Hydrothermal vents in sulfuric acid speleogenesis karst: isolated feeders with pristine hypogenic water or interconnected conduits with rapid flow and recycled water?

Authors

Jakub Mareš, Faculty of Science, Charles University in Prague, Czech RepublicFollow
Marek Audy, Czech Speleological Society, Czech RepublicFollow
Serban M. Sarbu, “Emil Racoviţă” Institute of Speleology, RomaniaFollow
Jan Kukačka, Faculty of Environmental Sciences, Czech University of Life Sciences Prague, Czech RepublicFollow
Romeo Eftimi, Rr. Rreshit Çollaku, pll. 10/3/18, Tirana, AlbaniaFollow
Jiří Bruthans, Faculty of Science, Charles University in Prague, Czech RepublicFollow

Highlights

• The modified model of sulfuric acid speleogenesis (SAS) presented
• First tracer tests performed in active SAS karst
• Feeders in SAS do not transport deep, pristine water, as previously believed
• The SAS hotspots are located in places where water whirls and releases H₂S
• Collapses of cave halls induce polyfurcation and maze patterns in caves

Abstract

Underwater connectivity and flow paths in the saturated zone of hypogenic sulfuric acid speleogenesis (SAS) karst remain unclear, despite sustained research over the past 30 years. Being regarded as sources of pristine H₂S-charged water, narrow inflow conduits called "feeders" are typically considered primary sources of water and hotspots of speleogenesis. In southeastern Albania, there is a newly discovered active SAS karst system comprising numerous caves and springs. Tracer tests were conducted to investigate the connection of these caves to the surrounding springs and to characterize the flow paths. The results show that water flows from cave lakes to all but one spring at a similar velocity, as in epigenic karst, including the feeders. These results indicate that feeders are not sources of deep, pristine groundwater. Instead, a mixture of water from lakes in upstream caves and deep groundwater flows to them. A SAS model was modified: deep, H₂S-charged groundwater causes intense enlargement of the caves until major collapses occur, blocking the outflow and creating cave lakes. Water bypasses the blockages via fractures oriented in various directions, resulting in polyfurcation and the formation of new feeders and maze patterns of caves. Hotspots of speleogenesis are at places of whirling, where H₂S is intensively released from water emerging from fractures. This has important consequences for our understanding of speleogenetic processes and organism migration routes in SAS karst.

DOI

https://doi.org/10.5038/1827-806X.ijs2573

Creative Commons License

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

Recommended Citation

Mareš, J., Audy, M., Sarbu, S.M., Kukačka, J., Eftimi, R., Bruthans, J., 2026. Hydrothermal vents in sulfuric acid speleogenesis karst: isolated feeders with pristine hypogenic water or interconnected conduits with rapid flow and recycled water? International Journal of Speleology, 55(1), ijs2573 https://doi.org/10.5038/1827-806X.ijs2573