Atlas Mountains

Atlas is the general name for the mountains of North Africa, in Morocco, Algeria and Tunisia. Its origin is unknown, but the Greeks already used it, and Strabo gives few details. The Arab geographers were imprecise, and often applied the name to chains otherwise called Adrar n-Deren, a term reserved in fact for the High Moroccan Atlas and the Saharan Atlas of Algeria. Ibn Khaldun took the Deren chains to form a girdle round the Maghrib al-Aqsa from Asfi to Taza. Leo Africanus distinguished the northern chains from the Atlas in the strict sense, and Marmol named the Little and the Great Atlas. French geologists of the last half-century determined their structure. ¹

The Atlas chains are folded mountains related to the Tertiary chains of Europe, raised again by Pliocene and Quaternary upheavals. The Sahara begins south of the Southern Atlas fault, which runs from Agadir to Gabes, so that the Dabar of southern Tunisia and the Nefusa are not part of the Atlas. The Anti-Atlas is a great asymmetrical massif of Precambrian and Primary rocks, rising above 2,500 metres, and it falls away to the Sus and Dades depressions, to the granitic and volcanic Sirwa (3,304 m) and to the plains of Dra and Tafilalet. The High Atlas is a huge fundamental fold some 750 km long, rising above 4,000 metres (Tubkal 4,165 m, Mgun 4,070 m), with traces of Quaternary glaciation. The Middle Atlas, with Ben Nacer (3,354 m), has the same style as the High Atlas, and its north-west descends in step plateaux covered by volcanic cones; it gives birth to the principal rivers of Morocco, the Oum er-Rebia, the Sebou and the Moulouya. ²

The Saharan Atlas of Algeria continues the High Atlas through massifs of the Ksur, the 'Amur, the Ouled Nail and the Zab, which lose height towards the north-east. Beyond the Biskra depression rises the Aures, the only massif of the Saharan Atlas and the highest mountain of Algeria (2,329 m at the Chelia). The Tunisian Dorsal and the High Tell, the Rif, and the Tell Atlas of Oran and Algiers form the mountains bordering the Mediterranean. The Rif is a crescent of mountains from Ceuta to Melilla (2,450 m at the Tidighine). The Dahra and Miliana mountains and the Ouarsenis (1,985 m) lie in the Algerian Tell, and the Djurdjura, the Babor (2,004 m) and the Kabylia mountains in the east. The Atlas makes North Africa a country of mountain chains encircling plains that are often both high and arid. ³

The relief accentuates the climatic contrasts between the Mediterranean and the Sahara, and dominates the Tell regions, the steppes of the high plains and the desert of the Saharan piedmont. The principal massifs were original geographical environments, which played a considerable, though mainly negative, role in the history of the Maghrib. ⁴