What evidence caused scientists to reconsider the idea that the Mediterranean Sea once dried up completely?

Initial studies of seabed sediment cores conducted in 1970 and 1975 led scientists to propose that the Mediterranean Sea had dried up completely approximately 6 million years ago, leaving behind a desert floor covered in evaporite salts.1

However, more recent seismic and microfossil studies have caused researchers to reconsider this theory. This new evidence suggests that the seafloor was never entirely dry. Instead, it is now believed that about 5 million years ago, the region consisted of several basins with varying topography and depths ranging from 650 to 5,000 feet (200 to 1,500 meters). Rather than a complete desiccation, these basins were likely filled with highly saline waters of varying depths that deposited the observed salts.1

The exact chronology and nature of these salt formations remain a subject of intense scientific debate, as ongoing analysis of core sampling and seismic data continues to refine our understanding of the Mediterranean's complex geological history.1