For high-frequency (fourth-order) depositional sequences, seismic-stratigraphic interpretation of vertical seismic sections commonly generates equivocal sequence boundaries and systems tracts because of limited vertical seismic resolution. Extending well-based, high-frequency sequence stratigraphy into a 3-D seismic survey area consequently proves to be a major challenge. We show that critical to such extension is recognition and interpretation of plano-form geomorphology of depositional systems. Emphasis should be shifted from interpreting vertical seismic data to developing new tools capable of extracting more horizontal, seismic-sedimentologic information. This case study of the Vermilion Block 50-Tiger Shoal field area, offshore Louisiana, shows that proportional, stratal slicing between Miocene flooding surfaces provides sequential and accurate seismic imagery of depositional systems. This imagery in turn serves as a basis for recognizing and mapping high-frequency systems tracts, sequence boundaries, and sequences in a geologic-time domain. In the Miocene interval, all of the fourth-order sequences or sequence sets from study wells can be seismically mapped at a resolution equivalent to 10 m in thickness, which is necessary for accurate reconstruction of the high-frequency sequence-stratigraphic framework in the region of seismic coverage outside well control.