Salt Tectonics and Hypersaline Anoxic Basins: Processes and Forms Shaping Significant Extreme Environments in The Mediterranean Sea

Deep-sea hypersaline anoxic basins (DHABs) in the Mediterranean Sea are extreme environments shaped by the interplay of salt tectonics and sedimentary processes over geological time scales. The foundational work of Maria Bianca Cita, who first provided evidence of the Messinian Salinity Crisis and contributed to the discovery of Mediterranean DHABs, has profoundly influenced our understanding of these unique settings. Her research revealed the dramatic environmental shifts that shaped the Mediterranean, laying the groundwork for investigating the relationship between salt tectonics and hypersaline basins.

Currently, eight main DHABs are recognized in the eastern Mediterranean, but a comprehensive geomorphological characterization of these features and their surrounding regions remains lacking. The seafloor in these areas is often described as exhibiting a "cobblestone topography," reflecting the complex terrain generated by salt tectonic deformation. However, high-resolution multibeam surveys from recent studies reveal a significant diversity of landforms that could characterize hundreds of square kilometers in the eastern Mediterranean Basin.

Using data collected during recent European-funded research cruises in the Mediterranean, we conducted a detailed geomorphometric analysis to better characterize the salt-tectonic-associated landforms mapped in the Levantine Basin. Our results confirm spatial patterns reflecting the influence of tectonic forces and sedimentary dynamics in shaping the DHABs, consistent with previous studies, while also unveiling a broader variety of submarine landforms associated with salt tectonics. This study highlights an underestimated ecological and environmental variability in the extreme environments of the deep Mediterranean. By focusing on these underexplored morphologies, we honor the legacy of Maria Bianca Cita and deepen our understanding of the unique ecosystems and geological processes that define the Mediterranean deep sea.