<sup>81</sup>Kr dating of 1 kg Antarctic ice.

Ritterbusch, F; Wang, J S; Feng, X; Shackleton, S; Bender, M; Brook, E; Higgins, J; Jia, Z-H et al. · Nat Commun · 2025

basic_science · Level V

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Abstract

Recovering earth's climate history from ice cores requires reliable dating of the ice. <sup>81</sup>Kr is ideal for radiometric dating up to more than one million years, but the isotope is so rare that it has long been a challenge to apply <sup>81</sup>Kr dating on ice cores where sample size is limited. Here, we show <sup>81</sup>Kr dating of 1-kg ice-core samples from Taylor Glacier, Antarctica. This is made possible by an advance in <sup>81</sup>Kr detection with an all-optical realization of Atom Trap Trace Analysis. The achieved sample-size reduction facilitates <sup>81</sup>Kr dating of basal ice-core sections with direct implications for open questions in paleoclimatology, such as the evolution of glaciers on the Tibetan Plateau or the stability of the Greenland and West-Antarctic ice sheets.