Abstract The geometry of faults exposed in the field is at least partly controlled by host-rock lithology. However, little work has been published on the effect of lithology on the geometry of very large faults imaged in seismic data. This paper presents such a study for seismic-scale faults in the Norwegian Barents Sea. Gamma-ray data are used to extract clay volumes of the host rock. These clay volume logs are used to populate 3D seismic cubes with lithology information. Finally, the clay volume cubes are co-rendered with seismic coherence cubes using opacity blending. This makes it possible to visualize both lithology information and fault geometries in the same volume. Intervals of different lithologies are studied in order to compare fault geometries. The results show some differences between claystone-rich intervals and the more sandstone-dominated intervals. The fault zone is more segmented and wider in the claystones, while the sandy intervals are narrower and more localized with less segmentation. Larger displacement faults penetrate into deeper stratigraphic levels than smaller displacement faults, and their basal tips are unrelated to lithological decoupling.