More than six million years ago, one of the most dramatic environmental events in Earth’s history unfolded in the Middle East.
The Red Sea, now home to vibrant coral reefs and bustling marine life, completely dried out before being suddenly refilled by a catastrophic flood from the Indian Ocean.
A new study from scientists at King Abdullah University of Science and Technology (KAUST) has now put a precise date on this astonishing transformation: it happened around 6.2 million years ago.
Using seismic imaging, microfossils, and advanced dating techniques, the team showed that the Red Sea’s shift from a dry salt desert back to a thriving marine basin happened in less than 100,000 years—a blink of an eye in geological terms.
The research is published in Communications Earth & Environment.
According to lead author Dr. Tihana Pensa, the Red Sea basin preserves “one of the most extreme environmental events on Earth,” when it first desiccated and then was rapidly flooded.
The event not only reshaped the landscape but also permanently reconnected the Red Sea to the world’s oceans through the Indian Ocean.
Originally, the Red Sea was linked to the Mediterranean Sea through a shallow northern passage. When that link was cut off, the basin turned into a barren salt plain as water evaporated faster than it could be replenished.
In the south, a volcanic ridge near today’s Hanish Islands blocked seawater from the Indian Ocean.
That barrier eventually gave way, unleashing a catastrophic flood that carved a massive 320-kilometer-long submarine canyon—still visible on the seafloor today.
The deluge quickly refilled the basin, drowning the salt flats and restoring marine conditions in less than 100,000 years.
This spectacular rebirth happened nearly a million years before the more famous Zanclean flood that refilled the Mediterranean Sea, giving the Red Sea its own unique story of destruction and renewal.
The geological history of the Red Sea began some 30 million years ago, when the Arabian Plate pulled away from the African Plate.
At first, the basin was more like a rift valley dotted with lakes. Later, around 23 million years ago, it was flooded by the Mediterranean and marine life flourished.
But over time, poor water circulation and high evaporation caused salinity to soar, wiping out marine ecosystems between 15 and 6 million years ago. The final stage of this crisis was complete desiccation, leaving behind thick deposits of salt and gypsum.
The flood from the Indian Ocean changed everything. It restored seawater circulation, revived ecosystems, and laid the foundation for today’s Red Sea, famous for its coral reefs and biodiversity.
“This study not only tells us how the Red Sea came back to life but also shows how oceans are born and shaped over time,” said co-author Professor Abdulkader Al Afifi. “It adds to our understanding of how climate, tectonics, and oceans interact over millions of years.”
Source: KSR.
