EGU22-9013, updated on 28 Mar 2022
https://doi.org/10.5194/egusphere-egu22-9013
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Towards 81Kr and 39Ar dating with 1 kg of ice

Florian Ritterbusch1, Ilaria Crotti2,3, Xi-Ze Dong1, Elise Fourré2, Ji-Qiang Gu1, Roxanne Jacob2, Wei Jiang1, Amaëlle Landais2, Zheng-Tian Lu1, Anaïs Orsi2, Frédéric Prié2, Lili Shao4, Lide Tian4, A-Min Tong1, Guo-Min Yang1, and Jie Wang1
Florian Ritterbusch et al.
  • 1University of Science and Technology of China (florian@ustc.edu.cn)
  • 2Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA-CNRS-UVSQ, Université Paris-Saclay, 91191 Gif-sur-Yvette, France
  • 3Department of Environmental Sciences, Informatics and Statistics, Ca’ Foscari University, Venice, 30172, Italy
  • 4Institute of International Rivers and Eco-security, Yunnan University

Paleoclimate reconstructions from ice core records can be hampered due to the lack of a reliable chronology, especially when the stratigraphy is disturbed and conventional dating methods cannot be readily applied. The noble-gas radioisotopes 81Kr and 39Ar can in these cases provide robust constraints as they yield absolute, radiometric ages. 81Kr (half-life 229 ka) covers the time span of 30-1300 ka, which is particularly relevant for polar ice cores, whereas 39Ar (half-life 268 a) with a dating range of 50-1800 a is suitable for alpine glaciers. For a long time the use of 81Kr and 39Ar for dating of ice samples was impeded by the lack of a detection technique that can measure its extremely small abundance at a reasonable sample size.

We present 81Kr and 39Ar dating of Antarctic and Tibetan ice cores with the detection method Atom Trap Trace Analysis (ATTA), using 5-10 kg of ice for 81Kr and 2-5 kg for 39Ar. Recent studies in Antarctica include 81Kr dating in ice cores from the Larsen Blue ice area, Talos Dome and Epica Dome C. Moreover, we have used 39Ar for dating an ice core from central Tibet covering the past 1500 years, in order to validate a previous timescale based on layer counting. The  studies demonstrate how 81Kr and 39Ar can provide age constraints and complement other methods in developing an ice core chronology. As the sample size requirement for 81Kr and 39Ar analysis still hinders its use in ice cores, developments on the ATTA systems are in progress to further decrease the sample size and increase the dating precision. Here, we present our latest advances towards 81Kr and 39Ar dating with ~ 1 kg of ice.

[1] Z.-T. Lu, et al. (2014) Tracer applications of noble gas radionuclides in the geosciences, Earth-Science Reviews 138, 196-214

[2] C. Buizert et al. (2014), Radiometric 81Kr dating identifies 120,000-year-old ice at Taylor Glacier, Antarctica Proceedings of the National Academy of Sciences, 111, 6876

[3] L. Tian et al. (2019), 81Kr Dating at the Guliya Ice Cap, Tibetan Plateau, Geophysical Research Letters 46, 6636–6643

[4] Crotti I, et al. (2021) An extension of the TALDICE ice core age scale reaching back to MIS 10.1. Quaternary Science Reviews 266:107078

[5] Lee, G., et al. (2021) Chronostratigraphy of blue ice at the Larsen Glacier in Northern Victoria Land, East Antarctica, The Cryosphere Discuss. [in review]

How to cite: Ritterbusch, F., Crotti, I., Dong, X.-Z., Fourré, E., Gu, J.-Q., Jacob, R., Jiang, W., Landais, A., Lu, Z.-T., Orsi, A., Prié, F., Shao, L., Tian, L., Tong, A.-M., Yang, G.-M., and Wang, J.: Towards 81Kr and 39Ar dating with 1 kg of ice, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9013, https://doi.org/10.5194/egusphere-egu22-9013, 2022.