Atlas Mountains

• 1. Introduction

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  The Atlas Mountains run for around 2500 kilometres through Morocco, Algeria and Tunisia. They form a long barrier in the Maghreb, standing between the Sahara and the waters of the Mediterranean Sea and the Atlantic Ocean. Their name is linked to the Titan Atlas, a figure from myth. Yet the real range is stranger than its legend. What kind of collision raised peaks this high while leaving the crust beneath them so little changed? Who has built villages on these slopes, and what do they call the mountains in their own languages? And which animals once roamed these forests that no traveller will ever see again?

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• 2. Ancient Collisions

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  About 300 million years ago, in the Paleozoic Era, continents crashed together and raised the Anti-Atlas. It is the oldest of the three phases that built the Atlas, and it rests on basement rock from the Precambrian that is far older still. Geologists believe the Anti-Atlas formed as part of the Alleghenian orogeny. In that episode Africa and America collided, and North America, Europe and Africa were joined together. The chain they raised once rivaled today's Himalayas. Its worn remains can still be seen in the Fall Line region of the Eastern United States, and some remnants sit within the later Appalachians. The second phase of Atlas history came during the Mesozoic Era, before about 66 million years ago, and it worked in the opposite direction. The Earth's crust stretched widely and rifted those same continents apart. That stretching opened thick sedimentary basins inside the continents, including the one that became the Atlas. Most of the rock now at the surface of the High Atlas was laid down under the ocean in those years.

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• 3. Raising the Range

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  Between roughly 66 million and 1.8 million years ago, in the Paleogene and Neogene Periods, the mountain chains of the Atlas were pushed upward. The cause was the collision of Europe and Africa at the southern end of the Iberian Peninsula. Such collisions happen where plates slide toward each other. If one plate moves beneath the other, the result is a subduction zone. If both plates carry continental crust, the result is a continental collision. In the Africa-Europe case, this convergence partly explains the High Atlas. It also helps account for the closing of the Strait of Gibraltar and the formation of the Alps and the Pyrenees. Yet the Atlas keep a secret from geologists. Evidence is lacking for the nature of any subduction in the region, and for the thickening of the crust that collisions usually bring. The range stands high but shows surprisingly little crustal thickening and tectonic shortening. Recent studies suggest that deep processes rooted in the Earth's mantle may have helped lift the High and Middle Atlas.

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• 4. Morocco's Three Ranges

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  Toubkal, at 4,167 metres, is the highest summit in North Africa, and it crowns the High Atlas of central Morocco. Several other High Atlas peaks pass 4000 metres. Ighil m'Goun, at 4,071 metres, is the second major summit of the range. The High Atlas rises at the Atlantic coast and stretches east to the Moroccan-Algerian border. Toward the Atlantic and the southwest it drops abruptly into the coast and the Anti-Atlas. Toward Marrakesh in the north the descent is gentler. Near Ouarzazate, the Draa Valley cuts through the massif and opens to the south. Berber people live here in small villages and farm the high plains of the Ourika Valley. Near Barrage Cavagnac, a hydroelectric dam holds back the artificial lake Lalla Takerkoust, where local fishermen draw their catch. The largest settlements include Ouarzazate, Tahannaout, Amizmiz, Imlil, Tin Mal and Ijoukak.

  The Anti-Atlas runs about 500 kilometres, from the Atlantic in the southwest of Morocco toward the northeast. It reaches the heights of Ouarzazate and continues east to the city of Tafilalt. Along its southern side it borders the Sahara, where the much lower Jebel Bani runs beside it. Its easternmost point is the Jbel Saghro range, and sections of the High Atlas flank its northern edge. Djebel Siroua, a massif of volcanic origin, carries the highest summit of the Anti-Atlas at 3,304 metres.

  The Middle Atlas lies wholly within Morocco and is the northernmost of the three main ranges. The Moulouya and Oum Er-Rbia rivers separate it from the High Atlas, and the Sebou River divides it from the Rif mountains. Its high point is Jbel Bou Naceur, at 3,340 metres. West of the range lie the coastal plains and many of Morocco's major cities, while to the east stretches a high barren plateau. Rain falls more heavily here than in the southern ranges, so the Middle Atlas serves as an important water catchment for the coastal plains. It is also valuable for biodiversity, and it shelters the majority of the world's Barbary macaque population.

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• 5. Algeria and Tunisia

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  At 2,308 metres, Lalla Khadidja in the Djurdjura range of Kabylia is the highest summit of the Tell Atlas. This chain is over 1500 kilometres long and stretches from eastern Morocco through Algeria and into Tunisia. It parallels the Mediterranean coast, merges with the Middle Atlas at its western end, and joins the Saharan Atlas in eastern Algeria and Tunisia. South of it lies the high plateau of the Hautes Plaines, where lakes fill in the wet season and salt flats appear in the dry. The eastern half of the Tell Atlas has the most humid climate in North Africa. Annual precipitation climbs well above 1000 millimetres and sometimes passes 1500 millimetres, as on the Collo Peninsula or near Ain Draham. Heavy snow falls on the summits in winter.

  The Saharan Atlas crosses Algeria from the Moroccan border, east of the High Atlas, and runs on into Tunisia. Outside the Aures Mountains, its highest peak is the 2,236-metre Djebel Aissa. These mountains mark the northern edge of the Sahara Desert. They receive some rain, which makes them better suited to agriculture than the plateau region to the north. Most people living there today are Berbers, who also call themselves Imazighen. The Aures Mountains are often presented as the easternmost part of the Saharan Atlas. They cover parts of Algeria and Tunisia and give their name to the Aurès natural region. Though lower than the High Atlas, they reach altitudes similar to those of the Tell Atlas to the north.

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• 6. Names, People and Ore

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  In some Berber languages, the words Adrar and adras mean mountain. These terms are believed to be cognates of the place name Atlas, which would root the range's name in the speech of the people who live there. Berber populations still make up most of the people of the mountains. Their climate is generally cool, though summers are sunny, and the average temperature is 25 degrees Celsius. Beneath those slopes lies a remarkable inventory of resources. Miners and geologists have recorded deposits of iron ore, lead ore, copper, silver and mercury. The mountains also hold rock salt, phosphate, marble, anthracite coal and natural gas, among other resources. Together they make the Atlas rich in natural wealth. The same slopes that hold this wealth also shelter forests and animals found almost nowhere else.

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• 7. Cedars, Oaks and Leopards

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  The Atlas cedar is among the trees of these mountains, alongside evergreen oak and many semi-evergreen oaks such as the Algerian oak. Where rain is heavier, as in the Kabylie range, the forests change character. Cork oaks grow there, along with arbutus, which is also called cane apple. Heather shrub, rockroses and lavender fill the undergrowth. The animals are mostly found within Africa, though a few also live in Europe. The Barbary leopard, Barbary stag and Barbary sheep share the slopes with the Atlas Mountain badger, Cuvier's gazelle and the North African boar. Striped hyenas and red foxes also live here. Among the birds are the northern bald ibis, the Algerian nuthatch and the dipper. The Atlas mountain viper completes a list of animals of which many are endangered. Others have not been so fortunate.

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• 8. Vanished Giants

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  The Atlas bear, the North African elephant, the North African aurochs, the bubal hartebeest and the Atlas wild ass once lived in these mountains. All five are now extinct. These subspecies belong to the few animals of the range already lost for good. The Barbary lion has a different fate. It no longer survives in the wild, yet its descendants still exist in captivity, living reminders of what the Atlas once held.

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