Condensation corrosion in caves on Cayman Brac and Isla de Mona

Many speleothems in caves on Cayman Brac and Isla de Mona have suffered considerable dissolution. It is suggested that this is a consequence of condensation corrosion rather than of aqueous flooding of the entire cave. A program of temperature and relative humidity measurements during the rainy seasons showed that the entrance zones are areas of comparatively large diurnal variation where condensation from warm air onto cooler walls may occur. Artificial condensation was induced using ice bottles: chemical analysis of the condensation waters determined that they were generally undersaturated with respect to calcite and/or dolomite but that this changes over space and time. Gypsum tablets were suspended inside three sample caves on Cayman Brac and one on Isla de Mona for 16 and 13 months, respectively. At the end of this period, tablets close to the entrances and to the floor was found to have undergone considerable dissolution; this could only have been the result of condensation corrosion.