Accumulations of oil and gas are closely related to unconformities in almost every oil region of the world. Except for classifications and early attempts to utilize them in regional correlations, the location, origin, and geometry of successive unconformities largely have been ignored.

Unconformities occur in every tectonic and depositional environment. They are most common on the continental platform, where disconformities occur in close rhythmic succession. In the coastal areas between basin and platform, frequent warping has resulted in intersecting low-angle unconformities. Basins have the fewest unconformities, but angular unconformities may occur associated with midbasin uplift and diapirism.

In the typical platform area, traps above disconformities are mainly in quartz sandstones and are long and narrow; carbonate rocks are the principal reservoirs beneath disconformities. Traps in the hinge area between the platform and the basin are associated with low-angle unconformities; they are commonly very large and generally have arenaceous reservoir rocks. In basins not later deformed by tectonism, most unconformity traps are on the upthrown side of growth faults and on and around midbasin ridges, where submarine erosion has produced local unconformities. Reservoir rocks are commonly thin and discontinuous, fine-grained turbidites and residual sandstones.