Algeria’s Plateau of Rivers holds a lunar forest of sandstone
Tassili n’Ajjer—Berber for Plateau of rivers—covers about 72,000 square kilometres of southeastern Algerian Sahara near Libya and Niger. UNESCO listed the park and biosphere reserve in 1982 for eroded sandstone pillars and world-famous Saharan rock art, one of the most important prehistoric cave-art groupings on Earth.
The plateau stretches from roughly 26°20′N 5°00′E toward 24°00′N 10°00′E. Desert varnish paints sandstone from near-black to dull red, and erosion has carved nearly 300 natural rock arches in the south alone, yielding the so-called rock forests that look lunar. The Tuareg Shield’s terranes assembled here between about 750 and 550 million years ago, linking today’s Ahaggar, Aïr, and Adrar des Ifoghas massifs. Cambrian sediments, Silurian meltwater channels under vanished ice, and later Silurian–Devonian seas stacked the strata visitors walk on.
For some 200 million years afterward the region stayed a quiet mainland; Miocene uplift and Pliocene volcanism then raised and peppered the Adrar zone with cones and lava. Higher elevation and water-holding sandstone now support West Saharan montane xeric woodlands slightly greener than surrounding desert. An isolated West African crocodile population survived here into the twentieth century; the aoudad, or Barbary sheep, is the only animal painted in the ancient artwork that still survives. BirdLife lists the park as an Important Bird Area for sandgrouse, desert larks, and other arid specialists.
The highest point, Adrar Afao, reaches 2,158 m, and Djanet and Illizi are the nearest towns; deep gorges in the north still hold permanent pools. Europeans have studied Algerian rock art since 1863, but the wider public first saw Tassili through sketches by French legionnaires, notably Lieutenant Charles Brenans in the 1930s, who brought the archaeologist Henri Lhote, whose later expeditions drew heavy criticism. Archaeologists now see the plateau as a Neolithic dry-season base for small herding groups, with wadis linking highlands and sandy lowlands after the African Humid Period. Its paintings help trace pastoralism across North Africa: cattle were herded widely by 3000 to 2000 BCE, horses appeared before 1000 BCE, and camels came later.
Source: Tassili n'Ajjer
