| Evidence has shown that the Sahara desert was at one time a fertile plain. Between 7000 and 2000 BC the plains were fertile and rich with wild life. The lakes reached their maximum extent around 3,500 BC. Around 750 BC and again around 500 BC the lakes began to dwindle and revert to desert. It is possible to trace a highly complex pattern of ancient watercourses and powerful rivers. All of these did not run out to the sea, but rather into inland basins. When a normal river drains towards the sea, it carries with it silt which it deposits in a delta. In the Sahara, this debris was deposited in inland basins, gradually filling them. The slopes of the streams were reduced and the currents flowed less strongly. The water was eventually forced to find different outlets and spread to form marshes, which the sun dried out. This silt became the sands of the Sahara desert as we know it. Today only Lake Chad remains, and it has been reduced to 15,000 square miles from the original 200,000 square miles it once covered. Interestingly enough, the camel is only first mentioned in texts as being in Africa around 46 BC. The Sahara desert if filled with petroglyphs (ancient drawings) illustrating hunters, wild animals, and life in a much more lush era. |
