Scientists have found traces of ancient rivers from which the Euphrates may have emerged

Scientists have found traces of two ancient rivers that millions of years ago flowed in a very different direction from where the Euphrates flows today. These rivers, which the researchers call Paleo-Karasu and Paleo-Murat, were once heading towards the Mediterranean Sea. Later, the movement of the Earth's crust changed their path and they gradually became part of the river system from which the modern Euphrates emerged.

Details

The study is published in Nature Geoscience.

The authors studied ancient river sediments, topography and seismic data - that is, "snapshots" of the layers beneath the ground and under the seabed. Using this data, it is possible to reconstruct where rivers used to flow in the past, even if their beds have long since disappeared from the surface.

The main protagonists of the research are two ancient rivers: the Palaeo-Karasu and Palaeo-Murat. Today, the Karasu and Murat are linked to the headwaters of the Euphrates, but in the distant past their ancestors, according to the authors' reconstruction, flowed south-westwards and flowed into the eastern Mediterranean Sea.

This occurred in the late Miocene, during the so-called Messinian Salinity Crisis. In simple words, it was a period about 5.97-5.33 million years ago when the Mediterranean Sea partially dried up and its level changed dramatically. In such conditions, ancient rivers were able to cut into the topography and leave thick sediments that can now be found beneath the seabed.

Then came the changes associated with the movement of the Earth's crust. The region was rising, deforming, and surface slopes were changing. For a river, this is critical: water is always looking for a way down, so even a slow rise or fall of land areas can cause the river to change direction.

According to a retelling of the study, until about 3.6 million years ago, the ancient Karasu and Murat were still connected to the direction towards the Mediterranean Sea. Then the Paleo-Murat began to change paths, and the Paleo-Karasu was rerouted later. By about 1.6 million years ago, the two systems had already merged into a river that began flowing southeast - towards the Persian Gulf, like the modern Euphrates.

Simply put, the Euphrates may not have emerged as one river "from the beginning" but as the result of a major realignment. The two ancient rivers first flowed towards the Mediterranean Sea, then due to tectonics changed direction, merged and became part of a new river system.

Why it matters

The Euphrates is not just a place name. It's a river without which it's hard to imagine the history of Mesopotamia, the Fertile Crescent and early agriculture. But a new study shows that the foundations of this landscape were laid long before humans existed.

Work like this helps us understand how geology influences the history of life. Plate movement changes mountains, plains and riverbeds. Rivers, in turn, bring water and sediment, create fertile land, shape valleys and the migration routes of animals and people.

The study is also important to the debate about the ancient Mediterranean Sea. Traces of river sediments help reconstruct how much it dried up during the Messina Crisis and which rivers then flowed into its eastern side.

Background

The Euphrates today originates in Turkey, flows through Syria and Iraq and is connected to the Tigris and Euphrates system. This river system was the basis for ancient Mesopotamia, a region often referred to as one of the "cradles of civilisation".

But the geological history of the river is much older than human history. Millions of years ago, the shape of the seas, mountains and river valleys in the region were different. The Mediterranean Sea experienced dramatic level changes, and plate movements gradually reshaped the topography of the Middle East.

A new study shows that modern rivers can retain traces of very ancient systems. Even if a channel has disappeared, its "traces" may remain in sediments, under the seabed, or in landforms.

Source

Research: Andrew S. Madof et al, "Late Miocene Euphrates River drained into a partially desiccated eastern Mediterranean", Nature Geoscience, 2026.