ISTerre seminar

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IntoMess: Salinity reconstruction of the Mediterranean into the Messinian Salinity Crisis

Thursday 26 March 2026 - 10h00

Iuliana Vasilie - Senckenberg Biodiversity and Climate Research Centre (BiK-F), Frankfurt, Germany
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Restricted basins are part of the oceanic system that are affected mostly by global climate. At times, the interchange of the tectonics and climate, especially in the gateway vicinity, can take over and be expressed in unpredictable alterations of the water temperature and salinity conditions. Multiple proxies (e.g., foraminifera-based Mg/Ca, biomarkers-based TEX86 and UK37, clumped isotopes) are available for quantitatively assessing the water temperature, even in restricted marine basins, although cautious need to be exerted. Past salinity reconstruction is still one of the parameters that are particularly challenging to reconstruct, even for the Open Ocean. The task becomes even more difficult in restricted basins. We will exemplify part of the challenges by combining sea surface temperature (TEX86, UK37) and δ18O foram data to quantify salinity changes in the pre-MSC Mediterranean, focusing on the interval between 7.5 and 5.9 Ma. Even though δ18O foram analysis of Mediterranean Messinian successions exists for some time it was only recently that such data were combined with SST for a paleo-salinity reconstructions during the Messinian. We provided the first SSS estimates, unexpectedly discovering that, before the onset of the MSC, the Eastern Mediterranean (Kalamaki section, Greece) was a basin with similar-to-present salinity of 39. In contrast, calculated SSS for the Mediterranean between 6.41 and 6.15 Ma, reached 48, much higher than anywhere in the present-day. Extreme salinity (up to 48) was calculated for earlier Messinian in the Eastern Mediterranean. Two distinct warm and hypersaline events (at 6.9-6.82 Ma and 6.72 Ma) resulted in stressful conditions for the marine fauna during periods of overall strong evaporation (6.9-6.7 Ma). We found that, at 6.72 Ma, an important step in the Mediterranean restriction may have resulted from shallowing of the Mediterranean gateways, which would have reduced the Mediterranean marine outflow.

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Organizing team : Tectonique, reliefs et bassins

Amphithéâtre Killian, Maison des Géosciences, 38400 Saint Martin d'Hères