The extreme Mediterranean sea-level drop during the Messinian salinity crisis has been known for >50 years, but its amplitude and duration remain a challenge. Here we estimate its amplitude by restoring the topography of the Messinian Nile canyon and the vertical position of the Messinian coastline by unloading of post-Messinian sediment and accounting for flexural isostasy and compaction. We estimate the original depth of the geomorphological base level of the Nile River at ~600 m below present sea level, implying a drawdown 2–4 times smaller than previously estimated from the Nile canyon and suggesting that salt precipitated under 1–3 km deep waters. This conclusion is at odds with the nearly-desiccated basin model (>2 km drawdown) dominating the scientific literature for 50 years. Yet, a 600 m drawdown is ca. five times larger than eustatic fluctuations and its impact on the Mediterranean continental margins is incomparable to any glacial sea-level fall.
Bibliographical noteFunding Information:
The article was supported by COST Action “Uncovering the Mediterranean salt giant” (MEDSALT), funded by the European Cooperation in Science and Technology. It was also supported by the SALTGIANT program, a European project funded by the European Union’s Horizon 2020 research and innovation program under the Marie Sklodowska Curie grant agreement number 765256. We appreciate the thorough review and constructive comments by Joe Cartwright and another anonymous reviewer, that significantly improved the manuscript.
© 2022, The Author(s).