EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

The tip of the iceberg: U-Pb dating shows that cave systems can be twice as old as their surface expression

Rieneke Weij1,2, Jon Woodhead1, Kale Sniderman1, John Hellstrom1, Elizabeth Reed3,4, Steven Bourne5, and Russell Drysdale1
Rieneke Weij et al.
  • 1School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, Australia (
  • 2Human Evolution Research Institute, Department of Geological Sciences, The University of Cape Town, Cape Town, South Africa
  • 3Ecology and Evolutionary Biology, School of Biological Sciences, University of Adelaide, Adelaide, Australia
  • 4Earth and Biological Sciences (Palaeontology), South Australian Museum, Adelaide, Australia
  • 5Limestone Coast Landscape Board, Mount Gambier, Australia

Caves are important fossil repositories providing records extending back over million-year timescales. While the physical processes of cave formation are well understood, a more important parameter to studies of palaeontology, palaeoanthropology and archaeology — that of the timing of initial cave development and opening — has proved more difficult to constrain. The Naracoorte Cave Complex (NCC) in southern Australia is a World Heritage site with a rich record of Pleistocene vertebrate fossils, including extinct megafauna, and serves as a natural laboratory in which to investigate these fundamental cave processes. Using U-Th-Pb dating of speleothems we show that the NCC is at least 1.32 million years old, extending the current understanding of initial speleothem formation by ~70% and the antiquity of initial cave development at this site by at least ~20%. We use charcoal and pollen trapped in the same speleothems to place robust constraints on the timing and extent of subsequent cave opening. The findings of this study provide an important means for researchers working on the plethora of fossil-rich sites worldwide to assess the potential upper limit of vertebrate fossil records within caves.

How to cite: Weij, R., Woodhead, J., Sniderman, K., Hellstrom, J., Reed, E., Bourne, S., and Drysdale, R.: The tip of the iceberg: U-Pb dating shows that cave systems can be twice as old as their surface expression, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-506,, 2022.


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