The Red Sea experienced a dramatic transformation approximately 6.2 million years ago, according to a recent study by researchers at King Abdullah University of Science and Technology in Saudi Arabia. The sea completely dried up, leaving a vast salt desert where a thriving marine environment once existed. This desiccation occurred during a 640,000-year-long “salinity crisis” when sea levels dropped and salt levels soared.
Salt deposits as deep as 1.2 miles accumulated, wiping out marine life in the region. The Red Sea’s fate changed when a cataclysmic flood from the Indian Ocean breached the Hanish Sill, a volcanic ridge. The flood refilled the Red Sea, restoring it to a marine basin in less than 100,000 years.
The flood was so intense that it likely carved a nearly 200-mile-long submarine canyon in the sea floor. “Our findings show that the Red Sea basin records one of the most extreme environmental events on Earth,” said study lead author Tihana Pensa.
Red Sea’s ancient transformation unveiled
“The flood transformed the basin, restored marine conditions, and established the Red Sea’s lasting connection to the Indian Ocean.”
The Red Sea began forming around 30 million years ago when the African and Arabian tectonic plates started to rift apart. It was initially a deep valley with scattered lakes until the Mediterranean Sea flooded it 23 million years ago. Researchers analyzed rock layers and seismic data from the seabed to understand the historical changes.
They found an unconformity, a geological feature where older sediment layers are abruptly overlain by newer ones, indicating that drying and reflooding events had occurred. The study combines geological and biological evidence to tell a dramatic story of environmental upheaval. The absence of microfossils between 14 million and 6.2 million years ago, followed by their reappearance, marks the transition from a hyper-saline desert back to a thriving marine ecosystem.
This research enriches our understanding of the Red Sea’s geological history and highlights the dynamic nature of Earth’s environmental systems. The new insights offer a compelling narrative, connecting past geophysical events with present-day marine conditions, and underscore how cataclysmic natural events can transform entire ecosystems.