Integrated interpretation of geological and seismic data on the northeastern Caucasus foreland thrust belt shows that its subsurface structure is dominated by northerly verging tectonic wedging of Paleozoic-Eocene sediments. The up to 5.5 km thick Oligocene-Quaternary section represents a passive-roof sequence complicated by backthrusts. Along the thrust front remarkable lateral variations in structural styles have been identified. The western segment, known as the Terek-Sunzha fold zone, of the belt is a composite buried thrust belt consisting of two tectonic wedges, A narrow (20-30 km) and high-taper (20 degrees) lower wedge in the southern part of the thrust belt includes Paleozoic to Jurassic rocks in stacked thrust sheets. This wedge is underthrust beneath a wide (60 km) low-taper (<5 degrees) upper wedge generated above a regional detachment in Upper Jurassic evaporites. The upper wedge is complicated by two large ramp anticlinal zones developed in the foreland. In the Dagestan salient, which constitutes the eastern segment of the belt, the wedge aperture is about 15 degrees. The allochthonous assemblage is formed by stacking of thrust sheets consisting of Jurassic to Eocene beds. The prominent structural variations between these segments are thought to have been controlled mostly by the distribution of the Upper Jurassic salt, which is restricted to the western part of the foreland. The salt provided a low-friction gliding horizon and facilitated the formation of the low-taper wedge in the western segment. The absence of such an efficient decoupling level in the eastern part of the area results in the development of a splay of thrusts, which step up from the major detachment at high angles, producing a higher-taper wedge. The interpreted geometry of the belt suggests bed-length shortening in the order of 30-50 km.