- 1Northumbria University, geography and Environmental Science, Newcastle Upon Tyne, United Kingdom of Great Britain – England, Scotland, Wales (stuart.umbo@northumbria.ac.uk)
- 2Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, 14473 Potsdam, Germany
- 3Department of Chemistry, Biochemistry, and Pharmaceutical Sciences and Oeschger Centre for Climate Change Research, University of Bern, Bern 3012, Switzerland
- 4Geological Survey of Israel, 32 Yeshayahu Leibowitz Street, 9692100 Jerusalem, Israel
- 5Department of Earth Sciences, University of Oxford, South Parks Road, OX1 3AN Oxford, UK
- 6Speleoclub Arabika, St. Mamina-Sibiryaka 6a, 664058 Irkutsk, Russia
Our understanding of global temperature in the recent geological past is predominantly derived from oceanic proxies and modelling reconstructions1–3. Terrestrial proxy data, particularly in continental environments, is sparse and based largely on palaeobotanical and palaeozoological data which can be difficult to accurately date4.
We present approximately 30 temperature reconstructions over a six-million-year interval from Botovskaya Cave (N 55.3°, E 105.3°) in Siberia, ca. 300 km west of Lake Baikal. We provide chronological constraint with U-series techniques5 and multi-annual absolute temperature estimates from clumped isotope analyses of speleothems (carbonate cave deposits, e.g. stalagmites and flowstones). Clumped isotope analysis directly infers quantitative paleotemperature estimates, overcoming difficulties associated with conventional stable isotope (δ18O) techniques which require knowledge of the isotopic composition of carbonate precipitation waters – which is often unknown. By targeting subaqueous material, we overcome dis-equilibrium effects which have hindered widespread application of clumped isotopes to speleothems6,7.
Our record is the longest palaeotemperature timeseries from continental Eurasia and suggests a ca. 4 – 5°C temperature drop between the Messinian (7.24 – 5.33 Ma) and the present day, coincident with declining atmospheric carbon dioxide8, and in agreement with existing estimates of global temperature over the same interval9,10.
References
1. Clark, P. U. et al, Global and Regional Temperature Change over the Past 4.5 Million Years. Science (2024).
2. Herbert, T. D. et al. Late Miocene global cooling and the rise of modern ecosystems. Nat Geosci (2016).
3. Judd, E. J. et al. A 485-million-year history of Earth’s surface temperature. Science, (2024).
4. Bradshaw, C. D. et al. The relative roles of CO2 and palaeogeography in determining late Miocene climate: Results from a terrestrial model-data comparison. Climate of the Past (2012).
5. Mason, A. J. et al, Simplified isotope dilution approach for the U-Pb dating of speleogenic and other low-232Th carbonates by multi-collector ICP-MS. Geochronology (2022).
6. Daëron, M. et al. 13C18O clumping in speleothems: Observations from natural caves and precipitation experiments. Geochim Cosmochim Acta (2011).
7. Affek, H. P. et al, Glacial/interglacial temperature variations in Soreq cave speleothems as recorded by ‘clumped isotope’ thermometry. Geochim Cosmochim Acta (2008).
8. Rae, J. W. B., et al. Atmospheric CO2 over the past 66 million years from marine archives. Annual Review of Earth and Planetary Sciences. (2021).
9. Westerhold, T. et al. An astronomically dated record of Earth’s climate and its predictability over the last 66 million years. Science (2020).
10. Pound, M. J. et al, Global vegetation dynamics and latitudinal temperature gradients during the Mid to Late Miocene (15.97-5.33Ma). Earth-Science Reviews (2012).
How to cite: Umbo, S., Modestou, S., Opel, T., Lechleitner, F., Vaks, A., Golan, T., Mason, A., Margerum, J., Kwiecien, O., Osintsev, A., and Breitenbach, S.: A six-million-year speleothem derived clumped isotope temperature record of continental Eurasia, EGU General Assembly 2025, Vienna, Austria, 27 Apr–2 May 2025, EGU25-16094, https://doi.org/10.5194/egusphere-egu25-16094, 2025.
