Can caves record sea-level changes?
Secondary carbonate deposits in caves, known as speleothems (e.g., stalagmites and stalactites), preserve a variety of paleoclimatic and palaeoenvironmental signals. The coastal caves of Mallorca (Spain) display an unusual type of carbonate encrustation that was precipitated on pre-existing speleothems during periods of Mediterranean sea-level high or lowstands (Figs. 1-3). The precise timing of sea-level changes has the potential to test the Milankovitch theory of Earth’s orbital forcing on global ice-volume fluctuations. In our Science paper we reconstructed western Mediterranean Sea level between ~82 and ~80 thousands years (kyr) based on precise U/Th TIMS ages on carbonate encrustations. We find that the sea level on Mallorca stood ~1 m above the present during marine isotope substage (MIS) 5a. We observe that timing of the MIS 5a sea-level highstand in Mallorca is in general agreement with data from deep-sea oxygen isotope stratigraphy. Although our data constrain the age of the M
