Last interglacial sea level changes in Mallorca island (Western Mediterranean). High precision U-series data from phreatic overgrowths on speleothems

The karst of Mallorca Island (Balearic Archipelago, Spain) is characterized by the occurrence of many coastal caves where phreatic speleothems accrete on conventional vadose-zone speleothems in correspondence with the current sea. These carbonate precipitates have recorded ancient high and low stands of the sea level, as indicated by means of strictly horizontal alignments of the Phreatic Overgrowths on Speleothems (POS) respectively located above and below present sea level. Mallorca has proved to be a good spot for investigations on eustatic sea level changes because it is located far from former margins of the major ice-sheets and was only affected by a minor tectonic tilt in the last 117,000 yr. A number of POS now located above and below present sea level have been dated by the U-series method using MC-ICPMS and TIMS. The obtained high precision ages fall within a time interval ranging from 140,000 to 80,000 yr and allowed the construction of a tentative sea level changes curve for the Last Interglaciation in the Western Mediterranean. Such curve emphasizes the occurrence of marine level fluctuations greater than 18 metres in amplitude within short time spans (lower than 10,000 yr).