labyrithe of rock formation called d`oyo in ennedi plateau on sahara dessert, chad, africa

039 abstract africa african called canyon chad cliff climatic desert dessert doyo dune dunes ennedi erg erosion exploring extreme formation geology gorge hill hot labyrinth labyrithe landscape mountain mountains north oasis oyo panorama panoramic pinnacles plateau rock sahara sahel sand sandstone scenery scenic stone subsaharan tibesti tuareg valley vegetation wilderness