The field consists of lava domes, lava flows, maars, scoria cones and volcanic necks which cover an area of about with a volume of about of volcanic rock. Basalts form a thick plateau, and deep gorges lead up to the volcanic field and split the Hoggar Mountains in a number of segments. Wadis diverge from the Atakor volcanic field; some of them reached Lake Chad in the past, others continued through the Grand Erg Oriental towards Chott Melrhir.