Finally we see that foreland areas can have a wide range of styles, and that one style should not necessarily be used in all trends in that foreland area (Fig. 120). However, close examination of many forelands that have undergone regional deformation after the development of the associated thrust belts reveals a structural style shown in this discussion to be the result primarily of horizontal compression. This causes basins to downwarp and the resulting volumetric problems give rise to detachment type structures. The foreland trends can be compartmentalized into segments, bounded by high angle oblique slip faults that allow different structural features to develop simultaneously, but independently.