Tassili n'Ajjer (Berber: Tassili n Ajjer, Arabic: طاسيلي ناجر, romanized: ṭāssīlī naʾjir; "Plateau of rivers") is a mountain range in the Sahara desert, located in southeastern Algeria. It has one of the most important collections of prehistoric cave art in the world and covers an area larger than 72,000 square kilometers (28,000 square miles).

The site was named a national park and a Biosphere Reserve. It was added to the UNESCO World Heritage Site list in 1982.

The literal English translation of Tassili n'Ajjer is "plateau of rivers."

Geography

Tassili n'Ajjer is a highland area in southeastern Algeria, near the borders of Libya and Niger. It covers about 72,000 square kilometers. The area stretches from 26°20′N 5°00′E to 24°00′N 10°00′E. Its highest point is a mountain called Adrar Afao, which reaches 2,158 meters (7,080 feet) high. This mountain is located at 25°10′N 8°11′E. The nearest towns are Djanet on the southeastern side and Illizi on the northern side.

The plateau has important geological and artistic features. It has many different rock shapes and structures made of eroded sandstone, which look like a moon-like landscape. The area also has many types of ancient artwork carved into the rocks.

Geology

The area is mostly made of sandstone. This sandstone has a dark, shiny layer called desert varnish, which is made of tiny metal oxides. This layer gives the rocks colors ranging from almost black to a dull red. Erosion in the region has created nearly 300 natural rock arches in the southeast, along with deep canyons and permanent water pools in the north.

The Tuareg Shield is a collection of ancient rock layers that formed between 750 and 550 million years ago during the Neoproterozoic era. This shield covered areas that are now the Ahaggar Mountains in Algeria, the Aïr Mountains in Niger, and the Adrar des Ifoghas in Mali. To the west of the shield is the West African Craton, and to the east is the Saharan Metacraton. The shield expanded by adding more land from the north and south, covering the area of today’s Tassili n'Ajjer. During this time, the supercontinent Gondwana formed, which included all the cratons and shields that later became Africa.

During the Cambrian period (541 to 485 million years ago), the first sediment layers still found today were created in the Tassili n'Ajjer region. Gondwana moved from near the equator to the southern hemisphere, placing the Sahara region near the South Pole during the Upper Ordovician (458 to 443 million years ago). At the end of this period, the Hirnantian ice age lasted for about a million years. An ice sheet covered much of northern Africa. In the early Silurian period (starting 443 million years ago), the ice on the Tuareg Shield melted, leaving behind channels formed by meltwater. This completed the formation of the geological layers of the Inner Tassili Group, which is mostly sandstone with some clay.

During the Silurian and Devonian periods, the sea moved inland from the north and northwest, covering large parts of the Sahara with more sediment layers. At this time, Tassili n'Ajjer was a seabed near the coast, later becoming a floodplain. During the Silurian period, the Intra Tassili Group formed, containing clay mixed with small animal burrows and some sandstone. During the Devonian period, the External Tassili Group formed, with sandstone, clay containing larger fossils, and some limestone. These layers are the main source of petroleum and natural gas in the Illizi Basin, north of Illizi.

For about 200 million years after this, the region remained geologically stable with little change. Starting as early as the Cretaceous period and especially during the Miocene (23 to 5.3 million years ago), the Tuareg Shield began to rise due to underground magma activity. This uplift caused the Ahaggar region to rise up to 4,000 to 5,000 meters. The Tassili n'Ajjer area tilted northward. Alongside this uplift, basins formed north and south of the shield, collecting eroded sediment, such as the Illizi Basin. During the Miocene, the top layers of the External Tassili Group were completely eroded in parts of Tassili n'Ajjer. In the northern part, rivers carved deep channels into the sandstone and clay due to increased slope.

The last major geological change happened during the Pliocene (5.3 to 2.58 million years ago). Volcanic activity in the Adrar region of southwestern Tassili n'Ajjer created craters, volcanic cones, and lava flows. This activity continued into the early Quaternary period.

Key features include:
– The barren Hamada of the External Tassili south of Illizi
– Three layers of the Intra-Tassilian Group from Oued Imihrou
– The outpost of the Tassili n'Ajjer in the Oued Essendilène: two layers of the Inner Tassili Group

Tassili n'Ajjer is part of the West Saharan montane xeric woodlands ecoregion. The higher elevation and water-holding ability of the sandstone make the vegetation here more lush than in lower desert areas. This supports a variety of animal life, from tiny invertebrates to mammals. The park has open woodlands in its eastern half, mainly made of the endangered and unique Saharan cypress and Saharan myrtle. The Tassili cypress is one of the longest-living trees on Earth, similar to the bristlecone pines of the Western US.

A small group of West African crocodiles lived in Tassili n'Ajjer until the 20th century. Today, the species is found mainly in tropical and sub-Saharan regions of Western and Central Africa, from Senegal to Chad. The aoudad, or Barbary sheep, is the only animal shown in the area’s ancient rock art.

Tassili n'Ajjer has been designated an Important Bird Area (IBA) because it supports large populations of birds such as spotted and crowned sandgrouse, Lichtenstein's sandgrouse, Pharaoh eagle-owls, greater hoopoe-larks, bar-tailed and desert larks, pale rock martins, fulvous babblers, white-crowned and mourning wheatears, desert sparrows, and trumpeter finches.

Archaeology

Algerian rock art has been studied by Europeans since 1863. Surveys were conducted by A. Pomel (1893–1898), Stéphane Gsell (1901–1927), G. B. M. Flamand (1892–1921), Leo Frobenius and Hugo Obermaier (1925), Henri Breuil (1931–1957), L. Joleaud (1918–1938), and Raymond Vaufrey (1935–1955).

Tassili was known to people in the early 20th century, but Westerners learned more about it through sketches made by French soldiers, especially Lieutenant Charles Brenans in the 1930s. Brenans brought Henri Lhote, a French archaeologist, who returned to Tassili in 1956–1957, 1959, 1962, and 1970. Some people criticized Lhote’s work because his team was accused of making fake images and damaging paintings by brightening them for tracing and photography, which harmed the original colors.

Tassili was mainly occupied during the Neolithic period by groups that moved their animals seasonally. The area’s geography, height, and natural resources made it ideal for small groups to camp during dry seasons. Wadis, or dry riverbeds, acted as paths between rocky highlands and sandy lowlands. The highlands show evidence of human activity from 5500 to 1500 BCE, while the lowlands have stone mounds and fire pits from 6000 to 4000 BCE. The lowlands were likely used as living areas during rainy seasons. Many rock shelters in the sandstone forests contain Neolithic items like ceramic pots, arrowheads, bowls, beads, and jewelry.

The shift to pastoralism after the African Humid period is shown in Tassili’s artifacts, rock art, and studies of animal remains. Tassili’s occupation is part of a larger climate change in the Central Sahara. Studies of ancient climates began in the Central Sahara around 14,000 years ago, followed by a dry period that limited living spaces. However, the Sahara had both dry lowlands and wet highlands. Archaeological finds show that hunter-gatherer groups lived there from 10,000 to 7500 years ago. After 7500 years ago, people began forming pastoral groups due to unpredictable weather. A dry period from 7900 to 7200 years ago preceded the first pastoral groups, matching patterns in other Saharan regions. Pre-pastoral pottery from Tassili dates to 9,000–8,500 years ago, while pastoral pottery is from 7100–6000 years ago.

Rock art at Tassili is studied with sites like Dhar Tichitt in Mauritania to understand the spread of animal herding and trade across North Africa. Cattle were herded across large areas as early as 3000–2000 BCE. This was followed by horses (before 1000 BCE) and then camels in the next millennium. Camels appeared as trans-Saharan trade grew, since they were used for transport in caravans.

Tassili’s rock formations are an archaeological site with many prehistoric rock art pieces first reported in 1910. These date to the early Neolithic era, when the Sahara was a savanna, not a desert. The oldest art is estimated to be 12,000 years old. Most art dates to the 9th and 10th millennia BP, based on sediment analysis. Art was dated by collecting dried, flaked paint fragments. Among 15,000 engravings found, images include large animals like antelopes and crocodiles, cattle herds, and humans hunting or dancing. These paintings are some of the earliest in the Central Sahara and are most concentrated at Tassili. Though Algeria is near the Iberian Peninsula, Tassili’s rock art developed separately from European traditions. UNESCO notes that the large number of paintings and engravings made Tassili world famous.

Like other Saharan rock art sites, Tassili can be divided into five styles: Archaic (10,000–7500 BCE), Round Head (7550–5050 BCE), Bovidian or Pastoral (4500–4000 BCE), Horse (2000 BCE–50 CE), and Camel (1000 BCE onward).

The Archaic period shows wild animals from the Early Holocene, mostly etched into rock. These works are linked to hunter-gatherers and include naturalistic depictions of large animals, with some geometric patterns and human figures, often in hunting scenes.

The Round Head period features humanoid figures with round, featureless heads and formless bodies, appearing to float on the rock. These paintings are concentrated in specific areas, suggesting they were used for rituals. Animals like moufl

In popular culture

• Tassili is the name of a place where music was recorded and also the title of a 2011 album by the Tuareg band Tinariwen.
• Tassili Plain is the name of a song on the 1994 album Natural Wonders of the World in Dub by the dub music group Zion Train.
• In the video game Fate/Extella: The Umbral Star, the character Altera is a broken version of a god called Sefar. This god is based on one of the drawings found in a group of caves and is also referred to in the story as The White Titan of Tassili n'Ajjer.

Gallery

• Rock art, cypress trees, and landscapes of the Tassili n'Ajjer
• Photograph of tall rock columns taken from 30,000 feet
• Copy of a drawing called the Tassili Mushroom Figure Matalem-Amazar found in Tassili
• Drawing of a person dancing or sitting
• Dunes in the Tassili n'Ajjer
• Sand and rock landscape on the southern edge of the Tassili n'Ajjer
• Local cypress trees
• Sandstone rocks and cliffs
• Figure believed to represent a ritual leader or shaman
• Drawings of people
• Drawings of people
• Drawings of people
• Drawings of people holding bows

The Tin-Taghirt site is located in the Tassili n'Ajjer region, between the cities of Dider and Iherir.

• An ostrich
• Drawing of a sleeping antelope—also found on the back of the 1000 Algerian dinar banknote
• Bubalus antiquus
• Footprints
• Drawings of humans