Where has the Sahara Desert been?

In mid-February 2006, Science magazine published the results of a study by the French National Center for Scientific Research (CNRS) on the age of the Sahara desert. The research team is led by Prof. Michel Brunet (Poitier University), in collaboration with N'Djaména University and N'Djaména National Research Sponsorship Center. The team gathered 60 scientists from 10 countries, discovered and analyzed the creation of fossil dunes in Chad (a country located in Central Africa, on the Sahara). Studies show the need to re-examine the Sahara desert age: The largest and most massive desert on the planet is not 86,000 years old as people think, at least 7 million years. !

Sand dunes in Saharan Desert (Photo: explorator)

According to research results, several thousand years ago, in the position of the Sahara desert today encompasses a humid climate, there are many large rivers and lakes, of which the famous Lake Méga-Chad has been available since (Méga-Chad is the largest ancient lake in Sahara, covering an area of ​​350,000 km ² , equal to the area of ​​the Caspienne Sea or the area of ​​Germany). Thus, the Sahara desert is not a 'young' desert . Previously, according to the analysis and age records of the oldest Sahara desert, it was only 86,000 years. Some specimens found in drill bits on the African continental shelf have hinted at signs of existence in the region for much longer than before but there has been no Sahara study. conducted to check this out.

The Republic of Chad, especially the Djourab desert in the basin of Lake Méga-Chad has become a key place to study the origin and progress of the ancient gibbon . It is here, since 1994, Prof. Michel Brunet and his research team have continuously discovered the relics of ancient gibbon. The first was the ape-man Australopithecus bahrelghazali described in the western part of the Rift valley and followed by Sahelanthropus tchadensis - the oldest gibbon known to this day.

Scientists have studied the appearance of ancient gibbons through their habitat at the time - ancient habitats. These are paleontological studies through the study of the sediments, flora, and landscape of the ancient ape of Sahara. The research is carried out according to the principle of 'modern theory': From the current sediment systems, scientists set the identification criteria for each environment so that the level of assessment can be assessed. their 'neck' . Each environment has its own biogeographic signs, in other words, it has its own sediment characteristics. These characteristics are determined by the method of sedimentary petrography, sedimentary structure, geometry of sediment and biological neck.

Today's dunes (Photo: cnrs)

For the study of sediments, all the typical elements of a desert are represented by the following characteristics: White, clean sand, little binder, no life, there are round and smooth quartz particles. , oblique sediment deposits, wavy wind-created roads at the foot of the dunes . Researchers have discovered the creation of fossils in the Toros Ménalla region , the center of the Djourab desert. This is important evidence to confirm the existence of the desert from the Upper Mioxel period, 7 million years ago. Previously, there was a period of desert climate, characterized by green trees and overflowing lakes but short life.

The team also identified the different levels of sediment deposits in the Djourab region to come to the observation that the Sahara had undergone harsh barren conditions for at least 10 million years ago . The results of this study are considered the first milestone for the re-establishment of the story of the biogeographic climate of the ancient Sahara desert, which has not been properly evaluated for a long time.