Sulfur (³⁴S/³²S) isotope composition of gypsum and implications for deep cave formation on the Nullarbor Plain, Australia

Authors

Matej Lipar, Anton Melik Geographical InstituteFollow
Mateja Ferk, Anton Melik Geographical Institute
Sonja Lojen, Jožef Stefan Institute & University of Nova Gorica
Milo Barham, Curtin University

Highlights

• Gypsum appears in caves on the Nullarbor Plain
• δ³⁴S of gypsum shows relatively high positive δ³⁴S values
• Cave sulphate minerals are evaporates

Abstract

Large deep caves with little relation to surface topography are distinctive karst features on the Nullarbor Plain of Australia. The presence of gypsum deposits and chemoautotrophic bacteria within the caves have been suggested as evidence for cave formation and (or) enlargement via sulfuric acid speleogenesis. To test this hypothesis, the stable sulfur isotope compositions (δ³⁴S) of both cave gypsum and surface gypsum were measured. Analyses yielded relatively high, positive δ³⁴S values from both cave gypsum and surface gypsum, arguing against gypsum genesis via microbial chemoautotrophy, and more broadly, sulfuric acid speleogenesis. Instead, the gypsum is interpreted as forming via evaporation of seawater during the Quaternary.

DOI

https://doi.org/10.5038/1827-806X.48.1.2196

Creative Commons License

This work is licensed under a Creative Commons Attribution-Noncommercial 4.0 License

Recommended Citation

Lipar, Matej; Mateja Ferk; Sonja Lojen; and Milo Barham. 2019. Sulfur (³⁴S/³²S) isotope composition of gypsum and implications for deep cave formation on the Nullarbor Plain, Australia. International Journal of Speleology, 48: 1-9.
Available at: https://digitalcommons.usf.edu/ijs/vol48/iss1/1