Dating speleothems in Southern Italy (Apulia and Sardinia): palaeoclimate implications and speleogenetic clues

This study reports the results of a comprehensive radiometric dating campaign carried out on 51 speleothems from caves in Apulia and Sardinia during the last ~7 years. Around 230 ages were produced by exploiting the U‐Th method. Sampling targeted 5 caves in Apulia and 12 caves in Sardinia. All caves are located ~41°N (±1°) latitude, representing an ideal location for the understanding speleothem deposition in relation to past Mediterranean climate. U‐Th dates can be used as minimum age for the caves in which they formed, hence providing geochronological constraints on speleogenetic processes. The preliminary results attest that in both regions: 1) there is evidence of speleothem deposition since 600‐800 thousand years before present (ka), implying that speleogenesis occurred beforehand. According to cave morphology observations, and in relation to local geology, the formation of most of the explored caves is estimated to have occurred several millions of years before present; 2) speleothem deposition occurred during glacial (last glacial, MIS6, MIS8, MIS10) and interglacial (Holocene, MIS5, MIS7, MIS9, MIS13) stages over the last ~500 ka. This implies that climate during the glacial stages was never too cold and dry to impede speleothem deposition, as has been the case in other parts of Europe.