EGU21-14642
https://doi.org/10.5194/egusphere-egu21-14642
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

First investigations of fine-grained cryogenic cave carbonates from a High-Arctic permafrost karst system in Greenland

Anika Donner1, Christoph Spötl1, Paul Töchterle1, Irka Hajdas2, and Gina E. Moseley1
Anika Donner et al.
  • 1University of Innsbruck, Institute of Geology, Austria (anika.donner@uibk.ac.at)
  • 2ETH Zürich, Laboratory of Ion Beam Physics, Switzerland

In recent years, cryogenic cave carbonates (CCC) have become the focus of studies tracking past climate change in periglacial environments. Two types of these speleothems occur, fine-grained CCC (CCCfine), which form due to the rapid freezing of a thin water film on ice, and coarse-grained CCC whose origin is related to the slow freezing of water pockets inside cave ice. Here, we report for the first time the occurrence of CCCfine from a cave in northeast Greenland, presently situated in continuous permafrost.

Eqik Qaarusussuaq (Cove Cave), located at 80.2° N, is a 103 m long, gently-dipping phreatic passage that was discovered during the 2019 Greenland Caves Project Expedition (www.greenlandcavesproject.org). CCCfine were found in a dry chamber 65 m behind the entrance. The cave air temperature at the CCC site of -14.7 °C contrasts with outside air temperatures of up to +18.0 °C in July 2019. This, together with current dry conditions at the sampling site, indicates that water infiltration, necessary for CCC formation, is not possible under present-day climate conditions. This is further supported by a lack of ice found within the cave.

Stable isotope analyses of CCC show δ18O values ranging from -21.9 to -16.0 ‰ and δ13C values between 8.4 and 11.7 ‰ VPDB. While the δ13C values are consistent with published data of CCCfine from caves at lower latitudes, the δ18O values are significantly lower and plot in the field of CCCcoarse (cf. Žák et al., 2018). This shift reflects the much lower δ18O values of meteoric precipitation in northeast Greenland compared to lower latitude sites.

Exploratory radiocarbon dating suggests that CCCfine formed in this High Arctic cave as recent as during the end of the Little Ice Age.

 

Reference

Žák, K., Onac, B.P., Kadebskaya, O.I., Filippi, M., Dublyansky, Y., Luetscher, M., 2018. Cryogenic mineral formation in caves. In: Perşoiu, A., Lauritzen, S.-E. (Eds.), Ice caves. Elsevier, Amsterdam, Netherlands, pp. 123–162.

How to cite: Donner, A., Spötl, C., Töchterle, P., Hajdas, I., and Moseley, G. E.: First investigations of fine-grained cryogenic cave carbonates from a High-Arctic permafrost karst system in Greenland, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-14642, https://doi.org/10.5194/egusphere-egu21-14642, 2021.

This abstract will not be presented.