Stratigraphic frame of the Nefza-Sejnane district (Tunisia), including the new (U-Th)/He data on Fe (oxyhydr-)oxides. In red: data on supergene goethite; in red purple: data on mixed hydrothermal-meteoric hematite-goethite. Olig. = Oligocene. Questions marks (?) refer to potential larger stratigraphic extension.