EGU General Assembly 2022
© Author(s) 2022. This work is distributed under
the Creative Commons Attribution 4.0 License.

Aftermath of catastrophic flooding of a desiccated ocean basin

Udara Amarathunga1, Andrew Hogg1, Eelco Rohling1,2, Andrew Roberts1, Katharine Grant1, David Heslop1, Pengxiang Hu1, Diederik Liebrand3,4, Thomas Westerhold3, Xiang Zhao1, and Stewart Gilmore5
Udara Amarathunga et al.
  • 1Australian National University, Research School of Earth Sciences, Acton, Australia
  • 2Ocean and Earth Science, University of Southampton, National Oceanography Centre, Southampton SO14 3ZH, UK
  • 3MARUM, University of Bremen, D-28359 Bremen, Germany
  • 4PalaeoClimate.Science, Allerton Bywater, United Kingdom
  • 5Geoscience Australia, GPO Box 378, ACT 2609, Canberra, Australia

5.33 Million years ago, a mile-high marine cascade terminated the Messinian Salinity Crisis due to partial collapse of the Gibraltar arc/sill that isolated a largely desiccated Mediterranean from the Atlantic Ocean. Atlantic waters may have refilled the basin within 2 years. Prevailing hypotheses suggest that normal marine conditions were established across the Mediterranean immediately after the catastrophic flooding. Here we use new proxy data and modelling to show that normal conditions were likely for the western Mediterranean (wMed), but that flooding caused massive wMed salt transfer to the eastern Mediterranean (eMed), which became a hyper-salinity-stratified basin. Hyper-stratification inhibited deep-water ventilation, causing anomalously long-lasting organic-rich (sapropel) sediment deposition. Model:data agreement indicates that hyper-stratification breakdown required 26,000 years. Testing an alternative hypothesis—reconnection of a largely refilled Mediterranean—reveals hyper-stratification in both the wMed and eMed, which would have left sapropels in both basins, in disagreement with observations. Our findings offer novel insight into the processes involved in re-establishing normal marine conditions following abrupt refilling of a previously desiccated ocean basin.

How to cite: Amarathunga, U., Hogg, A., Rohling, E., Roberts, A., Grant, K., Heslop, D., Hu, P., Liebrand, D., Westerhold, T., Zhao, X., and Gilmore, S.: Aftermath of catastrophic flooding of a desiccated ocean basin, EGU General Assembly 2022, Vienna, Austria, 23–27 May 2022, EGU22-9593,, 2022.


Display file