How did the soil of the sahara desert become so dry?
What made the Sahara Desert go dry — and are there ancient waters still hidden below the sands? In a study published in the journal Science researchers argue that the drying of the Sahara took place over thousands of years. The controversial finding contradicts several previous studies, which argue that the Sahara dried up much more suddenly. Geo-archaeologist Stefan Kropelin explains how the team looked at sediment samples taken from cores drilled in the bottom of Lake Yoa, one of the Sahara’s few remaining lakes. The researchers say that the sediment layers at the bottom of the lake show slow change — a gradual reduction in the abundance of tropical vegetation and the eventual establishment of the modern desert plant community. The team found that arid conditions similar to those today were in place as long as 2,700 years ago.
