, Marie, Landais, Amaëlle, Grisart, Antoine, Parrenin, Frédéric, Prié, Frédéric, Jacob, Roxanne, Fourré, Elise, Capron, Emilie, Raynaud, Dominique, Lipenkov, Vladimir Ya, Loutre, Marie-France, Extier, Thomas, Svensson, Anders, Legrain, Etienne, Martinerie, Patricia, Leuenberger, Markus, Jiang, Wei, Ritterbusch, Florian, Lu, Zheng-Tian, Yang, Guo-Min
• Format: Text
• Language: English
• Published: 2023
• Subjects: Antarctic; East Antarctica; Tac; Antarc*; Antarctica; EPICA; ice core
• Online Access: https://doi.org/10.5194/egusphere-2023-1081; https://egusphere.copernicus.org/preprints/2023/egusphere-2023-1081/

The EPICA (European Project for Ice Coring in Antarctica) Dome C (EDC) ice core drilling in East Antarctica reaches a depth of 3260 m. The reference EDC chronology, the AICC2012 (Antarctic Ice Core Chronology 2012), provides an age vs. depth relationship covering the last 800 kyr (thousands of years), with an absolute uncertainty rising up to 8000 years at the bottom of the ice core. The origins of this relatively large uncertainty are twofold: (1) the δ 18 O atm , δ O 2 / N 2 <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="41pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="846b6f765641c697b19d3c3c2c555269"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cp-19-2257-2023-ie00001.svg" width="41pt" height="14pt" src="cp-19-2257-2023-ie00001.png"/></svg:svg> and total air content (TAC) records are poorly resolved and show large gaps over the last 800 kyr, and (2) large uncertainties are associated with their orbital targets. Here, we present new highly resolved δ 18 O atm , δ O 2 / N 2 <svg:svg xmlns:svg="http://www.w3.org/2000/svg" width="41pt" height="14pt" class="svg-formula" dspmath="mathimg" md5hash="26bb89727c0d5d655d1ccea7435b6d94"><svg:image xmlns:xlink="http://www.w3.org/1999/xlink" xlink:href="cp-19-2257-2023-ie00002.svg" width="41pt" height="14pt" src="cp-19-2257-2023-ie00002.png"/></svg:svg> and δ 15 N measurements for the EDC ice core covering the last five glacial–interglacial transitions; a new low-resolution TAC record over the period 440–800 ka BP (ka: 1000 years before 1950); and novel absolute 81 Kr ages. We have compiled chronological and glaciological information including novel orbital age markers from new data on the EDC ice core as well as accurate firn modeling estimates in a Bayesian dating tool to construct the new AICC2023 chronology. For the first time, three orbital tools are used simultaneously. Hence, it is possible to observe that they are consistent with each other and with the other age markers over most ...