EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Direct evidence for elevated UV-B radiation and ozone layer disruption during the end-Permian mass extinction

Phillip Jardine1, Huiping Peng2, John Marshall3, Barry Lomax4, Benjamin Bomfleur1, Matthew Kent4, Wesley Fraser5, and Feng Lui2,6
Phillip Jardine et al.
  • 1Institute of Geology and Palaeontology, University of Münster, Münster, Germany (
  • 2Nanjing Institute of Geology and Palaeontology, Chinese Academy of Sciences, Nanjing, China
  • 3School of Ocean and Earth Science, University of Southampton, Southampton, U.K.
  • 4School of Biosciences, University of Nottingham, Sutton Bonington, U.K.
  • 5School of Social Sciences, Oxford Brookes University, Oxford, U.K.
  • 6State Key Laboratory of Palaeobiology and Stratigraphy and Center for Excellence in Life and Paleoenvironment, Nanjing, China

The end-Permian mass extinction (EPME) is the largest extinction event of the Phanerozoic, but the specific causal pathways, especially in the terrestrial realm, are unresolved. Malformed pollen and spores recovered from the EPME interval have been taken as indicators of extreme environmental stress in terrestrial ecosystems. However, whether they relate to volcanism-driven ozone-layer deterioration and enhanced ultraviolet-B (UV-B) flux, or volcanogenic toxic pollutants including mercury and acid rain, or some combination of the two, remains unclear. Here, we take advantage of a novel palynological proxy, which utilises the ability of land plants to adjust the concentration of protective UV-B-absorbing compounds (UACs) in the outer wall of their reproductive propagules in response to changes in ambient UV-B flux. We analysed UAC abundances in ca. 800 pollen grains from an independently-dated Permian-Triassic boundary section in southern Tibet, in order to infer changes in UV-B-radiation flux at the Earth’s surface during the EPME. Our data reveal an excursion in UACs that coincides with a spike in mercury concentration and a negative carbon-isotope excursion in the latest Permian deposits, suggesting a close temporal link between large-scale volcanic eruptions, global carbon- and mercury-cycle perturbations, and ozone-layer disruption. Because enhanced UV-B radiation can exacerbate the environmental deterioration induced by massive magmatism, ozone depletion is considered a compelling ecological driver for the terrestrial mass extinction.

How to cite: Jardine, P., Peng, H., Marshall, J., Lomax, B., Bomfleur, B., Kent, M., Fraser, W., and Lui, F.: Direct evidence for elevated UV-B radiation and ozone layer disruption during the end-Permian mass extinction, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-5978,, 2023.