A recent study has revealed the dramatic decrease in the Mediterranean Sea’s level during the Messinian Salinity Crisis, an important geological event that altered the Mediterranean into a massive salt basin between 5.97 and 5.33 million years ago.
The Mediterranean Sea experienced a significant decrease in water level during the Messinian Salinity Crisis, a pivotal geological occurrence that converted the area into a vast salt basin between 5.97 and 5.33 million years ago2.
Previously, the mechanism behind the accumulation of a million cubic kilometers of salt in the Mediterranean basin over a brief period was not understood. However, through the examination of chlorine isotopes3 found in salt extracted from the seabed of the Mediterranean, researchers have discovered two stages of this intense evaporation process. The first stage, which lasted roughly 35,000 years, saw salt formation occur solely in the eastern Mediterranean. This was instigated by a reduction in the outflow of Mediterranean water to the Atlantic, creating a basin that was otherwise filled with brine. The second stage saw salt accumulation throughout the entire Mediterranean. This phase was marked by a rapid evaporative decrease that occurred in less than 10,000 years, during which the sea level plummeted by 1.7-2.1 km in the eastern Mediterranean and about 0.85 km in the western part. Consequently, the Mediterranean Basin lost up to 70% of its total water volume.
This dramatic sea level drop likely affected both land animals and the Mediterranean scenery, prompting localized volcanic eruptions due to the unloading of Earth’s crust and causing global climate effects triggered by the substantial depression from the falling sea levels.
The findings, published in Nature Communications on November 18, enhance our knowledge of extreme geological phenomena, the region’s evolution, and the subsequent global impacts.
This research was financed by the European Union and the CNRS.
Notes :
- Conducted by the French research institute Institut de physique du globe de Paris (CNRS/Université Paris Cité/Institut de physique du globe de Paris).
- This extraordinary event left the floor of the Mediterranean Sea covered with a salt layer as thick as 3 km. Understanding the causes, impacts, and environmental transformations that the Mediterranean experienced during the Messinian Salinity Crisis has been a significant challenge facing the scientific community for many decades.
- The study of the two stable chlorine isotopes (³⁷Cl and ³⁵Cl) allowed scientists to evaluate the rate of salt accumulation and ascertain the decline in sea level.
