Sandstone is the main rock type forming the Sahara Desert’s Tassili n’Ajjer plateau.
Tassili n’Ajjer in southeastern Algeria is a high plateau built chiefly from weathered sandstone. Erosion has carved the rock into dramatic cliffs, arches, ravines, and stone forests. These landforms give the plateau a distinctive appearance and help explain why it is one of the Sahara’s most important geological and archaeological landscapes.
The plateau is also famous for thousands of prehistoric rock paintings and engravings. Many depict animals and human figures, providing evidence that the central Sahara supported wetter environments during earlier climatic periods. The art is a separate cultural feature from the sandstone geology that preserved its surfaces.
Tassili n’Ajjer is a protected area and UNESCO World Heritage Site. It is sometimes described simply as a mountain range, but its defining landform is a deeply eroded sandstone plateau.