Sea-level stands from the Western Mediterranean over the past 6.5 million years

Sea-level reconstructions are important for understanding past ice sheet variability and its response to past and future warming. Here we present Neogene and Quaternary sea-level snapshots using phreatic overgrowths on speleothems (POS) from caves on Mallorca, Spain. POS are excellent sea level index points because of their clear relationship to sea level and precise U-Pb chronology. We find that local sea-level before and at the onset of the Messinian Salinity Crisis was at 33.3 +/- 0.25 m (6.54 +/- 0.37 Ma) and 31.8 +/- 0.25 m (5.86 +/- 0.60 Ma) above present levels, respectively. We further present global mean sea level (GMSL) estimates, i.e. local sea level corrected for glacial isostatic adjustment and long-term uplift, for three other POS. The results show that GMSL during the Pliocene-Pleistocene Transition was 6.4 m (- 2.0-8.8 m) at 2.63 +/- 0.11 Ma and during the beginning and the end of the Mid-Pleistocene Transition was - 1.1 m (- 5.6-2.4 m) and 5 m (1.5-8.1 m), respectively. These estimates provide important constraints for the past evolution of sea level and show that local sea level prior to the MSC was similar to the highest stand during the Pliocene, with markedly lower position afterwards.

Automated summary

Sea-level reconstructions using phreatic overgrowths on speleothems from caves in Mallorca, Spain provided snapshots of Neogene and Quaternary sea levels, with estimates of global mean sea level during significant transitions in the Earth's history. The study highlights the importance of understanding past sea level variation in relation to climate change.