🌊 How the Red Sea Went Completely Dry — and Was Later Reborn by a Catastrophic Flood

A Sea that Vanished—and Then Returned

More than 6 million years ago, the Red Sea — one of the world’s youngest and most unique marine environments — completely dried up. What today is a deep, vibrant sea bordered by coral reefs was once a vast salt desert, barren and lifeless.

Now, scientists from King Abdullah University of Science and Technology (KAUST) have confirmed that around 6.2 million years ago, a catastrophic flood from the Indian Ocean breached a volcanic ridge near the Bab el-Mandab Strait, refilling the empty basin in a geological instant — roughly within 100,000 years.

Uncovering a Geological Catastrophe

The research team used seismic imaging, microfossil records, and geochemical dating to trace the dramatic transformation.

Before the flood, the Red Sea had been isolated from the Mediterranean Sea and slowly evaporated under intense heat, leaving behind thick layers of salt, gypsum, and anhydrite. Then, a sudden breakthrough in the south triggered a massive flood, cutting a 320-kilometer-long submarine canyon—a scar still visible on the seafloor today.

Lead author Dr. Tihana Pensa describes it as “one of the most extreme environmental events on Earth — a total desiccation followed by an ocean-scale reflooding.”

A Timeline of the Red Sea’s Transformation

• ~30 million years ago: The Arabian and African plates began to separate, forming a rift valley.

• ~23 million years ago: The area was flooded by the Mediterranean, becoming a narrow marine gulf.

• 15–6 million years ago: Isolation increased, salinity spiked, and marine life died off; the basin filled with salt deposits.

• ~6.2 million years ago: A volcanic barrier near the Hanish Islands collapsed, unleashing the Indian Ocean flood that refilled the basin.

• <100,000 years: The Red Sea was reborn, restoring marine conditions and biodiversity.

This event predates the Zanclean flood that refilled the Mediterranean by almost a million years — giving the Red Sea its own, lesser-known “flood of rebirth.”

Why It Matters

The Red Sea is not just a body of water — it’s a natural archive of Earth’s tectonic, climatic, and oceanic evolution.

Its sediments and fossils tell stories about:

• How new oceans form through continental rifting.

• How salt giants (massive evaporite deposits) accumulate during desiccation.

• How life adapts to extreme environmental collapse and recovery.

As co-author Professor Abdulkader Al Afifi explains, this research reinforces KAUST’s position as a global leader in Red Sea studies and sheds light on “the processes that form and expand oceans on Earth.”

A Lesson in Planetary Resilience

The Red Sea’s rebirth serves as a striking reminder of Earth’s dynamic balance — how cataclysmic change can give rise to new beginnings. Today’s coral reefs, seagrass meadows, and unique ecosystems exist because of that ancient flood, transforming a desolate salt basin into one of the planet’s most vibrant marine sanctuaries.

The Red Sea stands as a living monument to resilience — proof that even after total desiccation, life and oceans can return, reshaping our understanding of Earth’s geological and biological cycles.

References:

• Pensa, T., Al Afifi, A., et al. (2025). The Red Sea dried out and was reflooded by the Indian Ocean ~6.2 million years ago. Communications Earth & Environment. DOI: 10.1038/s43247-025-02642-1.

• King Abdullah University of Science and Technology (KAUST) Press Release.