EGU22-5867, updated on 12 Dec 2022
EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Combined 14C and 230Th/U dating of fine-grained cryogenic cave carbonates from a permafrost cave in Greenland

Anika Donner1, Paul Töchterle1, Christoph Spötl1, Irka Hajdas2, Xianglei Li3, R. Lawrence Edwards3, and Gina E. Moseley1
Anika Donner et al.
  • 1Institute of Geology, University of Innsbruck, Austria (
  • 2Laboratory of Ion Beam Physics, ETH Zürich, Switzerland
  • 3Department of Earth Sciences, University of Minnesota, USA

Cryogenic cave carbonates (CCC) have become a valuable tool for providing evidence for past permafrost presence, particularly in low-elevation mid-latitude temperate locations (e.g. Germany and UK) and high-elevation mid-latitude periglacial environments (e.g. Austria and Spain). This study focuses on CCC from a low-elevation high-latitude site in the continuous permafrost of the high Arctic. Specifically, the fine-grained form of cryogenic cave carbonates (CCCfine), which precipitate from rapidly freezing thin water films on top of cave ice, are investigated from Eqik Qaarusussuaq (cave) in northeast Greenland (80.2°N). Under contemporary conditions, the sampling site in the interior of the cave is dry, cold (-14.7°C) and ice-free, thus water infiltration to facilitate CCCfine formation is not possible.

Previously, 230Th/U dating efforts of CCCfine have suffered from poor age precision due to high detrital Th contamination. Similarly, 14C dating has been hindered by the unknown reservoir effect (dead carbon fraction). To address these dating issues, we applied a multi-method dating approach to produce a unique dataset comprising eleven 14C ages as well as six 230Th/U ages from a single patch of CCCfine. An isochron indicates that the CCCfine formed synchronously and that the cleanest 230Th/U age is representative for the whole patch. The dead carbon fraction is calculated based on this 230Th/U age.

The results of 230Th/U dating (97±34 a BP) agree with the calibrated 14C age range (40-70 a BP (37.9%), 115-139 a BP (28.2%), 226-254 a BP (29.4%)) that the CCCfine from Eqik Qaarusussuaq most likely formed towards the end of the Little Ice Age or shortly after.

How to cite: Donner, A., Töchterle, P., Spötl, C., Hajdas, I., Li, X., Edwards, R. L., and Moseley, G. E.: Combined 14C and 230Th/U dating of fine-grained cryogenic cave carbonates from a permafrost cave in Greenland, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-5867,, 2022.


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