North and Saharan Africa: geography and chronology

Northern Africa is the northernmost region of the African continent, linked by the Sahara to sub-Saharan Africa and by Egypt to the Sinai Peninsula, which is in Asia. Northern Africa can be divided into four big natural zones: the first is Maghreb that stretches from Tunisia to Morocco along the Mediterranean coast and is predominantly mountainous (Fig. 1). The second is the Sahara region, covered by the desert that goes from the Atlantic to the Red Sea, and the third is Sahel, a belt of grasslands and savannas south of the desert. Finally there is the Nile Valley that borders the Sahara desert to the east Northern Africa is underlain by folded sedimentary rock and is, geologically, more closelyrelated to Europe than to the rest of the continentof Africa. The Atlas Mountains, which occupy most of the region, are a part of the Alpine mountain system of southern Europe