The Manzaz volcanic field, north of the Atakor volcanic field in the Hoggar (Ahaggar) volcanic province of Algeria, consists of a large number of scoria cones and associated lava flows. The field covers an area of 1,500 km2, overlying Precambrian metamorphic and plutonic rocks of the Tuareg shield. Many cones are breached, and the dominantly basaltic and basanitic volcanic products are rich in peridotite and pyroxenite xenoliths and megacrysts. The youngest volcanoes rest on Neolithic terraces and are of Holocene age.