Niger is a landlocked nation in West Africa located along the border between the Sahara and Sub-Saharan regions. It is bordered by Nigeria and Benin to the south, Burkina Faso and Mali to the west, Algeria to the northwest, Libya to the northeast and Chad to the east. Niger covers a total area of 1.267,000km2 of which 300 km² is water. Niger is one of the hottest countries in the world with over 80% of the country covered by Sahara desert plains and sand dunes. The Aïr Massif in the northern part of the country is a deeply dissected high plateau averaging 500-900m above sea level and includes Niger’s highest point at 2,022m. The southern one-fifth is flat to rolling Sahelian savannah, suitable for livestock and limited agriculture. The Niger River, the third largest in Africa loops into southern Niger from Mali on its way to the Gulf of Guinea. Most of the country’s population is found in the far southwest and in the Niger River basin.


Precambrian rocks underlie large parts of Niger, but are mostly concealed by extensive Cenozoic continental deposits and sand dunes. Paleoproterozoic rocks, dominantly gneiss and migmatites, are exposed west of Niamey as a continuation of the belt of Birrimian rocks from Burkina Faso, and as ubiquitous granites, metamorphics and volcanics in the Air Massif in the north of the country. Neoproterozoic-Palaeozoic rocks crop out south of Niamey along the border with Benin and Burkina Faso in a continuation of the Volta Basin. Younger Palaeozoic marine sediments occupy parts of northeastern Niger and the Agadez basin west of the Air Massif and Cretaceous marine and epicontinental sediments of the Iullemidden Basin occur in central Niger. Volcanic activity evidenced by lavas, tuffs and ash deposition is recorded intermittently from the Devonian, and particularly well exposed in the Air Massif. Spectacular anorogenic ring-complexes of predominantly Palaeozoic age are also exposed in the Air Massif area of the Hoggar Mountains and include anorthosites.