EGU23-9969, updated on 26 Feb 2023
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Secular evolution of boron isotope composition of seawater archived in evaporites?

Hana Jurikova1, Fernando Gázquez2, Oscar Branson3, David Evans4, Matthew Dumont1, Eszter Sendula5,6, Robert Bodnar6, Mebrahtu Weldeghebriel7, Tim Lowenstein7, and James Rae1
Hana Jurikova et al.
  • 1University of St Andrews, School of Earth and Environmental Sciences, St Andrews, UK (
  • 2University of Almería, Department of Biology and Geology, Almería, Spain
  • 3University of Cambridge, Department of Earth Sciences, Cambridge, UK
  • 4Goethe University Frankfurt, Institute of Geosciences, Frankfurt, Germany
  • 5UiT The Arctic University of Norway, Department of Geosciences, Tromsø, Norway
  • 6Virginia Tech, Department of Geosciences, Blacksburg, USA
  • 7State University of New York, Department of Geological Sciences, Binghamton, USA

The boron isotope composition of the ocean is homogeneous, but varies on multi-million year time scales, given its residence time of approximately 10 million years. To date, the secular evolution of the oceanic boron isotope budget has been difficult to constrain. The lack of knowledge on past boron isotope composition of seawater (δ11Bsw) poses a major uncertainty for reliable boron-based pH and CO2 reconstructions from Earth’s geologic past and critically limits our understanding of the global biogeochemical cycling of this important element through time. Evaporitic minerals bearing fluid inclusions – and halites in particular – present a highly appealing archive for reconstructing δ11Bsw given their direct origin from seawater. However, the interpretation of their boron isotope signatures is not straightforward due to the possibility of fractionation during evaporation and crystallisation. Here we present first insights into boron isotope evolution during evaporite formation from laboratory experiments and natural modern evaporitic settings. These data enable us to place constraints on boron fractionation in ancient evaporites, offering new insights into δ11Bsw during some of the key periods of the Phanerozoic.

How to cite: Jurikova, H., Gázquez, F., Branson, O., Evans, D., Dumont, M., Sendula, E., Bodnar, R., Weldeghebriel, M., Lowenstein, T., and Rae, J.: Secular evolution of boron isotope composition of seawater archived in evaporites?, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-9969,, 2023.