page_title: Atlas Mountains
section_title: Geology
hierarchical_section_title: Atlas Mountains / Geology
caption_attribution_description: English: This is a section of the large image showing the Atlas Mountains and its tectonic plates.Español: Este es un recorte que muestra los Montes Atlas y sus placas tectónicas.
context_page_description: The Atlas Mountains are a mountain range in the Maghreb. It separates the Mediterranean and Atlantic coastlines from the Sahara Desert. It stretches around 2,500 km through Morocco, Algeria and Tunisia. The range's highest peak is Toubkal, which is in southwestern Morocco, with an elevation of 4,167 metres. The Atlas mountains are primarily inhabited by Berber populations. The terms for 'mountain' are adrar and adras in some Berber languages. These terms are believed to be cognates of the toponym Atlas. The mountains are also home to a number of animals and plants which are mostly found within Africa but some of which can be found in Europe. Many of these species are endangered and a few are already extinct.
context_section_description: The basement rock of most of Africa was formed during the Precambrian supereon and is much older than the Atlas Mountains lying on the continent. The Atlas was formed during three subsequent phases of Earth's geology.
  The first tectonic deformation phase involves only the Anti-Atlas, which was formed in the Paleozoic Era (~300 million years ago) as the result of continental collisions. North America, Europe and Africa were connected millions of years ago.
  The Anti-Atlas Mountains are believed to have originally been formed as part of Alleghenian orogeny. These mountains were formed when Africa and America collided, and were once a chain rivaling today's Himalayas. Today, the remains of this chain can be seen in the Fall Line region in the Eastern United States. Some remnants can also be found in the later formed Appalachians in North America.
  A second phase took place during the Mesozoic Era (before ~66 My). It consisted of a widespread extension of the Earth's crust that rifted and separated the continents mentioned above. This extension was responsible for the formation of many thick intracontinental sedimentary basins including the present Atlas. Most of the rocks forming the surface of the present High Atlas were deposited under the ocean at that time.
  
  Finally, in the Paleogene and Neogene Periods (~66 million to ~1.8 million years ago), the mountain chains that today constitute the Atlas were uplifted, as the land masses of Europe and Africa collided at the southern end of the Iberian Peninsula. Such convergent tectonic boundaries occur where two plates slide towards each other forming a subduction zone (if one plate moves underneath the other), and/or a continental collision (when the two plates contain continental crust). In the case of the Africa-Europe collision, it is clear that tectonic convergence is partially responsible for the formation of the High Atlas, as well as for the closure of the Strait of Gibraltar and the formation of the Alps and the Pyrenees. However, there is a lack of evidence for the nature of the subduction in the Atlas region, or for the thickening of the Earth's crust generally associated with continental collisions. In fact, one of the most striking features of the Atlas to geologists is the relative small amount of crustal thickening and tectonic shortening despite the important altitude of the mountain range. Recent studies suggest that deep processes rooted in the Earth's mantle may have contributed to the uplift of the High and Middle Atlas.
caption: The tectonic boundary
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