Calcite spar of Kryštálová Cave (Slovakia): Insights into formation conditions from fluid inclusions, stable isotopes, and noble gases

Authors

• Petronela Ševčíková, Slovak Hydrometeorological Institute, SlovakiaFollow
• Yuri Dublyansky, Institute of Geology, University of Innsbruck, Austria
• Stanislava Milovská, Earth Science Institute of Slovak Academy of Sciences, Slovakia
• László Palcsu, HUN-REN Institute for Nuclear Research (ATOMKI), Hungary
• Marjan Temovski, HUN-REN Institute for Nuclear Research (ATOMKI), Hungary
• Kata Molnár, HUN-REN Institute for Nuclear Research (ATOMKI), Hungary
• Gabriella I. Kiss, HUN-REN Institute for Nuclear Research (ATOMKI), Hungary
• Mário Olšavský, State Geological Institute of Dionýz Štúr, Slovakia
• Pavel Herich, Slovak Cave Administration, Slovakia
• Gabriella Koltai, Institute of Geology, University of Innsbruck, Austria
• Christoph Spötl, Institute of Geology, University of Innsbruck, Austria

Highlights

• First evidence of immiscible fluid entrapment in fluid inclusions of cave spar
• Implies a possibility of kinetic rather than equilibrium precipitation
• Fluid inclusion petrography proved essential for spar formation reconstruction
• Application of noble gas thermometry to phreatic spar is limited

Abstract

Phreatic calcite spar is an infrequently used yet promising archive for paleohydrology, a diagnostic tool for speleogenesis, and a robust geothermometer. In this study, we investigated phreatic calcite from Kryštálová cave (Malá Fatra Mts., Slovakia) to constrain its formation conditions, reconstruct the composition of its parent fluid, determine precipitation temperatures, and assess its potential for paleohydrology. Fluid-inclusion microthermometry and stable isotope analyses of inclusion water indicate that calcite precipitated at 45-80°C from a meteoric fluid (δ²H_meas = -87.4 to -84.4‰; δ¹⁸O_calc = -12.2 to -11.8‰) with a purely crustal noble gas signature. Stable isotope profiles along calcite growth axes combined with U-Th dating further show that the calcite spar represents a single generation formed prior to 650 ka. Noble gas concentrations in the fluid inclusions are unexpectedly high, rendering noble gas thermometry infeasible. Instead, these elevated gas concentrations combined with FI petrography and FIM suggest that the fluid existed, at least intermittently, in an immiscible state. Based on field and geological evidence, the presence of immiscible fluids in a deep phreatic speleogenetic setting is best explained by a sudden volume increase and consequent pressure drop within a confined, fluid-filled system, likely induced by (seismo)tectonic deformation.

DOI

https://doi.org/10.5038/1827-806X.ijs2629

Creative Commons License

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

Recommended Citation

Ševčíková, P., Dublyansky, Y., Milovská, S., Palcsu, L., Temovski, M., Molnár, K., Kiss, G.I., Olšavský, M., Herich, P., Koltai, G., Spötl, C., 2026. Calcite spar of Kryštálová Cave (Slovakia): Insights into formation conditions from fluid inclusions, stable isotopes, and noble gases. International Journal of Speleology, 55(3), ijs2629. https://doi.org/10.5038/1827-806X.ijs2629