In the past, the Red Sea underwent a spectacular transformation that radically changed its appearance. This body of water, now rich in marine life, went through a period of complete drying before being abruptly filled with water. Researchers have just precisely dated this major geological episode that redrew the map of this region of the world.
Scientists from King Abdullah University of Science and Technology used several investigation methods to reconstruct this ancient history. Seismic imaging, which allows visualization of deep geological layers, revealed traces of this transformation.
The formation of the Red Sea dates back 30 million years, when the Arabian plate separated from the African plate. This tectonic process first created a narrow rift valley filled with lakes, then a wider gulf when Mediterranean waters invaded it 23 million years ago. Marine life developed, as evidenced by fossil reefs along the northern coasts.
Then, analysis of microfossils and geochemical dating techniques allowed for the establishment of a precise timeline of a significant event. These different approaches converge toward the same scenario: in just 100,000 years, a blink of an eye on the geological timescale, the Red Sea went from an open sea to an empty, salty basin.
The reconstruction of events shows that the Red Sea was initially connected to the Mediterranean Sea by a shallow threshold to the north, a connection that broke. Intense evaporation then transformed the sea into a salt desert. To the south, a volcanic barrier near the Hanish islands completely isolated the basin from the Indian Ocean.
6.2 million years ago, the waters of the Indian Ocean breached this natural barrier in a cataclysmic deluge that carved a 200-mile-long (320 km) submarine canyon, still visible today on the seafloor.
This study published in
Communications Earth & Environment demonstrates that the Red Sea constitutes an exceptional natural laboratory for understanding ocean formation. The researchers emphasize that this episode of marine rebirth occurred nearly a million years before the similar filling of the Mediterranean by the famous Zanclean flood.