Scientists May Have Discovered the Origins of the Euphrates River, Which Helped Nurture Some of the Earliest Known Civilizations

The famous waterway began as two rivers, a new study suggests. Tectonic activity around five million years ago probably made them change course and merge, helping to birth the Fertile Crescent

Margherita Bassi | Daily Correspondent

June 22, 2026 4:51 p.m.

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Around 6,000 years ago, the world’s earliest known civilization arose in Mesopotamia, an area in western Asia whose name is ancient Greek for “between rivers” because it sits between the Tigris and Euphrates rivers.

Today, the Euphrates stretches about 1,700 miles from Turkey through Iraq and empties into the Persian Gulf. According to new research, however, the body of water likely looked very different 5.5 million years ago.

Back then, the Euphrates River didn’t exist. It originated as two river systems that flowed into the Mediterranean Sea, which eventually merged and changed course, researchers report in the journal Nature Geoscience on June 1. The findings shed light on how Mesopotamia became the first known “cradle of civilization,” and they might help settle a debate among researchers regarding a period in the Mediterranean called the “Messinian salinity crisis.”

During the salinity crisis, around 5.33 million to 5.97 million years ago, large quantities of salt accumulated at the bottom of the Mediterranean Sea. For that to have happened, much of the seawater must have evaporated. Researchers have long disagreed, though, about whether the sea level would have dropped dramatically or whether it was replenished by sources of new water.

Scientists previously identified five-million- to six-million-year-old sediment deposits sitting atop the thick salt layer in offshore Turkey, Syria, Lebanon, Israel, Cyprus and Egypt. The sediments were probably dropped off by a river system during the Messinian salinity crisis. But today, there aren’t any large rivers near the ancient sediment deposits, leaving researchers wondering what body of water left them behind.

So, scientists behind the new study relied on techniques such as seismic imaging, which works similarly to bouncing sound waves inside the body to create an ultrasound image. “But in this case, we use it to image buried gravels, sands, mud, limestone and salt that have been compacted and turned into rock,” study co-author Simon Lang, a sedimentologist at the University of Western Australia, tells Reuters’ Will Dunham.

Lang and his colleagues also used maps of the surface and satellite data to investigate how the Euphrates changed over time. Analyses revealed that around 5.5 million years ago, there were two ancient rivers, a northern one that the team called Paleo-Karasu and a southern one called Paleo-Murat. They were named after their modern-day versions, which are tributaries of the Euphrates.

Computer simulations suggested that these two rivers were quite large. Based on flow and sediment output, Paleo-Karasu was “larger than the Nile River,” while the Paleo-Murat was “larger than the modern Tigris and Euphrates combined,” study co-author Andrew Madof, a geologist at oil and gas company Chevron, tells National Geographic’s Noah Kirsch.

Toward the end of the Messinian salinity crisis, the rivers carried water from Anatolia into the eastern Mediterranean, creating the offshore sediment deposits seen today, the team found. Around five million years ago, shifting tectonic plates caused the waterways’ downstream segments to move away from the Mediterranean. By roughly 1.6 million years ago, they had combined to form today’s Euphrates River.

The work reveals important information regarding the Messinian salinity crisis, says Angelo Camerlenghi, an Earth scientist at the Italian National Institute of Oceanography and Applied Geophysics in Italy, who did not participate in the study, to National Geographic. The new research answers how much the Mediterranean Sea level dropped during this time—about 0.6 miles—and suggests the two ancient rivers may have helped fill its basin.

“I think this may be the end of a discussion that has lasted decades,” Camerlenghi adds.

What’s more, the two ancient rivers’ altered paths probably helped create the crescent-shaped region in western Asia and northern Africa that Mesopotamia sits within—the Fertile Crescent. It’s known for nutrient-rich silt that helped early agriculture and civilizations thrive.

“Without the reorganization of the Euphrates River course and its diversion from the Mediterranean to the Persian Gulf, the environment of the region, and so a large part of our history, might have been very different,” says study co-author Richard Walker, a plate tectonics researcher at the University of Oxford, in a statement.

Margherita Bassi | Read More

Margherita Bassi is a freelance journalist and trilingual storyteller. Her work has appeared in publications including BBC Travel, Discover magazine, Live Science, Atlas Obscura and Hidden Compass.