Foreland fold and thrust belts are linear or curvilinear bands of folded and thrust-faulted sedimentary rocks that lie along the external margins of orogenic belts. Typically a passive margin sequence has been detached from its basement, compressed, and displaced toward the craton. Clastic foredeeps (foreland basins) develop synchronously in advance of the thrust deformation.

The structural geometry of fold and thrust belts shows consistent patterns of faults, folds, and imbrication. Thrust fault trajectories occur in two common modes: (1) as listric or inclined-planar surfaces of sledrunner shape, and (2) as irregular surfaces of staircase shape, in which the fault is alternately parallel and oblique to bedding. Flexural-slip folding is dominant in foreland fold and thrust belts, commonly exhibiting chevron style (kink domain) shape in profile. Folds are rootless and have developed as a direct consequence of fault displacements. Thrust systems display imbricate overlapping of thrust sheets above a basal decollement. Where intermediate levels of detachment occur, duplex zones can develop a special type of imbrication that affects only a specific stratigraphic interval bounded at bottom and top by flat-lying detachments.

Palinspastic restoration is a useful aid for testing the geometric viability of a structural interpretation. Restoration is also useful for reconstructing pre-tectonic and syntectonic images of the developing fold belt. Provided the timing of major structural development is known or can be estimated, the construction of intermediate (syntectonic) stage restorations allows the timing and magnitude of tectonic burial by thrust faulting to be deduced. Intermediate restorations also permit evaluation of the sequential development of syntectonic sedimentary foredeeps at the leading edge of thrust deformation, relationships only rarely preserved from subsequent erosion.

The generation of hydrocarbons is a function of time and temperature. In fold and thrust belts, the thermal history is principally a function of burial, by tectonic as well as depositional events. Palinspastic restorations make it possible to estimate both the magnitude and the timing of burial along a profile. Applying a time-temperature model of oil generation, the maturation of organic source beds can then be modeled on the restorations.

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