Field gamma-ray patterns and stratigraphic reinterpretation of offshore well-log data from Lower Jurassic organic-rich units of the Lusitanian Basin (Portugal)

The highest GR values are interpreted to be linked with the 2nd- and 3rd-order maximum flooding intervals previously recognised in the Sinemurian-Pliensbachian successions in the western Iberian margin. Detailed GR maps linked to maximum flooding intervals highlight the variation of the vertical and lateral distributions of the organic-rich units in offshore areas of the Lusitanian Basin.