Some scientists believe that the African river Nile hides mysteries. There is a debate about the age of this longest river in the world – whether it was formed due to the diversion of water about five million years ago or the original Nile flows through the area for 30 million years. If the Nile is older, as the evidence of one scientific team shows, then it may reflect the direction of movement of the earth’s mantle material circulating beneath it.
The Earth’s mantle – the mantle of the core – is the largest layer of the planet and consists of a pressed rock below the crust and above the core.
“Maybe with the help of the river, we can understand how the cloak moves at all,” Claudio Fakena, author of the study and professor at the University of Texas at Austin.
With its 6,650 kilometers, the Nile is one of the longest rivers in the world – the Brazilian government claims that the Amazon is in the first place, although the Nile is listed as the first in most comparisons. It is famous for its ancient history and archeological sites along its coast. The fertile Nile ensured the development of Egyptian civilization, and its basin passes through 11 states.
There are currently two models trying to explain its origin. According to the first, the Nile was formed when the basin changed its course from west to north about six million years ago, due to the same process that created a crack in the African tectonic plate, the so-called East African rift. Another theory says that the river was created 30 million years ago as a result of long-lasting geological processes in the mantle that pushed the soil up in Ethiopia and lowered it near the Mediterranean.
Now, a team of scientists from the United States, Canada, Italy and Israel has presented new evidence in support of another theory. Their model of changing local topography over time suggests that the Ethiopian plateau may have begun to rise 30 million years ago, while in the eastern Mediterranean, at the mouth of the Nile, it began to sink. Researchers have linked this model to another in which the mantle moves and large pieces of rock move around.
Analyzes of rocks 20-30 million years old, the so-called zircons found at the mouth of the Nile, have shown that they correspond to the rocks found on the Ethiopian plateau at the source of the Nile, which indicates that the river is at least as old. Sediment density, as well as the amount of erosion in the Blue Nile – one of the two tributaries of the Nile – also supports the theory of an older river.
Aside from the year, researchers say they have shown that some rivers can serve as a tool for understanding the behavior of the Earth’s mantle beneath them. Some rivers usually originate from mountains or plateaus, but others, such as the Nile or the Yenisei River in Siberia, come simply from the place that pushed the Earth’s mantle up. Such rivers differ in the type of sediment deposited at their mouths and are usually of volcanic origin due to the accumulation of mantle.
- If we manage to find another sign of the depth of the mantle on the surface, that would be great – Fakena points out.
The work of scientists is based on a model and therefore subject to assumptions, but the very idea is that there are rivers on Earth that are a window into the underworld.