The ensuing synthesis summarizes the profound effects of plate tectonic interactions on the evolution of the supposedly stable interior cratonic basins. Analyses of the seven basins discussed in this volume, augmented with data on other well-known interior cratonic basins, indicate that these basins

-- subsided nonlinearly and episodically at different times and different places over their lengthy histories, which generally span several hundreds of millions of years.

-- subsided during periods of either crustal extension or compression.

-- were affected by directed stress fields propagated by plate tectonic interactions.

-- responded variably and differentially to the orientation and intensity of stress fields, depending on the alignment of older crustal inhomogeneities.

The interior cratonic basins contain multiple depositional sequences marked by major bounding unconformities. The major unconformities developed during times of lowstands of sea level. In many instances the geometry of a depositional sequence appears to have been controlled by tectonic processes. Evidence suggests that lowstands of sea level may also have been tectonically controlled and that they were perhaps influenced at times by climatic factors.

Basin-forming, -filling, and -modifying processes directly and indirectly control hydrocarbon occurrences and recovery. The controls of greatest importance include

-- repeated basin submergence and emergence, leading to development of multiple sequences bounded by major unconformities, coupled with basin reorientations and varying geometries over long periods of basin duration. These events created numerous opportunities for the development of source rocks, seals, reservoir rocks, and traps.

-- fluctuating sea level coupled with low but nonlinear subsidence rates and adequate sediment supply that led to rapid shifts of base level, widespread distribution of reservoir rocks, and facies changes conducive to the development of widely distributed stratigraphic traps.

-- ancient rifts that, where present, helped to control later structural development that ultimately influenced the maturation and migration of hydrocarbons.

-- structural overprinting apparently induced by intraplate forces.

-- recurrent structural movements associated with the evolution of interior cratonic basins.

While considerable information is presented in this volume on the nature of interior cratonic basins and the oil and gas fields they contain, unanswered questions are also highlighted, suggesting courses for future research. The epilogue sets out certain accepted principles of cratonic evolution, but it concludes that the question of the ultimate genesis of interior cratonic basins is still unresolved.