Global distribution and controls on cave drip water oxygen isotope composition

Baker, A.; Hartmann, A.; Duan, W.; Hankin, S.; Comas-Bru, L.; Cuthbert, M.O.; Treble, P.C.; Banner, J.; Genty, D.; Baldini, L.M.; Bartolome, M.; Moreno, A.; Perz-Mejias, C.

Abstract

The oxygen isotope composition of speleothems is a widely used proxy for past climate change. Robust use of this proxy depends on understanding the relationship between precipitation and cave drip water δ18O. Here, we present the first global analysis, based on data from 163 drip sites, from 39 caves on five continents, showing that drip water δ18O is most similar to the amount-weighted precipitation δ18O where mean annual temperature (MAT) is < 10 °C. By contrast, for seasonal climates with MAT > 10 °C and < 16 °C, drip water δ18O records the recharge-weighted δ18O. This implies that the δ18O of speleothems (formed in near isotopic equilibrium) are most likely to directly reflect meteoric precipitation in cool climates only. In warmer and drier environments, speleothems will have a seasonal bias toward the precipitation δ18O of recharge periods and, in some cases, the extent of evaporative fractionation of stored karst water.

Citation

Baker, A., Hartmann, A., Duan, W., Hankin, S., Comas-Bru, L., Cuthbert, M., …Perz-Mejias, C. (2019). Global distribution and controls on cave drip water oxygen isotope composition. Nature Communications, 10, Article 2984. https://doi.org/10.1038/s41467-019-11027-w

• Journal Article Type: Article
• Acceptance Date: May 30, 2019
• Online Publication Date: Jul 5, 2019
• Publication Date: Jul 5, 2019
• Deposit Date: Jan 31, 2019
• Publicly Available Date: Jul 16, 2019
• Journal: Nature Communications
• Publisher: Nature Research
• Peer Reviewed: Peer Reviewed
• Volume: 10
• Article Number: 2984
• DOI: https://doi.org/10.1038/s41467-019-11027-w
• Public URL: https://durham-repository.worktribe.com/output/1338473