Highlights
- Cave wall water-films typically measure between 25 and 70 µm
- On active speleothems, films reach 200–300 µm in thickness
- A confocal optical sensor enabled precise in-situ measurements
- High-frequency monitoring captured rapid film thickness variations
- The method was successfully applied in multiple prehistoric caves
Abstract
The water-film that coats cave walls and speleothems is a key player for the regulation of cave microclimate and the control of speleothem growth. In this paper, we demonstrate the capability of a confocal optical sensor to quantitatively measure on-site the rapid variations of water-film thickness when dripping, active condensation, or dryness occur on walls of various caves. Results obtained from a sample of four prehistoric caves and one stalagmite cave from Southwest France, indicate that the measurable thickness of water-films is generally in the 25-70 µm range for cave walls and reaches 200-300 µm on the horizontal plane of active speleothems. The high measurement frequency enables the monitoring of water-film dynamics for a few minutes, especially the tracking of thickness changes triggered by drop dripping and water flow. The optical sensor appears to be a promising tool for the conservation of prehistoric caves facing subsurface warming.
DOI
https://doi.org/10.5038/1827-806X.ijs2568
Creative Commons License
This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 4.0 License.
Recommended Citation
Honiat, A., Bourges, F., Skali-Lami, S., Lartiges, B., 2025. Measurements of water film thickness on cave walls and speleothems. International Journal of Speleology, 54(3), ijs2568. https://doi.org/10.5038/1827-806X.ijs2568
Supplementary information
