2,5,4,9,11,12,1,4,- 1CAS Center for Excellence in Quantum Information and Quantum Physics, School of Physical Sciences, University of Science and Technology of China, He Fei, China (xinf2000@mail.ustc.edu.cn)
- 2College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, USA
- 3Institute of Environmental Physics, Heidelberg University, Heidelberg, Germany
- 4Hefei National Laboratory, University of Science and Technology of China, Hefei, China
- 5Scripps Institution of Oceanography (SIO), University of California, San Diego, La Jolla, , USA
- 6Department of Geosciences, Princeton University, Princeton, NJ, USA
- 7Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou, China
- 8School of Nuclear Science and Technology, Chinese Academy of Sciences, Lanzhou, China
- 9National Ice Core Laboratory, Earth Sciences New Zealand, Gracefield, New Zealand
- 10School of Oceanography, Shanghai Jiao Tong University, Shanghai, China
- 11Antarctic Research Centre, Victoria University of Wellington, Wellington, New Zealand
- 12University of Chinese Academy of Sciences, Beijing, China
- 13Woods Hole Oceanographic Institution, Woods Hole, United States
81Kr (t1/2 = 229 ka) is a valuable isotope for radiometric dating of water and ice with a dating range from thirty thousand to over one million years. Based on laser cooling and trapping, the detection method Atom Trap Trace Analysis (ATTA) has enabled 81Kr analysis at extremely low isotopic abundance levels in the environment. Here, we present the realization of a new-generation ATTA system that overcomes previous large sample-size requirements, making it possible to date polar ice-core samples of ~1 kg with ages up to 1.5 Ma.
We demonstrate the field applicability of this system through successful 81Kr dating of two dated 1-kg ice-core samples from Taylor Glacier, Antarctica. Based on this validation, we apply 81Kr dating to ancient ice samples with unknown ages from both polar regions. In Antarctica, we dated basal ice from the RICE core providing constraints for the existence of the Ross Ice Shelf through the Last Interglacial. In Greenland, we dated basal ice from the GISP2 ice core, obtaining 81Kr ages which implies that the central Greenland Ice Sheet persisted through the prolonged warm period of Marine Isotope Stage 11. To further reconstruct history and extent of the Greenland ice sheet, dating of ice core samples from other drill sites in Greenland is currently ongoing.
These examples demonstrate that the presented sample size reduction for 81Kr dating enables absolute age determination for stratigraphically disturbed basal ice, providing valuable information on the history of polar ice sheets.
How to cite: Feng, X., Brook, E. J., Ritterbusch, F., Yang, G.-M., Severinghaus, J. P., Wang, J. S., Higgins, J. A., Zhao, L., Sun, L.-T., Harris, M., Bender, M. L., Bertler, N. A. N., Lin, Q.-S., Shackleton, S., Ferrick, T., Jiang, W., Jia, Z.-H., and Lu, Z.-T.: 81Kr Dating of 1 kg Polar Ice, EGU General Assembly 2026, Vienna, Austria, 3–8 May 2026, EGU26-15595, https://doi.org/10.5194/egusphere-egu26-15595, 2026.
