 Geologically, Mali consists mostly of vast flatlands of granite and shale covered by sandstone and alluvial quartz.Mali extends over two main geological structures, the West African craton in the west and the Tuareg shield in the southeast, which came together at the end of the Precambrian era between 600 and 550 million years ago.The suture zone is to the west of the Adrar des Ifoghas mountains.