The Seismic Expression of Core Complex‐Style Extensional Detachment Faults in Rifted Margins

The identification of core complex‐style extensional detachment faults (CCDFs) in rifted margins is crucial for accurately restoring their stratigraphic and thermal histories. Yet recognising CCDFs in seismic reflection images is challenging due to their faint topographic expression; the lack of associated abrupt offset in seismic reflections; the lack of discernible growth packages in overlying sediments; their overprint by high‐angle normal faults or erosion; and the common preconception that rifted margins are dominantly structured by high‐angle normal faults. Based on published thermo‐mechanical numerical simulations and seismic observations, we show that characteristic fingerprints of CCDFs in seismic sections are: (1) back‐tilted pre‐tectonic sedimentary sections; (2) back‐tilted and fanning reflections beneath the exhumed fault plane; and (3) a corrugated top basement where a mild topographic high, possibly flattened by erosion, is framed by two troughs with often apparently passive infill sediments.