Tibesti Mountains
The Tibesti mountains are part of a volcanic province that reaches from Libya into Chad and covers a total surface area of about . The Tibesti Mountains have been volcanically active since the late Cenozoic, with one old volcanic unit being dated to 17 million years ago. While all the higher peaks are volcanoes, not all of Tibesti is formed by volcanic material; the volcanoes have developed on top of a basement uplift.