(a) Location of the Eocene − lowermost Oligocene (?) red sands, conglomerates, glauconitic sands and gypsum on a shaded version of Figure 3, with their dominant facies association (FA; see table 2 for details). MG: Murs Graben, PG: Perréal Graben; JJ: Jean-Jean section; DG: Dog Head section. (b) Tera-Wasserburg diagram with isochron age of a secondary sparite in a pedogenic nodule near the base of the Jean-Jean section. (c) Green clays with a stage-IV caliche at the base of Jean-Jean section (facies Fmr), overlain by a bed of bioclastic limestones (facies Clm). (d) Glauconitic Sands Formation overlain by the Cyrènes Limestones at the Dog Head section, with regular alternations of laterally continuous, tabular beds of facies Sp-St and Smp-Fmp; trees for scale. (e) Regular alternations of facies Sp-St and Smp-Fmp (black arrows) at the Jean-Jean section; trees for scale. (f) Uppermost beds of the Glauconitic Sands Formation at the Jean-Jean section, showing a continuous Bk horizon overlain by an organic-rich sand bed (facies Sp; sharp erosional contact highlighted with a continuous line), overlain by a thin (<1 cm) bed of lignite (facies L); transition to the Cyrènes Limestones shown with a dashed line; shrub for scale. (g) Zoom on the last meter of the Glauconitic sands Formation at the Jean-Jean section, showing the Bk horizon with centimeter-sized nodules, the overlying Sp sand and the lignite L bed below the Cyrènes Limestones; hammer for scale.